Follow-up services for improving long-term outcomes in intensive care unit (ICU) survivors.

BACKGROUND: The intensive care unit (ICU) stay has been linked with a number of physical and psychological sequelae, known collectively as post-intensive care syndrome (PICS). Specific ICU follow-up services are relatively recent developments in health systems, and may have the potential to address PICS through targeting unmet health needs arising from the experience of the ICU stay. There is currently no single accepted model of follow-up service and current aftercare programmes encompass a variety of interventions and materials. There is uncertain evidence about whether follow-up services effectively address PICS, and this review assesses this. OBJECTIVES: Our main objective was to assess the effectiveness of follow-up services for ICU survivors that aim to identify and address unmet health needs related to the ICU period. We aimed to assess effectiveness in relation to health-related quality of life (HRQoL), mortality, depression and anxiety, post-traumatic stress disorder (PTSD), physical function, cognitive function, ability to return to work or education and adverse effects.Our secondary objectives were to examine different models of follow-up services. We aimed to explore: the effectiveness of service organisation (physician- versus nurse-led, face-to-face versus remote, timing of follow-up service); differences related to country (high-income versus low- and middle-income countries); and effect of delirium, which can subsequently affect cognitive function, and the effect of follow-up services may differ for these participants. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase and CINAHL on 7 November 2017. We searched clinical trials registers for ongoing studies, and conducted backward and forward citation searching of relevant articles. SELECTION CRITERIA: We included randomised and non-randomised studies with adult participants, who had been discharged from hospital following an ICU stay. We included studies that compared an ICU follow-up service using a structured programme and co-ordinated by a healthcare professional versus no follow-up service or standard care. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed studies for inclusion, extracted data, assessed risk of bias, and synthesised findings. We used the GRADE approach to assess the certainty of the evidence. MAIN RESULTS: We included five studies (four randomised studies; one non-randomised study), for a total of 1707 participants who were ICU survivors with a range of illness severities and conditions. Follow-up services were led by nurses in four studies or a multidisciplinary team in one study. They included face-to-face consultations at home or in a clinic, or telephone consultations or both. Each study included at least one consultation (weekly, monthly, or six-monthly), and two studies had up to eight consultations. Although the design of follow-up service consultations differed in each study, we noted that each service included assessment of participants' needs with referrals to specialist support if required.It was not feasible to blind healthcare professionals or participants to the intervention and we did not know whether this may have introduced performance bias. We noted baseline differences (two studies), and services included additional resources (two studies), which may have influenced results, and one non-randomised study had high risk of selection bias.We did not combine data from randomised studies with data from one non-randomised study. Follow-up services for improving long-term outcomes in ICU survivors may make little or no difference to HRQoL at 12 months (standardised mean difference (SMD) -0.0, 95% confidence interval (CI) -0.1 to 0.1; 1 study; 286 participants; low-certainty evidence). We found moderate-certainty evidence from five studies that they probably also make little or no difference to all-cause mortality up to 12 months after ICU discharge (RR 0.96, 95% CI 0.76 to 1.22; 4 studies; 1289 participants; and in one non-randomised study 79/259 deaths in the intervention group, and 46/151 in the control group) and low-certainty evidence from four studies that they may make little or no difference to PTSD (SMD -0.05, 95% CI -0.19 to 0.10, 703 participants, 3 studies; and one non-randomised study reported less chance of PTSD when a follow-up service was used).It is uncertain whether using a follow-up service reduces depression and anxiety (3 studies; 843 participants), physical function (4 studies; 1297 participants), cognitive function (4 studies; 1297 participants), or increases the ability to return to work or education (1 study; 386 participants), because the certainty of this evidence is very low. No studies measured adverse effects.We could not assess our secondary objectives because we found insufficient studies to justify subgroup analysis. AUTHORS' CONCLUSIONS: We found insufficient evidence, from a limited number of studies, to determine whether ICU follow-up services are effective in identifying and addressing the unmet health needs of ICU survivors. We found five ongoing studies which are not included in this review; these ongoing studies may increase our certainty in the effect in future updates. Because of limited data, we were unable to explore whether one design of follow-up service is preferable to another, or whether a service is more effective for some people than others, and we anticipate that future studies may also vary in design. We propose that future studies are designed with robust methods (for example randomised studies are preferable) and consider only one variable (the follow-up service) compared to standard care; this would increase confidence that the effect is due to the follow-up service rather than concomitant therapies.

Information or education interventions for adult intensive care unit (ICU) patients and their carers.

BACKGROUND: During intensive care unit (ICU) admission, patients and their carers experience physical and psychological stressors that may result in psychological conditions including anxiety, depression, and post-traumatic stress disorder (PTSD). Improving communication between healthcare professionals, patients, and their carers may alleviate these disorders. Communication may include information or educational interventions, in different formats, aiming to improve knowledge of the prognosis, treatment, or anticipated challenges after ICU discharge. OBJECTIVES: To assess the effects of information or education interventions for improving outcomes in adult ICU patients and their carers. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL, and PsycINFO from database inception to 10 April 2017. We searched clinical trials registries and grey literature, and handsearched reference lists of included studies and related reviews. SELECTION CRITERIA: We included randomised controlled trials (RCTs), and planned to include quasi-RCTs, comparing information or education interventions presented to participants versus no information or education interventions, or comparing information or education interventions as part of a complex intervention versus a complex intervention without information or education. We included participants who were adult ICU patients, or their carers; these included relatives and non-relatives, including significant representatives of patients. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed studies for inclusion, extracted data, assessed risk of bias, and applied GRADE criteria to assess certainty of the evidence. MAIN RESULTS: We included eight RCTs with 1157 patient participants and 943 carer participants. We found no quasi-RCTs. We identified seven studies that await classification, and three ongoing studies.Three studies designed an intervention targeted at patients, four at carers, and one at both patients and carers. Studies included varied information: standardised or tailored, presented once or several times, and that included verbal or written information, audio recordings, multimedia information, and interactive information packs. Five studies reported robust methods of randomisation and allocation concealment. We noted high attrition rates in five studies. It was not feasible to blind participants, and we rated all studies as at high risk of performance bias, and at unclear risk of detection bias because most outcomes required self reporting.We attempted to pool data statistically, however this was not always possible due to high levels of heterogeneity. We calculated mean differences (MDs) using data reported from individual study authors where possible, and narratively synthesised the results. We reported the following two comparisons.Information or education intervention versus no information or education intervention (4 studies)For patient anxiety, we did not pool data from three studies (332 participants) owing to unexplained substantial statistical heterogeneity and possible clinical or methodological differences between studies. One study reported less anxiety when an intervention was used (MD -3.20, 95% confidence interval (CI) -3.38 to -3.02), and two studies reported little or no difference between groups (MD -0.40, 95% CI -4.75 to 3.95; MD -1.00, 95% CI -2.94 to 0.94). Similarly, for patient depression, we did not pool data from two studies (160 patient participants). These studies reported less depression when an information or education intervention was used (MD -2.90, 95% CI -4.00 to -1.80; MD -1.27, 95% CI -1.47 to -1.07). However, it is uncertain whether information or education interventions reduce patient anxiety or depression due to very low-certainty evidence.It is uncertain whether information or education interventions improve health-related quality of life due to very low-certainty evidence from one study reporting little or no difference between intervention groups (MD -1.30, 95% CI -4.99 to 2.39; 143 patient participants). No study reported adverse effects, knowledge acquisition, PTSD severity, or patient or carer satisfaction.We used the GRADE approach and downgraded certainty of the evidence owing to study limitations, inconsistencies between results, and limited data from few small studies.Information or education intervention as part of a complex intervention versus a complex intervention without information or education (4 studies)One study (three comparison groups; 38 participants) reported little or no difference between groups in patient anxiety (tailored information pack versus control: MD 0.09, 95% CI -3.29 to 3.47; standardised general ICU information versus control: MD -0.25, 95% CI -4.34 to 3.84), and little or no difference in patient depression (tailored information pack versus control: MD -1.26, 95% CI -4.48 to 1.96; standardised general ICU information versus control: MD -1.47, 95% CI -6.37 to 3.43). It is uncertain whether information or education interventions as part of a complex intervention reduce patient anxiety and depression due to very low-certainty evidence.One study (175 carer participants) reported fewer carer participants with poor comprehension among those given information (risk ratio 0.28, 95% CI 0.15 to 0.53), but again this finding is uncertain due to very low-certainty evidence.Two studies (487 carer participants) reported little or no difference in carer satisfaction; it is uncertain whether information or education interventions as part of a complex intervention increase carer satisfaction due to very low-certainty evidence. Adverse effects were reported in only one study: one participant withdrew because of deterioration in mental health on completion of anxiety and depression questionnaires, but the study authors did not report whether this participant was from the intervention or comparison group.We downgraded certainty of the evidence owing to study limitations, and limited data from few small studies.No studies reported severity of PTSD, or health-related quality of life. AUTHORS' CONCLUSIONS: We are uncertain of the effects of information or education interventions given to adult ICU patients and their carers, as the evidence in all cases was of very low certainty, and our confidence in the evidence was limited. Ongoing studies may contribute more data and introduce more certainty when incorporated into future updates of the review.

Intravenous versus inhalational maintenance of anaesthesia for postoperative cognitive outcomes in elderly people undergoing non-cardiac surgery.

BACKGROUND: The use of anaesthetics in the elderly surgical population (more than 60 years of age) is increasing. Postoperative delirium, an acute condition characterized by reduced awareness of the environment and a disturbance in attention, typically occurs between 24 and 72 hours after surgery and can affect up to 60% of elderly surgical patients. Postoperative cognitive dysfunction (POCD) is a new-onset of cognitive impairment which may persist for weeks or months after surgery.Traditionally, surgical anaesthesia has been maintained with inhalational agents. End-tidal concentrations require adjustment to balance the risks of accidental awareness and excessive dosing in elderly people. As an alternative, propofol-based total intravenous anaesthesia (TIVA) offers a more rapid recovery and reduces postoperative nausea and vomiting. Using TIVA with a target controlled infusion (TCI) allows plasma and effect-site concentrations to be calculated using an algorithm based on age, gender, weight and height of the patient.TIVA is a viable alternative to inhalational maintenance agents for surgical anaesthesia in elderly people. However, in terms of postoperative cognitive outcomes, the optimal technique is unknown. OBJECTIVES: To compare maintenance of general anaesthesia for elderly people undergoing non-cardiac surgery using propofol-based TIVA or inhalational anaesthesia on postoperative cognitive function, mortality, risk of hypotension, length of stay in the postanaesthesia care unit (PACU), and hospital stay. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 11), MEDLINE (1946 to November 2017), Embase (1974 to November 2017), PsycINFO (1887 to November 2017). We searched clinical trials registers for ongoing studies, and conducted backward and forward citation searching of relevant articles. SELECTION CRITERIA: We included randomized controlled trials (RCTs) with participants over 60 years of age scheduled for non-cardiac surgery under general anaesthesia. We planned to also include quasi-randomized trials. We compared maintenance of anaesthesia with propofol-based TIVA versus inhalational maintenance of anaesthesia. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed studies for inclusion, extracted data, assessed risk of bias, and synthesized findings. MAIN RESULTS: We included 28 RCTs with 4507 randomized participants undergoing different types of surgery (predominantly cardiovascular, laparoscopic, abdominal, orthopaedic and ophthalmic procedures). We found no quasi-randomized trials. Four studies are awaiting classification because we had insufficient information to assess eligibility.All studies compared maintenance with propofol-based TIVA versus inhalational maintenance of anaesthesia. Six studies were multi-arm and included additional TIVA groups, additional inhalational maintenance or both. Inhalational maintenance agents included sevoflurane (19 studies), isoflurane (eight studies), and desflurane (three studies), and was not specified in one study (reported as an abstract). Some studies also reported use of epidural analgesia/anaesthesia, fentanyl and remifentanil.We found insufficient reporting of randomization methods in many studies and all studies were at high risk of performance bias because it was not feasible to blind anaesthetists to study groups. Thirteen studies described blinding of outcome assessors. Three studies had a high of risk of attrition bias, and we noted differences in the use of analgesics between groups in six studies, and differences in baseline characteristics in five studies. Few studies reported clinical trials registration, which prevented assessment of risk of selective reporting bias.We found no evidence of a difference in incidences of postoperative delirium according to type of anaesthetic maintenance agents (odds ratio (OR) 0.59, 95% confidence interval (CI) 0.15 to 2.26; 321 participants; five studies; very low-certainty evidence); we noted during sensitivity analysis that using different time points in one study may influence direction of this result. Thirteen studies (3215 participants) reported POCD, and of these, six studies reported data that could not be pooled; we noted no difference in scores of POCD in four of these and in one study, data were at a time point incomparable to other studies. We excluded one large study from meta-analysis because study investigators had used non-standard anaesthetic management and this study was not methodologically comparable to other studies. We combined data for seven studies and found low-certainty evidence that TIVA may reduce POCD (OR 0.52, 95% CI 0.31 to 0.87; 869 participants).We found no evidence of a difference in mortality at 30 days (OR 1.21, 95% CI 0.33 to 4.45; 271 participants; three studies; very low-certainty evidence). Twelve studies reported intraoperative hypotension. We did not perform meta-analysis for 11 studies for this outcome. We noted visual inconsistencies in these data, which may be explained by possible variation in clinical management and medication used to manage hypotension in each study (downgraded to low-certainty evidence); one study reported data in a format that could not be combined and we noted little or no difference between groups in intraoperative hypotension for this study. Eight studies reported length of stay in the PACU, and we did not perform meta-analysis for seven studies. We noted visual inconsistencies in these data, which may be explained by possible differences in definition of time points for this outcome (downgraded to very low-certainty evidence); data were unclearly reported in one study. We found no evidence of a difference in length of hospital stay according to type of anaesthetic maintenance agent (mean difference (MD) 0 days, 95% CI -1.32 to 1.32; 175 participants; four studies; very low-certainty evidence).We used the GRADE approach to downgrade the certainty of the evidence for each outcome. Reasons for downgrading included: study limitations, because some included studies insufficiently reported randomization methods, had high attrition bias, or high risk of selective reporting bias; imprecision, because we found few studies; inconsistency, because we noted heterogeneity across studies. AUTHORS' CONCLUSIONS: We are uncertain whether maintenance with propofol-based TIVA or with inhalational agents affect incidences of postoperative delirium, mortality, or length of hospital stay because certainty of the evidence was very low. We found low-certainty evidence that maintenance with propofol-based TIVA may reduce POCD. We were unable to perform meta-analysis for intraoperative hypotension or length of stay in the PACU because of heterogeneity between studies. We identified 11 ongoing studies from clinical trials register searches; inclusion of these studies in future review updates may provide more certainty for the review outcomes.

Colloids versus crystalloids for fluid resuscitation in critically ill people.

BACKGROUND: Critically ill people may lose fluid because of serious conditions, infections (e.g. sepsis), trauma, or burns, and need additional fluids urgently to prevent dehydration or kidney failure. Colloid or crystalloid solutions may be used for this purpose. Crystalloids have small molecules, are cheap, easy to use, and provide immediate fluid resuscitation, but may increase oedema. Colloids have larger molecules, cost more, and may provide swifter volume expansion in the intravascular space, but may induce allergic reactions, blood clotting disorders, and kidney failure. This is an update of a Cochrane Review last published in 2013. OBJECTIVES: To assess the effect of using colloids versus crystalloids in critically ill people requiring fluid volume replacement on mortality, need for blood transfusion or renal replacement therapy (RRT), and adverse events (specifically: allergic reactions, itching, rashes). SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase and two other databases on 23 February 2018. We also searched clinical trials registers. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi-RCTs of critically ill people who required fluid volume replacement in hospital or emergency out-of-hospital settings. Participants had trauma, burns, or medical conditions such as sepsis. We excluded neonates, elective surgery and caesarean section. We compared a colloid (suspended in any crystalloid solution) versus a crystalloid (isotonic or hypertonic). DATA COLLECTION AND ANALYSIS: Independently, two review authors assessed studies for inclusion, extracted data, assessed risk of bias, and synthesised findings. We assessed the certainty of evidence with GRADE. MAIN RESULTS: We included 69 studies (65 RCTs, 4 quasi-RCTs) with 30,020 participants. Twenty-eight studied starch solutions, 20 dextrans, seven gelatins, and 22 albumin or fresh frozen plasma (FFP); each type of colloid was compared to crystalloids.Participants had a range of conditions typical of critical illness. Ten studies were in out-of-hospital settings. We noted risk of selection bias in some studies, and, as most studies were not prospectively registered, risk of selective outcome reporting. Fourteen studies included participants in the crystalloid group who received or may have received colloids, which might have influenced results.We compared four types of colloid (i.e. starches; dextrans; gelatins; and albumin or FFP) versus crystalloids.Starches versus crystalloidsWe found moderate-certainty evidence that there is probably little or no difference between using starches or crystalloids in mortality at: end of follow-up (risk ratio (RR) 0.97, 95% confidence interval (CI) 0.86 to 1.09; 11,177 participants; 24 studies); within 90 days (RR 1.01, 95% CI 0.90 to 1.14; 10,415 participants; 15 studies); or within 30 days (RR 0.99, 95% CI 0.90 to 1.09; 10,135 participants; 11 studies).We found moderate-certainty evidence that starches probably slightly increase the need for blood transfusion (RR 1.19, 95% CI 1.02 to 1.39; 1917 participants; 8 studies), and RRT (RR 1.30, 95% CI 1.14 to 1.48; 8527 participants; 9 studies). Very low-certainty evidence means we are uncertain whether either fluid affected adverse events: we found little or no difference in allergic reactions (RR 2.59, 95% CI 0.27 to 24.91; 7757 participants; 3 studies), fewer incidences of itching with crystalloids (RR 1.38, 95% CI 1.05 to 1.82; 6946 participants; 2 studies), and fewer incidences of rashes with crystalloids (RR 1.61, 95% CI 0.90 to 2.89; 7007 participants; 2 studies).Dextrans versus crystalloidsWe found moderate-certainty evidence that there is probably little or no difference between using dextrans or crystalloids in mortality at: end of follow-up (RR 0.99, 95% CI 0.88 to 1.11; 4736 participants; 19 studies); or within 90 days or 30 days (RR 0.99, 95% CI 0.87 to 1.12; 3353 participants; 10 studies). We are uncertain whether dextrans or crystalloids reduce the need for blood transfusion, as we found little or no difference in blood transfusions (RR 0.92, 95% CI 0.77 to 1.10; 1272 participants, 3 studies; very low-certainty evidence). We found little or no difference in allergic reactions (RR 6.00, 95% CI 0.25 to 144.93; 739 participants; 4 studies; very low-certainty evidence). No studies measured RRT.Gelatins versus crystalloidsWe found low-certainty evidence that there may be little or no difference between gelatins or crystalloids in mortality: at end of follow-up (RR 0.89, 95% CI 0.74 to 1.08; 1698 participants; 6 studies); within 90 days (RR 0.89, 95% CI 0.73 to 1.09; 1388 participants; 1 study); or within 30 days (RR 0.92, 95% CI 0.74 to 1.16; 1388 participants; 1 study). Evidence for blood transfusion was very low certainty (3 studies), with a low event rate or data not reported by intervention. Data for RRT were not reported separately for gelatins (1 study). We found little or no difference between groups in allergic reactions (very low-certainty evidence).Albumin or FFP versus crystalloidsWe found moderate-certainty evidence that there is probably little or no difference between using albumin or FFP or using crystalloids in mortality at: end of follow-up (RR 0.98, 95% CI 0.92 to 1.06; 13,047 participants; 20 studies); within 90 days (RR 0.98, 95% CI 0.92 to 1.04; 12,492 participants; 10 studies); or within 30 days (RR 0.99, 95% CI 0.93 to 1.06; 12,506 participants; 10 studies). We are uncertain whether either fluid type reduces need for blood transfusion (RR 1.31, 95% CI 0.95 to 1.80; 290 participants; 3 studies; very low-certainty evidence). Using albumin or FFP versus crystalloids may make little or no difference to the need for RRT (RR 1.11, 95% CI 0.96 to 1.27; 3028 participants; 2 studies; very low-certainty evidence), or in allergic reactions (RR 0.75, 95% CI 0.17 to 3.33; 2097 participants, 1 study; very low-certainty evidence). AUTHORS' CONCLUSIONS: Using starches, dextrans, albumin or FFP (moderate-certainty evidence), or gelatins (low-certainty evidence), versus crystalloids probably makes little or no difference to mortality. Starches probably slightly increase the need for blood transfusion and RRT (moderate-certainty evidence), and albumin or FFP may make little or no difference to the need for renal replacement therapy (low-certainty evidence). Evidence for blood transfusions for dextrans, and albumin or FFP, is uncertain. Similarly, evidence for adverse events is uncertain. Certainty of evidence may improve with inclusion of three ongoing studies and seven studies awaiting classification, in future updates.

Continuation versus discontinuation of antiplatelet therapy for bleeding and ischaemic events in adults undergoing non-cardiac surgery.

BACKGROUND: Antiplatelet agents are recommended for people with myocardial infarction and acute coronary syndromes, transient ischaemic attack or stroke, and for those in whom coronary stents have been inserted. People who take antiplatelet agents are at increased risk of adverse events when undergoing non-cardiac surgery because of these indications. However, taking antiplatelet therapy also introduces risk to the person undergoing surgery because the likelihood of bleeding is increased. Discontinuing antiplatelet therapy before surgery might reduce this risk but subsequently it might make thrombotic problems, such as myocardial infarction, more likely. OBJECTIVES: To compare the effects of continuation versus discontinuation for at least five days of antiplatelet therapy on the occurrence of bleeding and ischaemic events in adults undergoing non-cardiac surgery under general, spinal or regional anaesthesia. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 1), MEDLINE (1946 to January 2018), and Embase (1974 to January 2018). We searched clinical trials registers for ongoing studies, and conducted backward and forward citation searching of relevant articles. SELECTION CRITERIA: We included randomized controlled trials of adults who were taking single or dual antiplatelet therapy, for at least two weeks, and were scheduled for elective non-cardiac surgery. Included participants had at least one cardiac risk factor. We planned to include quasi-randomized studies.We excluded people scheduled for minor surgeries under local anaesthetic or sedation in which bleeding that required transfusion or additional surgery was unlikely. We included studies which compared perioperative continuation of antiplatelet therapy versus discontinuation of antiplatelet therapy or versus substitution of antiplatelet therapy with a placebo for at least five days before surgery. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed studies for inclusion, extracted data, assessed risk of bias and synthesized findings. Our primary outcomes were: all-cause mortality at longest follow-up (up to six months); all-cause mortality (up to 30 days). Secondary outcomes included: blood loss requiring transfusion of blood products; blood loss requiring further surgical intervention; risk of ischaemic events. We used GRADE to assess the quality of evidence for each outcome MAIN RESULTS: We included five RCTs with 666 randomized adults. We identified three ongoing studies.All study participants were scheduled for elective general surgery (including abdominal, urological, orthopaedic and gynaecological surgery) under general, spinal or regional anaesthesia. Studies compared continuation of single or dual antiplatelet therapy (aspirin or clopidogrel) with discontinuation of therapy for at least five days before surgery.Three studies reported adequate methods of randomization, and two reported methods to conceal allocation. Three studies were placebo-controlled trials and were at low risk of performance bias, and three studies reported adequate methods to blind outcome assessors to group allocation. Attrition was limited in four studies and two studies had reported prospective registration with clinical trial registers and were at low risk of selective outcome reporting bias.We reported mortality at two time points: the longest follow-up reported by study authors up to six months, and time point reported by study authors up to 30 days. Five studies reported mortality up to six months (of which four studies had a longest follow-up at 30 days, and one study at 90 days) and we found that either continuation or discontinuation of antiplatelet therapy may make little or no difference to mortality up to six months (risk ratio (RR) 1.21, 95% confidence interval (CI) 0.34 to 4.27; 659 participants; low-certainty evidence); the absolute effect is three more deaths per 1000 with continuation of antiplatelets (ranging from eight fewer to 40 more). Combining the four studies with a longest follow-up at 30 days alone showed the same effect estimate, and we found that either continuation or discontinuation of antiplatelet therapy may make little or no difference to mortality at 30 days after surgery (RR 1.21, 95% CI 0.34 to 4.27; 616 participants; low-certainty evidence); the absolute effect is three more deaths per 1000 with continuation of antiplatelets (ranging from nine fewer to 42 more).We found that either continuation or discontinuation of antiplatelet therapy probably makes little or no difference in incidences of blood loss requiring transfusion (RR 1.37, 95% CI 0.83 to 2.26; 368 participants; absolute effect of 42 more participants per 1000 requiring transfusion in the continuation group, ranging from 19 fewer to 119 more; four studies; moderate-certainty evidence); and may make little or no difference in incidences of blood loss requiring additional surgery (RR 1.54, 95% CI 0.31 to 7.58; 368 participants; absolute effect of six more participants per 1000 requiring additional surgery in the continuation group, ranging from seven fewer to 71 more; four studies; low-certainty evidence). We found that either continuation or discontinuation of antiplatelet therapy may make little or no difference to incidences of ischaemic events (to include peripheral ischaemia, cerebral infarction, and myocardial infarction) within 30 days of surgery (RR 0.67, 95% CI 0.25 to 1.77; 616 participants; absolute effect of 17 fewer participants per 1000 with an ischaemic event in the continuation group, ranging from 39 fewer to 40 more; four studies; low-certainty evidence).We used the GRADE approach to downgrade evidence for all outcomes owing to limited evidence from few studies. We noted a wide confidence in effect estimates for mortality at the end of follow-up and at 30 days, and for blood loss requiring transfusion which suggested imprecision. We noted visual differences in study results for ischaemic events which suggested inconsistency. AUTHORS' CONCLUSIONS: We found low-certainty evidence that either continuation or discontinuation of antiplatelet therapy before non-cardiac surgery may make little or no difference to mortality, bleeding requiring surgical intervention, or ischaemic events. We found moderate-certainty evidence that either continuation or discontinuation of antiplatelet therapy before non-cardiac surgery probably makes little or no difference to bleeding requiring transfusion. Evidence was limited to few studies with few participants, and with few events. The three ongoing studies may alter the conclusions of the review once published and assessed.

Automated monitoring compared to standard care for the early detection of sepsis in critically ill patients.

BACKGROUND: Sepsis is a life-threatening condition that is usually diagnosed when a patient has a suspected or documented infection, and meets two or more criteria for systemic inflammatory response syndrome (SIRS). The incidence of sepsis is higher among people admitted to critical care settings such as the intensive care unit (ICU) than among people in other settings. If left untreated sepsis can quickly worsen; severe sepsis has a mortality rate of 40% or higher, depending on definition. Recognition of sepsis can be challenging as it usually requires patient data to be combined from multiple unconnected sources, and interpreted correctly, which can be complex and time consuming to do. Electronic systems that are designed to connect information sources together, and automatically collate, analyse, and continuously monitor the information, as well as alerting healthcare staff when pre-determined diagnostic thresholds are met, may offer benefits by facilitating earlier recognition of sepsis and faster initiation of treatment, such as antimicrobial therapy, fluid resuscitation, inotropes, and vasopressors if appropriate. However, there is the possibility that electronic, automated systems do not offer benefits, or even cause harm. This might happen if the systems are unable to correctly detect sepsis (meaning that treatment is not started when it should be, or it is started when it shouldn't be), or healthcare staff may not respond to alerts quickly enough, or get 'alarm fatigue' especially if the alarms go off frequently or give too many false alarms. OBJECTIVES: To evaluate whether automated systems for the early detection of sepsis can reduce the time to appropriate treatment (such as initiation of antibiotics, fluids, inotropes, and vasopressors) and improve clinical outcomes in critically ill patients in the ICU. SEARCH METHODS: We searched CENTRAL; MEDLINE; Embase; CINAHL; ISI Web of science; and LILACS, clinicaltrials.gov, and the World Health Organization trials portal. We searched all databases from their date of inception to 18 September 2017, with no restriction on country or language of publication. SELECTION CRITERIA: We included randomized controlled trials (RCTs) that compared automated sepsis-monitoring systems to standard care (such as paper-based systems) in participants of any age admitted to intensive or critical care units for critical illness. We defined an automated system as any process capable of screening patient records or data (one or more systems) automatically at intervals for markers or characteristics that are indicative of sepsis. We defined critical illness as including, but not limited to postsurgery, trauma, stroke, myocardial infarction, arrhythmia, burns, and hypovolaemic or haemorrhagic shock. We excluded non-randomized studies, quasi-randomized studies, and cross-over studies . We also excluded studies including people already diagnosed with sepsis. DATA COLLECTION AND ANALYSIS: We used the standard methodological procedures expected by Cochrane. Our primary outcomes were: time to initiation of antimicrobial therapy; time to initiation of fluid resuscitation; and 30-day mortality. Secondary outcomes included: length of stay in ICU; failed detection of sepsis; and quality of life. We used GRADE to assess the quality of evidence for each outcome. MAIN RESULTS: We included three RCTs in this review. It was unclear if the RCTs were three separate studies involving 1199 participants in total, or if they were reports from the same study involving fewer participants. We decided to treat the studies separately, as we were unable to make contact with the study authors to clarify.All three RCTs are of very low study quality because of issues with unclear randomization methods, allocation concealment and uncertainty of effect size. Some of the studies were reported as abstracts only and contained limited data, which prevented meaningful analysis and assessment of potential biases.The studies included participants who all received automated electronic monitoring during their hospital stay. Participants were randomized to an intervention group (automated alerts sent from the system) or to usual care (no automated alerts sent from the system).Evidence from all three studies reported 'Time to initiation of antimicrobial therapy'. We were unable to pool the data, but the largest study involving 680 participants reported median time to initiation of antimicrobial therapy in the intervention group of 5.6 hours (interquartile range (IQR) 2.3 to 19.7) in the intervention group (n = not stated) and 7.8 hours (IQR 2.5 to 33.1) in the control group (n = not stated).No studies reported 'Time to initiation of fluid resuscitation' or the adverse event 'Mortality at 30 days'. However very low-quality evidence was available where mortality was reported at other time points. One study involving 77 participants reported 14-day mortality of 20% in the intervention group and 21% in the control group (numerator and denominator not stated). One study involving 442 participants reported mortality at 28 days, or discharge was 14% in the intervention group and 10% in the control group (numerator and denominator not reported). Sample sizes were not reported adequately for these outcomes and so we could not estimate confidence intervals.Very low-quality evidence from one study involving 442 participants reported 'Length of stay in ICU'. Median length of stay was 3.0 days in the intervention group (IQR = 2.0 to 5.0), and 3.0 days (IQR 2.0 to 4.0 in the control).Very low-quality evidence from one study involving at least 442 participants reported the adverse effect 'Failed detection of sepsis'. Data were only reported for failed detection of sepsis in two participants and it wasn't clear which group(s) this outcome occurred in.No studies reported 'Quality of life'. AUTHORS' CONCLUSIONS: It is unclear what effect automated systems for monitoring sepsis have on any of the outcomes included in this review. Very low-quality evidence is only available on automated alerts, which is only one component of automated monitoring systems. It is uncertain whether such systems can replace regular, careful review of the patient's condition by experienced healthcare staff.

Enteral versus parenteral nutrition and enteral versus a combination of enteral and parenteral nutrition for adults in the intensive care unit.

BACKGROUND: Critically ill people are at increased risk of malnutrition. Acute and chronic illness, trauma and inflammation induce stress-related catabolism, and drug-induced adverse effects may reduce appetite or increase nausea and vomiting. In addition, patient management in the intensive care unit (ICU) may also interrupt feeding routines. Methods to deliver nutritional requirements include provision of enteral nutrition (EN), or parenteral nutrition (PN), or a combination of both (EN and PN). However, each method is problematic. This review aimed to determine the route of delivery that optimizes uptake of nutrition. OBJECTIVES: To compare the effects of enteral versus parenteral methods of nutrition, and the effects of enteral versus a combination of enteral and parenteral methods of nutrition, among critically ill adults, in terms of mortality, number of ICU-free days up to day 28, and adverse events. SEARCH METHODS: We searched CENTRAL, MEDLINE, and Embase on 3 October 2017. We searched clinical trials registries and grey literature, and handsearched reference lists of included studies and related reviews. SELECTION CRITERIA: We included randomized controlled studies (RCTs) and quasi-randomized studies comparing EN given to adults in the ICU versus PN or versus EN and PN. We included participants that were trauma, emergency, and postsurgical patients in the ICU. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias. We assessed the certainty of evidence with GRADE. MAIN RESULTS: We included 25 studies with 8816 participants; 23 studies were RCTs and two were quasi-randomized studies. All included participants were critically ill in the ICU with a wide range of diagnoses; mechanical ventilation status between study participants varied. We identified 11 studies awaiting classification for which we were unable to assess eligibility, and two ongoing studies.Seventeen studies compared EN versus PN, six compared EN versus EN and PN, two were multi-arm studies comparing EN versus PN versus EN and PN. Most studies reported randomization and allocation concealment inadequately. Most studies reported no methods to blind personnel or outcome assessors to nutrition groups; one study used adequate methods to reduce risk of performance bias.Enteral nutrition versus parenteral nutritionWe found that one feeding route rather than the other (EN or PN) may make little or no difference to mortality in hospital (risk ratio (RR) 1.19, 95% confidence interval (CI) 0.80 to 1.77; 361 participants; 6 studies; low-certainty evidence), or mortality within 30 days (RR 1.02, 95% CI 0.92 to 1.13; 3148 participants; 11 studies; low-certainty evidence). It is uncertain whether one feeding route rather than the other reduces mortality within 90 days because the certainty of the evidence is very low (RR 1.06, 95% CI 0.95 to 1.17; 2461 participants; 3 studies). One study reported mortality at one to four months and we did not combine this in the analysis; we reported this data as mortality within 180 days and it is uncertain whether EN or PN affects the number of deaths within 180 days because the certainty of the evidence is very low (RR 0.33, 95% CI 0.04 to 2.97; 46 participants).No studies reported number of ICU-free days up to day 28, and one study reported number of ventilator-free days up to day 28 and it is uncertain whether one feeding route rather than the other reduces the number of ventilator-free days up to day 28 because the certainty of the evidence is very low (mean difference, inverse variance, 0.00, 95% CI -0.97 to 0.97; 2388 participants).We combined data for adverse events reported by more than one study. It is uncertain whether EN or PN affects aspiration because the certainty of the evidence is very low (RR 1.53, 95% CI 0.46 to 5.03; 2437 participants; 2 studies), and we found that one feeding route rather than the other may make little or no difference to pneumonia (RR 1.10, 95% CI 0.82 to 1.48; 415 participants; 7 studies; low-certainty evidence). We found that EN may reduce sepsis (RR 0.59, 95% CI 0.37 to 0.95; 361 participants; 7 studies; low-certainty evidence), and it is uncertain whether PN reduces vomiting because the certainty of the evidence is very low (RR 3.42, 95% CI 1.15 to 10.16; 2525 participants; 3 studies).Enteral nutrition versus enteral nutrition and parenteral nutritionWe found that one feeding regimen rather than another (EN or combined EN or PN) may make little or no difference to mortality in hospital (RR 0.99, 95% CI 0.84 to 1.16; 5111 participants; 5 studies; low-certainty evidence), and at 90 days (RR 1.00, 95% CI 0.86 to 1.18; 4760 participants; 2 studies; low-certainty evidence). It is uncertain whether combined EN and PN leads to fewer deaths at 30 days because the certainty of the evidence is very low (RR 1.64, 95% CI 1.06 to 2.54; 409 participants; 3 studies). It is uncertain whether one feeding regimen rather than another reduces mortality within 180 days because the certainty of the evidence is very low (RR 1.00, 95% CI 0.65 to 1.55; 120 participants; 1 study).No studies reported number of ICU-free days or ventilator-free days up to day 28. It is uncertain whether either feeding method reduces pneumonia because the certainty of the evidence is very low (RR 1.40, 95% CI 0.91 to 2.15; 205 participants; 2 studies). No studies reported aspiration, sepsis, or vomiting. AUTHORS' CONCLUSIONS: We found insufficient evidence to determine whether EN is better or worse than PN, or than combined EN and PN for mortality in hospital, at 90 days and at 180 days, and on the number of ventilator-free days and adverse events. We found fewer deaths at 30 days when studies gave combined EN and PN, and reduced sepsis for EN rather than PN. We found no studies that reported number of ICU-free days up to day 28. Certainty of the evidence for all outcomes is either low or very low. The 11 studies awaiting classification may alter the conclusions of the review once assessed.

Melatonin for the promotion of sleep in adults in the intensive care unit.

BACKGROUND: Patients in the intensive care unit (ICU) experience sleep deprivation caused by environmental disruption, such as high noise levels and 24-hour lighting, as well as increased patient care activities and invasive monitoring as part of their care. Sleep deprivation affects physical and psychological health, and patients perceive the quality of their sleep to be poor whilst in the ICU. Artificial lighting during night-time hours in the ICU may contribute to reduced production of melatonin in critically ill patients. Melatonin is known to have a direct effect on the circadian rhythm, and it appears to reset a natural rhythm, thus promoting sleep. OBJECTIVES: To assess whether the quantity and quality of sleep may be improved by administration of melatonin to adults in the intensive care unit. To assess whether melatonin given for sleep promotion improves both physical and psychological patient outcomes. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 8), MEDLINE (1946 to September 2017), Embase (1974 to September 2017), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1937 to September 2017), and PsycINFO (1806 to September 2017). We searched clinical trials registers for ongoing studies, and conducted backward and forward citation searching of relevant articles. SELECTION CRITERIA: We included randomized and quasi-randomized controlled trials with adult participants (over the age of 16) admitted to the ICU with any diagnoses given melatonin versus a comparator to promote overnight sleep. We included participants who were mechanically ventilated and those who were not mechanically ventilated. We planned to include studies that compared the use of melatonin, given at an appropriate clinical dose with the intention of promoting night-time sleep, against no agent; or against another agent administered specifically to promote sleep. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed studies for inclusion, extracted data, assessed risk of bias, and synthesized findings. We assessed the quality of evidence with GRADE. MAIN RESULTS: We included four studies with 151 randomized participants. Two studies included participants who were mechanically ventilated, one study included a mix of ventilated and non-ventilated participants and in one study participants were being weaned from mechanical ventilation. Three studies reported admission diagnoses, which varied: these included sepsis, pneumonia and cardiac or cardiorespiratory arrest. All studies compared melatonin against no agent; three were placebo-controlled trials; and one compared melatonin with usual care. All studies administered melatonin in the evening.All studies reported adequate methods for randomization and placebo-controlled trials were blinded at the participant and personnel level. We noted high risk of attrition bias in one study and were unclear about potential bias introduced in two studies with differences between participants at baseline.It was not appropriate to combine data owing to differences in measurement tools, or methods used to report data.The effects of melatonin on subjectively rated quantity and quality of sleep are uncertain (very low certainty evidence). Three studies (139 participants) reported quantity and quality of sleep as measured through reports of participants or family members or by personnel assessments. Study authors in one study reported no difference in sleep efficiency index scores between groups for participant assessment (using Richards-Campbell Sleep Questionnaire) and nurse assessment. Two studies reported no difference in duration of sleep observed by nurses.The effects of melatonin on objectively measured quantity and quality of sleep are uncertain (very low certainty evidence). Two studies (37 participants) reported quantity and quality of sleep as measured by polysomnography (PSG), actigraphy, bispectral index (BIS) or electroencephalogram (EEG). Study authors in one study reported no difference in sleep efficiency index scores between groups using BIS and actigraphy. These authors also reported longer sleep in participants given melatonin which was not statistically significant, and improved sleep (described as "better sleep") in participants given melatonin from analysis of area under the curve (AUC) of BIS data. One study used PSG but authors were unable to report data because of a large loss of participant data.One study (82 participants) reported no evidence of a difference in anxiety scores (very low certainty evidence). Two studies (94 participants) reported data for mortality: one study reported that overall one-third of participants died; and one study reported no evidence of difference between groups in hospital mortality (very low certainty). One study (82 participants) reported no evidence of a difference in length of ICU stay (very low certainty evidence). Effects of melatonin on adverse events were reported in two studies (107 participants), and are uncertain (very low certainty evidence): one study reported headache in one participant given melatonin, and one study reported excessive sleepiness in one participant given melatonin and two events in the control group (skin reaction in one participant, and excessive sleepiness in another participant).The certainty of the evidence for each outcome was limited by sparse data with few participants. We noted study limitations in some studies due to high attrition and differences between groups in baseline data; and doses of melatonin varied between studies. Methods used to measure data were not consistent for outcomes, and use of some measurement tools may not be effective for use on the ICU patient. All studies included participants in the ICU but we noted differences in ICU protocols, and one included study used a non-standard sedation protocol with participants which introduced indirectness to the evidence. AUTHORS' CONCLUSIONS: We found insufficient evidence to determine whether administration of melatonin would improve the quality and quantity of sleep in ICU patients. We identified sparse data, and noted differences in study methodology, in ICU sedation protocols, and in methods used to measure and report sleep. We identified five ongoing studies from database and clinical trial register searches. Inclusion of data from these studies in future review updates would provide more certainty for the review outcomes.

Propofol for the promotion of sleep in adults in the intensive care unit.

BACKGROUND: People in the intensive care unit (ICU) experience sleep deprivation caused by environmental disruption, such as high noise levels and 24-hour lighting, as well as increased patient care activities and invasive monitoring as part of their care. Sleep deprivation affects physical and psychological health, and people perceive the quality of their sleep to be poor whilst in the ICU. Propofol is an anaesthetic agent which can be used in the ICU to maintain patient sedation and some studies suggest it may be a suitable agent to replicate normal sleep. OBJECTIVES: To assess whether the quantity and quality of sleep may be improved by administration of propofol to adults in the ICU and to assess whether propofol given for sleep promotion improves both physical and psychological patient outcomes. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 10), MEDLINE (1946 to October 2017), Embase (1974 to October 2017), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1937 to October 2017) and PsycINFO (1806 to October 2017). We searched clinical trials registers for ongoing studies, and conducted backward and forward citation searching of relevant articles. SELECTION CRITERIA: We included randomized and quasi-randomized controlled trials with adults, over the age of 16 years, admitted to the ICU with any diagnoses, given propofol versus a comparator to promote overnight sleep. We included participants who were and were not mechanically ventilated. We included studies that compared the use of propofol, given at an appropriate clinical dose with the intention of promoting night-time sleep, against: no agent; propofol at a different rate or dose; or another agent, administered specifically to promote sleep. We included only studies in which propofol was given during 'normal' sleeping hours (i.e. between 10 pm and 7 am) to promote a sleep-like state with a diurnal rhythm. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed studies for inclusion, extracted data, assessed risk of bias and synthesized findings. MAIN RESULTS: We included four studies with 149 randomized participants. We identified two studies awaiting classification for which we were unable to assess eligibility and one ongoing study.Participants differed in severity of illness as assessed by APACHE II scores in three studies and further differences existed between comparisons and methods. One study compared propofol versus no agent, one study compared different doses of propofol and two studies compared propofol versus a benzodiazepine (flunitrazepam, one study; midazolam, one study). All studies reported randomization and allocation concealment inadequately. We judged all studies to have high risk of performance bias from personnel who were unblinded. We noted that some study authors had blinded study outcome assessors and participants for relevant outcomes.It was not appropriate to combine data owing to high levels of methodological heterogeneity.One study comparing propofol with no agent (13 participants) measured quantity and quality of sleep using polysomnography; study authors reported no evidence of a difference in duration of sleep or sleep efficiency, and reported disruption to usual REM (rapid eye movement sleep) with propofol.One study comparing different doses of propofol (30 participants) measured quantity and quality of sleep by personnel using the Ramsay Sedation Scale; study authors reported that more participants who were given a higher dose of propofol had a successful diurnal rhythm, and achieved a greater sedation rhythmicity.Two studies comparing propofol with a different agent (106 participants) measured quantity and quality of sleep using the Pittsburgh Sleep Diary and the Hospital Anxiety and Depression Scale; one study reported fewer awakenings of reduced duration with propofol, and similar total sleep time between groups, and one study reported no evidence of a difference in sleep quality. One study comparing propofol with another agent (66 participants) measured quantity and quality of sleep with the Bispectral Index and reported longer time in deep sleep, with fewer arousals. One study comparing propofol with another agent (40 participants) reported higher levels of anxiety and depression in both groups, and no evidence of a difference when participants were given propofol.No studies reported adverse events.We used the GRADE approach to downgrade the certainty of the evidence for each outcome to very low. We identified sparse data with few participants, and methodological differences in study designs and comparative agents introduced inconsistency, and we noted that measurement tools were imprecise or not valid for purpose. AUTHORS' CONCLUSIONS: We found insufficient evidence to determine whether administration of propofol would improve the quality and quantity of sleep in adults in the ICU. We noted differences in study designs, methodology, comparative agents and illness severity amongst study participants. We did not pool data and we used the GRADE approach to downgrade the certainty of our evidence to very low.

Hypothermia for traumatic brain injury.

BACKGROUND: Hypothermia has been used in the treatment of brain injury for many years. Encouraging results from small trials and laboratory studies led to renewed interest in the area and some larger trials. OBJECTIVES: To determine the effect of mild hypothermia for traumatic brain injury (TBI) on mortality, long-term functional outcomes and complications. SEARCH METHODS: We ran and incorporated studies from database searches to 21 March 2016. We searched the Cochrane Injuries Group's Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE (OvidSP), Embase Classic+Embase (OvidSP), PubMed, ISI Web of science (SCI-EXPANDED, SSCI, CPCI-S & CPSI-SSH), clinical trials registers, and screened reference lists. We also re-ran these searches pre-publication in June 2017; the result from this search is presented in 'Studies awaiting classification'. SELECTION CRITERIA: We included randomised controlled trials of participants with closed TBI requiring hospitalisation who were treated with hypothermia to a maximum of 35 ºC for at least 12 consecutive hours. Treatment with hypothermia was compared to maintenance with normothermia (36.5 to 38 ºC). DATA COLLECTION AND ANALYSIS: Two review authors assessed data on mortality, unfavourable outcomes according to the Glasgow Outcome Scale, and pneumonia. MAIN RESULTS: We included 37 eligible trials with a total of 3110 randomised participants; nine of these were new studies since the last update (2009) and five studies had been previously excluded but were re-assessed and included during the 2017 update. We identified two ongoing studies from searches of clinical trials registers and database searches and two studies await classification.Studies included both adults and children with TBI. Most studies commenced treatment immediately on admission to hospital or after craniotomies and all treatment was maintained for at least 24 hours. Thirty-three studies reported data for mortality, 31 studies reported data for unfavourable outcomes (death, vegetative state or severe disability), and 14 studies reported pneumonia. Visual inspection of the results for these outcomes showed inconsistencies among studies, with differences in the direction of effect, and we did not pool these data for meta-analysis. We considered duration of hypothermia therapy and the length of follow-up in collected data for these subgroups; differences in study data remained such that we did not perform meta-analysis.Studies were generally poorly reported and we were unable to assess risk of bias adequately. Heterogeneity was evident both in the trial designs and participant inclusion. Inconsistencies in results may be explained by heterogeneity among study participants or bias introduced by individual study methodology but we did not explore this in detail in subgroup or sensitivity analyses. We used the GRADE approach to judge the quality of the evidence for each outcome and downgraded the evidence for mortality and unfavourable outcome to very low. We downgraded the evidence for the pneumonia outcome to low. AUTHORS' CONCLUSIONS: Despite a large number studies, there remains no high-quality evidence that hypothermia is beneficial in the treatment of people with TBI. Further research, which is methodologically robust, is required in this field to establish the effect of hypothermia for people with TBI.

Intravenous nutrients for preventing inadvertent perioperative hypothermia in adults.

BACKGROUND: Inadvertent perioperative hypothermia (a drop in core temperature to below 36°C) occurs because normal temperature regulation is disrupted during surgery, mainly because of the effects of anaesthetic drugs and exposure of the skin for prolonged periods. Many different ways of maintaining body temperature have been proposed, one of which involves administration of intravenous nutrients during the perioperative period that may reduce heat loss by increasing metabolism, thereby increasing heat production. OBJECTIVES: To assess the effectiveness of preoperative or intraoperative intravenous nutrients in preventing perioperative hypothermia and its complications during surgery in adults. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL; November 2015) in the Cochrane Library; MEDLINE, Ovid SP (1956 to November 2015); Embase, Ovid SP (1982 to November 2015); the Institute for Scientific Information (ISI) Web of Science (1950 to November 2015); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL, EBSCO host; 1980 to November 2015), as well as the reference lists of identified articles. We also searched the Current Controlled Trials website and ClincalTrials.gov. SELECTION CRITERIA: Randomized controlled trials (RCTs) of intravenous nutrients compared with control or other interventions given to maintain normothermia in adults undergoing surgery. DATA COLLECTION AND ANALYSIS: Two review authors extracted data and assessed risk of bias for each included trial, and a third review author checked details if necessary. We contacted some study authors to request additional information. MAIN RESULTS: We included 14 trials (n = 565), 13 (n = 525) of which compared intravenous administration of amino acids to a control (usually saline solution or Ringer's lactate). The remaining trial (n = 40) compared intravenous administration of fructose versus a control. We noted much variation in these trials, which used different types of surgery, variable durations of surgery, and different types of participants. Most trials were at high or unclear risk of bias owing to inappropriate or unclear randomization methods, and to unclear participant and assessor blinding. This may have influenced results, but it is unclear how results might have been influenced.No trials reported any of our prespecified primary outcomes, which were risk of hypothermia and major cardiovascular events. Therefore, we decided to analyse data related to core body temperature instead as a primary outcome. It was not possible to conduct meta-analysis of data related to amino acid infusion for the 60-minute and 120-minute time points, as we observed significant statistical heterogeneity in the results. Some trials showed that higher temperatures were associated with amino acids, but not all trials reported statistically significant results, and some trials reported the opposite result, where the amino acid group had a lower core temperature than the control group. It was possible to conduct meta-analysis for six studies (n = 249) that provided data relating to the end of surgery. Amino acids led to a statistically significant increase in core temperature in comparison to those receiving control (MD = 0.46°C 95% CI 0.33 to 0.59; I2 0.0%; random-effects; moderate quality evidence).Three trials (n = 155) reported shivering as an outcome. Meta-analysis did not show a clear effect, and so it is uncertain whether amino acids reduce the risk of shivering (RR 0.36, 95% CI 0.13 to 1.00; I2 = 93%; random-effects model; very low-quality evidence). AUTHORS' CONCLUSIONS: Intravenous amino acids may keep participants up to a half-degree C warmer than the control. This difference was statistically significant at the end of surgery, but not at other time points. However, the clinical importance of this finding remains unclear. It is also unclear whether amino acids have any effect on the risk of shivering and if intravenous nutrients confer any other benefits or harms, as high-quality data about these outcomes are lacking.

Alpha-2 adrenergic agonists for the prevention of shivering following general anaesthesia.

BACKGROUND: Shivering after general anaesthesia is common. It is unpleasant but can also have adverse physiological effects. Alpha-2 (α-2) adrenergic agonist receptors, which can lead to reduced sympathetic activity and central regulation of vasoconstrictor tone, are a group of drugs that have been used to try to prevent postoperative shivering. OBJECTIVES: To assess the following: the effects of α-2 agonists on the prevention of shivering and subsequent complications after general anaesthesia in people undergoing surgery; the effects of α-2 agonists on the risk of inadvertent perioperative hypothermia; and whether any adverse effects are associated with these interventions. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and EMBASE on 13 June 2014. Our search terms were relevant to the review question and limited to studies that assessed shivering or hypothermia. We also carried out searches of clinical trials registers, and forward and backward citation tracking. SELECTION CRITERIA: We considered all randomized controlled trials, quasi-randomized studies, and cluster-randomized studies with adult participants undergoing surgery with general anaesthesia in which an α-2 agonist was compared with another α-2 agonist or a placebo for the prevention of shivering. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trial quality and extracted data, consulting a third review author in the case of disagreements. We used standard Cochrane methodological procedures, including an assessment of risk of bias and use of GRADEpro software to interpret findings. MAIN RESULTS: We included 20 studies with 1401 surgical participants comparing an α-2 agonist against a control. Thirteen studies compared clonidine with a control, whilst seven compared dexmedetomidine with a control. The doses, methods, and time of administration varied between studies: three studies gave the drug orally or as an intravenous bolus preoperatively and nine intraoperatively; one study gave the drug as an infusion starting preoperatively and seven started at varying points from anaesthetic induction to the end of surgery. Whilst all the studies were described as randomized, many provided insufficient detail on methods used. We had anticipated that attempts would be made to reduce performance bias by blinding of personnel and participants, however this was detailed in only six of the papers. Similarly, in some studies detail was lacking on methods to reduce the risk of detection bias. We therefore downgraded the quality of evidence in our 'Summary of findings' table by one level for risk of bias using the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach.All 20 included studies presented outcome data for postoperative shivering, and in meta-analysis α-2 agonists were shown to significantly reduce the risk of shivering (Mantel-Haenszel risk ratio 0.28, 95% confidence interval 0.18 to 0.43, P value < 0.0001). We found significant evidence of heterogeneity (I(2) = 80%) for this result that was not explained by sensitivity or subgroup analysis; we therefore downgraded the inconsistency of the evidence by one level. Although we did not feel that there were concerns with imprecision or indirectness of the data, we downgraded the quality of the evidence for the risk of publication bias following visual analysis of a funnel plot. Using GRADEpro, we rated the overall quality of the data for shivering as very low. Only one study reported the incidence of core hypothermia, whilst 12 studies measured core temperature. However, as the results for core temperature were reported in different styles, pooling the results was inappropriate. We found no studies with participant-reported outcomes such as experience of shivering or participant satisfaction. We found limited data for the outcomes of length of stay in the postanaesthetic care unit (three studies, 200 participants) and the following adverse effects: sedation (nine studies, 875 participants), bradycardia (eight studies, 716 participants), and hypotension (seven studies, 688 participants). Unpooled analysis suggested that sedation and bradycardia were significantly more common with dexmedetomidine than placebo, with all seven dexmedetomidine studies and none of the clonidine studies reporting statistically significantly higher levels of sedation as an adverse effect. AUTHORS' CONCLUSIONS: There is evidence that clonidine and dexmedetomidine can reduce postoperative shivering, but patients given dexmedetomidine may be more sedated. However, our assessment of the quality of this evidence is very low.

The impact of Cochrane Reviews: a mixed-methods evaluation of outputs from Cochrane Review Groups supported by the National Institute for Health Research.

BACKGROUND: The last few decades have seen a growing emphasis on evidence-informed decision-making in health care. Systematic reviews, such as those produced by Cochrane, have been a key component of this movement. The National Institute for Health Research (NIHR) Systematic Review Programme currently supports 20 Cochrane Review Groups (CRGs) in the UK and it is important that this funding represents value for money. AIMS AND OBJECTIVES: The overall aim was to identify the impacts and likely impacts on health care, patient outcomes and value for money of Cochrane Reviews published by 20 NIHR-funded CRGs during the years 2007-11. DESIGN: We sent questionnaires to CRGs and review authors, undertook interviews with guideline developers (GDs) and used bibliometrics and documentary review to get an overview of CRG impact and to evaluate the impact of a sample of 60 Cochrane Reviews. The evaluation was guided by a framework with four categories (knowledge production, research targeting, informing policy development and impact on practice/services). RESULTS: A total of 3187 new and updated reviews were published on the Cochrane Database of Systematic Reviews between 2007 and 2011, 1502 (47%) of which were produced by the 20 CRGs funded by the NIHR. We found 40 examples where reviews appeared to have influenced primary research and reviews had contributed to the creation of new knowledge and stimulated debate. Twenty-seven of the 60 reviews had 100 or more citations in Google Scholar™ (Google, CA, USA). Overall, 483 systematic reviews had been cited in 247 sets of guidance. This included 62 sets of international guidance, 175 sets of national guidance (87 from the UK) and 10 examples of local guidance. Evidence from the interviews suggested that Cochrane Reviews often play an instrumental role in informing guidance, although reviews being a poor fit with guideline scope or methods, reviews being out of date and a lack of communication between CRGs and GDs were barriers to their use. Cochrane Reviews appeared to have led to a number of benefits to the health service including safer or more appropriate use of medication or other health technologies or the identification of new effective drugs or treatments. However, whether or not these changes were directly as a result of the Cochrane Review and not the result of subsequent clinical guidance was difficult to judge. Potential benefits of Cochrane Reviews included economic benefits through budget savings or the release of funds, improvements in clinical quality, the reduction in the use of unproven or unnecessary procedures and improvements in patient and carer experiences. CONCLUSIONS: This study identified a number of impacts and likely impacts of Cochrane Reviews. The clearest impacts of Cochrane Reviews are on research targeting and health-care policy, with less evidence of a direct impact on clinical practice and the organisation and delivery of NHS services. Although it is important for researchers to consider how they might increase the influence of their work, such impacts are difficult to measure. More work is required to develop suitable methods for defining and quantifying the impact of research. FUNDING: The NIHR Health Technology Assessment programme.

Warming of intravenous and irrigation fluids for preventing inadvertent perioperative hypothermia.

BACKGROUND: Inadvertent perioperative hypothermia (a drop in core temperature to below 36°C) occurs because of interference with normal temperature regulation by anaesthetic drugs, exposure of skin for prolonged periods and receipt of large volumes of intravenous and irrigation fluids. If the temperature of these fluids is below core body temperature, they can cause significant heat loss. Warming intravenous and irrigation fluids to core body temperature or above might prevent some of this heat loss and subsequent hypothermia. OBJECTIVES: To estimate the effectiveness of preoperative or intraoperative warming, or both, of intravenous and irrigation fluids in preventing perioperative hypothermia and its complications during surgery in adults. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2014, Issue 2), MEDLINE Ovid SP (1956 to 4 February 2014), EMBASE Ovid SP (1982 to 4 February 2014), the Institute for Scientific Information (ISI) Web of Science (1950 to 4 February 2014), Cumulative Index to Nursing and Allied Health Literature (CINAHL) EBSCOhost (1980 to 4 February 2014) and reference lists of identified articles. We also searched the Current Controlled Trials website and ClinicalTrials.gov. SELECTION CRITERIA: We included randomized controlled trials or quasi-randomized controlled trials comparing fluid warming methods versus standard care or versus other warming methods used to maintain normothermia. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data from eligible trials and settled disputes with a third review author. We contacted study authors to ask for additional details when needed. We collected data on adverse events only if they were reported in the trials. MAIN RESULTS: We included in this review 24 studies with a total of 1250 participants. The trials included various numbers and types of participants. Investigators used a range of methods to warm fluids to temperatures between 37°C and 41°C. We found that evidence was of moderate quality because descriptions of trial design were often unclear, resulting in high or unclear risk of bias due to inappropriate or unclear randomization and blinding procedures. These factors may have influenced results in some way. Our protocol specified the risk of hypothermia as the primary outcome; as no trials reported this, we decided to include data related to mean core temperature. The only secondary outcome reported in the trials that provided useable data was shivering. Evidence was unclear regarding the effects of fluid warming on bleeding. No data were reported on our other specified outcomes of cardiovascular complications, infection, pressure ulcers, bleeding, mortality, length of stay, unplanned intensive care admission and adverse events.Researchers found that warmed intravenous fluids kept the core temperature of study participants about half a degree warmer than that of participants given room temperature intravenous fluids at 30, 60, 90 and 120 minutes, and at the end of surgery. Warmed intravenous fluids also further reduced the risk of shivering compared with room temperature intravenous fluidsInvestigators reported no statistically significant differences in core body temperature or shivering between individuals given warmed and room temperature irrigation fluids. AUTHORS' CONCLUSIONS: Warm intravenous fluids appear to keep patients warmer during surgery than room temperature fluids. It is unclear whether the actual differences in temperature are clinically meaningful, or if other benefits or harms are associated with the use of warmed fluids. It is also unclear if using fluid warming in addition to other warming methods confers any benefit, as a ceiling effect is likely when multiple methods of warming are used.

Managing conflicts of interest in the UK National Institute for Health and Care Excellence (NICE) clinical guidelines programme: qualitative study.

BACKGROUND: There is international concern that conflicts of interest (COI) may bias clinical guideline development and render it untrustworthy. Guideline COI policies exist with the aim of reducing this bias but it is not known how such policies are interpreted and used by guideline producing organisations. This study sought to determine how conflicts of interest (COIs) are disclosed and managed by a national clinical guideline developer (NICE: the UK National Institute for Health and Care Excellence). METHODS: Qualitative study using semi-structured telephone interviews with 14 key informants: 8 senior staff of NICE's guideline development centres and 6 chairs of guideline development groups (GDGs). We conducted a thematic analysis. RESULTS: Participants regard the NICE COI policy as comprehensive leading to transparent and independent guidance. The application of the NICE COI policy is, however, not straightforward and clarity could be improved. Disclosure of COI relies on self reporting and guideline developers have to take "on trust" the information they receive, certain types of COI (non-financial) are difficult to categorise and manage and disclosed COI can impact on the ability to recruit clinical experts to GDGs. Participants considered it both disruptive and stressful to exclude members from GDG meetings when required by the COI policy. Nonetheless the impact of this disruption can be minimised with good group chairing skills. CONCLUSIONS: We consider that the successful implementation of a COI policy in clinical guideline development requires clear policies and procedures, appropriate training of GDG chairs and an evaluation of how the policy is used in practice.

Anaesthetic and sedative agents used for electrical cardioversion.

BACKGROUND: Electrical cardioversion is an effective procedure for restoring normal sinus rhythm in the hearts of patients with irregular heart rhythms. It is important that the patient is not fully conscious during the procedure, as it can be painful and distressing. The drug used to make patients unaware of the procedure should rapidly achieve the desired level of sedation, should wear off quickly and should not cause cardiovascular or respiratory side effects. OBJECTIVES: We aimed to compare the safety, effectiveness and adverse events associated with various anaesthetic or sedative agents used in direct current cardioversion for cardiac arrhythmia in both elective and emergency settings.We sought answers to the following specific questions.• Which drugs deliver the best outcomes for patients undergoing electrical cardioversion?• Does using a particular agent confer advantages or disadvantages?• Is additional analgesic necessary to prevent pain? SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) on 27 March 2014. Our search terms were relevant to the review question and were not limited by outcomes. We also carried out searches of clinical trials registers and forward and backward citation tracking. SELECTION CRITERIA: We considered all randomized controlled trials and quasi-randomized and cluster-randomized studies with adult participants undergoing electrical cardioversion procedures in the elective or emergency setting. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trial quality and extracted data, consulting with a third review author for disagreements. We used standard Cochrane methodological procedures, including assessment of risk of bias for all studies. MAIN RESULTS: We included 23 studies with 1250 participants that compared one drug with one or more other drugs. Of these comparisons, 19 studies compared propofol with another drug. Seven of these compared propofol with etomidate (four of which combined the drugs with remifentanil or fentanyl), five midazolam, six thiopentone and two sevoflurane. Three studies compared etomidate with thiopentone, and three etomidate with midazolam. Two studies compared thiopentone with midazolam, one thiopentone with diazepam and one midazolam with diazepam. Drug doses and the time over which the drugs were given varied between studies. Although all studies were described as randomized, limited information was provided about the methods used for selection and group allocation. A high level of performance bias was observed across studies, as study authors had not attempted to blind the anaesthetist to group allocation. Similarly, study authors had rarely provided sufficient information on whether outcome assessors had been blinded.Included studies presented outcome data for hypotension, apnoea, participant recall, success of cardioversion, minor adverse events of nausea and vomiting, pain at injection site and myoclonus, additional analgesia and participant satisfaction. We did not pool the data from different studies in view of the multiple drug comparisons, differences in definitions and reporting of outcomes, variability of endpoints and high or unclear risk of bias across studies. AUTHORS' CONCLUSIONS: Few studies reported statistically significant results for our relevant outcomes, and most study authors concluded that both, or all, agents compared in individual studies were adequate for cardioversion procedures. It is our opinion that at present, there is no evidence to suggest that current anaesthetic practice for cardioversion should change.

Drug-disease and drug-drug interactions: systematic examination of recommendations in 12 UK national clinical guidelines.

OBJECTIVE: To identify the number of drug-disease and drug-drug interactions for exemplar index conditions within National Institute of Health and Care Excellence (NICE) clinical guidelines. DESIGN: Systematic identification, quantification, and classification of potentially serious drug-disease and drug-drug interactions for drugs recommended by NICE clinical guidelines for type 2 diabetes, heart failure, and depression in relation to 11 other common conditions and drugs recommended by NICE guidelines for those conditions. SETTING: NICE clinical guidelines for type 2 diabetes, heart failure, and depression MAIN OUTCOME MEASURES: Potentially serious drug-disease and drug-drug interactions. RESULTS: Following recommendations for prescription in 12 national clinical guidelines would result in several potentially serious drug interactions. There were 32 potentially serious drug-disease interactions between drugs recommended in the guideline for type 2 diabetes and the 11 other conditions compared with six for drugs recommended in the guideline for depression and 10 for drugs recommended in the guideline for heart failure. Of these drug-disease interactions, 27 (84%) in the type 2 diabetes guideline and all of those in the two other guidelines were between the recommended drug and chronic kidney disease. More potentially serious drug-drug interactions were identified between drugs recommended by guidelines for each of the three index conditions and drugs recommended by the guidelines for the 11 other conditions: 133 drug-drug interactions for drugs recommended in the type 2 diabetes guideline, 89 for depression, and 111 for heart failure. Few of these drug-disease or drug-drug interactions were highlighted in the guidelines for the three index conditions. CONCLUSIONS: Drug-disease interactions were relatively uncommon with the exception of interactions when a patient also has chronic kidney disease. Guideline developers could consider a more systematic approach regarding the potential for drug-disease interactions, based on epidemiological knowledge of the comorbidities of people with the disease the guideline is focused on, and should particularly consider whether chronic kidney disease is common in the target population. In contrast, potentially serious drug-drug interactions between recommended drugs for different conditions were common. The extensive number of potentially serious interactions requires innovative interactive approaches to the production and dissemination of guidelines to allow clinicians and patients with multimorbidity to make informed decisions about drug selection.

Interventions for treating inadvertent postoperative hypothermia.

BACKGROUND: Inadvertent postoperative hypothermia (a drop in core body temperature to below 36°C) occurs as an effect of surgery when anaesthetic drugs and exposure of the skin for long periods of time during surgery result in interference with normal temperature regulation. Once hypothermia has occurred, it is important that patients are rewarmed promptly to minimise potential complications. Several different interventions are available for rewarming patients. OBJECTIVES: To estimate the effectiveness of treating inadvertent perioperative hypothermia through postoperative interventions to decrease heat loss and apply passive and active warming systems in adult patients who have undergone surgery. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2014, Issue 2), MEDLINE (Ovid SP) (1956 to 21 February 2014), EMBASE (Ovid SP) (1982 to 21 February 2014), the Institute for Scientific Information (ISI) Web of Science (1950 to 21 February 2014) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL), EBSCO host (1980 to 21 February 2014), as well as reference lists of articles. We also searched www.controlled-trials.com and www.clincialtrials.gov. SELECTION CRITERIA: Randomized controlled trials of postoperative warming interventions aiming to reverse hypothermia compared with control or with each other. DATA COLLECTION AND ANALYSIS: Three review authors identified studies for inclusion in this review. One review author extracted data and completed risk of bias assessments; two review authors checked the details. Meta-analysis was conducted when appropriate by using standard methodological procedures as expected by The Cochrane Collaboration. MAIN RESULTS: We included 11 trials with 699 participants. Ten trials provided data for analysis. Trials varied in the numbers and types of participants included and in the types of surgery performed. Most trials were at high or unclear risk of bias because of inappropriate or unclear randomization procedures, and because blinding of assessors and participants generally was not possible. This may have influenced results, but it is unclear how the results may have been influenced. Active warming was found to reduce the mean time taken to achieve normothermia by about 30 minutes in comparison with use of warmed cotton blankets (mean difference (MD) -32.13 minutes, 95% confidence interval (CI) -42.55 to -21.71; moderate-quality evidence), but no significant difference in shivering was noted. Active warming was found to reduce mean time taken to achieve normothermia by almost an hour and a half in comparison with use of unwarmed cotton blankets (MD -88.86 minutes, 95% CI -123.49 to -54.23; moderate-quality evidence), and people in the active warming group were less likely to shiver than those in the unwarmed cotton blanket group (Relative Risk=0.61 95% CI= 0.42 to 0.86; low quality evidence). There was no effect on mean temperature difference in degrees celsius at 60 minutes (MD=0.18°C, 95% CI=-0.10 to 0.46; moderate quality evidence), and no data were available in relation to major cardiovascular complications. Forced air warming was found to reduce time taken to achieve normothermia by about one hour in comparison to circulating hot water devices (MD=-54.21 minutes 95% CI= -94.95, -13.47). There was no statistically significant difference between thermal insulation and cotton blankets on mean time to achieve normothermia (MD =-0.29 minutes, 95% CI=-25.47 to 24.89; moderate quality evidence) or shivering (Relative Risk=1.36 95% CI= 0.69 to 2.67; moderate quality evidence), and no data were available for mean temperature difference or major cardiovascular complications. Insufficient evidence was available about other comparisons, adverse effects or any other secondary outcomes. AUTHORS' CONCLUSIONS: Active warming, particularly forced air warming, appears to offer a clinically important reduction in mean time taken to achieve normothermia (normal body temperature between 36°C and 37.5°C) in patients with postoperative hypothermia. However, high-quality evidence on other important clinical outcomes is lacking; therefore it is unclear whether active warming offers other benefits and harms. High-quality evidence on other warming methods is also lacking; therefore it is unclear whether other rewarming methods are effective in reversing postoperative hypothermia.

The impact of Cochrane Systematic Reviews: a mixed method evaluation of outputs from Cochrane Review Groups supported by the UK National Institute for Health Research.

BACKGROUND: There has been a growing emphasis on evidence-informed decision-making in health care. Systematic reviews, such as those produced by the Cochrane Collaboration, have been a key component of this movement. The UK National Institute for Health Research (NIHR) Systematic Review Programme currently supports 20 Cochrane Review Groups (CRGs). The aim of this study was to identify the impacts of Cochrane reviews published by NIHR-funded CRGs during the years 2007-2011. METHODS: We sent questionnaires to CRGs and review authors, interviewed guideline developers and used bibliometrics and documentary review to get an overview of CRG impact and to evaluate the impact of a sample of 60 Cochrane reviews. We used a framework with four categories (knowledge production, research targeting, informing policy development and impact on practice/services). RESULTS: A total of 1,502 new and updated reviews were produced by the 20 NIHR-funded CRGs between 2007 and 2011. The clearest impacts were on policy with a total of 483 systematic reviews cited in 247 sets of guidance: 62 were international, 175 national (87 from the UK) and 10 local. Review authors and CRGs provided some examples of impact on practice or services, for example, safer use of medication, the identification of new effective drugs or treatments and potential economic benefits through the reduction in the use of unproven or unnecessary procedures. However, such impacts are difficult to objectively document, and the majority of reviewers were unsure if their review had produced specific impacts. Qualitative data suggested that Cochrane reviews often play an instrumental role in informing guidance, although a poor fit with guideline scope or methods, reviews being out of date and a lack of communication between CRGs and guideline developers were barriers to their use. CONCLUSIONS: Health and economic impacts of research are generally difficult to measure. We found that to be the case with this evaluation. Impacts on knowledge production and clinical guidance were easier to identify and substantiate than those on clinical practice. Questions remain about how we define and measure impact, and more work is needed to develop suitable methods for impact analysis.

Physician anaesthetists versus non-physician providers of anaesthesia for surgical patients.

BACKGROUND: With increasing demand for surgery, pressure on healthcare providers to reduce costs, and a predicted shortfall in the number of medically qualified anaesthetists it is important to consider whether non-physician anaesthetists (NPAs), who do not have a medical qualification, are able to provide equivalent anaesthetic services to medically qualified anaesthesia providers. OBJECTIVES: To assess the safety and effectiveness of different anaesthetic providers for patients undergoing surgical procedures under general, regional or epidural anaesthesia. We planned to consider results from studies across countries worldwide (including developed and developing countries). SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and CINAHL on 13 February 2014. Our search terms were relevant to the review question and not limited by study design or outcomes. We also carried out searches of clinical trials registers, forward and backward citation tracking and grey literature searching. SELECTION CRITERIA: We considered all randomized controlled trials (RCTs), non-randomized studies (NRS), non-randomized cluster trials and observational study designs which had a comparison group. We included studies which compared an anaesthetic administered by a NPA working independently with an anaesthetic administered by either a physician anaesthetist working independently or by a NPA working in a team supervised or directed by a physician anaesthetist. DATA COLLECTION AND ANALYSIS: Three review authors independently assessed trial quality and extracted data, contacting study authors for additional information where required. In addition to the standard methodological procedures, we based our risk of bias assessment for NRS on the specific NRS risk of bias tool presented at the UK Cochrane Contributors' Meeting in March 2012. We considered case-mix and type of surgical procedure, patient co-morbidity, type of anaesthetic given, and hospital characteristics as possible confounders in the studies, and judged how well the authors had adjusted for these confounders. MAIN RESULTS: We included six NRS with 1,563,820 participants. Five were large retrospective cohort studies using routinely collected hospital or administrative data from the United States (US). The sixth was a smaller cohort study based on emergency medical care in Haiti. Two were restricted to obstetric patients whilst the others included a range of surgical procedures. It was not possible to combine data as there was a degree of heterogeneity between the included studies.Two studies failed to find a difference in the risk of death in women undergoing caesarean section when given anaesthesia by NPAs compared with physician anaesthetists, both working independently. One study reported there was no difference in mortality between independently working provider groups. One compared mortality risks between US states that had, or had not, 'opted-out' of federal insurance requirements for physician anaesthetists to supervise or direct NPAs. This study reported a lower mortality risk for NPAs working independently compared with physician anaesthetists working independently in both 'opt-out' and 'non-opt out' states.One study reported a lower mortality risk for NPAs working independently compared with supervised or directed NPAs. One reported a higher mortality risk for NPAs working independently than in a supervised or directed NPA group but no statistical testing was presented. One reported a lower mortality risk in the NPA group working independently compared with the supervised or directed NPA group in both 'opt-out' and 'non-opt out' states before the 'opt-out' rule was introduced, but a higher mortality risk in 'opt-out' states after the 'opt-out' rule was introduced. One reported only one death and was unable to detect a risk in mortality. One reported that the risk of mortality and failure to rescue was higher for NPAs who were categorized as undirected than for directed NPAs.Three studies reported the risk of anaesthesia-related complications for NPAs working independently compared to physician anaesthetists working independently. Two failed to find a difference in the risk of complications in women undergoing caesarean section. One failed to find a difference in risk of complications between groups in 'non-opt out' states. This study reported a lower risk of complications for NPAs working independently than for physician anaesthetists working independently in 'opt-out' states before the 'opt-out' rule was introduced, but a higher risk after, although these differences were not tested statistically.Two studies reported that the risk of complications was generally lower for NPAs working independently than in the NPA supervised or team group but no statistical testing was reported. One reported no evidence of increased risk of postoperative complications in an undirected NPA group versus a directed NPA group.The risk of bias and assessment of confounders was particularly important for this review. We were concerned about the use of routine data for research and the likely accuracy of such databases to determine the intervention and control groups, thus judging four studies at medium risk of inaccuracy, one at low and one, for which there was insufficient detail, at an unclear risk. Whilst we expected that mortality would have been accurately reported in record systems, we thought reporting may not be as accurate for complications, which relied on the use of codes. Studies were therefore judged as at high risk or an unclear risk of bias for the reporting of complications data. Four of the six studies received funding, which could have influenced the reporting and interpretation of study results. Studies considered confounders of case-mix, co-morbidity and hospital characteristics with varying degrees of detail and again we were concerned about the accuracy of the coding of data in records and the variables considered during assessment. Five of the studies used multivariate logistic regression models to account for these confounders. We judged three as being at low risk, one at medium risk and one at high risk of incomplete adjustment in analysis. AUTHORS' CONCLUSIONS: No definitive statement can be made about the possible superiority of one type of anaesthesia care over another. The complexity of perioperative care, the low intrinsic rate of complications relating directly to anaesthesia, and the potential confounding effects within the studies reviewed, all of which were non-randomized, make it impossible to provide a definitive answer to the review question.