Anaesthesia and COVID-19: infection control.

The world is currently facing an unprecedented healthcare crisis caused by a pandemic novel beta coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The pathogen is spread by human-to-human transmission via droplets exposure and contact transfer, causing mild symptoms in the majority of cases, but critical illness, bilateral viral pneumonia, and acute respiratory distress syndrome (ARDS) in a minority. Currently, controlling infection to prevent the spread of SARS-CoV-2 is the primary public healthcare intervention used. The pace of transmission and global scale of SARS-CoV-2 infections has implications for strategic oversight, resource management, and responsiveness in infection control. This article presents a summary of learning points in epidemiological infection control from the SARS epidemic, alongside a review of evidence connecting current understanding of the virologic and environmental contamination properties of SARS-CoV-2. We present suggestions for how personal protective equipment policies relate to the viral pandemic context and how the risk of transmission by and to anaesthetists, intensivists, and other healthcare workers can be minimised.

Oral vs intravenous iron therapy for postpartum anemia: a systematic review and meta-analysis.

OBJECTIVE: To perform a systematic review of randomized trials comparing oral vs intravenous (IV) iron therapy to treat postpartum anemia. DATA SOURCES: Data sources were as follows: PubMed (1972-2017); Cochrane Central Register of Controlled Trials, CENTRAL (1972-2017); CINAHL (1972-2017); Web of Science; Excerpta Medica Database, and EMBASE (1972-2017). STUDY ELIGIBILITY CRITERIA: We included randomized trials comparing oral vs IV iron monotherapy to treat postpartum anemia (classified as a hemoglobin <12 g/dL). STUDY APPRAISAL AND SYNTHESIS METHODS: Study quality was assessed with the Cochrane risk of bias assessment tool. The primary outcome was hemoglobin concentration at 6 weeks postpartum. Secondary outcomes included hemoglobin concentration at 1-5 weeks postpartum, ferritin concentration at 1-6 weeks postpartum, and maternal adverse outcomes. For meta-analysis, mean differences and odds ratios using a random effects model were calculated. Risk of heterogeneity was reported as I2. RESULTS: A total of 15 randomized trials met our inclusion criteria (n = 1001 and 1 181 women receiving oral iron and IV iron, respectively); 4 studies reported data for our primary outcome. We observed higher postpartum week 6 hemoglobin concentrations in the IV iron group compared to the oral iron group (mean difference, 0.9 g/dL; 95% confidence interval (CI), 0.4-1.3; P = .0003). Compared to oral iron, women receiving IV iron had higher hemoglobin concentrations at postpartum weeks 1, 2, and 3; higher ferritin concentrations at postpartum weeks 1, 2, 4, and 6; an increased likelihood of skin flushing (odds ratio [OR], 6.95; 95% CI, 1.56-31.03; P = .01; I2 = 0%); and a decreased likelihood of constipation (OR, 0.08; 95% CI, 0.03-0.21; P < .00001, I2 = 27%) and dyspepsia (OR, 0.07; 95% confidence interval, 0.01-0.42; P = .004; I2 = 0%). The reported event rate for anaphylaxis among women receiving IV iron was 0.6%. CONCLUSION: In this systematic review, among women with postpartum anemia, hemoglobin concentrations at 6 weeks postpartum were almost 1 g/dL higher in women who received IV iron compared to oral iron. The safety profile of IV iron was also reassuring. Given the weaker hemoglobin response and higher risk of gastrointestinal side effects with oral iron use, our findings suggest that IV iron be considered as a viable treatment option for postpartum iron deficiency anemia.

Systematic review and consensus definitions for the Standardised Endpoints in Perioperative Medicine initiative: clinical indicators.

BACKGROUND: Clinical indicators are powerful tools to quantify the safety and quality of patient care. Their validity is often unclear and definitions extremely heterogeneous. As part of the International Standardised Endpoints in Perioperative Medicine (StEP) initiative, this study aimed to derive a set of standardised and valid clinical outcome indicators for use in perioperative clinical trials. METHODS: We identified clinical indicators via a systematic review of the anaesthesia and perioperative medicine literature (PubMed/OVID, EMBASE, and Cochrane Library). We performed a three-stage Delphi consensus-gaining process that involved 54 clinician-researchers worldwide. Indicators were first shortlisted and the most suitable definitions for evaluation of quality and safety interventions determined. Indicators were then assessed for validity, reliability, feasibility, and clarity. RESULTS: We identified 167 clinical outcome indicators. Participation in the three Delphi rounds was 100% (n=13), 68% (n=54), and 85% (n= 6), respectively. A final list of eight outcome indicators was generated: surgical site infection at 30 days, stroke within 30 days of surgery, death within 30 days of coronary artery bypass grafting, death within 30 days of surgery, admission to the intensive care unit within 14 days of surgery, readmission to hospital within 30 days of surgery, and length of hospital stay (with or without in-hospital mortality). They were rated by the majority of experts as valid, reliable, easy to use, and clearly defined. CONCLUSIONS: These clinical indicators can be confidently used as endpoints in clinical trials measuring quality, safety, and improvement in perioperative care. REGISTRATION: PROSPERO 2016 CRD42016042102 (http://www.crd.york.ac.uk/PROSPERO/display_record.php? ID=CRD42016042102).

Systematic review of enhanced recovery protocols for elective caesarean section versus conventional care.

BACKGROUND: Enhanced recovery protocols for caesarean section have been introduced in many maternity units with the aim of improving clinical outcomes and improving service efficiency. AIM: Our aim was to assess the available evidence for the efficacy of enhanced recovery protocols for elective caesarean section compared to conventional care. MATERIALS AND METHODS: A systematic review was performed through a search of MEDLINE, EMBASE, The Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Trials Database. RESULTS: After screening 118 records and reviewing 38 articles, no studies met the inclusion criteria for this systematic review. However, from ten articles we were able to describe 29 individual interventions that are included in the enhanced recovery pathways of care for elective caesarean sections. Early reintroduction of fluids and food was the only intervention that was common to all pathways. CONCLUSION: This review reveals that while the adoption of enhanced recovery pathways for caesarean sections is increasing, there remains a paucity of evidence in the published literature on outcomes. This is reflected in the significant heterogeneity of the individual components included in various pathways currently in practice. Furthermore, development of standardised outcome metrics is required to facilitate meaningful comparison of multiple interventions. Further well-designed research is needed to properly assess the potential benefits of these interventions to improve maternal outcomes after obstetric surgery.

Perioperative administration of buffered versus non-buffered crystalloid intravenous fluid to improve outcomes following adult surgical procedures.

BACKGROUND: Perioperative fluid strategies influence clinical outcomes following major surgery. Many intravenous fluid preparations are based on simple solutions, such as normal saline, that feature an electrolyte composition that differs from that of physiological plasma. Buffered fluids have a theoretical advantage of containing a substrate that acts to maintain the body's acid-base status - typically a bicarbonate or a bicarbonate precursor such as maleate, gluconate, lactate, or acetate. Buffered fluids also provide additional electrolytes, including potassium, magnesium, and calcium, more closely matching the electrolyte balance of plasma. The putative benefits of buffered fluids have been compared with those of non-buffered fluids in the context of clinical studies conducted during the perioperative period. This review was published in 2012, and was updated in 2017. OBJECTIVES: To review effects of perioperative intravenous administration of buffered versus non-buffered fluids for plasma volume expansion or maintenance, or both, on clinical outcomes in adults undergoing all types of surgery. SEARCH METHODS: We electronically searched the Clinicaltrials.gov major trials registry, the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 6) in the Cochrane Library, MEDLINE (1966 to June 2016), Embase (1980 to June 2016), and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to June 2016). We handsearched conference abstracts and, when possible, contacted leaders in the field. We reran the search in May 2017. We added one potential new study of interest to the list of 'Studies awaiting classification' and will incorporate this trial into formal review findings when we prepare the review update. SELECTION CRITERIA: Only randomized controlled trials that compared buffered versus non-buffered intravenous fluids for surgical patients were eligible for inclusion. We excluded other forms of comparison such as crystalloids versus colloids and colloids versus different colloids. DATA COLLECTION AND ANALYSIS: Two review authors screened references for eligibility, extracted data, and assessed risks of bias. We resolved disagreements by discussion and consensus, in collaboration with a third review author. We contacted trial authors to request additional information when appropriate. We presented pooled estimates for dichotomous outcomes as odds ratios (ORs) and for continuous outcomes as mean differences (MDs), with 95% confidence intervals (CIs). We analysed data via Review Manager 5.3 using fixed-effect models, and when heterogeneity was high (I² > 40%), we used random-effects models. MAIN RESULTS: This review includes, in total, 19 publications of 18 randomized controlled trials with a total of 1096 participants. We incorporated five of those 19 studies (330 participants) after the June 2016 update. Outcome measures in the included studies were thematically similar, covering perioperative electrolyte status, renal function, and acid-base status; however, we found significant clinical and statistical heterogeneity among the included studies. We identified variable protocols for fluid administration and total volumes of fluid administered to patients intraoperatively. Trial authors variably reported outcome data at disparate time points and with heterogeneous patient groups. Consequently, many outcome measures are reported in small group sizes, reducing overall confidence in effect size, despite relatively low inherent bias in the included studies. Several studies reported orphan outcome measures. We did not include in the results of this review one large, ongoing study of saline versus Ringer's solution.We found insufficient evidence on effects of fluid therapies on mortality and postoperative organ dysfunction (defined as renal insufficiency leading to renal replacement therapy); confidence intervals were wide and included both clinically relevant benefit and harm: mortality (Peto OR 1.85, 95% CI 0.37 to 9.33; I² = 0%; 3 trials, 6 deaths, 276 participants; low-quality evidence); renal insufficiency (OR 0.82, 95% CI 0.34 to 1.98; I² = 0%; 4 trials, 22 events, 276 participants; low-quality evidence).We noted several metabolic differences, including a difference in postoperative pH measured at end of surgery of 0.05 units - lower in the non-buffered fluid group (12 studies with a total of 720 participants; 95% CI 0.04 to 0.07; I² = 61%). However, this difference was not maintained on postoperative day one. We rated the quality of evidence for this outcome as moderate. We observed a higher postoperative serum chloride level immediately after operation, with use of non-buffered fluids reported in 10 studies with a total of 530 participants (MD 6.77 mmol/L, 95% CI 3.38 to 10.17), and this difference persisted until day one postoperatively (five studies with a total of 258 participants; MD 8.48 mmol/L, 95% CI 1.08 to 15.88). We rated the quality of evidence for this outcome as moderate. AUTHORS' CONCLUSIONS: Current evidence is insufficient to show effects of perioperative administration of buffered versus non-buffered crystalloid fluids on mortality and organ system function in adult patients following surgery. Benefits of buffered fluid were measurable in biochemical terms, particularly a significant reduction in postoperative hyperchloraemia and metabolic acidosis. Small effect sizes for biochemical outcomes and lack of correlated clinical follow-up data mean that robust conclusions on major morbidity and mortality associated with buffered versus non-buffered perioperative fluid choices are still lacking. Larger studies are needed to assess these relevant clinical outcomes.

Development, implementation and evaluation of high-quality virtual preoperative anaesthetic assessment during COVID-19 and beyond: a quality improvement report.

BACKGROUND: Preoperative risk factor identification and optimisation are widely accepted as the gold standard of care for elective surgery and are essential for reducing morbidity and mortality. COVID-19 public health restrictions required a careful balance between ensuring best medical practices and maintaining safety by minimising patient face-to-face attendance in the hospital. Based on the successful implementation of telemedicine (TM) in other medical specialties and its feasibility in the preoperative context, this study aimed to develop, implement and evaluate a high-quality virtual preoperative anaesthetic assessment process. METHODS: The three-step model for improvement was used. The specific, measurable, actionable, relevant, time aim (step 1) and measures for improvement (step 2) were defined at the onset of the project. The plan-do-study-act tool was used for the structured implementation of improvement interventions (step 3) in three phases. Data relating to virtual and in-person referrals, assessments, did-not-attend (DNA) rate, consultation time, day of surgery delays and cancellations, and service-user and provider experience surveys were recorded prospectively. RESULTS: A total of 2805 patients were assessed in the preoperative anaesthetic assessment clinic between July 2020 and March 2021. The mean rate of virtual preoperative assessments was 50% (SD ±10) (1390/2805). 0.1% (30/2805) were inappropriately referred on the alternative pathway. The DNA rate was 0.4% (8/1398) and 3% (43/1458) for virtual and in-person pathways, respectively. The mean consultation times for virtual and in-person attendance were 19 (SD ±7) and 31 (SD ±13) min, respectively. There were five same-day surgery cancellations and one delay due to medical reasons. When asked about their experience with the virtual assessment, both service users and providers reported high satisfaction, minimal technical difficulties and shared concerns about limited opportunities for physical examination. CONCLUSION: This is one of the first implementational studies to comprehensively outline the feasibility of TM in preoperative anaesthetic assessment during COVID-19.

Managing anticoagulation in pregnancy for the anaesthetist on the labour ward.

Pregnancy is a hypercoaguable state. As part of the multidisciplinary team on labour ward, the anaesthetist plays a role particularly in advising the women and the obstetric team regarding the timing and even choice of regional analgesia given the potential risk of complications, as this may be affected by the anticoagulation treatment pregnant women may be on. It is important to understand the type of anticoagulation regimens parturients might be on and what sort of risk assessment they must undergo, as this has obstetric and anaesthetic implications. Although a rare presentation, management of women with mechanical prosthetic heart valves who are pregnant requires detailed and highly specialised care in tertiary care centres with a well-developed multidisciplinary team and pathway. Despite their rare presentation, it is important to understand the intricate and complex management that these women require as they have a high morbidity and mortality rate.

The risk of postoperative deterioration of non-cardiac surgery patients with ICU referral status who are admitted to the regular ward: a retrospective observational cohort study.

BACKGROUND: Higher-risk surgical patients may not be admitted to the intensive care unit due to stable immediate post-operative status on review. The outcomes of this cohort are not well described. Our aim was to examine the subsequent inpatient course of intensive care unit -referred but not admitted surgical patients. METHODS: All patients aged ≥18 years who were referred but not admitted for post-operative management in a tertiary metropolitan intensive care unit following non-cardiac surgery between 1/7/2017 and 30/6/2018 were eligible for inclusion in this retrospective observational cohort study. Primary outcome was Medical Emergency Team activation. Secondary outcomes included unplanned intensive care unit admission; length of stay; and 30-day mortality. Risk of serious complications and predicted length of stay were calculated using the National Surgical Quality Improvement Program scoring tool. RESULTS: Fifteen of 60 patients (25%) had a MET-call following surgery, eight (13%) patients required unplanned intensive care unit admission, with median (IQR) time to Medical Emergency Team call 9 (6-13) hours. No patients died within 30-days. There was no significant difference between mean National Surgical Quality Improvement Program predicted and actual length of stay; after adjustment, National Surgical Quality Improvement Program predicted risk of serious complications was associated with unplanned intensive care unit admission (OR [95% CI] = 1.08 [1.00-1.16], p = 0.04), although not Medical Emergency Team calls. CONCLUSIONS: Post-operative deterioration occurs frequently, and early, in a cohort of high-risk surgical patients initially assessed as being safe for ward care. Changes to current triage models for post-operative intensive care unit admission may reduce the impact of complications in this high-risk group.

Perioperative interventions for prevention of postoperative pulmonary complications: systematic review and meta-analysis.

OBJECTIVE: To identify, appraise, and synthesise the best available evidence on the efficacy of perioperative interventions to reduce postoperative pulmonary complications (PPCs) in adult patients undergoing non-cardiac surgery. DESIGN: Systematic review and meta-analysis of randomised controlled trials. DATA SOURCES: Medline, Embase, CINHAL, and CENTRAL from January 1990 to December 2017. ELIGIBILITY CRITERIA: Randomised controlled trials investigating short term, protocolised medical interventions conducted before, during, or after non-cardiac surgery were included. Trials with clinical diagnostic criteria for PPC outcomes were included. Studies of surgical technique or physiological or biochemical outcomes were excluded. DATA EXTRACTION AND SYNTHESIS: Reviewers independently identified studies, extracted data, and assessed the quality of evidence. Meta-analyses were conducted to calculate risk ratios with 95% confidence intervals. Quality of evidence was summarised in accordance with GRADE methods. The primary outcome was the incidence of PPCs. Secondary outcomes were respiratory infection, atelectasis, length of hospital stay, and mortality. Trial sequential analysis was used to investigate the reliability and conclusiveness of available evidence. Adverse effects of interventions were not measured or compared. RESULTS: 117 trials enrolled 21 940 participants, investigating 11 categories of intervention. 95 randomised controlled trials enrolling 18 062 participants were included in meta-analysis; 22 trials were excluded from meta-analysis because the interventions were not sufficiently similar to be pooled. No high quality evidence was found for interventions to reduce the primary outcome (incidence of PPCs). Seven interventions had low or moderate quality evidence with confidence intervals indicating a probable reduction in PPCs: enhanced recovery pathways (risk ratio 0.35, 95% confidence interval 0.21 to 0.58), prophylactic mucolytics (0.40, 0.23 to 0.67), postoperative continuous positive airway pressure ventilation (0.49, 0.24 to 0.99), lung protective intraoperative ventilation (0.52, 0.30 to 0.88), prophylactic respiratory physiotherapy (0.55, 0.32 to 0.93), epidural analgesia (0.77, 0.65 to 0.92), and goal directed haemodynamic therapy (0.87, 0.77 to 0.98). Moderate quality evidence showed no benefit for incentive spirometry in preventing PPCs. Trial sequential analysis adjustment confidently supported a relative risk reduction of 25% in PPCs for prophylactic respiratory physiotherapy, epidural analgesia, enhanced recovery pathways, and goal directed haemodynamic therapies. Insufficient data were available to support or refute equivalent relative risk reductions for other interventions. CONCLUSIONS: Predominantly low quality evidence favours multiple perioperative PPC reduction strategies. Clinicians may choose to reassess their perioperative care pathways, but the results indicate that new trials with a low risk of bias are needed to obtain conclusive evidence of efficacy for many of these interventions. STUDY REGISTRATION: Prospero CRD42016035662.

Clinical Pharmacokinetics and Pharmacodynamics of Levobupivacaine.

Levobupivacaine is a long-acting amide local anaesthetic used in analgesia and anaesthesia. Like other local anaesthetic drugs, levobupivacaine exhibits effects on motor and sensory nerves by inhibiting the opening of voltage-gated sodium channels, and hence propagation of neuronal action potentials. Levobupivacaine is the S(-) stereoisomer of dextrobupivacaine, although both are used commercially in the racemic form bupivacaine. A favourable safety and drug effect profile for levobupivacaine has led to widespread use. Levobupivacaine is generally well tolerated but dose adjustment is important in populations such as paediatrics and the elderly. The pharmacokinetic properties of levobupivacaine are similar to that of bupivacaine; both extensively metabolised in the liver, and excreted in the urine and faeces. In vitro, animal model and human studies confirm a lower risk of cardiac and central nervous system toxicity with levobupivacaine compared with bupivacaine. Clinical trials of relative potency are impaired by the variability in chosen endpoints for sensory and motor function blockade, but clinically significant differences in potency are minor, with most clinical trials showing similar duration and quality of anaesthesia between levo- and racemic bupivacaine. In practice, levobupivacaine is most commonly used in regional anaesthesia, neuraxial anaesthesia and local infiltration analgesia. This review includes an appraisal of evidence from clinical trials of the pharmacokinetic and pharmacodynamic properties of levobupivacaine.

Risk of infection associated with intravenous iron preparations: protocol for updating a systematic review.

INTRODUCTION: The benefits and risk of intravenous iron have been documented in previous systematic reviews and continue to be the subject of randomised controlled trials (RCTs). An ongoing issue that continues to be raised is the relationship between administering iron and developing infection. This is supported by biological plausibility from animal models. We propose an update of a previously published systematic review and meta-analysis with the primary focus being infection. METHODS AND ANALYSIS: We will include RCTs and non-randomised studies (NRS) in this review update. We will search the relevant electronic databases. Two reviewers will independently extract data. Risk of bias for RCTs and NRS will be assessed using the relevant tools recommended by The Cochrane Collaboration. Data extracted from RCTs and NRS will be analysed and reported separately. Pooled data from RCTs will be analysed using a random effects model. We will also conduct subgroup analyses to identify any patient populations that may be at increased risk of developing infection. We will provide a narrative synthesis on the definitions, sources and responsible pathogens for infection in the included studies. Overall quality of evidence on the safety outcomes of mortality and infection will be assessed using the Grading of Recommendations, Assessment, Development and Evaluation approach. ETHICS AND DISSEMINATION: This systematic review will only investigate published studies and therefore ethical approval is not required. The results will be broadly distributed through conference presentations and peer-reviewed publications. TRIAL REGISTRATION NUMBER: PROSPERO (CRD42018096023).

Clinical indicators for reporting the effectiveness of patient quality and safety-related interventions: a protocol of a systematic review and Delphi consensus process as part of the international Standardised Endpoints for Perioperative Medicine initiative (StEP).

INTRODUCTION: Clinical indicators are used to measure and quantify the safety and quality of patient care. They are also often used as endpoints in clinical trials. Definitions of clinical indicators in common use are extremely heterogeneous, limiting their applicability. As part of the international Standardised Endpoints in Perioperative Medicine initiative, this study will identify clinical indicators by systematically reviewing the anaesthesia and perioperative medicine literature, and will provide consensus, clinically useful definitions for those indicators using a Delphi process. METHODS AND ANALYSIS: An electronic database search will be conducted of Medline (PubMed/OVID), EMBASE and the Cochrane Library in order to meet this review's objectives that are: (1) To identify clinical indicators and their definitions used in randomised controlled trials that assess patient-related quality and safety interventions in perioperative medicine; (2) To select a shortlist of recommended indicators and definitions that are the most suitable for evaluation of quality and safety interventions following an expert-based consensus-gaining process (Delphi method) and (3) To provide a classification scale for each indicator related to its clarity of definition, validity (strength), reliability, feasibility (ease of use) and frequency of use. This systematic review protocol is reported in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidance. ETHICS AND DISSEMINATION: Ethical approval is not required for this systematic review and Delphi process. The results of this study will be disseminated to the anaesthesia and perioperative medicine clinical and academic community through national and international presentations and through publication in a peer reviewed journal. PROSPERO REGISTRATION NUMBER: CRD42016042102.

Perioperative administration of buffered versus non-buffered crystalloid intravenous fluid to improve outcomes following adult surgical procedures: a Cochrane systematic review.

BACKGROUND: Buffered intravenous fluid preparations contain substrates to maintain acid-base status. The objective of this systematic review was to compare the effects of buffered and non-buffered fluids administered during the perioperative period on clinical and biochemical outcomes. METHODS: We searched MEDLINE, EMBASE, CINAHL and the Cochrane Library until May 2017 and included all randomised controlled trials that evaluated buffered versus non-buffered fluids, whether crystalloid or colloid, administered to surgical patients. We assessed the selected studies for risk of bias and graded the level of evidence in accordance with Cochrane recommendations. RESULTS: We identified 19 publications of 18 randomised controlled trials, totalling 1096 participants. Mean difference (MD) in postoperative pH was 0.05 units lower immediately following surgery in the non-buffered group (12 studies of 720 participants; 95% confidence interval (CI) 0.04 to 0.07; I 2 = 61%). This difference did not persist on postoperative day 1. Serum chloride concentration was higher in the non-buffered group at the end of surgery (10 trials of 530 participants; MD 6.77 mmol/L, 95% CI 3.38 to 10.17). This effect persisted until postoperative day 1 (5 trials of 258 participants; MD 8.48 mmol/L, 95% CI 1.08 to 15.88). Quality of this evidence was moderate. We identified variable protocols for fluid administration and total volumes of fluid administered to patients intraoperatively. Outcome data was variably reported at disparate time points and with heterogeneous patient groups. Consequently, the effect size and overall confidence interval was reduced, despite the relatively low inherent risk of bias. There was insufficient evidence on the effect of fluid composition on mortality and organ dysfunction. Confidence intervals of this outcome were wide and the quality of evidence was low (3 trials of 276 participants for mortality; odds ratio (OR) 1.85, 95% CI 0.37 to 9.33; I 2 = 0%). CONCLUSIONS: Small effect sizes for biochemical outcomes and lack of correlated clinical follow-up data mean that robust conclusions on major morbidity and mortality associated with buffered versus non-buffered perioperative fluid choices are still lacking. Buffered fluid may have biochemical benefits, including a significant reduction in postoperative hyperchloraemia and metabolic acidosis.

Cardiac Output Monitoring: Validation Studies-how Results Should be Presented.

PURPOSE OF REVIEW: Cardiac output monitors can be assessed by a variety of techniques, but a common principle is quantifying agreement between a reference standard and new monitor. The current standard analysis technique is a Bland-Altman plot. The Bland-Altman plot evaluates bias between mean differences of cardiac output, from which an agreement interval is derived. These limits are, however, statistical limits of agreement and the clinical acceptability will depend upon context and application. This article provides suggestions for understanding and presenting the results of cardiac output validation, using standard metrology alongside proposals for criteria used to accept new techniques. RECENT FINDINGS: Confusion about the appropriate way to report "precision" in method comparison studies stem from a lack of clarity on how single or repeated measurements should be interpreted. During serial measurements of cardiac output the true value changes, thus measurement should be considered as serial rather than repeated. Method agreement based upon precision achieved by cardiac output monitors needs to consider each method's general variability around true values obtained and this data should be generated and presented as part of each study design. SUMMARY: Studies should report serial measurements from two techniques for cardiac output monitoring. Results of similar techniques from other studies may not always be transferred and compared. Bias and intervals of agreement should be presented as Bland-Altman plots with dynamic cardiac output trends in polar plots. Percentage error should be calculated to allow appropriate comparison of techniques for study populations with different expected cardiac output values.

The surgical epidemic.

This article outlines the growing demand for surgical services globally, both in developing and developed countries. The implications of this increasing demand are explored, with particular attention focused on the enduring burden of perioperative complications. The role of critical care in ensuring the safe delivery of surgical services is also examined. Solutions to the 'surgical epidemic' are proposed including the role of perioperative medicine in reconfiguring services to provide safe surgical care.

Prolonged motor block following epidural anaesthesia: A proposed pathway for investigation and management to facilitate rapid MRI scanning to exclude vertebral canal haematoma.

Vertebral canal haematoma following epidural anaesthesia is a rare but potentially devastating occurence, which can lead to permanent neurological damage. Early clinical identification and diagnosis using MRI imaging with surgical decompression of the haematoma can lead to full recovery (Kebaish 2004). However surgical patients often have metal clips or staples, which are left inside the body, some of which are not MRI compatible. Currently there is no process to document which surgical clips have been used and their MRI compatibility in an accessible format. This can lead to a delay in performing MRI imaging. We propose a clinical pathway to expedite diagnosis of vertebral canal haematoma to incorporate a system to allow rapid identification of MRI compatibility of surgical clips used during surgery.

A systematic review and overview of health economic evaluations of emergency laparotomy.

BACKGROUND: Little is known about the economic impact of emergency laparotomy (EL) surgery in healthcare systems around the world. The aim of this systematic review is to describe the primary resource utilisation, healthcare economic and societal costs of EL in adults in different countries. METHODS: MEDLINE, EMBASE, ISI Web of Knowledge, Cochrane Central Register Controlled Trials, Cochrane Database of Systematic Reviews and CINAHL were searched for full and partial economic analyses of EL published between 1 January 1991 and 31 December 2015. Quality of studies was assessed using the Consensus on Health Economic Criteria (CHEC) checklist. RESULTS: Sixteen studies were included from a range of countries. One study was a full economic analysis. Fifteen studies were partial economic evaluations. These studies revealed that emergency abdominal surgery is expensive compared to similar elective surgery when comparing primary resource utilisation costs, with an important societal impact. Most contemporaneous studies indicate that in-hospital costs for EL are in excess of US$10,000 per patient episode, rising substantially when societal costs are considered. DISCUSSION: EL is a high-risk and costly procedure with a disproportionate financial burden for healthcare providers, relative to national funding provisions and wider societal cost impact. There is substantial heterogeneity in the methodologies and quality of published economic evaluations of EL; therefore, the true economic costs of EL are yet to be fully defined. Future research should focus on developing strategies to embed health economic evaluations within national programmes aiming to improve EL care, including developing the required measures and infrastructure. CONCLUSIONS: Emergency laparotomy is expensive, with a significant cost burden to healthcare and systems and society worldwide. Novel strategies for reducing this econmic burden should urgently be explored if greater access to this type of surgery is to be pursued as a global health target. TRIAL REGISTRATION: PROSPERO registration no. 42015027210.