Anaesthesia associates' clinical activity, case mix, supervision and involvement in peri-operative cardiac arrest: analysis from the 7th National Audit Project.

BACKGROUND: We analysed the clinical practice of anaesthesia associates in the UK, as reported to the 7th National Audit Project of the Royal College of Anaesthetists, and compared these with medically qualified anaesthetists. METHODS: We included data from our baseline survey, activity survey and case registry as with other reports from the project. RESULTS: Among 197 departments of anaesthesia, 52 (26%) employed anaesthesia associates. Of 10,009 responding anaesthesia care providers, 71 (< 1%) were anaesthesia associates, of whom 33 (47%) reporting working nights or weekends (compared with 97% of medically qualified anaesthetists in training and > 90% of consultants). Anaesthesia associates reported less training and confidence in managing peri-operative cardiac arrest and its aftermath compared with medically qualified anaesthetists. Anaesthesia associates were less directly involved in the management and the aftermath of peri-operative cardiac arrest than medically qualified anaesthetists, and the psychological impacts on professional and personal life appeared to be less. Among 24,172 cases, anaesthesia associates attended 432 (2%) and were the senior anaesthesia care provider in 63 (< 1%), with indirect supervision in 27 (43%). Anaesthesia associates worked predominantly in a small number of surgical specialties during weekdays and working daytime hours. Complication rates were low in cases managed by anaesthesia associates, likely reflecting case mix. However, activity and registry case mix data show anaesthesia associates do manage high-risk cases (patients who are older, comorbid, obese and frail) with the potential for serious complications. Registry cases included higher risk cases with respect to the clinical setting and patient factors. CONCLUSION: Anaesthesia associates work in enhanced roles, relative to the scope of practice at qualification agreed by organisations. Recent changes mean the Royal College of Anaesthetists and Association of Anaesthetists do not currently support an enhanced scope of practice.

Advanced life support interventions during intra-operative cardiac arrest among adults as reported to the 7th National Audit Project of the Royal College of Anaesthetists.

BACKGROUND: Few existing resuscitation guidelines include specific reference to intra-operative cardiac arrest, but its optimal treatment is likely to require some adaptation of standard protocols. METHODS: We analysed data from the 7th National Audit Project of the Royal College of Anaesthetists to determine the incidence and outcome from intra-operative cardiac arrest and to summarise the advanced life support interventions reported as being used by anaesthetists. RESULTS: In the baseline survey, > 50% of anaesthetists responded that they would start chest compressions when the non-invasive systolic pressure was < 40-50 mmHg. Of the 881 registry patients, 548 were adult patients (aged > 18 years) having non-obstetric procedures under the care of an anaesthetist, and who had arrested during anaesthesia (from induction to emergence). Sustained return of spontaneous circulation was achieved in 425 (78%) patients and 338 (62%) were alive at the time of reporting. In the 365 patients with pulseless electrical activity or bradycardia, adrenaline was given as a 1 mg bolus in 237 (65%). A precordial thump was used in 14 (3%) patients, and although this was associated with return of spontaneous circulation at the next rhythm check in almost three-quarters of patients, in only one of these was the initial rhythm shockable. Calcium (gluconate or chloride) and 8.4% sodium bicarbonate were given to 51 (9%) and 25 (5%) patients, but there were specific indications for these treatments in less than half of the patients. A thrombolytic drug was given to 5 (1%) patients, and extracorporeal cardiopulmonary resuscitation was used in 9 (2%) of which eight occurred during cardiac procedures. CONCLUSIONS: The specific characteristics of intra-operative cardiac arrest imply that its optimal treatment requires modifications to standard advanced life support guidelines.

Preoperative inflammatory mediators and postoperative delirium: systematic review and meta-analysis.

BACKGROUND: Postoperative delirium has eluded attempts to define its complex aetiology and describe specific risk factors. The role of neuroinflammation as a risk factor, determined by measuring blood levels of preoperative 'innate' inflammatory mediator levels, has been investigated. However, results have been conflicting. We conducted a systematic review and meta-analysis of the evidence on associations between preoperative blood levels of inflammatory mediators and postoperative delirium in the older person. Influence of type of surgery was also assessed. METHODS: Original, low risk of bias studies, published in peer-reviewed journals, which fulfilled the eligibility criteria were included. Seventeen articles fulfilled study criteria. Data extraction, synthesis, and risk of bias analysis were guided by Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) and quality in prognostic studies guidelines. Meta-analyses used a random-effects model. Inflammatory mediators included C-reactive protein, interleukin-6, -8, and -10, tumour necrosis factor-α, insulin-like growth factor-1, cortisol, and neopterin. Surgical groups were cardiac, noncardiac, and hip fracture. RESULTS: Higher preoperative interleukin-6 was associated with postoperative delirium with a standardised mean difference (95% confidence interval) of 0.33 (0.11-0.56) and P=0.003. Higher neopterin was also associated with postoperative delirium. CONCLUSIONS: The association of preoperative blood levels of inflammatory mediators with postoperative delirium may be influenced by the type of surgery and the specific mediator. The potential modulating effect of type of surgery, intrinsic brain vulnerability, and the complex interactions between inflammatory mediators and binding proteins will need to be considered in future studies. CLINICAL TRIAL REGISTRATION: CRD42019159471 (PROSPERO).

A restrictive versus liberal transfusion strategy to prevent myocardial injury in patients undergoing surgery for fractured neck of femur: a feasibility randomised trial (RESULT-NOF).

BACKGROUND: The optimum transfusion strategy in patients with fractured neck of femur is uncertain, particularly if there is coexisting cardiovascular disease. METHODS: We conducted a prospective, single-centre, randomised feasibility trial of two transfusion strategies. We randomly assigned patients undergoing surgery for fractured neck of femur to a restrictive (haemoglobin, 70-90 g L-1) or liberal (haemoglobin, 90-110 g L-1) transfusion strategy throughout their hospitalisation. Feasibility outcomes included: enrolment rate, protocol compliance, difference in haemoglobin, and blood exposure. The primary clinical outcome was myocardial injury using troponin estimations. Secondary outcomes included major adverse cardiac events, postoperative complications, duration of hospitalisation, mortality, and quality of life. RESULTS: We enrolled 200 (22%) of 907 eligible patients, and 62 (31%) showed decreased haemoglobin (to 90 g L-1 or less) and were thus exposed to the intervention. The overall protocol compliance was 81% in the liberal group and 64% in the restrictive group. Haemoglobin concentrations were similar preoperatively and at postoperative day 1 but lower in the restrictive group on day 2 (mean difference [MD], 7.0 g L-1; 95% confidence interval [CI], 1.6-12.4). Lowest haemoglobin within 30 days/before discharge was lower in the restrictive group (MD, 5.3 g L-1; 95% CI, 1.7-9.0). Overall, 58% of patients in the restrictive group received no transfusion compared with 4% in the liberal group (difference in proportion, 54.5%; 95% CI, 36.8-72.2). The proportion with the primary clinical outcome was 14/26 (54%, liberal) vs 24/34 (71%, restrictive), and the difference in proportion was -16.7% (95% CI, -41.3 to 7.8; P=0.18). CONCLUSION: A clinical trial of two transfusion strategies in hip fracture with a clinically relevant cardiac outcome is feasible. CLINICAL TRIAL REGISTRATION: NCT03407573.

Acute and chronic kidney disease in elderly patients with hip fracture: prevalence, risk factors and outcome with development and validation of a risk prediction model for acute kidney injury.

BACKGROUND: Hip fracture is a common injury in older people with a high rate of postoperative morbidity and mortality. This patient group is also at high risk of acute kidney injury (AKI) and chronic kidney disease (CKD), but little is known of the impact of kidney disease on outcome following hip fracture. METHODS: An observational cohort of consecutive patients with hip fracture in a large UK secondary care hospital. Predictive modelling of outcomes using development and validation datasets. Inclusion: all patients admitted with hip fracture with sufficient serum creatinine measurements to define acute kidney injury. Main outcome measures - development of acute kidney injury during admission; mortality (in hospital, 30-365 day and to follow-up); length of hospital stay. RESULTS: Data were available for 2848 / 2959 consecutive admissions from 2007-2011; 776 (27.2%) male. Acute kidney injury occurs in 24%; development of acute kidney injury is independently associated with male sex (OR 1.48 (1.21 to 1.80), premorbid chronic kidney disease stage 3B or worse (OR 1.52 (1.19 to 1.93)), age (OR 3.4 (2.29 to 5.2) for >85 years) and greater than one major co-morbidities (OR 1.61 (1.34 to 1.93)). Acute kidney injury of any stage is associated with an increased hazard of death, and increased length of stay (Acute kidney injury: 19.1 (IQR 13 to 31) days; no acute kidney injury 15 (11 to 23) days). A simplified predictive model containing Age, CKD stage (3B-5), two or more comorbidities, and male sex had an area under the ROC curve of 0.63 (0.60 to 0.67). CONCLUSIONS: Acute kidney injury following hip fracture is common and associated with worse outcome and greater hospital length of stay. With the number of people experiencing hip fracture predicted to rise, recognition of risk factors and optimal perioperative management of acute kidney injury will become even more important.

Emergency pediatric anesthesia - accessibility of information.

BACKGROUND: Emergency pediatric situations are stressful for all involved. Variation in weight, physiology, and anatomy can be substantial and errors in calculating drugs and fluids can be catastrophic. OBJECTIVES: To evaluate the reliability of information resources that anesthetic trainees might use when faced with common pediatric emergencies. METHODS: Anesthetic trainees from a single UK deanery were recruited and timed while they identified 18 predetermined pieces of information from three Advanced Pediatric Life Support (APLS) scenarios. The two most popular smartphone applications identified from a previous survey, PaedsED (PaedsED. iED limited, Version 1.0.8, Updated March 2011. ©2009) and Anapaed (AnaPaed. Thierry Girard, Version 1.4.2, Updated Nov 2, 2012. ©Thierry Girard), the British National Formulary for Children (cBNF) and trainee's inherent knowledge were compared with a local, check-list style, handbook of pediatric emergency algorithms - Pediatric Anesthetic Emergency Data sheets (PAEDs). RESULTS: Twenty anesthetic trainees were recruited. The fastest source of information was the trainees own knowledge (median 61 s, IQR 51-83 s). Second fastest was PAEDs (80, [59-110] s), followed by PaedsED (84, [65-111]). The most accurate source overall was PaedsED (100, [83-100]) although the accuracy varied between scenarios. The handbook was rated as the most popular resource by the trainees. CONCLUSION: Although fastest, trainees own knowledge is inaccurate, highlighting the need for additional, rapidly accessible, information. Of the two smartphone applications, PaedsED proved to be fast, accurate, and more popular, while Anapaed was accurate but slow to use. The PAEDs handbook, with its checklist-style format, was also fast, accurate and rated the most popular information source.

Total intravenous anaesthesia with propofol and remifentanil is associated with reduction in operative time in surgery for glioblastoma when compared with inhalational anaesthesia with sevoflurane.

BACKGROUND: Total intravenous anaesthesia (TIVA) is emerging as a preferred neuroanaesthetic agent compared with inhalational anaesthetic (IA) agents. We asked if TIVA with propofol and remifentanil was associated with shorter operative times compared to IA using sevoflurane in brain tumour surgery under GA. METHODS: We performed a retrospective analysis of all patients undergoing surgery for glioblastoma (GBM). We assessed choice of GA agent (TIVA or IA) with total time patient was under GA (anaesthetic time), operative time and time taken to recover fully from GA (recovery time). RESULTS: Over a two year period 263 patients underwent surgery under GA for their GBM including 188 craniotomy operations, 63 burr hole biopsy procedures and 12 open biopsy procedures. Of these, 79 operations took place under TIVA and 184 operations under IA. TIVA was associated with significantly reduced mean operative time including time taken to wake up in theatre (104 min with TIVA, 129 min with IA; p = 0.02). TIVA was also associated with trends toward shorter mean recovery time (118 min, versus 135 min with IA; p = 0.08) and shorter mean anaesthetic time (163 min, versus 181 min with IA; p = 0.07). There was no difference between TIVA and IA groups as regards duration of inpatient stay, readmission rates, complications or survival. CONCLUSIONS: TIVA with propofol and remifentanil may reduce anaesthetic, operative and recovery times in patients undergoing surgery for their GBM. These findings may be attributable to favourable effects on intracranial pressure and cerebral perfusion, as well as rapid recovery from GA. In addition to clinical advantages, there may be financial and logistical benefits.

Retinal imaging with hand-held optical coherence tomography in older people with or without postoperative delirium after hip fracture surgery: A feasibility study.

INTRODUCTION: Postoperative delirium in older people may result from the interaction between intrinsic brain vulnerability (e.g. neurodegeneration) and precipitating factors (e.g. surgery induced cytokines). Intrinsic brain vulnerability may be overt (e.g. Alzheimer's disease) or preclinical. In cognitively intact older people presenting for surgery, identification of preclinical neurodegeneration using bedside tools could aid postoperative delirium risk stratification. Thinning of the circumpapillary retinal nerve fibre layer thickness is associated with neurodegenerative disorders e.g. Alzheimer's disease. We propose that thinning of the retinal nerve fibre layer may be present some older people with postoperative delirium due to preclinical neurodegeneration, albeit to a lesser extent than in overt dementia. OBJECTIVES: The primary objective: Feasibility of acquiring usable retinal images with the hand-held optical coherence device, at the bedside of older, hip fracture surgery patients. Secondary objective: Comparison of the circumpapillary retinal nerve fibre layer thickness between people who did/did not have postoperative delirium. Proportion of exclusions due to retinal pathology. METHOD: Feasibility study involving 30, cognitively intact, older people recovering from hip fracture surgery. Retinal images were obtained using the hand-held optical coherence tomography device at the participants' bedside. Imaging was deferred in participants who had postoperative delirium. RESULTS: Retinal images that could be assessed for circumpapillary retinal nerve fibre layer thickness were obtained in 26 participants (22 no postoperative delirium, 4 postoperative delirium). The mean circumpapillary retinal nerve fibre layer thickness was lower in the participants who had postoperative delirium compared to those who did not experience postoperative delirium (Mean (95% CI) of 76.50 (62.60-90.40) vs 89.19 (85.41-92.97) respectively). CONCLUSION: Retinal imaging at the patient's bedside, using hand-held OCT is feasible. Our data suggests that the circumpapillary retinal nerve fibre layer may be thinner in older people who experience postoperative delirium compared to those who do not. Further studies are required.

Clinician perspectives on nonoperative management of hip fractures during COVID-19.

Aims: To identify factors influencing clinicians' decisions to undertake a nonoperative hip fracture management approach among older people, and to determine whether there is global heterogeneity regarding these factors between clinicians from high-income countries (HIC) and low- and middle-income countries (LMIC). Methods: A SurveyMonkey questionnaire was electronically distributed to clinicians around the world through the Fragility Fracture Network (FFN)'s Perioperative Special Interest Group and clinicians' personal networks between 24 May and 25 July 2021. Analyses were performed using Excel and STATA v16.0. Between-group differences were determined using independent-samples t-tests and chi-squared tests. Results: A total of 406 respondents from 51 countries answered the questionnaire, of whom 225 came from HIC and 180 from LMIC. Clinicians from HIC reported a greater median and mean estimated proportion of admitted patients with hip fracture undergoing surgery (median 96% (interquartile range (IQR) 95% to 99%); mean 94% (SD 8%)) than those from LMIC (median 85% (IQR 75% to 95%); mean 81% (SD 16%); p < 0.001). Global heterogeneity seems to exist regarding factors such as anticipated life expectancy, insufficient resources, ability to pay, treatment costs, and perception of risk in hip fracture management decision-making. Conclusion: This study represents the first international sampling of clinician perspectives regarding nonoperative hip fracture management. Several factors seemed to influence the clinician decision-making process. Further research is needed to inform the development of best practice guidelines to improve decision-making and the quality of hip fracture care among older people.

Vocalization assessed by electrolaryngography is unaffected by topical lidocaine anesthesia: a prospective, crossover, randomized, double-blind placebo-controlled study.

BACKGROUND: Topical anesthesia of the upper airway is often recommended when difficulty in airway management is anticipated. There are published reports, however, of administration of topical anesthesia resulting in complete loss of airway control. Adverse effects are mostly attributed to interference with involuntary protective airway reflexes, while gross motor function itself generally is thought to be preserved. We hypothesized that if motor control is affected, measurable quantitative changes in vocalization should follow the use of topical anesthesia. METHODS: A prospective, crossover, randomized, double-blind study was conducted, in which 24 healthy volunteers each performed 2 vocal exercises, while having their glottic appearance recorded digitally via fiberoptic nasendoscopy. Subjects gargled with 3 test solutions on separate occasions (placebo, 2% lidocaine, and 4% lidocaine) and repeated the vocal exercises and nasendoscopy. The angle between the vocal cords was measured using MB-Ruler®, and the Laryngograph Speech Studio® software was used for vocal parameter analysis. RESULTS: The only significant changes in voice quality occurred between the control and test groups (P = 0.014). No difference could be found between the placebo and lidocaine groups. CONCLUSIONS: Although gargling with local anesthetic affected vocalization, no pharmacological effect attributable to local anesthetic was observed.

Perioperative intravenous iron to treat patients with fractured hip surgery: A systematic review and meta-analysis.

Background: Treatment of preoperative anemia with intravenous iron is common within elective surgical care pathways. It is plausible that this treatment may improve care for people with hip fractures many of whom are anemic because of pre-existing conditions, fractures, and surgery. Objective: To review the evidence for intravenous iron administration on outcomes after hip fracture. Design: We followed a predefined protocol and conducted a systematic review and meta-analysis of the use of intravenous iron to treat anemia before and after emergency hip fracture surgery. The planned primary outcome was a difference in length of stay between those treated with intravenous iron and the control group. Other outcomes analyzed were 30-day mortality, requirement for blood transfusion, changes in quality of life, and hemoglobin concentration on discharge from the hospital. Data Sources: EMBASE, MEDLINE, The Cochrane Library (CENTRAL, DARE) databases, Clinicaltrials.gov, and ISRCTN trial registries. Date of final search March 2022. Eligibility Criteria: Adult patients undergoing urgent surgery for hip fracture. Studies considered patients who received intravenous iron and were compared with a control group. Results: Four randomized controlled trials (RCT, 732 patients) and nine cohort studies (2986 patients) were included. The RCTs were at low risk of bias, and the nonrandomized studies were at moderate risk of bias. After metanalysis of the RCTs there was no significant difference in the primary outcome, length of hospital stay, between the control group and patients receiving intravenous iron (mean difference: -0.59, 95% confidence interval [CI]; -1.20 to 0.03; I 2 = 30%, p = 0.23). Intravenous iron was not associated with a difference in 30-day mortality (n = 732, OR: 1.14, 95% CI: 0.62-2.1; I 2 = 0%, p = 0.50), nor with the requirement for transfusion (n = 732, OR: 0.85, 95% CI: 0.63-1.14; I 2 = 0%, p < 0.01) in the analyzed RCTs. Functional outcomes and quality of life were variably reported in three studies. Conclusion: The evidence on the use of intravenous iron in patients with hip fracture is low quality and shows no difference in length of acute hospital stay and transfusion requirements in this population. Improved large, multicentre, high-quality studies with patient-centered outcomes will be required to evaluate the clinical and cost-effectiveness of this treatment.

Optical coherence tomography in mild cognitive impairment - Systematic review and meta-analysis.

Thinning of retinal layers, measured using optical coherence tomography (OCT), is associated with some neurodegenerative disorders such as established Alzheimer's disease and multiple sclerosis. The evidence for retinal layer thinning in both mild cognitive impairment (MCI), a precursor of dementia, and delirium, a potential pre-clinical stage of neurodegenerative disorder, is unclear. We performed a systematic review of the associations, in older people, between retinal layer thickness changes (measured using OCT) and delirium or MCI compared to controls (Protocol registration ID (Prospero) CRD42019122165). We did not identify any relevant studies on delirium. This report is therefore a review of retinal nerve layer changes in mild cognitive impairment. Databases were searched using predetermined keywords such as mild cognitive impairment, retinal nerve fibre layer and delirium. Where there were sufficient data, meta-analyses were performed. Twenty-six relevant studies were identified on retinal layer thickness in people with MCI compared to controls. There was significant heterogeneity in the studies for all retinal layers investigated (retinal nerve fibre layer (RNFL), ganglion cell inner plexiform layer (GCIP), foveal thickness and macular volume). Analysis of 17 studies of mean RNFL thickness in MCI (n = 622) compared to controls (n = 1154), irrespective of the type of OCT device, demonstrated a significant thinning in MCI (SMD: - 0·42 and 95 % confidence interval: - 0·68 to - 0·16). This difference was non-significant when studies using only spectral-domain devices were analysed. Subgroup analysis of studies using spectral-domain devices in amnestic MCI diagnosed using comparable criteria, showed statistically significant thinning of RNFL in amnestic MCI (p = 0·02). Meta-analysis of foveal thickness did not show a significant difference between MCI and controls. In conclusion, there is some evidence of an association between retinal nerve fibre layer thinning and MCI. We found no data on the association between RNFL and delirium.

Conflict resolution in anaesthesia: systematic review.

Background: Conflict is a significant and recurrent problem in most modern healthcare systems. Given its ubiquity, effective techniques to manage or resolve conflict safely are required. Objective: This review focuses on conflict resolution interventions for improvement of patient safety through understanding and applying/teaching conflict resolution skills that critically depend on communication and improvement of staff members' ability to voice their concerns. Methods: We used the Population-Intervention-Comparator-Outcome model to outline our methodology. Relevant English language sources for both published and unpublished papers up to February 2018 were sourced across five electronic databases: the Cochrane Library, EMBASE, MEDLINE, SCOPUS and Web of Science. Results: After removal of duplicates, 1485 studies were screened. Six articles met the inclusion criteria with a total sample size of 286 healthcare worker participants. Three training programmes were identified among the included studies: (A) crisis resource management training; (B) the Team Strategies and Tools to Enhance Performance and Patient Safety (TeamSTEPPS) training; and (C) the two-challenge rule (a component of TeamSTEPPS), and two studies manipulating wider team behaviours. Outcomes reported included participant reaction and observer rating of conflict resolution, speaking up or advocacy-inquiry behaviours. Study results were inconsistent in showing benefits of interventions. Conclusion: The evidence for training to improve conflict resolution in the clinical environment is sparse. Novel methods that seek to influence wider team behaviours may complement traditional interventions directed at individuals.

Short-term morbidity factors associated with length of hospital stay (LOS): Development and validation of a Hip Fracture specific postoperative morbidity survey (HF-POMS).

BACKGROUND: We aimed to describe and quantify postoperative complications in the older hip fracture population, develop and validate a hip fracture postoperative morbidity survey tool (HF-POMS). METHODS: A prospective clinical observation study of patients (≥ 70 years) admitted for emergency hip fracture surgery, was conducted across three English National Health Service hospitals. Outcome data items were developed from the Postoperative Morbidity Survey (POMS), Cardiac-POMS, hip fracture postoperative literature and orthogeriatric clinical team input. Postoperative outcome data were collected on days 1, 3, 5, 8 and 15; 341 patients participated. RESULTS: A 12-domain HF-POMS tool was developed with acceptable construct validity on all HF-POMS days. Patients with high perioperative risk scores as measured by the NHFS and ASA grade were more prone to develop HF-POMS defined morbidities. High morbidity rates occurred in the following domains; renal, ambulation assistance, pain and infectious. Presence of any morbidity on postoperative days 8 and 15 was associated with subsequent length of stay of 3.08 days (95% CI 0.90-5.26, p = 0.005) and 15.81 days (95% CI 13.35-18.27, p = 0.001) respectively. Observed average length of stay was 16.9 days. HF-POMS is a reliable and valid tool for measuring early postoperative complications in hip fracture patients. Additional domains are necessary to account for all morbidity aspects in this patient population compared to the original POMS. CONCLUSION: Many patients remained in hospital for non-medical reasons. HF-POMS may be a useful tool to assist in discharge planning and randomised control trial outcome definitions.

Anaesthesia workload measurement devices: qualitative systematic review.

Background: Management of mental workload is a key aspect of safety in anaesthesia but there is no gold-standard tool to assess mental workload, risking confusion in clinical and research use of such tools. Objective: This review assessed currently used mental workload assessment tools. Methods: A systematic literature search was performed on the following electronic databases; Cochrane, EMBASE, MEDLINE, SCOPUS and Web of Science. Screening and data extraction were performed individually by two authors. We included primary published papers focusing on mental workload assessment tools in anaesthesia. Results: A total of 2331 studies were screened by title, 32 by full text and 24 studies met the inclusion criteria. Six mental workload measurement tools were observed across included studies. Reliability for the Borg rating scales and Vibrotactile device was reported in two individual studies. The rest of the studies did not record reliability of the tool measurements used. Borg rating scales, NASA-TLX and task-oriented mental work load measurements are subjective, easily available, readily accessible and takes a few minutes to complete. However, the vibrotactile and eye-tracking methods are objective, require more technical involvement, considerable time for the investigator and moderately expensive, impacting their potential use. Conclusion: We found that the measurement of mental workload in anaesthesia is an emerging field supporting patient and anaesthetist safety. The self-reported measures have the best evidence base.

Predicting 30-day mortality in patients with sepsis: An exploratory analysis of process of care and patient characteristics.

BACKGROUND: Sepsis represents a significant public health burden, costing the NHS £2.5 billion annually, with 35% mortality in 2006. The aim of this exploratory study was to investigate risk factors predictive of 30-day mortality amongst patients with sepsis in Nottingham. METHODS: Data were collected prospectively from adult patients with sepsis in Nottingham University Hospitals NHS Trust as part of an on-going quality improvement project between November 2011 and March 2014. Patients admitted to critical care with the diagnosis of sepsis were included in the study. In all, 97 separate variables were investigated for their association with 30-day mortality. Variables included patient demographics, symptoms of systemic inflammatory response syndrome, organ dysfunction or tissue hypoperfusion, locations of early care, source of sepsis and time to interventions. RESULTS: A total of 455 patients were included in the study. Increased age (adjOR = 1.05 95%CI = 1.03-1.07 p < 0.001), thrombocytopenia (adjOR = 3.10 95%CI = 1.23-7.82 p = 0.016), hospital-acquired sepsis (adjOR = 3.34 95%CI = 1.78-6.27 p < 0.001), increased lactate concentration (adjOR = 1.16 95%CI = 1.06-1.27 p = 0.001), remaining hypotensive after vasopressors (adjOR = 3.89 95%CI = 1.26-11.95 p = 0.02) and mottling (adjOR = 3.80 95%CI = 1.06-13.55 p = 0.04) increased 30-day mortality odds. Conversely, fever (adjOR = 0.46 95%CI = 0.28-0.75 p = 0.002), fluid refractory hypotension (adjOR = 0.29 95%CI = 0.10-0.87 p = 0.027) and being diagnosed in surgical wards (adjOR = 0.35 95%CI = 0.15-0.81 p = 0.015) were protective. Treatment timeliness were not significant factors. CONCLUSION: Several important predictors of 30-day mortality were found by this research. Retrospective analysis of our sepsis data has revealed mortality predictors that appear to be more patient-related than intervention-specific. With this information, care can be improved for those identified most at risk of death.

Femoral Nerve Block Intervention in Neck of Femur Fracture (FINOF): a randomised controlled trial.

OBJECTIVE: Fractured neck of femur is a severely painful condition with significant mortality and morbidity. We investigated whether early and continuous use of femoral nerve block can improve pain on movement and mobility after surgery in older participants with fragility neck of femur fracture. DESIGN: Prospective single-centre, randomised controlled pragmatic trial. SETTING: Secondary care, acute National Health Service Trust, UK. PARTICIPANTS: Participants admitted with a history and examination suggesting fractured neck of femur. INTERVENTION: Immediate continuous femoral nerve block via catheter or standard analgesia. OUTCOME MEASURES: Primary outcome measures were Cumulative Dynamic Pain score and Cumulated Ambulation Score from surgery until day 3 postoperatively. Secondary outcome measures included pain scores at rest, cumulative side effects (nausea and constipation), quality of life (measured by EuroQOL 5 D instrument (EQ-5D) score) at day 3 and day 30, and rehabilitation outcome (measured by mobility score). RESULTS: 141 participants were recruited, with 23 excluded. No significant difference was detected between Cumulative Dynamic Pain Score (standard care (n=56) vs intervention (n=55) 20 (IQR 15-24) vs 20 (15-23), p=0.51) or Cumulated Ambulation Score (standard care vs intervention 6 (5-9) vs 7 (5-10), p=0.76). There were no statistically different differences in secondary outcomes except cumulative pain at rest: 5 (0.5-6.5) in the standard care group and 2 (0-5) in the intervention group (p=0.043). CONCLUSIONS: Early application of continuous femoral nerve block compared with standard systemic analgesia did not result in improved dynamic pain score or superior postoperative ambulation. This technique may provide superior pain relief at rest. Continuous femoral nerve block did not delay initial control of pain or mobilisation after surgery. TRIAL REGISTRATION NUMBER: ISRCTN92946117; Pre-results.

Modeling the causes of variation in brain tissue oxygenation.

BACKGROUND: Clinical markers of the adequacy of cerebral perfusion may be misleading. The effects of isolated changes in systemic blood pressure, Paco2, Pao2, and cerebral edema on cerebral blood flow and oxygenation are relatively well known, but the quantitative effects of interactions between these factors are not easily calculated. We aimed to investigate the relationship between these factors using a computational model. METHODS: Using a validated, quantitative, computational model of cerebral blood flow, the simulated effects of changes in systemic blood pressure (50-180 mm Hg), Paco2 (33-55 mm Hg [4.3-7.3 kPa]), Sao2 (0.8-1.0), and cerebral edema (0%-10% increase in intercapillary distance) on middle cerebral artery flow velocity (MCAFV), brain tissue oxygenation (Pbo2), and jugular venous oxygen saturation (Sjo2) were recorded. RESULTS: Individual markers of adequacy of cerebral perfusion (MCAFV, Sjo2, and Pbo2 behave in accordance with clinical data with single changes in the parameters studied: the lower limit of autoregulation for MCAFV and Sjo2 lies around 60 mm Hg mean arterial blood pressure. In our model, the upper limit of autoregulation lies around 170 mm Hg, but is much less distinct for Sjo2 and Pbo2 than for MCAFV. Significant cerebral ischemia appears unlikely to occur with isolated physiological changes according to our simulation. However, the combination of hypotension, hypoxia, and edema makes ischemia much more likely in this model. Edema increases the Sjo2:Pbo2 gradient, confirming that diffusion-limited oxygen delivery may make Sjo2 values falsely reassuring. CONCLUSION: The simulated effects of pathophysiological changes on cerebral oxygenation and perfusion have been quantitatively described. Significant cerebral ischemia is predicted in the presence of two or more physiological derangements. Cerebral edema is associated with an increased gradient between Sjo2 and Pbo2.

Development and validation of an integrated computational model of cerebral blood flow and oxygenation.

BACKGROUND: Various groups have constructed simulations and models of cerebral blood flow and oxygenation, each with its strengths and weaknesses. We describe the development and validation of a novel computational model, the Nottingham cerebral simulator (NCS), designed for experimental and teaching use. METHODS: Physiological hypotheses were converted into differential equations; these are solved numerically with respect to time. A battery of tests was derived from published literature against which to test the simulation: static and dynamic autoregulation responses; carbon dioxide reactivity; brain tissue oxygenation. The NCS was programmed to simulate the methodologies of published experiments and the results of the simulation and the published data were compared. RESULTS: The NCS results are qualitatively and quantitatively similar to published data. The values for regulatory indices were (published values in parentheses): index of autoregulation 0.9 (0.9); transient hyperemic response ratio 1.3 (1.3), carbon dioxide reactivity 2.4%-4.7% mm Hg(-1) (2-4.5); brain tissue oxygen tension 22 mm Hg (20-100). CONCLUSIONS: The NCS is a credible model of cerebral blood flow and oxygenation, which warrants further use as an experimental and teaching tool.