Association of Anaesthetists: anaesthesia and peri-operative care for Jehovah's Witnesses and patients who refuse blood.

There are approximately 8.5 million Jehovah's Witnesses and around 150,000 live in Great Britain and Ireland. Based on their beliefs and core values, Jehovah's Witnesses refuse blood component transfusion (including red cells, plasma and platelets). They regard non-consensual transfusion as a physical violation. Consent to treatment is at the heart of this guideline. Refusal of treatment by an adult with capacity is lawful. The reasons why a patient might refuse transfusion and the implications are examined. The processes and products that are deemed acceptable or unacceptable to Jehovah's Witnesses are described. When a team is faced with a patient who refuses transfusion, a thorough review of the clinical situation is advocated and all options for treatment should be explored. After discussion, a plan should then be made that is acceptable to the patient and appropriate consent obtained. When agreement cannot be reached between the doctor and the patient, referral for a second opinion should be considered. When the patient is a child, the same strategy should be used but on occasion the clinical team may have to obtain legal help.

Meta-analysis and trial sequential analysis of local vs. general anaesthesia for carotid endarterectomy.

Controversy exists regarding the best choice of anaesthesia for carotid endarterectomy. We aimed to evaluate the peri-operative outcomes of local vs. general anaesthesia for carotid endarterectomy. We conducted a systematic search of electronic information sources and applied a combination of free text and controlled vocabulary searches adapted to thesaurus headings, search operators and limits in each of the electronic databases. We defined peri-operative stroke, transient ischaemic attack, mortality and myocardial infarction as the primary outcome measures. We identified 12 randomised controlled trials and 21 observational studies reporting a total of 58,212 patients undergoing carotid endarterectomy under local or general anaesthesia. Analysis of observational studies demonstrated that local anaesthesia was associated with a significantly lower incidence of stroke (odds ratio (OR (95% CI) 0.66 (0.55-0.80), p < 0.0001), transient ischaemic attack (0.52 (0.38-0.70), p < 0.0001), myocardial infarction (0.55 (0.41-0.75), p = 0.0002) and mortality (0.72 (0.56-0.94), p = 0.01) compared with general anaesthesia. Analysis of randomised controlled trials did not find a significant difference in the risk of stroke (0.92 (0.67-1.28), p = 0.63), transient ischaemic attack (2.20 (0.48-10.03), p = 0.31), myocardial infarction (1.25 (0.57-2.72), p = 0.58) or mortality (0.61 (0.35-1.05), p = 0.07) between local and general anaesthesia. On trial sequential analysis of the randomised trials, the Z-curve did not cross the α-spending boundaries or futility boundaries for stroke, mortality and transient ischaemic attack, suggesting that more trials are needed to reach conclusive results. Our meta-analysis of observational studies suggests that local anaesthesia for carotid endarterectomy may be associated with lower peri-operative morbidity and mortality compared with general anaesthesia. Although randomised studies have not confirmed any advantage for local anaesthesia, this may be due to a lack of pooled statistical power in these trials.

Association of Anaesthetists guidelines: cell salvage for peri-operative blood conservation 2018.

The use of cell salvage is recommended when it can be expected to reduce the likelihood of allogeneic (donor) red cell transfusion and/or severe postoperative anaemia. We support and encourage a continued increase in the appropriate use of peri-operative cell salvage and we recommend that it should be available for immediate use 24 h a day in any hospital undertaking surgery where blood loss is a recognised potential complication (other than minor/day case procedures).

Deformation and dynamic response of abdominal aortic aneurysm sealing.

Endovascular sealing is a new technique for the repair of abdominal aortic aneurysms. Commercially available in Europe since 2013, it takes a revolutionary approach to aneurysm repair through minimally invasive techniques. Although aneurysm sealing may be thought as more stable than conventional endovascular stent graft repairs, post-implantation movement of the endoprosthesis has been described, potentially leading to late complications. The paper presents for the first time a model, which explains the nature of forces, in static and dynamic regimes, acting on sealed abdominal aortic aneurysms, with references to real case studies. It is shown that elastic deformation of the aorta and of the endoprosthesis induced by static forces and vibrations during daily activities can potentially promote undesired movements of the endovascular sealing structure.

Estimating the error of CT-based measurements of aortic lumen volume used in endovascular planning.

INTRODUCTION: Planning of endovascular sealing of abdominal aortic aneurysms requires measurement of the aortic lumen volume. The aim of this study was to investigate mathematically the effect of intra- and inter-observer variability error, as well as cardiac cycle-related variability, on these measurements. METHODS: Mean (±2SD) intra- and inter-observer error in lumen measurements and mean (+2SD) cardiac cycle-related variability were obtained from published literature and added to the measurement of the flow lumen volume of a 57 mm abdominal aortic aneurysm to calculate average and extreme error possibilities. RESULTS: The aneurysm volume was measured at 165 ml. The calculated possible mean measurement error due to cardiac cycle variation, intra- and inter-observer variability was +11.0%, resulting in a potential measurement of 183.1 ml. The calculated extreme errors were +24.3% (if 2SD of all errors were added to the mean) and +3.5% (if 2SD of all errors, except cardiac cycle, were subtracted from the mean), resulting in potential measurements of 170.8 ml and 205.1 ml, respectively. When considering the errors combined, the proportion of patients who may have volume measurement errors of up to ±2.5 ml, ±2.6 to ±5.0 ml and ±5.1 to ±7.5 ml were 18%, 17% and 15%, respectively. CONCLUSION: Measurement of CT-based aortic lumen volumes in abdominal aortic aneurysms is imprecise. This has practical implications for the planning and the performance of complex endovascular therapies.

Effect of beta-blockers on perioperative outcomes in vascular and endovascular surgery: a systematic review and meta-analysis.

BACKGROUND: To investigate the role of perioperative beta-blocker use in vascular and endovascular surgery. METHODS: We performed a systematic review in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement standards. The review protocol was registered with International Prospective Register of Systematic Reviews (registration number:CRD42016038111). We searched electronic databases to identify all randomized controlled trials and observational studies investigating outcomes of patients undergoing vascular and endovascular surgery with or without perioperative beta blockade. We used the Cochrane tool and the Newcastle-Ottawa scale to assess the risk of bias of trials and observational studies, respectively. Random-effects models were applied to calculate pooled outcome data. RESULTS: We identified three randomized trials, five retrospective cohort studies, and three prospective cohort studies, enrolling a total of 32,602 patients. Our analyses indicated that perioperative use of beta-blockers did not reduce the risk of all-cause mortality [odds ratio (OR) 1.10, 95% confidence interval (CI) 0.59-2.04, P = 0.77], cardiac mortality (OR 2.62, 95% CI 0.86-8.05, P = 0.09), myocardial infarction (OR 0.89, 95% CI 0.59-1.35, P = 0.58), unstable angina (OR 1.34, 95% CI 0.41- 4.38, P = 0.63), stroke (OR 2.45, 95% CI 0.89-6.75, P = 0.08), arrhythmias (OR 0.76, 95% CI 0.41-1.43, P = 0.40), congestive heart failure (OR 1.12, 95% CI 0.77-1.63, P = 0.56), renal failure (OR 1.48, 95% CI 0.90-2.45, P = 0.13), composite cardiovascular events (OR 0.88, 95% CI 0.55-1.40, P = 0.58), rehospitalisation (OR 0.86, 95% CI 0.48-1.52, P = 0.60), and reoperation (OR 1.17, 95% CI 0.42-3.27, P = 0.77) in vascular surgery. CONCLUSIONS: Beta-blockers do not improve perioperative outcomes in vascular and endovascular surgery.

Systematic Review and Meta-analysis of Dual Versus Single Antiplatelet Therapy in Carotid Interventions.

BACKGROUND: The importance of antiplatelet therapy for the management and prevention of ischaemic stroke cannot be overstated. Despite the established guidelines, there is no clear consensus on how to manage antiplatelet therapy during and after carotid interventions. OBJECTIVE: The objective was to undertake a systematic literature review and perform a meta-analysis to assess the effects of dual antiplatelet therapy in carotid endarterectomy (CEA) and stenting (CAS). DATA SOURCES: Electronic information sources (MEDLINE, EMBASE, CINAHL, CENTRAL) and bibliographic reference lists were searched to identify randomised controlled trials (RCTs) and observational studies reporting comparative outcomes of dual versus single antiplatelet therapy in CEA and CAS. METHODS: Primary outcomes were mortality and stroke within 30 days of intervention. Secondary outcomes were transient ischaemic attack (TIA), major bleeding, groin or neck haematoma, and myocardial infarction (MI). Dichotomous outcome measures were reported using the risk difference (RD) and 95% confidence interval (CI). Combined overall treatment effects were calculated using fixed-effect or random-effects models. RESULTS: Three RCTs and seven observational studies were identified reporting a total of 36,881 CEAs and 150 CAS procedures. In CEA, there were no differences in stroke/TIA/death between single and dual antiplatelet therapy, but there was a significant risk of major bleeding (RD, 0.00; 95% CI, 0.00-0.01; p = .0003) and neck haematoma with dual therapy (RD, 0.04; 95% CI, 0.01-0.06; p = .001). In addition, the rate of MI was higher in the dual therapy group than the single therapy group (RD, 0.00; 95% CI, 0.00-0.01; p = .003). In CAS, there was no difference in major bleeding or haematoma formation, but a significant difference in TIA in favour of dual therapy was identified (RD -0.13, 95% CI, -0.22 to -0.05; p = .003). CONCLUSIONS: Dual antiplatelet therapy demonstrates advantages over single therapy only in CAS, as indicated by a reduced risk of TIA. Dual antiplatelet therapy was associated with an increased risk of bleeding complications in patients undergoing CEA.

Influence of Social Deprivation on Outcome of Open Arterial Surgery in Tertiary Care: An Observational Study.

BACKGROUND AND OBJECTIVE: Health equity is playing an increasing role in British government health policy. Evidence of social deprivation affecting outcomes in surgery is poor. This study aimed to assess the influence of social deprivation on the outcome of major arterial surgery. MATERIALS AND METHODS: A retrospective cohort study was undertaken in patients undergoing elective or emergency open surgery for abdominal aortic aneurysms or lower limb arterial reconstruction over an eight and a half year period within one institution. Patient deprivation was calculated for each patient with the Index of Multiple Deprivation (IMD) score. This was then entered into multivariate models to determine its effect on mortality and postoperative length of stay after adjustment for confounders. RESULTS: Five hundred and six patients were included in the study. There were 45 deaths (8.9%) and median (IQR) postoperative length of stay was 8 (4-15) days. The median (IQR) IMD score was 46.4 (28.3-64.5). IMD score correlated with ASA grade and was significantly higher in smokers, patients with respiratory disease and those with left ventricular failure. IMD (OR = 1.01; 95% CI = 0.99-1.03; p = .45) did not affected mortality, which was associated with aortic surgery, emergency surgery, and high ASA grade. Postoperative length of stay, which was longer with/after aortic surgery, tissue loss, emergency surgery, high ASA grade, low haemoglobin, and age over 80 years was also independent of deprivation (Spearman's rho = -0.49, p = .28). DISCUSSION: No effect of social deprivation on mortality or length of stay in patients undergoing major arterial surgery was identified.

Reporting and Methodological Quality of Randomised Controlled Trials in Vascular and Endovascular Surgery.

BACKGROUND: Randomised controlled trials (RCTs) are subject to bias if they lack methodological quality. Moreover, optimal and transparent reporting of RCT findings aids their critical appraisal and interpretation. OBJECTIVES: The aim of this study was to ascertain whether the methodological and reporting quality of RCTs in vascular and endovascular surgery is improving. METHODS: The most recent 75 and oldest 75 RCTs published in leading journals over a 10-year period (2003-2012) were identified. The reporting quality and methodological quality data of the old and new RCTs were extracted and compared. The former was analysed using the Consolidated Standards of Reporting Trials (CONSORT) statement, the latter with the Scottish Intercollegiate Guidelines Network (SIGN) checklist. RESULTS: Reporting quality measured by CONSORT was better in the new studies than in the old studies (0.68 [95% CI, 0.66-0.7] vs. 0.60 [95% CI, 0.58-0.62], p < .001); however, both new and old studies had similar methodological quality measured by SIGN (0.9 [IQR 0.1] vs. .09 [IQR: 0.2], p = .787). Unlike clinical items, the methodological items of the CONSORT statement were not well reported in old and new RCTs. More trials in the new group were endovascular related (33.33% vs. 17.33%, p = .038) and industry sponsored (28% vs. 6.67%, p = .001). CONCLUSIONS: Despite some progress, there remains room for improvement in the reporting quality of RCTs in vascular and endovascular surgery. The methodological quality of recent RCTs is similar to that of trials performed >10 years ago.

The Effect of beta-blockade on objectively measured physical fitness in patients with abdominal aortic aneurysms--A blinded interventional study.

BACKGROUND: Perioperative beta-blockade is widely used, especially before vascular surgery; however, its impact on exercise performance assessed using cardiopulmonary exercise testing (CPET) in this group is unknown. We hypothesized that beta-blocker therapy would significantly improve CPET-derived physical fitness in this group. METHODS: We recruited patients with abdominal aortic aneurysms (AAA) of <5.5 cm under surveillance. All patients underwent CPET on and off beta-blockers. Patients routinely prescribed beta-blockers underwent a first CPET on medication. Beta-blockers were stopped for one week before a second CPET. Patients not routinely taking beta-blockers underwent the first CPET off treatment, then performed a second CPET after commencement of bisoprolol for at least 48 h. Oxygen uptake (.VO2) at estimated lactate threshold and .VO2 at peak were primary outcome variables. A linear mixed-effects model was fitted to investigate any difference in adjusted CPET variables on and off beta-blockers. RESULTS: Forty-eight patients completed the study. No difference was observed in .VO2 at estimated lactate threshold and .VO2 at peak; however, a significant decrease in .VE/.VCO2 at estimated lactate threshold and peak, an increase in workload at estimated lactate threshold., O2 pulse and heart rate both at estimated lactate threshold and peak was found with beta-blockers. Patients taking beta-blockers routinely (chronic group) had worse exercise performance (lower .VO2 ). CONCLUSIONS: Beta blockade has a significant impact on CPET-derived exercise performance, albeit without changing .VO2 at estimated lactate threshold and.VO2 at peak. This supports performance of preoperative CPET on or off beta-blockers depending on local perioperative practice. CLINICAL TRIAL REGISTRATION: NCT 02106286.

Neuromuscular electrical stimulation for thromboprophylaxis: A systematic review.

OBJECTIVE: To evaluate the effect of neuromuscular electrical stimulation on lower limb venous blood flow and its role in thromboprophylaxis. METHOD: Systematic review of randomised and non-randomised studies evaluating neuromuscular electrical stimulation, and reporting one or more of the following outcomes: incidence of venous thromboembolism, venous blood flow and discomfort profile. RESULTS: Twenty-one articles were identified. Review of these articles showed that neuromuscular electrical stimulation increases venous blood flow and is generally associated with an acceptable tolerability, potentially leading to good patient compliance. Ten comparative studies reported DVT incidence, ranging from 2% to 50% with neuromuscular electrical stimulation and 6% to 47.1% in controls. There were significant differences, among included studies, in terms of patient population, neuromuscular electrical stimulation delivery, diagnosis of venous thromboembolism and blood flow measurements. CONCLUSION: Neuromuscular electrical stimulation increases venous blood flow and is well tolerated, but current evidence does not support a role for neuromuscular electrical stimulation in thromboprophylaxis. Randomised controlled trials are required to investigate the clinical utility of neuromuscular electrical stimulation in this setting.

Comparison of oxygen uptake during arm or leg cardiopulmonary exercise testing in vascular surgery patients and control subjects.

BACKGROUND: Cardiopulmonary exercise testing by cycle ergometry (CPET(leg)) is an established assessment tool of perioperative physical fitness. CPET utilizing arm ergometry (CPET(arm)) is an attractive alternative in patients with lower limb dysfunction. We aimed to determine whether oxygen uptake obtained by CPET(leg) could be predicted by using CPET(arm) alone and whether CPET(arm) could be used in perioperative risk stratification. METHODS: Subjects underwent CPET(arm) and CPET(leg). To evaluate the ability of VO2 obtained from CPET(arm) to predict VO2 from CPET(leg), we calculated prediction intervals (PIs) at lactate threshold θ(L) and peak exercise in both groups. Receiver operating characteristic (ROC) curves were used to risk stratify patients into high and low categories based on published criteria. RESULTS: We recruited 20 vascular surgery patients (17 males and three females) and 20 healthy volunteers (10 males and 10 females). In both groups, PIs for at and peak were wider than clinically acceptable (patient group - VO2 at θ(L) CPET(arm) ranged from 55% to 108% of CPET(leg) and from 54% to 105% at peak; healthy volunteers - 37-77% and 41-79%, respectively). The area under the ROC for CPET(arm) VO2 in patients was 0.84 [95% confidence interval (CI): 0.66, 1.0] at θ(L), and 0.76 (95% CI: 0.54, 0.99) at peak. CONCLUSIONS: Although a relationship exists between VO2 values for CPET(arm) and CPET(leg), this is insufficient for accurate prediction using CPET(arm) alone. This however does not necessarily preclude the use of CPET(arm) in perioperative risk stratification.

Low hemoglobin concentration is associated with poor outcome after peripheral arterial surgery.

OBJECTIVE: To assess the influence of low hemoglobin (Hb) concentration on major adverse cardiac events (MACE) and mortality in patients undergoing peripheral arterial surgery. METHODS: This was a retrospective cohort study of patients undergoing peripheral arterial reconstructive surgery at a tertiary vascular center. Preoperative factors linked with the occurrence of MACE and death on univariate analysis (P ≤ .1) were included in a multivariate model to confirm the independent association with the outcome variables. RESULTS: A total of 360 consecutive patients (238 men) with a mean (standard deviation) age of 69 (10.7) years and Hb of 13.0 (2.12) g/dL treated under the care of a single specialist between January 2004 and December 2011 were included in the analysis. Of these, 193 (53.6%) were anemic. In all, 26 (7%) had a postoperative MACE and 18 (5%) died. On multivariate analysis, age > 80 years (odds ratio [OR] = 3; 95% confidence interval [CI] [1.2-7.5]; P = .025), renal impairment (OR = 3.2; 95% CI [.99-10.2]; P = .053), coronary disease (OR = 3.6; 95% CI [1.5-8.7]; P = .005), and low Hb (OR for each 1 g/dL drop below the mean = 1.4 [1.13-1.7]; P = .002) were independent risk factors for MACE. Unplanned surgery (OR = 4.5; 95% CI [1.2-16.9]; P = .025) and low Hb (OR for each 1 g/dL drop below the mean = 1.5; 95% CI [1.14-1.86]; P = .002) were independent risk factors for death. CONCLUSION: In peripheral arterial surgery, preoperative low Hb is associated with MACE and death. Further investigation is necessary to elucidate whether this relationship is causal. Meanwhile, consideration should be given to treating preoperative anemia as a significant risk factor for adverse outcome in this setting.

The basilic vein: an alternative conduit for complex iliofemoral reconstruction.

OBJECTIVES: To evaluate the basilic vein as an alternative conduit in iliofemoral arterial reconstructions. DESIGN: Retrospective cohort study. METHODS: We reviewed records of all patients undergoing iliofemoral arterial reconstruction with basilic vein between January 2006 and November 2011. Patients were identified via a prospective database, which also provided data on patients' comorbidity, indications for surgery and perioperative outcome. Long term outcome was confirmed by reviewing hospital records; graft patency was confirmed by clinical examination and imaging by ultrasound or CT angiography. RESULTS: We identified 15 patients undergoing 17 procedures (two patients underwent staged bilateral iliofemoral bypasses). Indications for vein (instead of prosthetic) graft use included prosthetic infection (4), suspected infection (2), proven hypercoagulable state (3), young age (3) and multiple graft occlusions (5). Preoperative mapping confirmed vein suitability in all cases, and all conduits were harvested from the upper limb. There were no major perioperative complications. After a median (range) follow up of 21.5 (1-42) months, all grafts were patent; one patient required secondary intervention on the graft. CONCLUSION: Iliofemoral arterial reconstruction with autologous basilic vein is feasible and may be a valid alternative when the use of prosthetic material is contraindicated.

Influence of muscle training on resting blood flow and forearm vessel diameter in patients with chronic renal failure.

BACKGROUND: Blood flow and vessel diameter are predictors of the success of vascular access procedures. This study investigated whether a simple exercise programme could influence these variables. METHODS: Twenty-three patients with chronic kidney disease were prescribed a simple exercise programme for one arm only; the investigators were blinded to the patients' choice. All underwent arterial and venous duplex imaging, handgrip strength and blood pressure measurements before and 1 month after the exercise programme. RESULTS: Twelve patients exercised their dominant and 11 their non-dominant arm. In the trained arm, the exercise programme resulted in a significant increase in handgrip strength, by a median (interquartile range) of 4 (0-8) kg (P < 0.001), and in the diameter of the brachial artery (0.2 (0.1-0.3) mm; P < 0.001), radial artery (0.3 (0.2-0.4) mm; P < 0.001), and cephalic vein (0.6 (0.4-1.2) mm in the forearm and 1.1 (0.4-1.2) mm above the elbow; P < 0.001). There was an increase in brachial artery mean velocity (3 (1-7) cm/s; P = 0.009) and peak systolic velocity (8 (1-15) cm/s; P = 0.020), despite a marginally lower systolic blood pressure (-8 (-16 to 0) mmHg; P = 0.007). There was no change in any of these parameters in the non-exercised arm. CONCLUSION: In patients with chronic kidney disease, forearm exercise increased blood flow and vessel diameters. This may be beneficial before vascular access formation.

Revision using distal inflow for treatment of heart failure secondary to arteriovenous fistula for hemodialysis.

In patients on hemodialysis, cardiovascular disease can be precipitated or worsened by the presence of a high flow arteriovenous fistula. Fistula closure and banding are the traditional treatment methods of dialysis associated high output cardiac failure. We present a case of fistula-related high output cardiac failure treated by revision using distal inflow (RUDI).