Nitrous oxide exposure does not seem to be associated with increased mortality, stroke, and myocardial infarction: a non-randomized subgroup analysis of the General Anaesthesia compared with Local Anaesthesia for carotid surgery (GALA) trial.

BACKGROUND: Nitrous oxide has been associated with increased vascular risk in the perioperative period. Here, we conducted a secondary analysis of the GALA trial to ascertain the impact of nitrous oxide on outcomes after carotid surgery under general anaesthesia (GA). METHODS: One thousand seven hundred and seventy-three patients underwent GA, but 158 patients were excluded from this analysis as nitrous oxide use was unknown. The decision to use nitrous oxide was at the discretion of the anaesthetist and was not randomized. Six hundred and seventy-one patients received nitrous oxide and 944 patients did not. Logistic regression was used to analyse the same primary outcome as the original trial (risk of death, stroke, or myocardial infarction within 30 days of the operation). RESULTS: Patients who received nitrous oxide were more likely to have had coronary artery disease, peripheral vascular disease, and atrial fibrillation (all P<0.05). Overall, there were 35 (5.2%) primary outcome events in patients receiving nitrous oxide compared with 44 (4.7%) in those who did not [relative risk 1.12, 95% confidence interval (CI: 0.73, 1.73); P=0.63]. The adjustment for the imbalanced baseline variables using logistic regression reduced the point estimate of harm for nitrous oxide [adjusted odds ratio 1.09, 95% CI (0.68, 1.74); P=0.73]. CONCLUSIONS: Given the greater prevalence of vascular risk factors in the nitrous oxide group and the lack of any definite effect on the primary outcome measure, these data do not support a clinically meaningful adverse effect of nitrous oxide on our composite outcome in patients undergoing carotid surgery.

Cost-effectiveness analysis of general anaesthesia versus local anaesthesia for carotid surgery (GALA Trial).

BACKGROUND: Health outcomes and costs are both important when deciding whether general (GA) or local (LA) anaesthesia should be used during carotid endarterectomy. The aim of this study was to assess the cost-effectiveness of carotid endarterectomy under LA or GA in patients with symptomatic or asymptomatic carotid stenosis for whom surgery was advised. METHODS: Using patient-level data from a large, multinational, randomized controlled trial (GALA Trial) time free from stroke, myocardial infarction or death, and costs incurred were evaluated. The cost-effectiveness outcome was incremental cost per day free from an event, within a time horizon of 30 days. RESULTS: A patient undergoing carotid endarterectomy under LA incurred fewer costs (mean difference pound178) and had a slightly longer event-free survival (difference 0.16 days, but the 95 per cent confidence limits around this estimate were wide) compared with a patient who had GA. Existing uncertainty did not have a significant impact on the decision to adopt LA, over a wide range of willingness-to-pay values. CONCLUSION: If cost-effectiveness was considered in the decision to adopt GA or LA for carotid endarterectomy, given the evidence provided by this study, LA is likely to be the favoured treatment for patients for whom either anaesthetic approach is clinically appropriate.

Jugular venous neurone specific enolase (NSE) increases following carotid endarterectomy under general, but not local, anaesthesia.

INTRODUCTION: Previous studies indicate that local (LA) rather than general anaesthesia (GA) for carotid endarterectomy (CEA) is associated with reflex hypertension and preservation of cerebral cytochrome oxidase after carotid clamping. The hypothesis that LA offers protection against ischaemic cerebral injury has been investigated by measuring ipsilateral jugular venous neurone specific enolase (NSE: neuronal glycolytic enzyme) and S-100B (glial cell protein) during and after CEA. METHODS: 27 patients with symptomatic carotid artery disease (70-99% stenosis) underwent CEA, 14 under LA and 13 under GA. Jugular venous blood samples were assayed for NSE and S-100B before carotid clamping and at 5min before and 5min, 2, 4, 6, 8, 12 and 24h after clamp release. RESULTS: No neurological complications occurred. S-100B levels were low and did not increase from baseline in either group. Pre-clamp NSE levels were similar in both groups (LA: 17.6 (15.2-20.7)microg/l, GA: 21.5 (11.3-26.2)microg/l; p=0.37) but increased significantly 2h after clamp release in GA patients (LA: 25.5 (16.6-27.8)microg/l, GA: 48.2 (31.4-61.3)microg/l, p=0.05) with a significant rise from baseline in GA patients (p=0.04). CONCLUSIONS: CEA performed under GA is associated with greater rises in jugular venous NSE, and hence cerebral injury, than CEA performed under LA.

Endovenous laser treatment for uncomplicated varicose veins.

OBJECTIVE: Endovenous laser ablation (EVLA) of incompetent truncal veins has been proposed as a minimally invasive alternative to conventional surgery for varicose veins. Various strategies have been proposed for successful treatment and this study reviews the evidence for these. METHOD: A Medline and 'controlled trials online database' search was performed to identify original articles and randomized controlled trials (RCTs) reporting outcomes for EVLA. Information on patient selection, equipment, technique and outcomes were recorded. RESULTS: Ninety-eight original studies, including five RCTs, were identified. RCT data indicate short-term outcomes (abolition of reflux, improvement in quality of life [QOL], patient satisfaction) were equivalent to those for surgery. Long-term follow-up is not available. A further RCT showed superior outcomes for ablation commencing at the lowest point of superficial venous reflux rather than at an arbitrary point (fewer residual varicosities, greater improvement in QOL). Non-randomized series suggest that laser energy of >60 J/cm results in reliable truncal vein occlusion and that longer wavelength lasers may be associated with less post-treatment discomfort. CONCLUSION: In the short-term EVLA is a safe and effective treatment for patients with varicose veins. Long-term follow-up is still required.

General anaesthesia versus local anaesthesia for carotid surgery (GALA): a multicentre, randomised controlled trial.

BACKGROUND: The effect of carotid endarterectomy in lowering the risk of stroke ipsilateral to severe atherosclerotic carotid-artery stenosis is offset by complications during or soon after surgery. We compared surgery under general anaesthesia with that under local anaesthesia because prediction and avoidance of perioperative strokes might be easier under local anaesthesia than under general anaesthesia. METHODS: We undertook a parallel group, multicentre, randomised controlled trial of 3526 patients with symptomatic or asymptomatic carotid stenosis from 95 centres in 24 countries. Participants were randomly assigned to surgery under general (n=1753) or local (n=1773) anaesthesia between June, 1999 and October, 2007. The primary outcome was the proportion of patients with stroke (including retinal infarction), myocardial infarction, or death between randomisation and 30 days after surgery. Analysis was by intention to treat. The trial is registered with Current Control Trials number ISRCTN00525237. FINDINGS: A primary outcome occurred in 84 (4.8%) patients assigned to surgery under general anaesthesia and 80 (4.5%) of those assigned to surgery under local anaesthesia; three events per 1000 treated were prevented with local anaesthesia (95% CI -11 to 17; risk ratio [RR] 0.94 [95% CI 0.70 to 1.27]). The two groups did not significantly differ for quality of life, length of hospital stay, or the primary outcome in the prespecified subgroups of age, contralateral carotid occlusion, and baseline surgical risk. INTERPRETATION: We have not shown a definite difference in outcomes between general and local anaesthesia for carotid surgery. The anaesthetist and surgeon, in consultation with the patient, should decide which anaesthetic technique to use on an individual basis. FUNDING: The Health Foundation (UK) and European Society of Vascular Surgery.

Carotid endarterectomy: technical practices of surgeons participating in the GALA trial.

OBJECTIVE: Recent meta-analyses confirm an advantage to patch angioplasty during carotid endarterectomy (CEA) and suggest a benefit from routine shunting. GALA Trial (RCT: general [GA] versus local [LA] anaesthesia for CEA) collaborators (non-UK [European] and UK) were surveyed to assess current practice techniques. MATERIALS AND METHODS: Postal questionnaires determined: shunt usage, monitoring techniques dictating shunt deployment, criteria for patching and the influence of anaesthetic technique upon these decisions. RESULTS: 157/216 surgeons (73%) replied. For UK surgeons (n=76) performing GA CEA a shunt was always, never, or selectively used by 73.6%, 4.2% and 22.2% respectively. Figures for non-UK surgeons (n=77) were 20.8% (p<0.0001), 26% (p<0.0002) and 53.2% (p<0.0001). When shunting selectively, fewer UK surgeons relied on stump pressure (26.4% v 48.1%; p<0.0064) with TCD more widely used (38.9% v 11.7%; p<0.0001). Shunting criteria during LA CEA were the same for both groups (impaired awake-testing). Routine patching was commoner amongst UK surgeons (GA: 76.4% v 34.2%, p<0.0001; LA: 70.1% v 31.9%, p<0.0001). CONCLUSIONS: These results indicate that more UK surgeons have adopted current suggestions for improving CEA outcomes. Future analysis of unblinded GALA Trial data may provide further information about the impact of different policies for shunting and patching.

Patient satisfaction for carotid endarterectomy performed under local anaesthesia.

OBJECTIVES: To develop, validate and use a procedure specific questionnaire to evaluate patient experience and satisfaction following carotid endarterectomy (CEA) under either general (GA) or local anaesthesia (LA). METHODS: Twenty post-CEA patients were interviewed. Data were content analysed and recurrent themes used to generate the specific carotid endarterectomy experience questionnaire (CEA-EQ). The CEA-EQ consists of 15 pre-op and 13 postoperative questions. Validity was established by correlation with the FRS Patient Satisfaction with Surgical Services (SSSQ) and State form of the State Trait Anxiety Inventory (STAI-S) in 69 patients (35 LA, 34 GA). Subsequently 88 patients randomised to GA CEA and 88 to LA CEA received the CEA-EQ. A local anaesthetic intraoperative experience questionnaire (LA-EQ) was also developed and given to LA patients only. RESULTS: Validity was confirmed through significant correlations with the STAI-S (r=0.67, p<0.001) and the SSSQ (r=0.44, p<0.001). In the randomised prospective study response rates were greater than 90%. Overall experience and satisfaction with CEA was high. There was no statistically significant difference in anxiety, satisfaction or overall experience between anaesthetic techniques. LA CEA was associated with a significantly better perception of recovery. The majority of LA patients found the procedure acceptable. CONCLUSIONS: The CEA-EQ is a valid tool to assess qualitative aspects of CEA patient care. Overall satisfaction and experience with CEA is good and not related to anaesthetic technique. LA CEA is not associated with any increased anxiety, is tolerated by the majority of patients and is associated with a better perception of recovery.

Carotid endarterectomy; local or general anaesthesia?

OBJECTIVES: to review the evidence for theoretical and clinical benefits of local or general anaesthesia for carotid endarterectomy. METHODS: literature review. RESULTS: animal studies suggest cerebral protection by a variety of general anaesthetic agents but clinical evidence is lacking. There is some clinical evidence that normal cerebral protective reflexes are preserved with local anaesthesia. Shunt insertion is the most widely used method of providing cerebral protection with awake testing the most reliable monitoring technique for the identification of ischaemia. There are therefore theoretical arguments for a reduced risk of perioperative stroke when local anaesthesia is used and this is supported by a meta-analysis of non-randomised studies. Intraoperative blood pressure is always higher with local anaesthesia but the incidence of postoperative haemodynamic instability seems to be independent of anaesthetic technique. There is little evidence that myocardial ischaemia is more common with either anaesthetic technique but meta-analysis of non-randomised again suggests fewer cardiac complications with local anaesthesia. Cranial nerve injury and haematoma formation may be less common with local anaesthesia but the evidence is weak. There is no evidence that surgery is more difficult with local anaesthesia or that it is poorly tolerated by the patients. CONCLUSIONS: there are theoretical arguments and clinical evidence that the outcome from carotid endarterectomy may be better when local anaesthesia is used with no significant disadvantages. An appropriately designed randomised trial is required to confirm this.

Do prostaglandins have a salutary role in skeletal muscle ischaemia-reperfusion injury?

OBJECTIVES: the effects of prostaglandins (PG) E1, E2, and the prostacyclin analogue iloprost with and without the addition of free-radical scavengers catalase and superoxide dismutase on gastrocnemius blood flow and oedema were studied in a rodent model of hindlimb ischaemia-reperfusion. METHODS: male Sprague-Dawley rats underwent 6-h hindlimb ischaemia with 4-h reperfusion. Prostaglandins were infused prior to reperfusion and their effects on limb blood flow and oedema examined. RESULTS: control animals exhibited a triphasic pattern of muscle blood flow during reperfusion compared to normal animals. PGE1 did not abolish low reflow at 10 min, relative reperfusion was preserved but reperfusion injury was abolished at 120 min. Muscle blood flow was increased at 240 min compared to controls. Increased limb swelling was also seen. Addition of free-radical scavengers caused the abolition of low reflow. Similar results were seen with iloprost. PGE2 abolished low reflow at 10 min and increased perfusion at 120 min but did not prevent reperfusion injury at 240 min. CONCLUSIONS: PGE1 and iloprost enhance muscle blood flow at 4-h reperfusion, though neither abolishes low reflow; PGE2 improved flow at 10 and 120 min but not after 240 min. This study demonstrates a potentially beneficial role for prostaglandins in improving muscle blood flow in skeletal muscle ischaemia-reperfusion injury.