A comparison of rectal and intramuscular codeine phosphate in children following neurosurgery.

Codeine is frequently used for postoperative analgesia in children. Intramuscular injections are not ideal and the rectal route may be preferable. We compared rectal and intramuscular codeine administered following neurosurgery. 20 children (over 3 months) undergoing elective neurosurgical procedures, were randomized to receive either rectal or intramuscular codeine phospate (1 mg.kg-1) at the end of the procedure. Serum levels of codeine and morphine were assayed at intervals following administration (0, 30, 60, 120, 240 min). Fentanyl was the intraoperative analgesic and postoperative rescue analgesia was paracetamol, diclofenac and intramuscular codeine. The Children's Hospital of Eastern Ontario Pain Scale was used to assess analgesia. Peak codeine levels in both groups were observed at 30 min and morphine levels were consistently low. The plasma codeine levels were significantly greater at 30 and 60 min following intramuscular injection, and were associated with slightly better analgesia scores, but did not reach statistical significance. However, the peak plasma level occurred at similar times in both groups. Codeine is absorbed as rapidly via the rectal route compared with the intramuscular route but the peak levels are lower.

Training in abdominal aortic aneurysm (AAA) repair: 1987-1997.

OBJECTIVES: in the U.K. a decrease in working hours has led to shortening of surgical training. Operative experience must, therefore, be gained more quickly. The aim of this study was to examine the effect of these changes in relation to outcome following abdominal aortic aneurysm (AAA) repair; a vascular "indicator" operation as defined by the U.K. Royal Colleges. DESIGN, MATERIALS AND METHODS: analysis of a prospectively gathered database of 1136 consecutive elective and emergency AAA repairs. Two time periods, 1987-1991 and 1992-1997, are compared. RESULTS: since 1991 consultants have performed fewer asymptomatic (95/130 vs. 135/244,p =0.0012, chi-square test), elective symptomatic (51/72 vs. 32/62, p =0.035), emergency symptomatic (33/49 vs. 38/82, p =0.031) and ruptured (173/229 vs. 160/268, p =0.0003) AAA repairs. This has been associated with a significant increase in the proportion of procedures where a trainee is assisted by a consultant or operates "solo". Operative mortality did not change significantly between the two time periods, and was not affected by the absence of a consultant from the operating table. CONCLUSIONS: supervised trainees can perform an increasing proportion of AAA surgery without increasing operative mortality and can safely operate "solo" in selected cases. Auditing training in relation to clinical outcome is mandatory if the needs of patients and training surgeons are both to be met.

Carotid endarterectomy before and after publication of randomized controlled trials.

BACKGROUND: In 1991, the European Carotid Surgery Trial (ECST) and the North American Symptomatic Carotid Endarterectomy Trial (NASCET) demonstrated that carotid endarterectomy (CEA), in addition to best medical therapy, significantly reduces ipsilateral stroke in patients with high-grade (70 per cent or more) carotid artery stenosis compared with best medical therapy alone. In 1995, the Asymptomatic Carotid Atherosclerosis Study demonstrated that CEA was of benefit in asymptomatic patients with stenosis greater than 60 per cent. The aim of this paper was to examine how the practice and outcome of CEA have changed since publication of these data. METHODS: A prospectively gathered computerized database comprising 634 consecutive CEAs was studied. Two time intervals were analysed: 1975-1991 inclusive (17 years) and 1 January 1992 to 1 May 1998 (6 years 4 months). RESULTS: Since 1991, there has been a fourfold increase in the number of CEAs performed annually for symptomatic disease. CEA is now performed almost exclusively for high-grade (more than 70 per cent) stenosis. There has been a significant reduction in the total peri-operative neurological event rate (12.5 versus 5.9 per cent, P < 0.05), and the 30-day combined major stroke (Rankin grade 3-5) and mortality rate has fallen to 2.0 per cent. The number of patients who have CEA for asymptomatic disease remains small with 16 of 30 being randomized within the Asymptomatic Carotid Surgery Trial. CONCLUSION: Publication of ECST and NASCET data has been associated with a major increase in the number of CEAs performed for symptomatic disease in this unit. Despite a greater proportion of high-risk patients, the results have improved progressively.

A 21-year experience of abdominal aortic aneurysm operations in Edinburgh.

BACKGROUND: This study reviews the results of infrarenal abdominal aortic aneurysm (AAA) surgery over 21 years (1 January 1976 to 31 December 1996). METHODS: A prospectively gathered database was analysed. RESULTS: Infrarenal AAA repair was performed in 1515 patients: 492 (32.5 per cent) had elective repair of an asymptomatic AAA; 194 (12.8 per cent) had elective repair of a symptomatic AAA; 156 (10.3 per cent) had emergency repair of a symptomatic non-ruptured AAA; and 673 (44.4 per cent) had surgery for a ruptured AAA. The 30-day and/or same admission mortality rates were 6.1, 5.8, 14.1 and 37 per cent respectively. Operative mortality increased in all four groups over the study interval, although this only attained statistical significance in patients having elective repair of a symptomatic, non-ruptured AAA. There was a significant increase in the age of patients undergoing elective repair of an asymptomatic AAA, but not in the other three groups. There was also a significant increase in the proportion of straight 'tube' grafts inserted in all four groups. CONCLUSIONS: It remains the minority of patients who have elective operation before the onset of symptoms and/or rupture. Despite anaesthetic and surgical specialization, the results of AAA repair have not improved over the past two decades. Operative mortality may be increasing, possibly because of the increasing age and associated comorbidity of the patients presenting to this unit.

The value of computed tomography in the assessment of suspected ruptured abdominal aortic aneurysm.

OBJECTIVE: The objective of this study was to determine the diagnostic value of computed tomography (CT) in patients with suspected ruptured abdominal aortic aneurysm. STUDY DESIGN: The study was an interrogation of a prospectively gathered computerized database. SETTING: The study was performed at a regional vascular surgery unit. SUBJECTS: Six hundred fifty-two consecutive patients were admitted to this unit with suspected ruptured abdominal aortic aneurysm between January 1, 1989, and December 31, 1996. Seventy-four patients (11.3%) in whom the diagnosis was in doubt on clinical grounds alone underwent urgent CT. A total of 47 men and 27 women with a median age of 73 years (range, 52 to 86 years) were evaluated. MAIN OUTCOME MEASURES: CT and operative findings were compared. RESULTS: CT correctly diagnosed rupture in 22 of 28 patients who underwent operation and correctly excluded rupture in 30 of 39 patients who underwent operation. The sensitivity and specificity of CT when compared with operative findings were therefore 79% and 77%, respectively. CONCLUSIONS: These data indicate that CT has little additional diagnostic value. If in the opinion of an experienced vascular surgeon rupture cannot be excluded on clinical grounds alone, and the patient has no medical contraindications to abdominal aortic aneurysm repair, then the patient should be taken directly to the operating department.

Rapid inhalation induction in children: 8% sevoflurane compared with 5% halothane.

Sevoflurane has a lower blood-gas solubility and a less pungent odour than halothane; this may allow more rapid induction of anaesthesia. In a randomized, blinded study, we compared the induction characteristics of maximum initial inspired concentration of 8% sevoflurane and 5% halothane using conventional vaporizers in children aged 3 months to 3 years. There was no statistically significant difference in induction times between the two groups: mean times to loss of consciousness were 1 min 12 s (SD 18 s, range 40 s-1 min 44 s) for sevoflurane and 1 min 16 s (SD 17 s, range 50 s-1 min 52 s) for halothane, although these times were shorter than in previous studies using a gradual increase in vapour concentration. A small number of complications were noted in both groups, although none interfered with induction of anaesthesia. Struggling scores were lower in the sevoflurane group than in the halothane group (chi-square for trends = 6.34, P < 0.02). A significant number (11 of 15) of parents of children in the sevoflurane group who had previous experience of halothane induction preferred sevoflurane (chi-square for trends = 4.03, P < 0.05). We conclude that with this technique, induction was rapid with both sevoflurane and halothane. Our assessment of patient struggling and parents' perceptions suggests that induction with sevoflurane was more pleasant than with halothane.

Twelve-year experience of the management of ruptured abdominal aortic aneurysm.

BACKGROUND: The operative mortality rate for elective repair of asymptomatic abdominal aortic aneurysm (AAA) is falling but the fate of patients with ruptured AAA may have changed little over the past decade. METHODS: This study was an analysis of a prospectively gathered computerized database. RESULTS: In the 12 years to 31 December 1994, 1144 patients underwent (attempted) repair of AAA. In 514 patients (44.9 per cent) who had an operation for ruptured AAA there was no significant change in the mean age, male:female ratio (418:96), or operative mortality rate (35.0 per cent) over the interval of the study. Forty-seven patients died before reaching the operating theatre, giving an 'intention to operate' mortality rate of 40.5 per cent. A further 68 patients (10.8 per cent of all patients who presented with a ruptured AAA) were not offered operation because of poor medical condition (n = 34) or extreme age (n = 34); three patients refused operation. A greater proportion of patients had surgery between 1989 and 1994 (276 of 323, 85.4 per cent) than between 1983 and 1988 (238 of 309, 77.0 per cent) (P < 0.01, chi2 test). CONCLUSION: The proportion of aneurysms operated on for rupture in this unit remains high (almost 50 per cent). The results of surgery for ruptured AAA have not improved in the past 12 years.

Supervised training in carotid endarterectomy is safe.

BACKGROUND: The number of carotid endarterectomies (CEAs) performed in the UK, and thus the need to train surgeons in this operation, has increased markedly in recent years and may continue to do so. The aim of the present study was to assess the quality, clinical outcome and case-mix of supervised training in CEA in this unit. METHODS: The study was an analysis of a prospectively gathered database of all CEAs performed in this unit since 1975. RESULTS: Between 1 January 1975 and 31 December 1991, 247 CEAs were performed of which only 12 were done by supervised trainees. By contrast, between 1 January 1992 and 1 July 1996, 219 CEAs were performed, 92 (42 per cent) by supervised trainees (P < 0.0001). In cases performed since 1 January 1992, there was no significant difference between trainee and consultant operations with regard to age and sex of patient, smoking history, ischaemic heart disease, hypertension, diabetes, presence of preoperative infarction on computed tomography, indications for operation, degree of ipsilateral carotid stenosis, status of the contralateral carotid artery, use of a shunt or patch angioplasty. Since 1 January 1992, the total perioperative neurological event rate for supervised trainees was seven of 92 (7.6 per cent) of which one was fatal (cerebral infarction). The total neurological event rate for operations done by a consultant was nine of 127 (7.1 per cent), of which one was permanent and disabling and two were fatal (one cerebral infarction and one haemorrhage). CONCLUSION: Since 1991 there has been a tenfold increase in the proportion of CEAs being performed by supervised trainees. This has been accomplished without deterioration in clinical outcome. With adequate supervision, training in CEA can be safe, even when trainees are exposed to a true cross-section of low-, medium- and high-risk cases.

Vascular trauma of the upper limb and associated nerve injuries.

In an analysis of vascular audit data on upper limb vascular trauma over a 10 year period in a major UK injury centre it was found that 15 patients required operation for subclavian or axillary artery injuries. Eleven cases were the result of blunt injury. Twelve patients had an ischaemic arm on presentation, all of whom had an associated brachial plexus lesion. Subclavian or axillary artery transections, irrespective of limb viability, also were found to have associated plexus trauma. Twenty-eight patients had brachial artery injuries repaired, 46 per cent of whom had an associated nerve injury. A good functional result was achieved in only half of the patients who underwent repair of a peripheral nerve injured in association with the brachial artery. Vascular reconstruction was successful in all cases. The long-term outcome of brachial plexus lesions was very poor and the role of exploratory surgery is discussed. The long-term outcome of upper limb injury is not dependent on the vascular injury which can be successfully managed, but upon the recognition, treatment, and outcome of the associated nerve injuries.

'Brachial/basilic vein' transposition for vascular access.

Permanent vascular access for haemodialysis usually involves the use of autogenous or prosthetic grafts when standard fistula sites and procedures are not available. We wish to present technique and results using a transposed upper arm deep vein for vascular access.

Duplex ultrasound surveillance of infrainguinal bypass grafts: auditing the process.

The effectiveness of an infrainguinal bypass graft surveillance programme using duplex scanning was assessed over a 2-year period. Of 220 infrainguinal bypass grafts (123 vein and 97 PTFE grafts; 114 to the above knee level, 94 below knee and 12 distal to popliteal artery) in 203 patients, 208 (94.5%) were available for follow-up surveillance. The protocol called for duplex scans at 6 weeks, 3, 6, 9 and 12 months. Fifty-seven grafts (27%) were found to have a V1/V2 ratio equal to or greater than 1.5 and in this group 25 grafts occluded. The median time between primary operation and positive duplex finding was 4 months. Thirty-nine grafts failed during follow-up (at time of analysis median follow-up was 12 months [range 2-83 months]). There were 18 interventions resulting from surveillance-detected stenoses. The median time between positive duplex finding and further investigation was 2 months. Further, there were significant differences in the site of abnormal findings between ePTFE and vein grafts. The value of a surveillance programme may be reduced if there are low rates of intervention and/or excessive delays in intervention following the demonstration of graft-related stenoses. Surveillance programmes and subsequent interventions need to be audited.

Factors influencing the hyperaemic response after carotid endarterectomy.

Transcranial Doppler ultrasonography was used to evaluate serially the changes in middle cerebral artery blood flow velocity (MCAV) in 37 consecutive patients during the first 72 h after carotid endarterectomy to identify factors that may predispose towards postoperative hyperaemia. Within 6 h of endarterectomy, median MCAV in the operated hemisphere was 48 per cent (95 per cent confidence interval 37-60 per cent) above that on admission and remained 27 per cent (95 per cent confidence interval 19-37 per cent) higher at 72 h. There was a similar, but less marked, increase in MCAV in the contralateral middle cerebral artery during the same time period. There was no association between the postoperative increase in MCAV and clinical presentation, admission MCAV, the presence or absence of a residual neurological deficit or infarction on computed tomography before operation, carotid clamp time, shunt usage, internal carotid artery stump pressure or MCAV during clamping. The greatest increase in MCAV was observed in patients with internal carotid artery stenosis > or = 50 per cent and, more particularly, in those with preoperative evidence of impaired cerebrovascular reserve. In the latter patients, MCAV was 100 per cent above the admission level within 12 h of operation and was still 50 per cent raised at 72 h.

Pressure natriuresis following therapy for "one-clip one-kidney" hypertension in man.

Decreased renal tubular reabsorption of sodium in response to increased renal artery perfusion pressure, or "pressure natriuresis", has been demonstrated directly in animal experiments but not in man. In bilateral or single-kidney renovascular hypertension, hypertension has been attributed to reduced pressure natriuresis, and a similar mechanism may operate in chronic renal failure. We report a patient who presented with bilateral renovascular disease and was treated initially by unilateral nephrectomy. At a second operation the remaining ischemic kidney was revascularised. There followed a dramatic natriuresis, sufficient to cause clinical and biochemical features of hypovolemia. However, despite the natriuresis, systemic blood pressure remained elevated in the few weeks following surgery. We attribute the natriuresis to increased renal artery perfusion pressure, and conclude that acute pressure natriuresis sufficient to over-ride neurohormonal antinatriuretic mechanisms does occur in man. However, the failure to normalize blood pressure acutely following the natriuresis suggests that decreased sodium excretion is not the only mechanism which maintains hypertension in this unusual syndrome.

Preoperative coagulopathy in ruptured abdominal aortic aneurysm predicts poor outcome.

In a prospective study of 50 consecutive patients undergoing operation for ruptured abdominal aortic aneurysm, a coagulation screen was performed on admission to hospital. Twenty patients with either a platelet count < 100 x 10(9)/l or a prothrombin time > 1.5 times the control value had a mortality rate of 65 per cent (95 per cent confidence interval 45-85 per cent); a further 23 patients with normal screen results had a mortality rate of 9 per cent (95 per cent confidence interval 0-20 per cent) (P < 0.001). Seven patients, of whom three died, did not have an admission coagulation screen performed. Patient age in the study group did not have independent statistical predictive power. This study indicates that coagulopathy at the time of admission predicts poor outcome in patients with ruptured aortic aneurysm. Current management strategies are inadequate for the treatment of these patients, who can be rapidly identified on admission by means of platelet and prothrombin counts.

Above-knee femoropopliteal bypass grafts and the consequences of graft failure.

In all, 290 femoral to above-knee popliteal artery bypasses were performed between January 1983 and September 1991. PTFE grafts were used in 113 cases (39%) and vein grafts in 177 (61%) (reversed in 146 cases and in situ in 31). Patients were followed up for a median time of 20 months. The 2-, 4- and 6-year patency rates for vein and PTFE grafts were 70%, 62% and 57%, respectively, compared with 58%, 46% and 41% (no statistical difference in survival curves, P = 0.2). The 2-, 4- and 6-year limb salvage rates were 82%, 78% and 62% compared with 75%, 64% and 58% (no statistical difference in survival curves, P = 0.6). A total of 99 grafts occluded during follow-up (45 PTFE and 54 vein grafts). Major amputation was required in 63 limbs; below-knee in 37 limbs (59%), and above-knee in 26 limbs (41%). There was no statistical difference in the amputation level with respect to the graft type. Final healing at the below-knee level was achieved in 23 of 35 (66%) failed vein grafts and in 14 of 28 (50%) failed PTFE grafts.

An audit of trends and current practice of carotid endarterectomy in Edinburgh (1975-1990).

Changes in the patient population and trends in management were studied for 260 consecutive carotid endarterectomies performed during the periods 1975-1982 and 1983-1990. A 43% increase was observed in the number of operations (from 107 to 153), an 81% increase taking into account patients randomized to medical treatment in the European Carotid Surgery Trial. There were significant reductions in patients continuing to smoke (79 to 60%, P = 0.001), in those with systolic hypertension (21 to 11%, P = 0.018) and diastolic hypertension (26 to 12%, P = 0.002), and in those with asymptomatic carotid lesions (8 to 2%, P = 0.031). There were significant increases in the proportion of patients with strokes presenting with a residual neurological deficit (40 to 66%, P = 0.024), and in those with ocular symptoms (30 to 50%, P = 0.001) and with stenoses greater than 50% (58 to 71%, P = 0.018). This study suggests a trend for a higher risk population with more severe carotid disease. In the light of results of clinical trials, further evolution of patient selection is likely to occur and should be taken into account when evaluating the risk of carotid endarterectomy.

Edinburgh Regional Vascular Surgery Unit: development of emergency practice 1983-1992.

Emergency referrals made to the Edinburgh Regional Vascular Surgery Unit in the first two months of 1983, 1987 and 1992 have been analysed with respect to demographic information, source, diagnosis and management. The total number of referrals made in the study period of each year was 72, 129 and 200 respectively. The male to female ratio was 1:1 for each year. Patients referred in 1992 were significantly older than those referred in 1983 (P < 0.05 by two-sample t test). The marked increase in the number of referrals from other hospitals and centres has been largely responsible for the dramatic threefold increase in the emergency workload. Overall, 80% of patients were referred with arterial disease and in over 50% this was infra-inguinal. In 1983, 50% of acute limb ischaemia was embolic compared with less than 25% in 1992. There has been a marked increase in the number of asymptomatic and symptomatic but non-ruptured abdominal aortic aneurysms referred compared with only a small increase in the number of ruptured aneurysms. Vascular access for renal dialysis remains an important part of the overall workload. Overall, 50% of patients referred were admitted and 37.5%, 26.5% and 15.5% of patients underwent emergency surgery in 1983, 1987 and 1992 respectively.

Immediate effects of carotid clamp release on middle cerebral artery blood flow velocity during carotid endarterectomy.

Transcranial Doppler ultrasound was employed in 44 patients undergoing carotid endarterectomy in order to identify factors associated with the greatest increases in middle cerebral artery blood flow velocity (MCAV) immediately after carotid clamp release and restoration of flow. Previous reports have suggested that such increases might reflect post-ischemic hyperaemia. Overall, the median increase in MCAV on restoration of flow [58 cm/s (95% Cl 44-68)] was greater than the median decrease in MCAV after initial carotid clamping [36 cm/s (95% Cl 26-43), p < 0.0001]. However, the immediate increase in MCAV tended to be transient and, in one patient, may have represented a hyperaemic response to a haemodynamically induced intraoperative neurological deficit. There was no association between the magnitude of MCAV increase and clinical presentation, degree of carotid stenosis, computed tomography scan findings, type of anaesthesia, nor the presence or absence of impaired cerebral vascular reserve, nor the occurrence of intraoperative air embolisation. The greatest increases in MCAV on clamp release were observed in patients with the greatest decreases in MCAV at clamping and those with the lowest internal carotid artery stump pressures. The most likely explanation for the findings is that they represent a transient hyperaemic response to carotid occlusion. It remains unclear whether this phenomenon is mediated by some degree of ischaemic injury or simply by the effect of a sudden surge of blood through low resistance arterioles that have dilated in order to maintain the collateral circulation during carotid clamping.

Acute thrombosis of the non-aneurysmal abdominal aorta.

Fourteen patients admitted over a 9 year period with acute thrombotic occlusion of the non-aneurysmal abdominal aorta have been reviewed. Twelve patients underwent aortic bifurcation graft reconstruction, one thromboendarterectomy alone, and one a re-entry operation for dissection. Two patients (14%) died in the perioperative period. The mean postoperative survival of the remaining patients is to date 55 (range 4-93) months with a mean follow-up period of 69 (range 18-100) months. The results indicate these patients should be treated aggressively by early reconstructive surgery in the expectation that the majority will survive their operation and gain a useful extension to their lives.

Comparison of long-term survival after successful repair of ruptured and non-ruptured abdominal aortic aneurysm.

Long-term survival was assessed after the repair of non-ruptured (n = 311) and ruptured (n = 227) abdominal aortic aneurysm. Follow-up was 94.2 per cent complete, and the overall survival rate at 8 years was 43.6 per cent. There was no significant difference in 8-year survival rates between patients with non-ruptured (45.2 per cent) and ruptured (40.5 per cent) aneurysms. The survival curves were also compared with that for an age- and sex-matched population derived from Scottish Home and Health Department data.