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J A Michaels

Publications and source records attributed to J A Michaels.

At least 37 records · Page 2Linked to original sources
PubMed1996

General surgery with a special interest in vascular surgery: changing patterns of workload.

Prospective surveys of workload were carried out during 1989, 1990 and 1995. Analysis of outpatient referrals, inpatients and operations performed over periods of 3 months was undertaken and the changing patterns of general surgical and vascular surgical workload noted. The number of outpatient referrals rose throughout the study period because of a significant increase in the number of patients with both varicose veins and other vascular problems. There was an increase in the number of emergency admissions for vascular disease. The number of patients having general surgical operations fell; there was a corresponding increase in the number for arterial and venous disease. The general surgical component of a general surgical unit with a vascular interest is gradually declining, as increased numbers of patients with vascular problems are being referred and managed.

Ambulatory Surgical Procedures↗
PubMed1996

A survey of methods used for cardiac risk assessment prior to major vascular surgery.

OBJECTIVES: To assess the frequency with which various methods of cardiac risk assessment are used prior to major vascular surgery and the way in which patients considered to the "high" risk are managed. DESIGN: Questionnaire survey. SETTING: Great Britain and Northern Ireland. MATERIALS: Vascular Surgeons who are current members of the Vascular Surgical Society of Great Britain and Northern Ireland. CHIEF OUTCOME MEASURES: Number of respondents reporting routine or frequent use of particular investigations and methods of management. MAIN RESULTS: Of 246 respondents, 52% had access to a high dependency unit and 77% used intensive therapy units routinely following aortic reconstruction. Some measure of ejection fraction was the most common investigation and was used routinely prior to aortic reconstruction by 35% and often by 33% of respondents, this being more frequent in respondents from teaching hospitals and those carrying out a greater number of reconstructions. Calculated clinical risk indices were rarely used. The identification of high risk patients led to referral to a cardiologist for 90% of respondents and influenced the choice of anaesthetist for 50%. CONCLUSIONS: It is concluded that there is considerable variation in practice, but that those who carry out more vascular surgery are more aggressive in their assessment of cardiac risk prior to reconstruction.

Aorta↗
PubMed1995

A comparison of clinical index and ejection fractions in predicting cardiac complications following infrarenal aortic reconstruction.

OBJECTIVE: To compare the Detsky clinical cardiac risk index with ejection fraction measurements in predicting postoperative cardiac events. DESIGN: Prospective study. SETTING: District General Hospital. MATERIALS: 48 patients undergoing infrarenal aortic reconstruction. CHIEF OUTCOME MEASURES: Ejection fractions were measured both by echocardiography and a technetium 99 MUGA scan. MAIN RESULTS: Three patients developed four major cardiac events (LVF three, fatal myocardial infarction one). Fourteen patients experienced 15 minor cardiac events (arrhythmia 11, ST segment depression four). The clinical index predicted postoperative cardiac problems (p = 0.0001). There was no correlation between ejection fraction measurement and postoperative cardiac events nor between ejection fraction measurements and the clinical index. Combining the index with ejection fraction measurement provided no additional information over the index alone. CONCLUSIONS: Calculation of a clinical index before aortic reconstruction is a simple and reliable way of selecting patients who are at risk of developing postoperative cardiac events.

Adult↗
PubMed1994

Organisation of vascular surgical services: evolution or revolution?

The trend towards subspecialisation in hospital services is likely to lead to the development of vascular surgery as a separate specialty. If vascular surgery is to emerge as a high quality service then vascular emergencies--a substantial component of the workload--should be dealt with by surgeons with adequate training, and all patients should have equal access to the service. A specialist vascular surgical unit would have to be large enough to make efficient use of other services that it needs, such as radiology, and so may require the amalgamation of smaller health district units. Because of the differing local degrees of subspecialisation, national or regional strategies for vascular surgery must be developed.

Emergencies↗
PubMed1994

Provision of vascular surgical services in the Oxford Region.

Vascular surgical practice across an entire health region was studied. There was a mean of 115.9 inpatient episodes and 46.9 vascular reconstructions per 100,000 population, with considerable variation between districts. Vein utilization for infrainguinal grafts was greater in the teaching hospital and few femorodistal grafts or carotid endarterectomies were carried out elsewhere; there were few tertiary referrals of elective vascular cases. Only two districts have formal arrangements for emergency vascular 'on-call'. There is marked inequality of provision of vascular surgical services across the region.

England↗
PubMed1994

General practitioner referral of patients with symptoms of peripheral vascular disease.

A questionnaire survey has been carried out to assess the circumstances under which general practitioners refer patients with peripheral vascular disease to a district general hospital. A single-page questionnaire was sent to 100 general practitioners seeking information about their referral of patients with claudication, ischaemic rest pain or abdominal aortic aneurysms. Of the 77% who responded, over half would not refer a 70-year-old with claudication at half a mile or an 80-year-old with claudication at 100 m, and 44% would not refer an 80-year-old with a palpable abdominal aortic aneurysm. The results suggest that many elderly patients with symptomatic claudication or asymptomatic aneurysms are not currently referred. Changing referral patterns due to a heightened awareness of minimally invasive methods of treatment or the benefits of aneurysm surgery have the potential for profound effects upon vascular surgical work-load.

Age Factors↗
PubMed1993

Popliteal aneurysm: morphology and management.

Since January 1988, 32 patients have presented with 44 popliteal aneurysms (22 thrombosed, 22 non-thrombosed). Patients with thrombosed aneurysms were older (median age 72 versus 66 years), and more likely to have bilateral lesions (P < 0.02) and serious associated cardiovascular disease (P < 0.02). Nineteen aneurysms thrombosed acutely; 12 were treated with intra-arterial thrombolysis, which was at least partially successful in seven. All 12 were subsequently bypassed, as were the other seven which were associated with such severe ischaemia that they required urgent operation. One patient died and two others required major amputation. Other complications included foot-drop (two patients), renal failure (one) and wound infection (two). Two grafts thrombosed and required re-exploration. Elective bypass was carried out in 11 patients without acutely thrombosed aneurysms; there were no significant postoperative problems. Distortion within the aneurysm (P < 0.01), large size (P < 0.01) and distortion of the popliteal artery above or below the lesion (P < 0.02) were all associated with thrombosis. Stenosis within the aneurysm was more likely in patients with multiple lesions (P < 0.01) and distortion with larger aneurysms (P < 0.01). After correcting for distortion, none of the other variables was independently significant. The combination of distortion and diameter > 3 cm was present in 13 of 15 thrombosed aneurysms. Morbidity is high following acute thrombosis of popliteal aneurysm. Distortion of the aneurysm appears to be a more sensitive predictor of thrombosis than size alone. The combination of distortion with a diameter > 3 cm may help to define popliteal aneurysms that should be bypassed electively.

Aged↗
PubMed1993

Management of asymptomatic popliteal aneurysms: the use of a Markov decision tree to determine the criteria for a conservative approach.

With recent improvements in the results of treatment of popliteal aneurysms, it has been suggested that it may be preferable to treat asymptomatic aneurysms conservatively and to operate only if symptoms develop. This hypothesis has been tested using decision analysis, with sensitivity and threshold analysis to establish the conditions under which such a policy would be appropriate. A Markov decision tree has been used to model the problem and the relevant probabilities have been obtained from a review of the current literature. A computer spreadsheet was used to calculate the results of policies of immediate operation or operation only if symptoms occur. Sensitivity and threshold analysis have been carried out to assess the effect of inaccuracy or alteration in the key variables and to determine the optimum policy under different conditions. The results suggest that early elective operation produces better results than conservative management at 1-2 years after presentation. Sensitivity analysis reveals that the most crucial data are the rate of development of symptoms in patients with asymptomatic aneurysms and the expected limb loss and mortality of treatment for symptomatic aneurysms. Threshold analysis has been used to define the values of these parameters that would be necessary for conservative management to be preferred. It is concluded that, based upon the currently available data, the optimum policy is elective treatment of asymptomatic aneurysms.(ABSTRACT TRUNCATED AT 250 WORDS)

Amputation, Surgical↗
PubMed1993

Case mix and outcome of patients referred to the vascular service at a district general hospital.

A prospective audit has been carried out to evaluate the trends in case mix and initial management of vascular surgical referrals to a single surgeon at a district general hospital. Over a 3-year period there were 1096 new emergency or routine referrals from a population of approximately 450,000. A total of 613 of these patients underwent vascular procedures, with a further 297 procedures subsequently being undertaken on the same patients during the period of the audit. There was a steady increase in the total number referred with little change in case mix with regard to age or diagnosis. Elderly patients had more severe symptoms and were less likely to be treated by minimally invasive means. The number of patients undergoing angioplasty or thrombolysis increased steadily without any corresponding reduction in the number of surgical procedures. It is concluded that there is a steady trend towards increasing vascular surgical workload which is not easily explained by a change in disease incidence or case mix. Elderly patients appear unlikely to be referred unless symptoms are severe and there are few referrals of elderly patients who might benefit from minimally invasive treatments.

Aged↗
PubMed1992

The management of small abdominal aortic aneurysms: a computer simulation using Monte Carlo methods.

Many small abdominal aortic aneurysms can now be identified by ultrasound screening and it is necessary to decide whether the risks of enlargement and rupture justify elective surgery. A computer simulation of the behaviour of small aneurysms has been constructed using Monte Carlo methods to model patterns of enlargement and rupture. The effect of policy with regard to the observation and timing of intervention has been evaluated for different patient groups. The results demonstrate the value of early intervention in otherwise fit patients with expected operative mortality rates of 5% or below, whereas, for older patients (over 70 years old) 6-monthly screening and operation if the aneurysm exceeds 5 cm is suggested. Higher risk patients with expected operative mortality of over 10% may be better treated conservatively up to an aneurysm diameter of 7 or 8 cm. The method used for simulation is flexible, being easily adjusted to take account of new information, and may have applications in other areas of clinical decision making.

Aged↗
PubMed1992

Case-control study of patient satisfaction with day-case and inpatient inguinal hernia repair.

A case-control study has been carried out to assess patient satisfaction with day-case or inpatient inguinal hernia repair using matched pairs of patients undergoing the same technique of inguinal hernia repair under general anaesthesia. Patients completed a single-page questionnaire 3-6 months after surgery. Although there was no objective difference in recovery, nearly half of the patients felt that they were discharged too early and the majority would prefer inpatient treatment. Day-case patients required significantly more medical attention after discharge and most of the reported wound complications were not known to the hospital. It is concluded that the introduction of day-case surgery in a district general hospital is not without problems and requires changes in working practices and resource availability with careful monitoring of outcome during its implementation.

Adult↗
PubMed1991

Prospective audit of vascular surgical emergencies in a district general hospital.

A prospective clinical audit was carried out to assess the volume and distribution of workload generated by vascular surgical emergencies over a 3-month period in a single health district in the UK. Of 53 consecutive patients referred as surgical emergencies with peripheral vascular problems, 45 were referred to a single vascular surgeon, 36 directly from a general practitioner or other specialist and nine from another general surgeon. A total of 39 operations and six radiological procedures were carried out, including 26 vascular reconstructions. To accommodate the 27 non-urgent operations, nine were performed 'out of hours' and 17 planned cases were cancelled. A median of five general surgical beds were required throughout the period studied and 11 patients required intensive therapy unit admission for a total of 39 days. It is concluded that vascular surgical emergencies constitute a substantial workload and are being dealt with mainly by a single vascular surgeon who effectively works a one in one rota. Inadequate facilities for urgent vascular surgery lead to a large number of cases being dealt with out of hours and frequent cancellation of routine operations.

Emergencies↗
PubMed1991

The selection of amputation level: an approach using decision analysis.

The choice of level for a major amputation of the leg depends upon the careful balancing of the advantages of preserving the knee joint against the risks of failure to heal and subsequent revision of the amputation stump. A study has been carried out to measure the values that health care professionals put upon different levels of disability resulting from amputation. The results show that the reduction of quality of life is thought to be 5-10% and 10-20%, respectively, for ambulation upon a below-knee and above-knee prosthesis and about 50% for failure to mobilise on an artificial limb. These utilities have been incorporated into a decision analysis to determine the optimum strategy for evaluation of amputation level, with other probabilities obtained from published data. The results demonstrate the advantage of attempting to preserve the knee joint, even if the chance of primary healing is as low as 20%. Tests of likely healing are most useful if the sensitivity is high, with specificity being less important, and the advantages may be outweighed by the costs of false negatives if sensitivity is below 90%. Sensitivity analysis shows that these findings remain valid over a wide range of possible values. Further research is required to gain more accurate information on which to base decisions, but on current evidence a policy of below-knee amputation in all cases of clinical doubt may be preferable to the use of currently available tests.

Amputation, Surgical↗