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Biomedical subjects

B D Braithwaite

Publications and source records attributed to B D Braithwaite.

33 records · Page 2Linked to original sources

Computerized angiographic analysis of the outcome of peripheral thrombolysis.

BACKGROUND: Catheter-directed peripheral thrombolysis is used increasingly for the management of acute limb ischemia. The comparison of different agents and techniques has proven difficult because of the variations in patient presentation, vessel involvement, and treatment methods. METHODS: A computerized database in which angiographic information is stored on computerized arterial maps has been designed to record details of thrombolysis. RESULTS: A total of 201 patients who presented with rest pain were recorded on the database, and their angiograms were analyzed. There were 123 native-vessel and 78 graft occlusions. Immediate success of lysis and 30-day outcome were not dependent on the site of the occlusion. If an underlying stenosis was revealed, limb salvage rates were significantly greater than when none was found (82% versus 58%, P < 0.01). The presence of at least 1 run-off vessel increased limb salvage rates by 30% (P < 0.001). If more than 5 arterial segments were occluded on the prelysis angiogram, limb salvage was worse than if there were fewer than 5 (57% versus 85%, P < 0.0001). For grafts, less than 5 segments of occlusion led to limb salvage rates of 90%, and more than 5 segments of occlusion led to rates of 72% (P = 0.07). CONCLUSIONS: This simple and user-friendly system of computerized angiographic analysis will enable detailed examination of thrombolytic practice and assist in the prediction of success.

Adult↗

Accelerated thrombolysis with high dose bolus t-PA extends the role of peripheral thrombolysis but may increase the risks.

Low dose intra-arterial thrombolysis is too slow for many patients with severe acute limb ischaemia. Accelerated thrombolysis with high dose bolus t-PA was used in a consecutive series of 43 patients. Complete or clinically useful lysis was achieved in 39 patients, with a median duration of 7 h. Lysis occurred in 46% in under 4 h. Fifty-six per cent of patients required further procedures after lysis. Eleven per cent suffered a major bleed. The limb salvage rate at 30 days was 56%. Amputation was required in 22% and 22% died. Most deaths were due to associated thrombotic conditions: myocardial infarction (5), pulmonary embolism (1) and malignant thrombosis (1). One patient died from pneumonia two weeks after lysis and two died from renal failure within a week of thrombolysis. The high mortality rate was not associated with bleeding but may reflect the high risks involved in treating this group of patients. High dose bolus t-PA infusion appears to predict immediate outcome of thrombolysis as well as reducing infusion times. It may expand the indications for the non-surgical treatment of acute limb ischaemia to include most patients with the condition. Careful case selection is still necessary for optimal results.

Acute Disease↗

Laparoscopic aortofemoral bypass. Initial experience in an animal model.

OBJECTIVE: The study objective was to evaluate the feasibility of laparoscopic aortofemoral bypass in a porcine model. SUMMARY BACKGROUND DATA: Laparoscopic techniques have been applied to numerous general and thoracic surgical procedures. Their application to vascular surgery has been virtually nonexistent. Open surgery for aortoiliac occlusive disease is accompanied by significant morbidity rates, and minimally invasive procedures have the disadvantage of reduced patency rates. Laparoscopic aortofemoral replacement has the theoretical advantage of long-term patency with reduced postoperative complications. METHODS: Between January and September 1993, laparoscopic surgery was performed on 16 pigs: 6 underwent transperitoneal laparoscopic aortic dissection and vessel control alone; 7 underwent complete transperitoneal laparoscopic aortofemoral bypass; and 3 underwent a retroperitoneal approach. The aortic anastomosis was performed using a combination of sutures and titanium clips in an end-to-side fashion in five pigs, and a custom-made nonsutured graft was secured with use of an end-to-end method in five pigs. Femoral anastomoses were performed with the standard open technique. RESULTS: Technical success was achieved in all 10 animals and with no major complications. Mean blood loss was 20 ml (range, 5-50 ml), and mean operative time was 2.45 hours (range, 2-4 hrs). On aortic-clamp release, 2 of the end-to-side anastomoses required additional sutures to stop bleeding between oversized staples, and 2 of the end-to-end anastomoses required additional ties to reinforce loose ties. All 10 grafts and anastomoses were patent and free of leaks after completion of the procedure. CONCLUSIONS: Laparoscopic aortofemoral bypass is technically feasible in a porcine model. Further experimental work with new instrumentation and technical refinement will make laparoscopic surgery feasible for the treatment of vascular disease in humans.

Anastomosis, Surgical↗

NATALI--a model for National Computer Databases in the investigation of new therapeutic techniques.

New medical treatments are often introduced without the benefit of randomized trials. We describe how a national computerized database was produced, by the Thrombolysis Study Group, for monitoring one such new treatment: peripheral arterial thrombolysis. A novel method for transferring angiograms to computer generated arterial maps that can help in the classification and analysis of the outcome of thrombolysis is also described. Data provided by prospective collection from 14 hospitals within the UK was entered onto the database (Auditbase for Windows), to give contributing members a continual audit of their own results and complications that can be compared with that of the group as a whole. This system may be an appropriate model for other forms of multi-centre audit and the monitoring of new treatments.

Computer Graphics↗

Haemostasis during carpal tunnel release under local anaesthesia: a controlled comparison of a tourniquet and adrenaline infiltration.

A randomized controlled comparison of tourniquet and local adrenaline infiltration for control of bleeding was performed in patients undergoing bilateral carpal tunnel release under local anaesthesia. Visual analogue scores for intra-operative pain were substantially greater for tourniquet (mean score 4.7) than for adrenaline (2.2). Incomplete control of bleeding was responsible for longer operating time and for the surgeons' perception of slightly greater operative difficulty with the use of adrenaline. There were no complications attributable to the use of adrenaline. The use of adrenaline-containing local anaesthesia for carpal tunnel release avoids tourniquet pain and is preferred by patients.

Anesthesia, Local↗

Pasteurella multocida infection of a total hip arthroplasty. A case report.

The authors report a case history of a diabetic woman requiring revision hip arthroplasty of a Charnley total hip prosthesis that was infected with Pasteurella multocida. The infection of the loose prosthesis followed a cat bite to the same leg. Advice is given on the management of patients with infection following animal inoculations, and the subject of increased risk with a loose prosthesis is discussed.

Animals↗

Simulator sickness in an army simulator.

Simulator sickness describes a symptom reported by aircrew during or after flight simulator training. Some features are common to motion sickness but others, which are unusual during real flight, are believed to result specifically from the simulator environment. This paper describes the results of a questionnaire study examining the incidence and factors influencing simulator sickness in any army training system. Case histories are described and conclusions drawn with respect to health and safety, training and the effect on flight operations. One hundred and fifteen aircrew were registered in the questionnaire study. Data were collected from a history questionnaire, a post-sortie report and a delayed report form. Sixty-nine per cent of aircrew gave a history of symptoms in the simulator and 59.9 per cent experienced at least one symptom during the study period although few symptoms were rated as being other than slight. Only 3.6 per cent of subjects reported symptoms of disequilibrium. Comparative analysis of the results was performed after scoring symptoms to produce a sickness rating. This showed: association between simulator-induced sickness and greater flying experience; adaptation to the simulator environment; a history of sea sickness may predict susceptibility to simulator sickness; and no association of crew role and simulator sickness. Although some authorities believe simulator sickness to be a potential flight safety hazard there was little evidence from this study. Guidelines for the prevention of the problem are presented now that many factors have been identified. A general policy to 'ground' aircrew for a period following simulator training is not necessary, but severe cases should be assessed individually.

Adult↗

Lower limb intraarterial thrombolysis as an adjunct to the management of arterial and graft occlusions.

Intraarterial thrombolysis is used increasingly for management of arterial and bypass graft occlusions. Current research has been directed at the indications for and methods of catheter-directed thrombolysis. Streptokinase, urokinase, and tissue plasminogen activator (t-PA) are the most commonly used agents. They are administered by a variety of techniques and in various doses involving intrathrombic infusions, thrombus lacing, high-dose bolus therapy, and pulse-spray lysis. The latter methods appear to produce thrombolysis within a few hours, so this chemical therapy has the potential to become the first-line management for all episodes of acute limb ischemia. The role of thrombolysis is to return patients to their prethrombotic or preembolic state, so the underlying condition can be treated by radiologic intervention, surgery, or anticoagulation. Intraarterial thrombolysis is indicated for occlusions of less than 2 weeks' duration where the limb is able to withstand a period of further ischemia. Older occlusions should be treated by surgery, reserving intraoperative lysis for specific situations.

Angiography↗