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Biomedical subjects

A J Bryan

Publications and source records attributed to A J Bryan.

105 records · Page 6Linked to original sources

Coronary artery bypass surgery: current practice in the United Kingdom.

A survey of current clinical practice was carried out among the 84 consultant cardiac surgeons currently performing coronary artery bypass surgery in the United Kingdom. The 80 surgeons who returned the questionnaire performed an estimated total of 17,100 coronary artery bypass graft operations in 1987, a mean case load of 214 operations each. Sixty two of the 80 surgeons regarded the internal mammary artery as the graft conduit of choice, and seven preferred the saphenous vein. The internal mammary artery was used in 73% of bypass grafts to the left anterior descending coronary artery but in only 4% of grafts to the circumflex and right coronary systems. Contraindications to the use of the internal mammary artery included advanced age of the patient (51 surgeons), insufficient flow through the internal mammary artery (49), and endarterectomy (35). Seventy four of the 80 surgeons considered intraoperative damage to the saphenous vein to be a possible cause of vein graft failure, but there was no agreement about how it should be reduced. All surgeons advocated pharmacological measures to enhance graft patency. Dipyridamole and aspirin constituted the most popular regimen (58 surgeons), though only 28 started dipyridamole preoperatively. Warfarin was prescribed postoperatively on occasion by 22 surgeons, but 14 of these used it only after endarterectomy.

Aged↗

Traumatic rupture of the thoracic aorta.

Traumatic rupture of the thoracic aorta is a lethal injury associated with high speed accidents. In multiply injured patients a high index of suspicion is required to allow prompt diagnosis of this condition. Urgent surgery is life saving in the majority of patients.

Adult↗

Unilateral digital ischaemia secondary to embolisation from subclavian atheroma.

Four cases of unilateral digital ischaemia in the upper limb secondary to embolisation from atheromatous plaques in the proximal subclavian artery are presented. Digital subtraction angiography or arch aortography were used to demonstrate the site of atheroma. In one case diagnostic delay resulted from failure to visualise the site of embolisation on the original aortogram and a repeat examination was necessary. Subclavian endarterectomy was undertaken in each case and irreversibly ischaemic digits were managed by local amputation in two cases. Direct surgery to remove the site of embolisation was preferred to bypass or transposition procedures. No further embolic episodes have been recorded with a follow-up of 6 months to 3 years. The important diagnostic features and options in surgical management of this syndrome are discussed.

Arteriosclerosis↗

Effects of concurrent response-independent reinforcement on fixed-interval schedule performance.

In three experiments, behavior maintained by fixed-interval schedules changed when response-independent reinforcement was delivered concurrently according to fixed- or variable-time schedules. In Experiment I, a pattern of positively accelerated responding during fixed interval was changed to a linear pattern when response-independent reinforcement occurred under a variable-time schedule. Overall response rates (total responses/total time) decreased as the frequency of response-independent reinforcement increased. Experiment II showed that the response-rate changes in the first experiment were controlled by the response-reinforcer relation, but the changes in patterns of responding were similar whether concurrently available reinforcement at varying times was response-dependent or response-independent. In the final experiment, the addition of response-independent reinforcement at fixed times to a fixed-interval schedule resulted in changes in both local and overall response rates and in the occurrence of positively accelerated responding between reinforcements. These results suggest that the temporal distribution of reinforcers determines response patterns and that both the response-reinforcement dependency and the schedule of reinforcement determine overall response rates during concurrently scheduled response-dependent and response-independent reinforcement.

Journal Article↗

Influence of recipient and donor gender on outcome after heart transplantation.

To investigate the effect of recipient and donor genders on the outcome after heart transplantation, a retrospective survey was undertaken of 356 patients (366 transplants: 316 males, 40 females) undergoing transplantation between January 1979 and December 31, 1989, at Papworth Hospital. Ninety-three organs came from female donors; 263 organs came from males. Twelve females (30%; 95% confidence interval 16% to 44%) and 51 males (16%; 95% confidence interval 12% to 20%) died in the early postoperative period (within 90 days of operation). To date, two females (5%) and 51 males (16%) have died in the late postoperative period. Comparison between recipient genders showed no statistically significant difference in early mortality rates from any cause or in actuarial survival overall, although fatal acute rejection was significantly more common in female recipients (7 of 40 female recipients versus 19 of 316 male recipients). The higher incidence of fatal rejection among female recipients was related to the higher proportion of female donors in this group, because recipients of female donor grafts had significantly higher mortality rates, particularly in the early postoperative period and as a result of acute rejection, than did recipients of organs from male donors. Death from rejection after the first 3 months and death from infection were not gender-related. Recipients of grafts from female donors did not suffer significantly more early morbidity, such as rejection and infection, or late morbidity in the form of coronary artery disease. Acute rejection episodes were more common in female recipients.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗

A simple method of scapular retraction for posterolateral thoracotomy.

A simple method of scapular retraction for posterolateral thoracotomy is presented. This technique allows for retraction and stabilisation of the scapula and prevents it from protruding over the intercostal space chosen for entry into the chest cavity. It also facilitates insertion of the chest retractor and spreading of the intercostal space since reduced tension is now exerted on the rib cage by the retracted scapula and muscle layers.

Humans↗

Wound infection following early repeat sternotomy for postoperative bleeding. An experience utilizing intraoperative irrigation with povidone iodine.

A prospective observational study of median sternotomy wound infection was carried out in two consecutive groups of unselected patients undergoing early repeat sternotomy for postoperative haemorrhage. In Group A the pericardial cavity and sternotomy wound layers were irrigated with aqueous povidone iodine prior to repeat closure, while Group B did not receive povidone iodine. No median sternotomy infections were recorded in Group A compared to 5 cases in Group B (0 out of 22 vs 5 out of 21 patients, p less than 0.05). Amongst the patients with wound infection, three developed sternal dehiscence and mediastinitis with one death. The data suggests that povidone iodine irrigation may be effective in reducing wound infection in patients undergoing early repeat sternotomy after cardiac surgery.

Aged↗