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Biomedical subjects

S Westaby

Publications and source records attributed to S Westaby.

At least 19 recordsLinked to original sources

Aortico-right ventricular tunnel.

We report successful closure of an aortico-right ventricular tunnel in a 3-month-old infant with heart failure. One-year follow-up shows the child to be developing normally.

Aorta

Cytokine responses to cardiopulmonary bypass with membrane and bubble oxygenation.

The systemic inflammatory response to cardiopulmonary bypass was assessed in 20 patients who underwent elective coronary artery bypass grafting with flat-sheet membrane oxygenation (group I; n = 10; age, 59 +/- 5 years) or bubble oxygenation (group II; n = 10; age, 62 +/- 8 years). The duration of cardiopulmonary bypass was 46 +/- 12 minutes in group I and 47 +/- 15 minutes in group II. Plasma interleukin-6, plasma interleukin-1 beta, transpulmonary leukocyte counts, pulmonary hemodynamic variables, and respiratory index were determined in all patients perioperatively. The plasma interleukin-6 response (median [range]) was similar in both groups at the end of the operation, peaked 4 hours postoperatively (99 [30 to 320] pg/mL in group I; 123 [21 to 300] pg/mL in group II; p greater than 0.05), and remained elevated 48 hours postoperatively (76 [9 to 140] pg/mL in group I; 65 [25 to 159] pg/mL in group II; p greater than 0.05). No significant interleukin-1 beta response was demonstrated. Pulmonary neutrophil and lymphocyte sequestration was observed on commencement of cardiopulmonary bypass in group II but did not occur in either group on discontinuation of cardiopulmonary bypass. Pulmonary vascular resistance at the end of the operation (82 [48 to 320] dynes.s.cm-5 in group I; 119 [54 to 385] dynes.s.cm-5 in group II; p greater than 0.05) was similar to preoperative values (151 [30 to 327] dynes.s.cm-5 in group I; 185 [62 to 291] dynes.s.cm-5 in group II; p greater than 0.05). The respiratory index at the end of the operation was similarly and significantly increased in both groups (1.26 [0.92 to 4.17] in group I; 1.44 [0.73 to 3.30] in group II).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged

Cardiac surgery: moving away from intensive care.

OBJECTIVE: To evaluate outcome in patients managed outside an intensive care unit after open heart surgery. BACKGROUND: The high cost of cardiac surgery is mainly due to the needs of traditional postoperative care. The requirements for intensive care and treatment has decreased with improvements in techniques of cardiac surgery and anaesthesia. In this setting the need to continue to depend on intensive care units for the recovery of cardiac surgical patients is questionable on clinical and economic grounds. DESIGN: Postoperative outcome in 245 patients over a four month period was studied prospectively. PATIENTS: Mean age of the patients was 63.2 years. They underwent a wide variety of operative procedures. Ninety percent of them recovered in a dedicated three bed cardiac surgical recovery area where the management protocol led to rapid extubation and step down in dependency care. RESULTS: Median time for ventilatory support was 90 minutes after transfer to the area. Only five patients were subsequently admitted to the general intensive care unit for prolonged respiratory and cardiac support. Ten patients were electively admitted to the general intensive care unit. Two deaths occurred in hospital in this group (0.8%). Four patients were ventilated for 24 hours in the recovery area itself and made an uncomplicated recovery. CONCLUSION: This study confirms that over 90% of patients undergoing cardiac surgery would recover safely and be treated effectively in a more economical area than intensive care.

Adult

Aortic root replacement: modifications of technique with improvements in technology.

Potential morbidity remains substantial in aortic root replacement. The tissues are often fragile, contributing to the risk of haemorrhage and postoperative complications. In the past surgery has been directed towards minimising haemorrhage by wraparound techniques and the right atrial fistula method of Cabrol. However, recent use of aortic homografts, collagen-impregnated grafts and tissue glues have reduced bleeding and simplified operative technique. Profound hypothermia and total circulatory arrest allows aneurysm resection to extend into the aortic arch. Between 1986 and 1991 25 aortic root replacements were carried out at the Oxford Heart Centre in 21- to 76-year-olds, 13 for aorto-annular ectasia (4 due to Marfan's syndrome), 7 for aortic dissection (2 Marfan's syndrome) and 2 for complications of previous aortic valve replacement. Three patients had homograft root replacement for aortic root endocarditis. We implanted 14 Medtronic composite grafts, 1 St Jude conduit and 7 collagen-coated Dacron grafts (Hemashield, Meadox) into which a Starr-Edwards valve was sewn, as well as 3 homografts. One patient with a massive chronic dissection following previous aortic valve replacement required an interposition graft to the coronary ostia. In the others, the coronary ostia were mobilised from the native aorta and directly implanted into the conduit. In dissections a ring of pericardium or GoreTex was used to buttress the coronary anastomoses. Six patients also required coronary artery grafting. Native aorta was excised and not wrapped around the conduit. Coagulation defects were corrected aggressively with platelets, fresh frozen plasma and cryoprecipitate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Combined cardiac and abdominal aortic aneurysm operations. The dual operation on cardiopulmonary bypass.

Eight patients underwent both cardiac operation and repair of abdominal aortic aneurysm. All had respiratory impairment and significant impairment of left ventricular function, whereas six patients had severe diffuse distal coronary disease. In all patients the cardiac procedure was performed first, and the patients continued to receive cardiopulmonary bypass. Rewarming was not commenced until the abdominal repair was well under way, to protect the vital organs. There were no problems in weaning the patients from bypass, and six of the patients were extubated within 24 hours; one required ventilation for 36 hours. One patient died of colonic infarction complicated by kidney failure without being extubated. Another patient who was initially extubated in 11 hours required reintubation because of poor lung function and eventually died of multisystem organ failure caused by bilateral lower limb ischemia that persisted despite embolectomies. All survivors are well and in New York Heart Association functional class I or II between 3 and 18 months postoperatively. We conclude that for patients considered unfit for abdominal aortic aneurysm operations because of the nature of the cardiac disease, the combined operation with cardiopulmonary bypass is both safe and effective.

Aged

Thrombolysis and postinfarction ventricular septal rupture.

We studied all patients with postinfarction ventricular septal rupture referred to the Oxford Heart Centre for operation over a 4 1/2-year period. Twenty one women and 8 men were admitted to the Centre, 13 of whom had received streptokinase and 16 of whom had not. The median interval between symptomatic onset of myocardial infarction and the development of septal rupture was 24 hours for those treated by early thrombolysis (all streptokinase) and six days for those who were not. Of the 26 patients who underwent surgical repair, three were operated on less than 36 hours after streptokinase infusion, in one case within 12 hours of thrombolytic treatment. Macroscopic observation of the disintegrating myocardium showed muscle bundles dissected by blood rendered incoagulable by thrombolytic treatment, together with the histologic features of reperfusion injury. The overall surgical mortality rate for the streptokinase group was 33% and for the others 21%. The patient operated on within 12 hours of thrombolytic treatment recovered uneventfully. Six of seven surgical deaths were caused by left ventricular or biventricular failure and one by gastrointestinal hemorrhage. All survivors were in New York Heart Association classes II or III between 2 weeks and 4 1/2 years after operation. We conclude that thrombolysis leads to early breakdown of the interventricular septum after acute myocardial infarction but does not preclude early repair.

Aged

Return to work and quality of life after surgery for coronary artery disease.

Changes in work capability and quality of life were assessed retrospectively in 130 patients with ischaemic heart disease who had undergone aortocoronary bypass operations during 1976-7 because of medically uncontrollable angina. A total of 85 patients (65.4%) reported complete relief from angina six months after operation, though 12 later suffered a recurrence. Substantially fewer patients needed drugs after the operation. Before operation 9 out of 117 men fully employed at the onset of angina were working without restriction or doing lighter, fulltime work, 38 were at work but seriously incapacitated by angina, and 70 were forced to stop work. After operation 70 were working without restriction or engaged in lighter work, 15 were at work but still restricted by angina, and only 32 were forced to stop work. This result was highly significant (P less than 0.001). These differences were even more pronounced in heavy manual workers, of whom none cobld work normally before operation, whereas 16 were working without restriction afterwards. Of patients wishing to engage in hobbies or sports, social activity, and sexual intercourse but were restricted before operation, about two-thirds could resume these activities afterwards. Coronary artery surgery provided dramatic symptomatic relief in up to 90% of patients and permitted rehabilitation and return to gainful employment irrespective of type of labour. The degree of symptomatic improvement and increase in exercise tolerance after successful surgery is usually far greater than occurs with any other form of treatment and directly improves quality of life and work capability.

Activities of Daily Living

Spleen size and portal hypertension in cirrhosis.

In 210 patients with cirrhosis of the liver there was no correlation between spleen size and the rise in portal pressure, whether measured directly or assessed clinically from the size of varices on barium swallow and the presence of ascites. Despite this, there was a correlation between the occurrence of bleeding as a presenting symptom and the size of varices assessed radiologically.

Esophageal and Gastric Varices

Ventricular haemangioendothelioma diagnosed in life.

A case of right ventricular outflow obstruction is described in which the electrocardiogram and chest x-ray film suggested a cardiac tumour. Cardiac catheterisation confirmed outflow obstruction and angiography showed a tumour. At operation a haemangioendothelioma was found.

Child

Penumopericardium and tension pneumopericardium after closed-chest injury.

Three recent cases of pneumopericardium after closed-chest injury are described. The mechanism of pericardial inflation suspected in each was pleuropericardial laceration in the presence of an intrathoracic air leak. Deflation of the pericardium was achieved by underwater seal drainage of the right pleural cavity in the first patient, during thoracotomy for repair of tracheobronchial rupture in the second, and by subxiphoid pericardiotomy in the last. Haemodynamic changes after escape of air from the periion pneumopericardium and air tamponade.

Adolescent

Phrenic nerve and diaphragm function following open heart surgery: a prospective study with and without topical hypothermia.

In a prospective study, 100 patients undergoing open heart surgery were randomly allocated to receive ice/slush topical hypothermia for myocardial protection (Group I, n = 56) or not (Group II, n = 44). Chest radiographs, diaphragm screening, lung function and phrenic nerve conduction time were assessed pre-operatively and at 1 week and 1 month post-operatively in all patients and subsequently at 3 months, 6 months, 1 year and 2 years in all patients with radiological evidence of diaphragm paralysis. The two groups were similar in terms of age, sex, diabetes and smoking habits. Cardiopulmonary bypass and aortic cross-clamp times were similar in the two groups. Radiological evidence of partial left lower lobe collapse was more frequent in Group I (79 per cent vs. 36 per cent, p < 0.01). Twenty (36 per cent) Group I patients developed unilateral diaphragm paralysis (19 left-sided) compared with none in Group II. Diaphragm paralysis was still present in 19 patients (34 per cent) at 1 month, in five patients (9 per cent) at 1 year and in one patient (2 per cent) at 2 years post-operatively. Phrenic nerve conduction time was recorded in 98 per cent of patients pre-operatively, but was unrecordable on the appropriate side in all 20 patients with diaphragm paralysis 1 week post-operatively. Prolonged phrenic nerve conduction time on the left side was found in a further seven Group I patients 1 week post-operatively. There were no significant differences between the two groups in terms of post-operative arrhythmias, myocardial infarction or mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged

Platelet responses to cardiopulmonary bypass. Assessment by a shear stress activation technique.

Platelet responses before and during cardiopulmonary bypass were studied using a shear stress activation technique. Whole blood was passed through a 10 microns micro-porous filter and the percentage of platelets retained was determined. Retention in control subjects (n = 20, age 62 +/- 11 years) was 65.2 +/- 15.1%. Patients with ischaemic heart disease (n = 20, age 61 +/- 9 years) had significantly higher retention at 82.6 +/- 13.2%, p less than 0.001. In valvular heart disease (n = 15, age 57 +/- 14 years) the retention rate was 43.5 +/- 15.4%, lower than both controls and ischaemic heart disease patients (p less than 0.001). In vitro haemodilution had no significant effect on platelet retention. High retention rates were maintained in patients undergoing coronary artery surgery. During valve surgery retention increased before aortic cross-clamp removal (83.5 +/- 13.4%) compared with baseline values (p less than 0.001) and remained high 24 hours postoperatively (79.6 +/- 9.4%). Platelet retention also increased within 20 minutes of thoracotomy without cardiopulmonary bypass (n = 10, age 57 +/- 8 years, 79.3 +/- 11.6% versus 61.6 +/- 10.9% baseline, p less than 0.01) and remained high 24 hours postoperatively. Significant differences in platelet responses, assessed by shear stress activation, were demonstrated between healthy controls and patients with ischaemic and valvular heart disease. Surgery, with or without extracorporeal circulation, caused a significant increase in platelet retention.

Aged