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Biomedical subjects

B T Williams

Publications and source records attributed to B T Williams.

At least 181 records · Page 10Linked to original sources
PubMedDate not supplied

Community-based computerized donor record systems.

Computer programs for management of donor information have been developed for the Champaign County Blood Bank, a division of the Regional Health Resource Center, Urbana, Illinois. The system provides the blood bank with reports from the donor files, incorporating the donor's last donation dates, ABO groups and Rh factors, memberships in assurance programs, and rare donor information to generate lists to meet either daily or emergency inventory needs. The system was designed to decrease time requirements for donor recruitment, improve donor base sampling, aid in support of special recruitment programs, and provide statistical profiles of the community donor base. Experiences in the development and use of the system indicate requirements for effective development of such systems include careful design, strict monitoring of performance, use of a versatile programming language, and incorporation of program modifications via staff-programmer interaction throughout implementation.

Blood Donors↗
PubMedDate not supplied

The lifespan personal health record.

A system for entry of health data in a computer-based patient record by lay individuals is described. The lay user is supported in data entry and data clarification, as well as by system-supported summarization of the data in context to show relationships, highlight sentinel events, and assist in evaluation of alternative decisions and actions as needed.

Decision Support Techniques↗
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Paraprosthetic leak: a complication of cardiac valve replacement.

Paraprosthetic leak (PPL) is a rare but potentially serious complication of cardiac valve replacement. Between 1974 and 1988, 1175 prosthetic valves were implanted in 1026 patients by one cardiac surgeon at St. Thomas' Hospital, London. Of these 539 (52.5%) were aortic (AVR), 334 (32.6%) mitral (MVR), 7 (0.7%) tricuspid, and 144 (14%) AV and MV double valve replacements (DVR). There were only 2 triple valve replacements. The prosthetic valves implanted were the Starr-Edwards (7%), Bjork Shiley (11.8%), Lillehei-Kaster (23%), Carpentier-Edwards bioprosthesis (35.2%), Duromedics bileaflet (16.4%) and a variety of other mechanical and bioprosthetic valves (6.6%). Over the 15 year period there were a total of 82 (7%) valve failures of which PPL was diagnosed in 29 (2.5%) valves in 24 patients. Presenting features included cardiac decompensation in 72%, bacterial endocarditis in 12% and haemolytic anaemia in 12%. One patient (4%) had no symptoms. Nineteen patients underwent re-operation. Median time to re-operation was 15 months (range 1-65 months) with a re-operative mortality of 22%. Clinical evidence of prosthetic valve infection was found in 79% of MVR and 67% of AVR. A heavily calcified aortic annulus, found in 47% of patients, may also have contributed to PPL after AVR.

Aortic Valve↗
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Fracture of the Duromedics mitral valve housing with leaflet escape.

We report a case of leaflet embolisation consequent upon a hemicircumferential fracture of the pyrolytic valve housing of a 29 mm mitral Duromedics Valve implanted for seven months. The clinical presentation is discussed and the literature on mechanical valve failure compared. Unlike pivoting disc valves where absent valve clicks equate with serious occluder dysfunction, valve sounds may persist with bileaflet valve malfunction due to the unimpeded movement of the normally functioning second leaflet. Whilst intrinsic structural failure is increasingly uncommon constant clinical awareness of its occurrence in a patient with a mechanical valve presenting with unexplained acute heart failure and pulmonary oedema, and prompt surgical intervention offers the best chance of survival. The aetiology of the primary fracture in this case remains unclear.

Acute Disease↗
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Traction injury in the internal mammary artery. Report of a case and review of the literature.

The internal mammary artery (IMA) is now used routinely along with saphenous vein for myocardial revascularization procedures. We have documented a particular form of non-perforating injury which may reduce blood flow during operation or may lead to early closure of the IMA bypass graft. Traction injury to the intima is well documented in other vessles but has not been previously reported in the IMA. We present a potentially disastrous example of traction injury to the IMA.

Humans↗
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The management of cardiac surgical patients in a general surgical recovery ward.

A suitable combination of anaesthetic and surgical techniques has allowed the safe management of post-operative cardiac surgical patients to be conducted in a surgical recovery area rather than in the intensive care ward. The results of the first 103 patients so managed (aged 49 +/- 10.7 years) are presented. Coronary artery bypass grafts were performed on 98 patients, 4 patients underwent repair of atrial septal defect and on 1 patient a pulmonary valvotomy was performed. The complications and their management are described.

Adult↗
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Operative considerations in active native valve infective endocarditis.

During a 12 year period from 1974 to 1986, 38 patients with native valve infective endocarditis were treated surgically. All patients were in the active phase of infection at the time of surgery. Surgical intervention was performed as an extreme emergency in 21 patients, 10 patients were operated on the next day, and 7 patients underwent elective surgery within 3-4 days. Indications for operation were heart failure alone in 52% of patients, heart failure accompanied by sepsis and emboli in 42% and uncontrolled sepsis in the remaining 6% of patients. The hospital and late mortality was 10.5% and 5.2% respectively. Recurrence of infection and paravalvular regurgitation was only seen in one case. Thus, we believe that the risk of surgical intervention for infective endocarditis can be minimised if operative treatment is carried out early, before advanced haemodynamic and irrevocable valvular deterioration ensues.

Adolescent↗
PubMedDate not supplied

Dysrhythmias following coronary artery surgery. A comparison between cold cardioplegic and intermittent ischaemic arrest (32 degrees C) with the effect of right coronary endarterectomy.

Dysrhythmias, particularly of supraventricular origin, are an important cause of morbidity following coronary artery bypass grafting (CABG). This study compared the incidence of dysrhythmias in patients undergoing CABG using either cold crystalloid cardioplegia or intermittent ischaemic arrest (32 C). We conclude that the incidence correlated well with right coronary endarterectomy irrespective of the technique of myocardial preservation employed and to the exclusion of other variables.

Arrhythmias, Cardiac↗
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A quick and atraumatic method of autologous vein harvesting using the subcutaneous extraluminal dissector.

Subcutaneous harvesting using an extraluminal vein dissector was used to obtain saphenous and cephalic veins for aortocoronary vein bypass grafting (CVBG) in 428 unselected consecutive patients without complications. The operative technique is simple, quick and easy to learn. Advantages of the method include expeditious harvesting, limited tissue dissection and vein handling, with minimal overt and occult blood loss. Symptomatic benefits include a considerable reduction of leg wound infection (3% superficial inflammation), comfort and improved early mobility. Reduction in late morbidity due to saphenous nerve damage (1.6%), prolonged oedema (0.7%), and delayed sinus formation were also noticeable features. Light and Scanning Electron Microscope (SEM) studies of 57 vein samples showed no excessive trauma to the vein wall but more specifically no evidence of distraction injury to the tributaries when compared with the more traditional dissection technique.

Coronary Artery Bypass↗
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Protamine sulphate and heparin rebound following open-heart surgery.

The efficacy of heparin reversal was investigated in 35 patients undergoing open-heart surgery. A total protamine sulphate dose of 3.0 mgs/kg was administered in divided doses and given as a continuous infusion. On this regime complete heparin neutralisation was observed 10 min after decannulation, but heparin levels were again detectable in 29% of cases 2 hours later. This phenomenon was found to correlate with the total circulating load of heparin to be neutralised. All cases with detectable postoperative heparin levels had in-vivo protamine sulphate: heparin ratios of less than 1.6. These data suggest that in-vitro assays of protamine sulphate neutralisation of heparin may seriously underestimate the required dose of protamine sulphate following open-heart surgery.

Adult↗
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Significance of the whole blood activated clotting time in cardiopulmonary bypass.

Recent publications have described a poor correlation between whole blood activated clotting time (WBACT) values and plasma heparin levels during cardiopulmonary bypass (CPB). A prospective, controlled study was undertaken to investigate the variables which may influence the WBACT in this situation. Antithrombin III levels over a range of 35-93 u/dl did not influence either the WBACT value or plasma heparin level. However, reduced platelet function following infusion of prostacyclin (10 ng/kg/min prior to CPB and 20 ng/kg/min thereafter); platelet number (range 63-287 X 10(9)/l) and packed cell volume (range 16-30%) were found to correlate with the WBACT. It is concluded that in addition to the circulating plasma heparin level, the wide variations in platelet number, platelet function and packed cell volume which are frequently observed during cardiopulmonary bypass may also influence the WBACT value.

Adult↗
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The incidence and management of coronary ostial stenosis.

Coronary ostial stenosis in the absence of more peripheral coronary artery disease was present in four patients (0.093%) of 4298 angiograms performed on patients with coronary artery disease. Case reports of four patients undergoing coronary artery bypass graft surgery for isolated coronary ostial stenosis are presented and surgical techniques discussed. Three patients were young females (mean age 31 years). It is suggested that coronary ostial stenosis is a rare variant of coronary artery disease, more common in young women.

Adult↗