Biomedical subjects

L Sharples

Publications and source records attributed to L Sharples.

42 records · Page 3Linked to original sources

PubMedDate not supplied

Coronary care unit ST-trending system: interpreting complex output data.

Analysis of the ST segment is an accepted part of the assessment of coronary ischaemia. Traditionally, such analysis has been applied to 12-lead surface electrocardiograms, but it is increasingly applied to 24-hour Holter recordings and bedside monitoring systems, using complex computer algorithms. There is a potential for results to be misleading as a consequence of uncritical acceptance of complex medical data processing.

Bias↗

PubMedDate not supplied

Donor heart preservation survey.

A questionnaire requesting information on donor heart preservation technique and outcomes during the first 6 months of 1990 was circulated to heart transplantation centers worldwide. Seventy-nine usable replies representing 1371 clinical transplant operations were received. Twenty-seven percent of the respondents reported using some form of donor pretreatment. Most (90%) used single flush cardioplegic induction with the use of eight different types of cardioplegic solutions, only 5% of which were oxygenated. Six different types of storage media were used, and the coolant was melting ice in 66% of the centers. Storage temperatures between 0 degrees C and 7 degrees C were reported, with 78% of the respondents using 4 degrees C storage. Fifty-five percent of the centers used some form of reperfusion modification. No statistically significant associations were noted between outcome and technique, apart from the use of storage medium in which the use of cardioplegic solution conferred a 2.5 times increase in deaths compared with cold saline. The results of this questionnaire provide evidence for the diversity of techniques currently used for donor heart preservation, reflecting the lack of any one optimal method.

Cardioplegic Solutions↗

PubMedDate not supplied

Some prognostic factors for the development of transplant-related coronary artery disease in human cardiac allografts.

The study of endomyocardial biopsy specimens taken in the first 130 days after transplantation has yielded no histologic features predictive of later development of transplant-related coronary artery disease. This study, however, indicated that a combination of the following factors might be predictive in cyclosporine-treated patients: untreated histologically proven episodes of rejection, infection with cytomegalovirus or reactivation of infection, ischemic heart disease in the recipient as the reason for heart transplantation, and possibly HLA-B5 or -B8 mismatch.

Adult↗

PubMedDate not supplied

Who waits longest for heart and lung transplantation?

Between August 1982 and December 1992, 260 patients were accepted for heart and lung transplantation, of whom 139 patients underwent transplant surgery. One hundred twenty-one patients have not received transplants, of whom 80 have died, four were transferred to other lists, and 37 were still waiting for suitable organs at the close of the study. Median waiting time for those patients who underwent heart and lung transplantation was 7 months, whereas patients who died waiting spent a median of 5 months on the list. Recipients are matched to donor organs according to blood type, size (total lung capacity), and cytomegalovirus antibody status. These factors, along with age, gender, underlying diagnosis, and Toxoplasma antibody status, were studied to assess their influence on survival after acceptance and time to transplantation. The only characteristic that significantly influenced survival after acceptance was the underlying disease, with patients with Eisenmenger's syndrome having significantly longer survival than the other groups (relative risk = 0.21; p < 0.001). Patients with Eisenmenger's syndrome underwent transplantation at a slower rate than did other patients (relative risk = 0.51; p = 0.012). Patients who had a total lung capacity of more than 6 L underwent transplantation significantly more quickly than did smaller patients (relative risk = 1.98; p = 0.005). Male patients underwent heart and lung transplantation at a quicker rate than did female patients (relative risk = 1.86; p < 0.001), although this was related to size. Patients who had cytomegalovirus-positive antibodies underwent transplantation at almost twice the rate of patients who had cytomegalovirus-negative antibodies (relative risk = 1.92; p < 0.001). Age at acceptance, blood type, and Toxoplasma status did not significantly influence time to heart and lung transplantation. In summary, cytomegalovirus antibody status, patient size, and gender significantly affect the waiting time to heart and lung transplantation. Patients with Eisenmenger's syndrome wait longer than other patients as a result of the natural history of their disease.

Adolescent↗

PubMedDate not supplied

Heart-lung transplantation for end-stage respiratory disease in patients with cystic fibrosis at Papworth Hospital.

Between October 1985 and July 1992 we performed heart-lung transplantation in 42 patients with end-stage respiratory disease caused by cystic fibrosis. Twenty-eight of these patients are alive at 3 months to 7 years after heart-lung transplantation. Actuarial survival at 1 year and 3 years after transplantation was 78% and 65%, respectively, in this group, which compares favorably with 77% and 60%, respectively, in patients without cystic fibrosis undergoing heart-lung transplantation. Similarly no significant difference was found in the incidence of postoperative infections between patients with cystic fibrosis and patients without cystic fibrosis undergoing heart-lung transplantation. Quality of life indexes analyzed by the Nottingham Health Profile reveal significant improvements for patients surviving longer than 3 months from surgery. Long-term survival is determined by the development of obliterative bronchiolitis, which has occurred in 11 patients, six of whom have died. Early postoperative survival appears to be compromised by poor preoperative nutritional status. The study provides evidence that patients with end-stage respiratory disease caused by cystic fibrosis gain a survival advantage and improvement in quality of life after heart-lung transplantation when compared with patients who do not receive this form of therapy.

Actuarial Analysis↗

PubMedDate not supplied

Prognosis of patients with cystic fibrosis awaiting heart and lung transplantation.

Heart-lung transplantation is a successful treatment for patients with cystic fibrosis and chronic respiratory failure. Patients are assessed for surgery when life expectancy is deemed short. This study assesses the ability of measurements of pulmonary function, blood gas levels, and nutritional status to predict survival of patients awaiting heart-lung transplantation and to assess the effect of heart-lung transplantation on survival. Sixty-seven patients with cystic fibrosis were accepted for heart-lung transplantation from 1985 through 1990. Each patient underwent tests of pulmonary function, exercise tolerance, blood-gas levels, and nutritional status. Cox regression was used to analyze the prognostic value of these data. Of the 67 patients accepted for heart-lung transplantation, organs became available for 30; 24 patients died waiting, and 13 patients were on the list December 31, 1990. Eight patients died after transplantation. Patients with above-average forced expiratory volume in 1 second (FEV1) (median, 17% predicted) at assessment were half as likely to die waiting (relative risk, 0.47; 95% confidence interval, 0.23 to 0.97) as patients with below-average FEV1. The relative risk of death for patients on the waiting list was 1.44 (95% confidence interval, 1.17 to 1.77) for each increment in PCO2 of 1 kPa. No effect of nutritional status on waiting list death was found, but seven of eight patients who died after heart-lung transplantation were below 80% predicted weight for height. Using a time-dependent analysis, heart-lung transplantation almost halved the risk of death (relative risk, 0.57; 95% confidence interval, 0.22 to 1.48). Postoperative actuarial survival was 79% (95% confidence interval, 63% to 95%).(ABSTRACT TRUNCATED AT 250 WORDS)

Carbon Dioxide↗