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Biomedical subjects

K Dawkins

Publications and source records attributed to K Dawkins.

30 records · Page 2Linked to original sources
PubMed1985

Determinants of operative mortality for patients undergoing aortic valve replacement. Discriminant analysis of 1,479 operations.

The influence of 35 preoperative and intraoperative characteristics on operative mortality risk after 1,479 isolated aortic valve replacement procedures (1967 to 1981) was investigated utilizing univariate and multivariate logistic regression analyses. Mean age at operation was 58 +/- 13 years; 72% of patients were men. Physiology was classified as aortic stenosis (58%), regurgitation (30%), or both (9%). The overall operative mortality rate was 7% +/- 1%, but there were substantial differences in operative mortality rates among physiological subgroups (aortic regurgitation, 10% +/- 2%; aortic stenosis, 6% +/- 1%; stenosis/regurgitation, 5% +/- 2%). Independent determinants of operative mortality rate in the entire group were advanced New York Heart Association functional class, renal dysfunction, physiological subgroup, atrial fibrillation, and older age. In the aortic regurgitation subgroup, functional class, atrial fibrillation, and operative year were independent predictors. In the aortic stenosis subgroup, the significant determinants were functional class, renal dysfunction, age, prosthetic valve dysfunction, and absence of angina. Concomitant coronary bypass grafting, previous operation, endocarditis, and ascending aortic replacement had no independent predictive effect on operative mortality rate. Thus, the early results of aortic valve replacement can be related to several specific variables describing the functional and physiological status of the patient. Operative mortality rate is not independently related to previous operation or concomitant operative procedures. Specific differences in risk factors exist among the various physiological subgroups, probably reflecting the pathophysiology of the different hemodynamic lesions. This information should provide for a more rational approach to aortic valve replacement, at least in terms of early risk/benefit deliberations.

Adult↗
PubMed1984

Heart and lung transplantation for pulmonary hypertension.

Seventeen patients received combined heart and lung transplants at Stanford University between March 1981 and December 1983. All recipients were suffering from end-stage pulmonary hypertension. Five patients died within the first few postoperative weeks, but the remainder were well between 2 and 35 months after operation. Immunosuppression consisted of cyclosporine with an initial course of rabbit antithymocyte globulin, and azathioprine was given for the first 2 postoperative weeks. Maintenance immunosuppression was achieved with cyclosporine and prednisone. Rejection, as diagnosed by cardiac biopsy, was treated with intravenous methylprednisolone. The functional status of the survivors has been good, and upon discharge from the hospital, all returned to normal activity. Our preliminary experience indicates that cardiopulmonary transplantation represents a realistic therapeutic approach for patients with end-stage pulmonary disease.

Adult↗
PubMed1984

Heart-lung transplantation for irreversible pulmonary hypertension.

Combined heart and lung transplantation was carried out in 17 patients at Stanford University between March, 1981, and December, 1983. The recipients were between 22 and 45 years old. All patients had end-stage pulmonary hypertension; 10 had Eisenmenger's syndrome and the remaining 7, primary pulmonary hypertension. Five patients died within the first few postoperative weeks. The remainder are well between four weeks and 33 months from operation. The immunosuppressive protocol has consisted of cyclosporine with an initial course of rabbit antithymocyte globulin. Azathioprine also was given for the first two weeks and then was replaced with prednisone. Rejection, as diagnosed by cardiac biopsy, was treated with high doses of methylprednisolone. Modifications of technique that have developed include the removal of the recipient heart and lungs separately, and preservation of the lungs with a modified Collins' solution instead of a cardioplegic solution. Rejection occurred in 6 of the 12 survivors. Infections developed in 9 patients, but only one resulted in a fatal outcome (Legionella). Thus, the results of clinical heart-lung transplantation have been considerably superior to clinical efforts in lung transplantation. It is suggested that the combined operation is preferable for the following reasons: (1) all diseased tissue is removed, thus eliminating recurrent infection and ventilation/perfusion disparity; (2) transplantation of the entire heart-lung block preserves coronary-bronchial vascular anastomoses and makes airway dehiscence less likely; and (3) to date, diagnosis of rejection by cardiac biopsy has appeared to be a satisfactory method of diagnosing and treating pulmonary rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Response of pulmonary circulation to oral pirbuterol in chronic airflow obstruction.

The effects of the oral beta agonist pirbuterol on pulmonary haemodynamics and gas exchange were studied in nine patients with severe irreversible airflow obstruction and moderate arterial hypoxaemia. After administration of 15 mg pirbuterol pulmonary vascular resistance fell by 19% but cardiac output rose by 24%, so that pulmonary arterial pressure showed no significant change. Systemic arterial oxygen pressure fell by 7%, limiting the rise in oxygen delivery to 21%. All changes were significant at the 2% level. These results show that pirbuterol dilates the pulmonary bed at the cost of a slight worsening of gas exchange, which is compensated by an independent rise in blood flow.

Adrenergic beta-Agonists↗
PubMed1983

Open mitral valvotomy: fourteen years' experience.

During the period 1968 to 1980, 222 patients with mitral valve disease in which stenosis was the dominant lesion were admitted under the care of the senior author. All patients presented with severe dyspnoea (NYHA grades 3 or 4). One hundred and fifty seven (71%) patients were treated by open mitral valvotomy. One patient died within 30 days of operation (0.6% hospital mortality) and one suffered a transient cerebrovascular accident. One hundred and twenty four (70%) patients were followed up for one to 14 years (mean 7.5 years). There were seven late deaths. Actuarial curves predict the 90.2% 10 year survival after open mitral valvotomy. Eight patients required mitral valve replacement for restenosis corresponding to 16% at 10 years. The remaining patients are in NYHA grades 1 and 2.

Adolescent↗
PubMed1983

Effect of a timed interval between inhalation of beta-agonist and corticosteroid aerosols on the control of chronic asthma.

A randomised double-blind crossover study was undertaken in 25 patients with variable airflow obstruction to assess the benefit of separating the inhalation of beta-agonist aerosols and corticosteroid aerosols by a timed interval of more than five minutes. Twenty-two patients (11 men and 11 women) completed 12 weeks of study; they inhaled 200 micrograms salbutamol followed either immediately or after a timed interval by 100 micrograms beclomethasone dipropionate two to four times daily. Morning and evening peak expiratory flow rates, symptom scores, additional beta-agonist inhaler usage, and subjective responses on a visual-analogue scale were recorded throughout. Results from the two last four-week periods, with and without the interval between drugs, were analysed. No differences were found. It is concluded that the theoretical benefit of delaying corticosteroid inhalation until optimum bronchodilatation has been achieved with a beta-agonist is not demonstrable in outpatient practice.

Adolescent↗
PubMedDate not supplied

The results of surgery for active endocarditis of the native aortic valve.

Between 1968 and 1981, 40 patients with active endocarditis of the native aortic valve were treated by aortic valve replacement (A.V.R.). There were 8 postoperative deaths (hospital mortality 20%). This included 5 patients who had developed cardiogenic shock prior to surgery. Antibiotic treatment for less than one week and positive cultures on the excised valve had poor prognostic implications but tended to be associated with irreversible haemodynamic failure. Twenty five patients underwent A.V.R. following the onset of severe pulmonary oedema. The hospital mortality in this group was 28% and the 5 year actuarial survival 56% (+/- 11%). Fifteen patients who had developed premature closure of the mitral valve (P.C.M.V.) on M-mode echocardiography but who had no overt signs of cardiac failure underwent A.V.R. with a single death (7% hospital mortality). The 5 year actuarial survival in this group was 87% (+/- 9%). P.C.M.V. is a useful prognostic sign identifying those patients with endocarditis on the native aortic valve likely to benefit from early surgery.

Adolescent↗
PubMedDate not supplied

Long-term survival following left ventricular aneurysmectomy.

Ninety-four patients who underwent left ventricular aneurysmectomy between 1971 and 1980 are reviewed. In thirty-four cases this operation was combined with myocardial revascularisation. The overall hospital mortality was 6% with a five-year survival of 72% +/- 6%. Symptomatology dominated by dyspnoea, a raised left ventricular end diastolic pressure (L.V.E.D.P.) and ventricular dysrhythmias adversely affected survival. Combined myocardial revascularisation did not affect the hospital mortality but was associated with a trend toward improved long-term survival in two groups of patients viz those presenting with predominant angina and those with major stenoses of two or more coronary arteries. Fifteen patients agreed prospectively to post-operative cardiac catheterisation. Despite symptomatic relief no improvement in L.V.E.D.P. or ejection fraction was demonstrated in this group.

Angina Pectoris↗