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Biomedical subjects

R S Fraser

Publications and source records attributed to R S Fraser.

69 records · Page 4Linked to original sources
PubMed1970

Hemodynamic changes following correction of severe aortic stenosis using the Cutter-Smeloff prosthesis.

Twelve patients with pure or dominant stenosis were studied before and after aortic valve replacement (Cutter-Smeloff). The changes in cardiac output and A-V O2 difference were small and insignificant, but exercise stroke volume increased from 72 to 96 ml after the surgery. The aortic peak systolic gradient was 92 +/- 29 mm Hg before and 4 +/- 9.8 mm Hg after surgery. The PA wedge pressure, taken as a measure of the LV diastolic pressure, decreased from 18 mm Hg to 12 mm Hg at rest and 30 mm Hg to 16 mm Hg on exercise. The PA pressures also decreased from 37/18 (mean, 26) to 28/11 (17) mm Hg at rest, and 61/31 (43) to 41/17 (27) mm Hg on exercise, but the PA and PA wedge pressures maintained their tendency to increase in a linear manner with oxygen consumption (Vo2) on exercise after surgery. As a result of decreased wedge pressure, the pulmonary vascular resistance also decreased significantly afterward. The adequacy of cardiac output at rest and on exercise expressed by cardiac output as the linear function of Vo2 improved toward the normal (values before operation, CO = 2.78 + 0.0069 Vo2, r = 0.84; after operation, CO = 3.80 + 0.0062 Vo2, r = 0.91). The exercise factor (delta CO/delta Vo2) or the regression coefficient, however, was similar before and after surgery. The hemodynamic result was satisfactory although some abnormalities of the left ventricular function persisted after operation.

Adult↗
PubMed1967

Bacterial endocarditis occurring after open-heart surgery.

A review was made of 520 patients who survived cardiopulmonary bypass for repair of congenital or acquired heart disease between 1956 and 1965. The incidence of early and late bacterial endocarditis was 2.7%, a figure which was higher than the reported incidence in the pre-bypass era but comparable to the experience reported by others. When those patients who had ball-valve prostheses inserted were considered separately, endocarditis was found to have occurred in 3.9%. The most common infecting organism was Staphylococcus albus (nine of 14 cases). Twelve of the 14 patients died, most often from complications of the infection, such as disruption of patches and prosthetic valves. The infections were difficult to control and in three patients recurred from one to three times. There was no apparent source of infection. Six patients developed infections six to 45 months after operation; the remaining eight had proved endocarditis within two months of operation. With one possible exception, treatment with antibiotics appeared to be ineffective in eradicating the infection unless foreign material was removed from the heart.

Adult↗