Mobile catheterization laboratories.
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Cardiac Catheterization↗
Biomedical subjects
L McKeever
Publications and source records attributed to L McKeever.
Comparative responses to dobutamine and nitroprusside in patients with chronic low output cardiac failure.
The acute hemodynamic effects of dobutamine and nitroprusside were compared in 19 patients with low output cardiac failure. At dosage levels yielding similar increases in cardiac index (12 patients), nitroprusside resulted in significantly lower arterial systolic and wedge pressures and did not increase heart rate suggesting advantages over dobutamine when reduction in myocardial oxygen requirement or pulmonary congestion is a major goal. Systemic arterial mean and diastolic pressures were minimally changed with dobutamine, but fell significantly with nitroprusside suggesting advantages of dobutamine over nitroprusside in patients where hypotension could limit coronary blood flow or perfusion of other vital organs. Reduction in pulmonary arteriolar resistance occurred only with nitroprusside. Arterial hypoxemia developed in three patients during nitroprusside infusion suggesting the possibility of increased right-to-left intrapulmonary shunting resulting from a direct vasodilating effect of nitroprusside on pulmonary arteriole smooth muscle. Although both inotropic and vasodilator drugs can result in hemodynamic improvement when administered to patients with chronic low output cardiac failure, significant differences of potential clinical importance exist between these two modes of therapy.
Adult↗
Perinatal reactions of the rabbit lung to maternal endotoxemia.
The reactions of the fetal and newborn lung to in utero injury were investigated in rabbits using as a model maternal administration of Escherichia coli endotoxin, 2 to 4 mug per kg. of body weight, injected intravenously at the 29th gestational day. At 6 hours after endotoxin injection, the lung revealed diffuse alveolar damage-sparing type II cells which appeared resistant to injury but more mature than type II cells from control lungs. These changes were followed by a reparative phase which over a 2-day period resulted in increased interstitial cellularity, replacement of the damaged type I cells by proliferated type II cells, and marked intraalveolar accumulation of myelin figures. The above reactions were associated with an average increase of 100 per cent in the phospholipid content of the surfactant fraction isolated from lung washing. Postnatally, the lungs showed structural changes resembling those seen in hyaline membrane disease of the newborn. The findings suggest that the response of the alveolar epithelim to injury inudced late in gestation follows a pattern similar to that described previously in adult lung, and is assoicated with in utero increased release of surfactant. It is proposed that alveolar injury and repair, including reduction of the intracellular surfactant reservoir occurring prior to breathing, may interfere postnatally with formation and maintenance of a normal surfactant layer, thereby predisposing to respiratory distress.
Animals↗