The Annals of Thoracic Surgery, Vol 22, 429-435, Copyright © 1976 by The Society of Thoracic Surgeons
Effects of morphine and halothane anesthesia on coronary blood flow
FL Grover, GE Webb, V Bevis and JG Fewel
This study was undertaken to determine the relative effects of morphine and
halothane anesthesia on coronary blood flow. Right heart bypass was
instituted in 20 dogs by draining the vena cava blood into a cardiotomy
reservoir and returning it to the main pulmonary artery. Coronary sinus
drainage was measured by a right ventricular cannula. Group I (10 dogs) was
sequentially given 0.5, 1, 1.5, 2.0, and 2.5% halothane. Group II (10 dogs)
was given 1, 2, 3, 4, and 5 mg per kilogram of morphine intravenously.
Arterial pressure, coronary sinus blood flow, cardiac output, arterial pH,
PCO2, and PO2 were determined and repeated at each dose level of anesthesia
and compared to the control values. Morphine significantly increased
coronary flow at 3, 4, and 5 mg/kg without pressure adjustment and at 2
mg/kg after pressure adjustment. Coronary flow with halothane was unchanged
from control values except for a decrease at 2.5%. Coronary flow was
significantly greater with 3, 4, and 5 mg/kg of morphine than with 1.0 and
1.5% halothane.