VENTRICULAR PUMP PERFORMANCE DURING HYPOCALCEMIA - CLINICAL AND EXPERIMENTAL STUDIES

  • 1 January 1979
    • journal article
    • research article
    • Vol. 78  (2) , 185-194
Abstract
Indices of ventricular function were compared during rapid transfusion of citrated (1.5 ml/kg per min) or heparinized (1.5 ml/kg per min) autologous blood in 6 patients following discontinuation of cardiopulmonary bypass. Infusion of citrated blood was associated with a lowering of plasma ionized [Ca2+], from 0.90 .+-. 0.04 to 0.71 .+-. 0.4 mM, P < 0.001) and an increase in pulmonary artery balloon-occluded pressure .**GRAPHIC**. from 9.4 .+-. 2.6 to 15.5 .+-. 1.7 mm Hg, P < 0.01), without a change in left ventricular stroke work index, stroke index or cardiac index. Transfusion of heparinized blood caused no change in plasma [Ca2+]. A rise in .**GRAPHIC**. which was equivalent to that during citrated blood transfusion, was associated with increased left ventricular stroke work index, stroke index, cardiac index and mean arterial pressure. Transient left ventricular dysfunction was suggested but could not be quantitated in ventricular function curves in relation to simultaneous change in [Ca2+]. Ventricular pump performance was studied in the anesthetized closed-chest dog by volume loading during hypocalcemia, when mean arterial pressure, heart rate, and [Ca2+] were in a steady state, both before and after .beta.-blockade with propranolol. Function curves obtained during severe hypocalcemia ([Ca2+] = 0.43 .+-. 0.02 mM) were shifted significantly to the right and downward, compared to those during normocalcemia ([Ca2+] = 1.06 .+-. 0.03 mM). Hypocalcemia combined with .beta. blockade resulted in severe left ventricular failure, as demonstrated by a flat ventricular function curve.