METABOLIC EFFECTS OF BLOOD TRANSFUSION.
Progress rept., 1 Jul 63-30 Jun 64,
STANFORD MEDICAL CENTER PALO ALTO CALIF
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The dissociation constants of several of the phosphate salts of calcium were studied with glass electrodes showing high selectivity for calcium. The interactions of calcium and pentobarbital and of calcium and potassium on the inotropic properties of the myocardium were studied in the isolated guinea pig atrium. The interaction of calcium and pH on the circulation of the intact dog, as reflected in cardiac output, total peripheral resistance, arterial blood pressure, cardiac work and rate of change of ventricular volume was examined. Interaction was mixed but showed a trend towards antagonism, possibly reflecting an increase in ionized calcium with fall in pH. In a separate series of experiments the hemodynamic effects of hyperkalemia were compared with those of hypocalcemia. Hyperkalemia produced an initial increase in heart activity, suggesting a sympathoadrenal response, followed by late depression. The linear and progressive circulatory depression of hypocalcemia was distinctly different. Calcium homeostasis during simulated blood transfusion was studied during diuresis in the dog under chloralose anesthesia. The infusion of sodium citrate was accompanied by massive renal losses of calcium and citrate with resulting considerable fall in serum total calcium and moderate to marked hemodynamic and electrocardiographic disturbances. The infusion of neutral sodium phosphate in concentrations which might occur during massive transfusion was well tolerated. Author