The influence of rapid potassium administration on hemodynamics and endogenous catecholamine production during extracorporeal circulation

Abstract

In a prospective randomized double-blind study, the peripheral vascular effects of potassium chloride (KCl) and potassium-magnesium-aspartate (KMA) were compared. Twenty patients undergoing coronary artery bypass graft surgery received either 12 mmol of KCl (n = 10) or 12 mmol of KMA (n = 10) into the oxygenator of the heart-lung machine during extracorporeal circulation (ECC). The most striking difference between these two solutions was vasoconstriction following KCl administration and vasodilation after KMA injection. In the KMA group, decreases of perfusion pressure (MAP) and systemic vascular resistance (SVR), as well as changes in the oxygenator volume (dV), were significant (P less than 0.01) between the first and the fifth minutes. Maximal changes of MAP, from 72 +/- 13 to 59 +/- 12 mmHg (mean +/- SD), and SVR were recorded in the first and second minutes. Oxygenator volume changes reached their maximum (285 +/- 163 mL) in the tenth minute. In the KCl group, maximal increases in MAP, from 70 +/- 16 to 81 +/- 20 mmHg (mean +/- SD), and SVR were found in the fourth minute. Maximal changes in dV (300 +/- 315 mL) were measured in the tenth minute. Plasma epinephrine levels, which were already elevated during ECC, showed further increases in all cases in the KCl group and in most of the cases in the KMA group. The change in plasma epinephrine concentration following KCl injection was significant (P less than 0.01). No characteristic change in plasma norepinephrine was found in either of the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)