Change in pH of infusion solutions upon mixing with blood.

Abstract

To the Editor.— recent communications by Lebowitz et al, The pH and Acidity of Intravenous Infusion Solutions ( 215 :1937, 1971) and Mostert, The pH and Osmolality of Intravenously Used Drugs ( 216 :1483, 1971) have prompted us to offer a portion of some of our recent work as testimony of the magnificent buffering capacity of human blood. Defibrinated blood and various commercially prepared intravenous infusion solutions were mixed in vitro in various blood:infusion solution ratios and the change in pH observedusing a recording pH meter. accompanying Table of three typical examples shows that the presence of blood in proportions as small as 1:500 (by volume) resulted in the immediate buffering of the acid infusion solutions toward the pH of blood (pH 7.4) and that more blood increased the rate of pH change. Certainly in the dynamic circulatory system in which the relative volume of blood to administered drug