Electrolyte and water distribution in the heart in irreversible hemorrhagic shock

Abstract

Electrolyte and water content were determined in left ventricular muscle in control dogs and dogs subjected to irreversible hemorrhagic shock. In shock, myocardial potassium increased from 39.6 to 47.7 mEq/100 g fat-free dry tissue, while sodium decreased from 16.4 to 13.2 mEq/100 g fat-free dry tissue. Water content, as well as levels of magnesium, calcium, and chloride were not significantly altered. Changes of intracellular potassium, sodium, magnesium, and calcium were within limits expected from Gibbs-Donnan equilibrium relationships. However, interstitial potassium and magnesium were markedly elevated from 4.56 to 7.52 mEq/kg and from 1.29 to 2.54 mEq/kg, respectively. As a result of the increase in interstitial potassium, the calculated average resting membrane potential differed by 11 mv from control dogs. The observed alterations in myocardial electrolytes in our shock experiments are not similar to those generally encountered in heart failure. On this basis, a cardiac factor may not be a major cause of the irreversible state of hemorrhagic shock.