Haemodynamic studies in shock associated with infection.

Abstract

Twenty-one patients in shock associated with infection were studied. Cardiac output, central venous pressure, and central aortic pressure were measured. Systemic vascular resistance was calculated. Measurements were made before and after infusions of methoxamine, noreplnephrine, isoprenaline, low molecular weight dextran, chlorpromazine, digitalis, and hydrocortisone. The importance of maintaining adequate central aortic pressure is emphasized and is illustrated by an improvement in cardiac function in 2 patients with coronary artery disease when methoxamine was used to increase central aortic pressure. Noreplnephrine, when used in small amounts after plasma volume expansion, is an effective drug for improving cardiac output. Isoprenaline may increase cardiac output and blood pressure but frequently will not increase central aortic pressure above shock levels. In the elderly patient these low pressures are associated with clinical deterioration. Low molecular weight dextran is an effective plasma volume expander and lowers systemic vascular resistance. Digitalis is often effective in increasing cardiac output in patients who have high central venous pressures after plasma volume expansion. Chlorpromazine is an active vasodilator and is useful when there is a precipltous rise in central venous pressure with plasma volume expansion. It is useful also in the patient who remains vasoconstricted after return of central venous and arterial pressures to normal levels. Hydrocortisone is ineffective as a vasodilator in pharmacological doses.