L-arginine: nitric oxide pathway in endotoxemia and human septic shock

Abstract

Objective: To investigate the relationship between nitric oxide production, endotoxemia, and hemodynamic alterations in human septic shock.

Design: Prospective study.

Setting: A 32-bed intensive care unit in a university referral hospital.

Patients: Two groups of septic patients with shock (n = 13) or without shock (n = 16) and an additional group of nonseptic patients as control group (n = 25).

Measurements: Plasma nitrite and nitrate concentrations were measured as an index of nitric oxide generation. Nitrite and nitrate concentrations were correlated with plasma endotoxin and hemodynamic variables.

Main results: Increased plasma nitrite and nitrate concentrations were found in patients with septic shock (p < .01). Nitrite and nitrate correlated directly with endotoxin concentration (r2 = .21, p < .05) and cardiac output (r2 = .49, p < .05), and inversely with systolic blood pressure (r2 = .24, p < .01).

Conclusions: This study demonstrated the activation of the L-arginine:nitric oxide pathway in human endotoxemic septic shock, suggesting that nitric oxide may be an important mediator of the hemodynamic disturbances in this pathophysiologic situation.