Objective: To investigate the relationship between nitric oxide produc
tion, 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: Increas
ed plasma nitrite and nitrate concentrations were found in patients wi
th septic shock (p < .01), Nitrite and nitrate correlated directly wit
h endotoxin concentrations r(2) = .21, p < .05) and cardiac output (r(
2) = .49, p < .05), and inversely with systolic blood pressure (r(2) =
.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 hem
odynamic disturbances in this pathophysiologic situation.