Effects of nitric oxide donor SIN-1 on oxygen availability and regional blood flow during endotoxic shock.
BACKGROUND
An excessive release of nitric oxide (NO) has been incriminated in the circulatory disturbances of septic shock.


OBJECTIVE
To study the effects of an NO donor, 3-morpholinosydnonimine (SIN-1), an oxygen availability and regional blood flow during endotoxic shock to see if a beneficial effect of NO synthase inhibitors in septic shock could be conclusively demonstrated.


METHODS
In 14 anesthetized and mechanically ventilated dogs, global invasive hemodynamic monitoring was completed and ultrasonic flow probes were placed around the superior mesenteric, left renal, and left femoral arteries for simultaneous measurements of regional blood flow. All dogs received Escherichia coli endotoxin, 2 mg/kg. A control group (n = 7) was administered saline at 20 mL/kg per hour, and a SIN-1 group (n = 7) was given a combination of saline with SIN-1 at successive doses of 1, 2, and 4 micrograms/kg per minute.


RESULTS
Neither systemic nor pulmonary arterial pressures were influenced by SIN-1. Cardiac index, stroke index, and left ventricular stroke work index did increase at low to moderate doses of SIN-1 but tended to decrease at the highest dose. Systemic and pulmonary vascular resistances decreased. Fractional blood flow increased in the mesenteric bed at all doses used, was not influenced in the renal bed, but decreased in the femoral bed at the highest dose. Oxygen-derived variables were similar in the 2 groups. Blood lactate and plasma concentrations of tumor necrosis factor were not significantly influenced. At the end of the SIN-1 infusion, the administration of 5 mg/kg of methylene blue increased arterial pressure, pulmonary arterial pressure, and systemic and pulmonary vascular resistances but decreased cardiac index and regional blood flow.


CONCLUSIONS
The administration of low to moderate doses of the NO donor SIN-1 can significantly increase cardiac index and superior mesenteric blood flow without deleterious effects on arterial pressure in this model of endotoxic shock. These findings support the hypothesis that NO is essential to maintain organ blood flow even during endotoxic shock.
Zhang
H
H
Department of Intensive Care, Erasme University Hospital, Free University of Brussels, Belgium.
Rogiers
P
P
Friedman
G
G
Preiser
J C
JC
Spapen
H
H
Buurman
W A
WA
Vincent
J L
JL
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D004285:Dogs; D005260:Female; D006439:Hemodynamics / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008981:Molsidomine / Q000031:analogs & derivatives* / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D012039:Regional Blood Flow / Q000187:drug effects; D012772:Shock, Septic / Q000503:physiopathology*; D013318:Stroke Volume / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*; D016277:Ventricular Function, Left / Q000187:drug effects
D014665:Vasodilator Agents; D009569:Nitric Oxide; C002385:linsidomine; D008981:Molsidomine; D019001:Nitric Oxide Synthase