Nitric oxide as a mediator of reduced arterial responsiveness in septic patients
Tsuneyoshi, I.; Kanmura, Y.; Yoshimura, N.
Critical Care Medicine 24(6): 1083-1086
1996
ISSN/ISBN: 0090-3493 PMID: 8681578 Document Number: 465105
Objective: To investigate the functional status of arteries in patients with septic shock, each of whom suffered from severe hypotension. Design: Experimental, comparative study. Seffing: Laboratory in a university hospital. Subjects: Mesenteric artery resected from omentum was obtained from patients (n = 3) with or without (n = 4) sepsis. Interventions: To study the effect of modification of the nitric oxide system in human arteries during sepsis, changes in norepinephrine-evoked isometric tension in mesenteric arterial rings were measured. Measurements and Main Results: Mesenteric arteries were isolated from omentum resected from three patients with septic shock and from four patients with no inflammatory conditions; in each case, during an intestinal anastomosis. In arterial rings, after a 1-hr equilibration with Krebs solution, changes in isometric tension evoked by norepinephrine were measured for 5 mins every 20 mins. The tension initially evoked in rings from septic patients was lower than in those rings from nonseptic patients and, unlike the controls, it decreased with a short time course. The addition of 300 mu-mol/L of N-G-nitro-L-arginine methyl ester or 10 mu-mol/L of methylene blue reversed this decrease. Conclusion: These results indicate that in patients with septic shock, the main cause of reduced sensitivity to pressor agents may be a massive generation of nitric oxide via the L-arginine pathway.