Changes in regional hemodynamics after nitric oxide inhibition during ovine bacteremia.
We studied the action of nitric oxide synthase (NOS) inhibition on changes in regional blood flow during a continuous infusion of live bacteria. Eighteen ewes were chronically instrumented. After a 7-day recovery period, an infusion of 10(6) colony-forming units/min Pseudomonas aeruginosa was begun. At 24 h, cardiac output increased significantly above baseline in all groups (5.9 +/- 0.4 vs. 8.2 +/- 0.6 l.min 1.m-2), systemic vascular resistance decreased (1,362 +/- 120 vs. 821 +/- 145 dyn.g.cm-5.m-2), and cerebral, cephalic mesenteric, and hindlimb blood flows increased. The animals were then equally and randomly assigned to a bolus of a NOS inhibitor, either 25 mg/kg N omega-nitro-L-arginine methyl ester (L-NAME) or 20 mg/kg N omega-monomethyl-L-arginine (L-NMMA), followed by a continuous infusion of 7 mg.kg-1.min-1 L-NMMA or saline. After NOS inhibition, cardiac index decreased [5.6 +/- 0.1 (L-NAME) and 5.5 +/- 0.4 l.min-1.m-2 (L-NMMA)] and remained significantly decreased for 12 h. 1-NAME decreased carotid and mesenteric blood flows to 64% of the preseptic baseline, and they remained below baseline for 20 h. L-NMMA decreased blood flows only to preseptic baseline values. NOS inhibitors may affect blood flows independently of their hemodynamic effects.
Lingnau
W
W
Department of Anesthesiology, University of Texas Medical Branch, Galveston, USA.
McGuire
R
R
Dehring
D J
DJ
Traber
L D
LD
Linares
H A
HA
Nelson
S H
SH
Kilbourn
R G
RG
Traber
D L
DL
D000818:Animals; D016470:Bacteremia / Q000503:physiopathology*; D001775:Blood Circulation / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors*; D011552:Pseudomonas Infections / Q000503:physiopathology; D012039:Regional Blood Flow / Q000187:drug effects; D012756:Sheep; D014655:Vascular Resistance / Q000187:drug effects; D019323:omega-N-Methylarginine / Q000494:pharmacology
D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D019331:NG-Nitroarginine Methyl Ester