Journal of Applied Physiology, Vol 76, Issue 6 2304-2309, Copyright © 1994 by American Physiological Society
Differing effects of anesthetics on splanchnic arterial blood flow during hemorrhagic shock
S. I. Myers, R. Hernandez and T. A. Miller
Department of Surgery, University of Texas Southwestern Medical School at Dallas.
The effect of anesthesia on splanchnic blood flow was examined during
hemorrhagic shock and resuscitation. Sprague-Dawley rats were anesthetized
with the inhalation anesthetic, methoxyflurane, or pentobarbital (65
mg/kg). Transonic Doppler flow probes were placed around the superior
mesenteric artery (SMA) and the abdominal aorta, and the animals were
subjected to acute hemorrhage (or sham) to 30 mmHg for 90 min followed by
30 min of resuscitation with shed blood (n = 6/group). At 90, 105, and 120
min, sham animals in both anesthetic groups showed comparable blood
pressures with a 50% decrease in SMA and aortic blood flow. Acute
hemorrhage decreased SMA blood flow by 94.5 +/- 0.01 and 86.0 +/- 2.8%,
respectively, in the pentobarbital and methoxyflurane groups, with similar
changes occurring in aortic blood flow. During resuscitation, arterial
pressure remained significantly depressed and SMA blood flow decreased by
65% in the pentobarbital group, whereas blood pressure returned to control
levels and SMA blood flow increased to 56% of control values (P < 0.001)
in the methoxyflurane group. The findings indicate that the choice of
anesthetic agent may significantly impact splanchnic blood flow and needs
to be taken into account when designing experiments examining effects of
hemorrhagic shock.
