Gastric mucosal perfusion in dogs: effects of halogenated anesthetics and of hemorrhage.
The gastrointestinal tract is one of the first organs affected by hypoperfusion during hemorrhagic shock. The hemodynamics and oxygen transport variables during hemorrhagic shock and resuscitation can be affected by the anesthetics used. In a model of pressure-guided hemorrhagic shock in dogs, we studied the effects of three halogenated anesthetics--halothane, sevoflurane, and isoflurane--at equipotent concentrations on gastric oxygenation. Thirty dogs were anesthetized with 1.0 minimum alveolar anesthetic concentration (MAC) of either halothane, sevoflurane, or isoflurane. A gastric tonometer was placed in the stomach to determine mucosal gastric CO(2) (PgCO(2)) and for the calculation of gastric-arterial PCO(2) gradient (PCO(2) gap). The dogs were splenectomized and hemorrhaged to hold mean arterial pressure at 40-50 mm Hg over 45 min and then resuscitated with the shed blood volume. Hemodynamics, systemic oxygenation, and PCO(2) gap were measured at baseline, after 45 min of hemorrhage, and at 15 and 60 min after blood resuscitation. Hemorrhage induced reductions of mean arterial pressure and cardiac index, while systemic oxygen extraction increased (p < .05), without significant differences among groups (p > .05). Halothane group showed significant lower PCO(2) gap values than the other groups (p < .05). After 60 min of shed blood replacement, all groups restored hemodynamics, systemic oxygenation, and PCO(2) gap to the prehemorrhage levels (p > .05), without significant differences among groups (p > .05). We conclude that halothane is superior to preserve the gastric mucosal perfusion in comparison to isoflurane and sevoflurane, in dogs submitted to pressure-guided hemorrhagic shock at equipotent doses of halogenated anesthetics.
Silva
Alexandre Evangelista
AE
Department of Anesthesiology, School of Medicine, São Paulo State University-UNESP, Botucatu, São Paulo State, Brazil.
do Nascimento
Paulo
P
Beier
Suzane Lilian
SL
Roberto
Wellington Matheus
WM
Braz
Leandro Gobbo
LG
Vane
Luiz Antonio
LA
Ganem
Eliana Marisa
EM
Braz
José Reinaldo Cerqueira
JR
D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism*; D004285:Dogs; D005260:Female; D005753:Gastric Mucosa / Q000098:blood supply / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D015424:Reperfusion; D012151:Resuscitation; D012771:Shock, Hemorrhagic / Q000378:metabolism*
D018685:Anesthetics, Inhalation; D002245:Carbon Dioxide; D010100:Oxygen