[Effects of nitric oxide synthase inhibitor on skin blood flow responses to acute isovolemic hemodilution during halothane and isoflurane anesthesia].

Eighteen dogs under halothane or isoflurane anesthesia were subjected for a study in skin blood flow of the forearm under acute isovolemic hemodilution. Hematocrit was intentionally reduced to about 50% of baseline in ten minutes and hematocrit changes were induced by exchange of blood with hydroxyethyl starch. The skin blood flow increase response, measured by laser Doppler flowmetry, to hemodilution was abolished after inhibition of endogenous nitric oxide synthesis by N omega-nitro-L-arginine methyl ester. Skin blood flow responses to hemodilution and N omega-nitro-L-arginine methyl ester were different between halothane group and isoflurane group. Nitric oxide may have an important part to play in vasodilation during acute isovolemic hemodilution, and it may be affected differently by halothane and isoflurane.