[Influence of the hypotensive anesthesia using halothane or trinitroglycerin on coronary blood flow--comparison of normal group and normovolemic hemodilution group].

We divided adult mongrel dogs under halothane anesthesia (1 MAC: 0.86%) into the normal group (N-group: no-hemodilution, with Hct 38 +/- 7%) and the hemodilutional group (H-group: normovolemic hemodilution, with Hct 38 +/- 4%-->21 +/- 4%). For dilution of blood, Dextran 70 was used. In both groups, control values of respiratory and circulatory parameters and coronary blood flow (CBF) were measured. We repeated these measurements after animals had been anesthetized by two different methods:halothane hypotensive anesthesia and trinitroglycerine hypotensive anesthesia. Under hypotensive anesthesia with halothane, CI, LV dp/dt max, and LVSWI decreased significantly as compared to control values in both group. CBF also decreased significantly as compared to the control values in both groups. Under trinitroglycerine hypotensive anesthesia, CI, LV dp/dt max and LVSWI decreased significantly from the control values in both groups as observed under halothane hypotensive anesthesia. Differing from these findings, under trinitroglycerine hypotensive anesthesia no difference from the control group was observed in CBF in N-group, while in H-group CBF decreased significantly from the control value. It was indicated from our results that the increase in coronary blood flow induced by trinitroglycerine becomes obscure under hemodilutional state.