Changes of Mean Arterial Pressure, Intracranial Pressure, Blood Gas and Serum Electrolytes during N2O - Halothane Anesthesia in Rabbits / 대한마취과학회지

ABSTRACT

This experiment was undertaken to study the effects of different ratios of N2O-O2 in N2O- halothane anesthetized rabbits weighing about 4-4.5 Kg. The N2O-O2 ratios were 21 (group 1), 31 (group 2) and 41 (group 3). We measured the mean arterial pressure, intracranial pressure and cerebral pressure and analysed the blood gas and electrolytes in each group and compared each group to the other two. The results are summarized as follow; The mean arterial pressure was 101.7+/-14.6, 92.7+/-11.0 and 89.4+/-15.1mmHg in each group respectively. The mean arterial pressure of the group 3 decreased more significantly than that of group 1. The intracranial pressure was 12.7+/-4.3, 11.8+/-4.2 and 13.6+/-4.6mmHg in each group respectively and was non-significant as compared to other groups. The cerebral perfusion pressure was 90.8+/-13.3, 82.6+/-9.9 and 76.9+/-16.9mmHg in each group respectively and the cerebral perfusion pressure of group 3 decreased more significantly than that of group l. In the blood gas analysis, PaQ2 was 162+/-27, 119+/-13 and 105+/-8 mmHg in each group respectively and was non-significant in respect to other groups. PaCO2 and O2 content were not different significantly in each group and were within normal values. The oxygen saturation was 98.9+/-0.3, 97.8+/-0.4 and 97.6+/-1.1% in each group respectively and group 2 and 3 decreased more significantly than group 1. Na+, Cl-, HCO-(3), pH and BE were not different significantly in each group, pH, BE and HCO-(3) were measured as being slightly low values, but PaCO2 was kept within normal values. These are explained as probably being due to metabolic acidosis. The serum K' was 2.94+/-0.46, 3.07+/-0.44 and 3.40+/-0.7 mEq/1 in each group respectively and the serum K+ of group 3 increased more significantly than groups 1 and 2. With these results, it is suggested that a ratio above a 21 ratio of N2O-O2 is more dangerous in halothane-N2O anesthesia.