Intensification of the metabolic acidosis induced under alpha-chloralose anaesthesia with graded increase in the dose

Abstract

Surgical anaesthesia between planes 2-3 with alpha-chloralose in dogs induced simultaneous depression of ventilation viz., low oxygen (PaO2) tension, high carbon dioxide (PaCO2) tension and H+ion homeostasis (high base deficit). The anaesthesia on the aforesaid planes could be achieved only by doses not below 100 mg/kg. The progressive increase in the administered dose between 100 and 200 mg/kg did not alter the acid-base profile. Further increase beyond 200 mg/kg dose was followed by a steep increase in the base deficit enhancing H+ion (cH+) concentration. However, the steep fall in PaO2 accompanied by steep rise in PaCO2 was observed only when the dose was above 250 mg/kg. The findings in the present study indicated that depression of H+ion homeostasis under chloralose anaesthesia was induced by neural mechanism independent of respiratory centres. © 1983 The Italian Pharmacological Society.