Abstract

Background: Inhalational anesthesia using Isoflurane is a common technique in biomedical research due to its ability to precisely control the depth of anesthesia, stable hemodynamics, and rapid recovery time. In Vietnam, experimental data regarding the optimal anesthetic dose of Isoflurane in white mice remains limited.

Objective: To determine the effective inhalational anesthetic concentration of Isoflurane in an experimental mouse model.

Subjects and Methods: An experimental study was conducted on 90 Swiss albino mice. The mice were randomly divided into 6 groups (n=15/group) and anesthetized using a specialized vaporizer with Isoflurane concentrations of 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, and 3.0%, delivered via an oxygen flow rate of 1 L/min. Monitored parameters included clinical signs and the time to Loss of Righting Reflex. Probit analysis was performed to estimate the ED₅₀, ED₉₀, and ED₉₅ values.

Results: At a concentration of 0.5%, the mice showed no signs of excitation or unconsciousness. At 1.0%, 100% of the subjects exhibited an excitation phase but did not reach a state of unconsciousness. Notably, Loss of Righting Reflex was observed in all animals at concentrations of 1.5% and above. Probit analysis yielded estimated effective anesthetic concentrations ED₅₀, ED₉₀ and ED₉₅ of approximately 1.26%, 1.51%, and 1.58%, respectively.

Conclusion: A maintenance Isoflurane concentration of 1.6% was determined to be safe and effective, ensuring deep anesthesia for the majority of Swiss mice.