The Difference Of Sevoflurane Minimum Alveolar Concentration Between Newborn And Adult Rats

Objective: To investigate the difference of sevoflurane minimum alveolar concentration between newborn and adult rats.Methods: The rats were divided into newborn rat(6~8 days) group(25 cases) and adult rat(8~10 weeks) group(25 cases).All rats were settled in the self-made device for anesthesia with inhaled sevoflurane, and let the tails of rats expose to the out of the self-made anesthetic device for observation. Sevoflurane was given via an anesthesia machine. The initial sevoflurane concentration was 1.5% and maintaining for 20 minutes before clipping tail. If the rats were responsive to the stimulation of clipping tail(defined as positive response), the concentration of sevoflurane would be up-regulated 0.2% and also mainrainedfor 20 minutes before judgment the respose to clip tail stimulation again. If the rats were no response to the clip tail stimulation(defined as negative response), the concentration of sevoflurane would be down-regulated 0.2%, and also maintained for 20 minutes before the next clipping tail.. Above test process was repeated until a cross-over point of positive response vs. negative response in each rat was obtained. The gas sample of 3-5 ml obtained before each clipping tail was determined by a gas chromatography instrument.The middle point value of a positive response vs a negative response in each rat was difined the rat’s minimum alveolar concentration(MAC). The mean value of each rat in each group was difined as the group’s MAC value.Results: The MAC value of newborn rats was(2.58 ± 0.11)%, and the value of adult rats was(2.32 ± 0.13)%. A significant difference was found in the MAC values between newborn and adult rats(P <0.00001).Conclusion: The MAC value of newborn rats was much higher than that of adult rats.