| Minipigs are important animal models in medical and veterinary research and have been widely used in experiments requiring surgical anesthesia. BaMa minipig is a breed of minipigs from Guangxi, China, which has gentle temper and stable genetic characteristics that are suitable for medical research. Because of swine unique properties, most chemical restraining drugs are administrated intramuscularly. But single IM anesthesia administration cannot provide an appropriate anesthetic quality because it is difficult to control over the depth of anesthesia. While general anesthesia using inhalation anesthetics provides excellent, stable anesthesia for surgical procedures. Sevoflurane is an inhalant anesthetic with low blood-gas partition coefficient that makes it an ideal anesthetic for mask induction and anesthesia maintenance. However, there are relative few studies on sevoflurane in minipigs.The aim of this study was to determine the minimum alveolar concentration (MAC) of sevoflurane in minipigs, and assess the cardiopulmonary responses at different MACs of sevoflurane. An anesthesia protocol was designed with premedication used by Shumianning Ⅱ0.02mL·kg-1, induction anesthesia given by propofol5mg·kg-1intravenously, and maintainance anesthesia with a vaporizer setting of4%sevoflurane and an oxygen flow rate at2L·min-1in the first5min, then with a vaporizer seting of2.5%sevoflurane and an oxygen flow rate at0.5L·min-1for Low-flow anesthesia. Cardiopulmonary responses and the quality of Pro-Sev combined anesthesia were evaluated in BaMa minipigs, and the quailty of this anesthetic protocol was assessed in surgical minipigs.The results showed that the sevoflurane MAC value in minpigs was2.38±0.20%. HR and RR had no correlation with the concentration of sevoflurane (P>0.05), MBP, VT and MV decreased when received increased concentration of sevoflurane, while PETCO2 increased, all these data were significantly correlated with concentration of sevoflurane (P <0.05). PETCO2extreme significantly higher than baseline when the sevoflurane concentration increased from0.8to1.5MAC(P<0.01), MBP decreased significantly compared to the baseline when the sevoflurane concentration was augmented at1.3and1.5MAC(P<0.05). The induction time and the recovery time of the Pro-Sev combined anesthetic protocol were160.5±27.18s and53.17±7.05min, respectively. Scores of preanesthesia sedation quality, induction and intubation quality, anesthesia quality and recovery quality were4,3.7,4and4respectively. There was no significant change of HR and ABP parameters during anesthesia and recovery(P>0.05). RR and PetCO2were significantly higher than the baseline level while VT was significantly lower at some time points(P<0.05), but15min after set off the vaporizer, all these values returned to the baseline. During cystotomy, the qualities of sedation, analgesia and muscle relaxants were satisfied. Although there were some significant changes (P<0.05) of MBP, RR, VT, MV and PetCO2parameters during anesthesia and recovery compared with the baseline, the MBP parameters were in the normal physiologic range and respiratory parameters returned to the baseline15min after set off the vaporizer. RT was decreased significantly15min after start of operation compared with the baseline.In conclusion, Sevoflurane did not affect HR, arterial pressures and respiratory parameters were depressed in a dose-dependent pattern at different MAC of sevoflurane. The Pro-Sev combined anesthetic protocol was preferable for juvenile BaMa minipigs, and had slight effect on cardiovascular system. Although there were some significant changes in respiratory parameter, all values returned to baseline15min after set off the vaporizer. The duration of induction and recovery was smooth and rapid. The quality of this anesthetic protocol used for cystotomy was satisfied, but attention should be paid to keep warm during surgical anesthesiain in young BaMa minipigs. |
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