Medetomidine과 Tiletamine/Zolazepam을 병용마취한 개에서 통증자극이 뇌파 변화에 미치는 영향

Effects of Pain Stimulation on EEG in Dogs Anesthetized withMedetomidine and Tiletamine/Zolazepam

개에서 Medetomidine (MED)과 tiletamine/zolazepam (ZT) 병용마취시에 통증자극에 대한 반응으로 판단되는 외과적 마취기에 적절한 진통효과가 나타나는지를 확인하기 위해 뇌파를 이용하여 실험을 실시하였다. 임상적으로 건강한 비글견 7두를 이용하여 동일견을 대조군과 통증자극군에 이용하였다, 대조군은 MED $30\;{\mu}g/kg$ 투여 후 15분에 ZT 10 mg/kg을 각각 근육주사하였으며, 통증자극군은 대조군과 동일한 방법으로 약물을 투여한 다음 ZT 투여 후 10분부터 45분까지 5분 간격으로 pedal withdrawal reflex test를 실시하였다. 각각의 기록시간대에서 뇌파의 band power,평균동맥혈압과 심박수를 측정하여 실험군간 비교하였다. 뇌파 기록전극은 International 10-20 system을 이용하여 Cz에, 기준전극과 접지전극은 양쪽 귀에 장착하였다. 뇌파 분석상 저주파 band가 높은 power를 보이고 고주파 band가 낮은 power를 나타냈으나 군간 유의성 있는 차이는 발견할 수 없었다. 평균 동맥혈압과 심박수는 TZ 투여 10분 후 두 군 모두 상승하였으나 군간 유의성은 없었다. 본 실험 결과, 개에서 MED와 ZT 병용마취는 외과적 마취기에 우수한 진통효과를 제공하는 것으로 사료된다.

The aim of this study is to investigate whether medetomidine (MED) and tiletamine/zolazepam (ZT) combination in dogs provide the sufficient analgesia during the period of the stage of surgical anesthesia determined by the response to the noxious stimuli, which were evaluated by the change of electroencephalogram (EEG) and hemodynamic values. Seven clinically healthy, adult beagle dogs were used. They were used repeatedly at interval of a week, according to a randomized design. This study had 2 experimental groups. In Group 1, dogs received $30\;{\mu}g/kg$ of medetomidine and 10 mg/kg of tiletamine/zolazepam. Both drugs were administered intramuscularly. In Group 2, dogs were medicated with the same method as in Group 1, except the pedal withdrawal reflex test was done. In Group 2, interdigital regions were grasped with a mosquito forceps for 30 seconds, every 5 min from 10 min to 45 min after ZT injection. During all recording stages, the power for each band, mean arterial pressure and heart rates were calculated. On EEG, no significant changes were observed between groups. Although mean arterial pressure and heart rate were increased 10 min after ZT injection, no significant differences were observed between groups. In conclusion, the MED and ZT anesthesia in dogs are seemed to provide a satisfactory analgesic effect during the period of surgical anesthesia based on EEG with pedal withdrawal reflex test.