A PILOT-STUDY - DEFIBRILLATION THRESHOLDS IN DOGS ARE SIMILAR WITH ISOFLURANE, HALOTHANE, AND PENTOBARBITAL

The objective of this pilot study was to determine if three common ane sthetic drugs have differing effects on the measurement of defibrillat ion thresholds (DFT) in dogs. The drugs compared were pentobarbital, i soflurane, and halothane. We used six dogs, which were surgically inst rumented, in a chronic study design. Each dog had two internal defibri llation patches placed on its heart, which were used to deliver the de fibrillation energy. DFT was determined while each dog was anesthetize d under each of the listed drugs in a crossover design. This pilot stu dy suggests that differences in DFT due to the anesthetic drugs is not significant in studies with low numbers of animals (halothane 14.5 +/ - 1.0, isoflurane 14.2 +/- 1.0, pentobarbital 12.8 +/- 1.0; P = NS; me an +/- SE). The variation in DFT between individual animals is much la rger than the difference in DFT due to the drugs.