Cardiovascular effects of equipotent doses of isoflurane alone and isoflurane plus fentanyl in New Zealand white rabbits (Oryctolagus cuniculus)

OBJECTIVE To determine effects of equipotent concentrations of fentanyl and isoflurane, compared with isoflurane alone, on cardiovascular variables in New Zealand White rabbits (Oryctolagus cuniculus). ANIMALS 6 adult female New Zealand White rabbits. PROCEDURES Rabbits were anesthetized with isoflurane, and lungs were mechanically ventilated. The minimum alveolar concentration (MAC) of isoflurane alone (baseline) and with fentanyl administered IV to achieve 3 targeted plasma concentrations was determined for each rabbit by means of an electrical stimulus. Cardiovascular variables were measured in a separate experiment at 1.3X isoflurane MAC and equipotent doses of isoflurane plus fentanyl at the same 3 targeted plasma concentrations. Blood samples were collected for measurement of blood gas variables and plasma fentanyl concentrations. Treatment effects were evaluated by repeated-measures ANOVA followed by 2-tailed paired t tests with sequentially rejective Bonferroni correction. RESULTS Mean ± SD MAC of...