Heritable and pharmacological influences on pauses and apneas in inbred mice during anesthesia and emergence

Inherited differences in response to hypercapnia are augmented by volatile anesthetics. Therefore, the authors tested the hypotheses that (1) the incidence of pauses and apneas also increase under anesthesia; (2) there is a difference in the incidence between mouse strains; and (3) there is a difference in the incidence of pauses and apneas depending on the volatile agent. The authors assessed respiratory pauses and apneas at rest; during anesthesia with isoflurane, sevoflurane, and desflurane; and at recovery in C3, B6, and F1 mice. The results are compared using analysis of variance (ANOVA) (P<.05). Awake, there was no difference between mouse strains (Bb, 0.3+/-0.7 P min(-1), C3, 0.4+/-0.7 P min(-1) and F1, 0.4+/-0.5 P min(-1)). In contrast, during anesthesia C3 mice showed a significantly higher incidence of pauses and apneas. There was no increase for B6 and F1 mice. There was no difference depending on the volatile agent. These results indicate an inheritance of a susceptibility to pauses and apneas under the influence of volatile anesthetics, albeit independent of the agent used. This response seems to be independent from the inherited response to hypercapnia.