Emergence from general anaesthesia: stochastic or deterministic?

Is emergence from general anaesthesia fundamentally stochastic or deterministic? A recent study using genetically identical mice found significant intra-individual and inter-individual variability in emergence times. This variability was better explained by a stochastic neural dynamics model than by traditional deterministic pharmacokinetic-pharmacodynamic models. These findings offer a new perspective on the intrinsic nature of anaesthetic emergence as a stochastic process; however, they also raise important questions about how we define and measure emergence. In particular, since the commonly used righting reflex, a basic motor response, might not adequately reflect recovery of cognitive abilities, and higher-level cognitive functions might follow more predictable, deterministic emergence trajectories, we suggest that future research examine emergence across multiple levels of brain function and adopt more comprehensive, cognition-sensitive markers.