Trial Outcomes & Findings for A Test of Neural Inertia in Humans With Xenon (NCT NCT02768727)

Analyzed number completing study

To determine in healthy human volunteers if the brain concentrations of xenon (as determined by CT imaging) are identical at the point of loss and return of consciousness. If the values are significantly different, then we conclude that there is evidence for hysteresis in circuits regulating arousal.

To determine if the order of neurocognitive recovery upon emergence from xenon general anesthesia is sequential or simultaneous and if the former is true to determine if the pattern is identical to that of isoflurane (as measured in a previously completed study (PMID: 33970101).

To determine if transient exposure to xenon anesthesia induces a change in rest-activity rhythms (as measured from actigraphy) as has been previously reported for isoflurane. The plan was to collect wrist actigraphy for 1 week before the xenon exposure day and for 1 week following the xenon exposure day. Wrist actigraphy data would be fit with a cosinar analysis function (see Fig 5 from our previous work, PMID: 33970101).

EEG delta power was modeled as a function of estimated brain xenon concentration using nonlinear sigmoidal dose-response curves. Two models were evaluated: 1. a single curve fit to combined induction (increasing xenon concentration) and emergence (decreasing xenon concentration) data, and 2. separate curves fit to induction and emergence phases. Model fit was compared using Akaike Information Criterion (AIC) to assess whether a single (model 1) or phase-specific relationship (model 2) best described the data. Smaller Akaike Information Criterion values indicate a more likely model fit. Typically AIC differences greater than 4 are considered significant.