Strawman redux: management of end-tidal gases in patients at risk of perioperative neurocognitive disorder

Hyperoxia-induced brain ischemia: the Strawman comes up short

“…To the Editor, Dr. Mutch and colleagues hypothesized that intraoperative partial pressure of carbon dioxide (PaCO 2 ) may be a predictor of postoperative delirium due to ischemia induced by hypocapnia-induced cerebral vasoconstriction. 1 Support for this hypothesis was later provided by a retrospective analysis of 89 patients, in whom low end-tidal intraoperative PaCO 2 was a predictor of delirium after surgery. 2 Indeed, there is a credible rationale for this, as hypocapnia can reduce cerebral blood flow (CBF) to the point where there is loss of consciousness.…”

In reply: Hyperoxia-induced brain ischemia: the Strawman comes up short

“…Moon's interest and critique 1 of our recent correspondence to the Journal. 2 Dr. Moon suggests that the cerebral blood flow (CBF) effects of intraoperative hyperoxia are unlikely to contribute to postoperative delirium (POD).…”