Evaluating the relationship between cerebrovascular autoregulation and postoperative delirium in intensive care unit patients after high-risk, non-cardiac surgery
Nina Li1, Andrew Cheng2,3
1. Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
2. Department of Intensive Care, St George Hospital, Liverpool, NSW, Australia
3. St George & Sutherland Clinical School of Medicine, University of New South Wales, Sydney, NSW, Australia.
Background
An association between adverse outcomes and impaired cerebrovascular autoregulation (CVAR) during cardiac surgery has been documented, but it remains unknown whether an impairment after high-risk, non-cardiac surgery is associated with delirium.
Aim
To evaluate any association between impaired CVAR during the first 24 hours after high-risk surgery and delirium.
Methods
In this prospective cohort study, NIRS-derived regional cerebral oxygen saturation and invasive mean arterial blood pressure (MAP) were analysed to determine the tissue oxygenation reactivity (TOx), an index of CVAR. Delirium was evaluated using the Confusion assessment method for the ICU.
Results
When comparing patients that developed delirium (n=11) to those that did not (n=60), there was no significant difference in the TOx scores (p=0.12). MAP excursions above the upper limit of normal (ULA) was not associated with delirium (p=0.10).
Conclusions
In this study, delirium appeared to occur independently of postoperative CVAR impairment or MAP deviations above the ULA.