Cerebral desaturation and delirium in patients having non-cardiac surgery - a pilot study

Postoperative delirium (POD) is associated with increased short- and long-term mortality and several risk factors have been described. Decreased regional cerebral oxygen saturations (rScO2) may be a modifiable risk factor for POD yet its measurement is not used in routine clinical practice. The primary aim of this study was to assess the feasibility of measuring rScO2 and screening for POD in patients over 60 years of age having non-cardiac surgery. Our secondary aim was to perform exploratory analyses of the relationship between boluses of intra-operative vasopressor and rScO2 values. rScO2 were recorded in 60 patients over the age of 60 years having non-cardiac surgery in a single centre. Patients were screened daily for delirium for up to 7 days of the inpatient stay or until discharge, which ever occurred sooner. Of the 60 patients recruited, 58 underwent complete daily assessment for POD. Of those, 2 developed POD (3.4%). Patients that developed POD tended to be older, but no other statistically significant differences were observed. Analysis of the effect of phenylephrine boluses on rScO2 observed a ‘rise, drop, return’ pattern in an 8-minute window post-bolus administration. The study protocol was found to be feasible to deliver. The study was unable to find any associations between rScO2 and POD, however, the study identified a relationship between intraoperative vasopressor boluses and subsequent rScO2.