Association between intraoperative blood pressure variability and postoperative delirium after hepatectomy: a retrospective cohort study

Postoperative delirium (POD) commonly complicates surgical recovery, and intraoperative blood pressure variability (BPV) may be a modifiable contributor. We examined the association between intraoperative BPV and POD after hepatectomy using average real variability independent of mean (ARVIM), a novel BPV index that incorporates temporal blood pressure changes while reducing dependence on mean blood pressure. This single-center retrospective study included adults who underwent elective hepatectomy under general anesthesia with invasive arterial pressure monitoring from May 2021 to March 2025. Mean arterial pressure (MAP) was recorded at 1-min intervals, and ARVIM was calculated as the mean of successive absolute MAP differences corrected for mean MAP. POD within 7 postoperative days was identified using the Chart-based Delirium Identification Instrument, supplemented by routine Confusion Assessment Method for the Intensive Care Unit assessments during the postoperative intensive care unit (ICU) stay. Associations were evaluated with multivariable logistic regression using restricted cubic splines and ARVIM quartiles, with adjustment for prespecified risk factors. Among 493 patients, 103 (20.9%) developed POD. Restricted cubic spline analysis showed no significant association between ARVIM and POD ( P = 0.70). Associations with POD were also not significant for the other BPV indices examined. Compared with the lowest ARVIM quartile, adjusted odds ratios for POD were 1.39 (98.33% confidence interval [CI], 0.58–3.30), 0.92 (0.38–2.21), and 1.13 (0.47–2.75) for the second, third, and fourth quartiles, respectively (P for trend = 0.95). Findings were similar among patients aged ≥ 65 years. Intraoperative BPV quantified using ARVIM was not independently associated with POD after hepatectomy. Within the range of BPV observed in this cohort, these findings do not support an independent association between greater intraoperative BPV and POD.