Impact of intraoperative blood pressure fluctuations on postoperative delirium in elderly patients undergoing hip fracture surgery: a retrospective cohort study.

Postoperative delirium (POD) is a frequent and serious complication in elderly patients undergoing hip fracture surgery, frequently resulting in adverse outcomes. Due to the scarcity of effective treatments, targeting modifiable intraoperative factors, such as blood pressure fluctuations, may mitigate risk. This study investigated the association between intraoperative blood pressure fluctuations and POD and evaluated whether vasopressor use contributes to this relationship. In this retrospective cohort study, 330 patients aged ≥65 years who underwent hip fracture surgery between June 2019 and May 2020 were included. Fluctuations were defined as the count of episodes in which the absolute fractional change in median systolic blood pressure over two-minute intervals exceeded 0.10 (|FCM| SBP>0.10). The primary outcome was in-hospital POD. Multivariable logistic regression assessed the association between blood pressure fluctuations and POD, and mediation analysis investigated the role of vasopressor administration. The incidence of POD was significantly higher in the high fluctuation group (≥nine episodes: 11.0%) compared to the low fluctuation group (<nine episodes: 4.8%, P=0.037). Blood pressure fluctuations were independently associated with POD (adjusted OR=6.30, 95% CI 1.63-24.30, P=0.008), with uniform findings across subgroups. Mediation analysis showed intermittent bolus vasopressor use increased POD risk by intensifying blood pressure fluctuations (mediation effect=0.02, 95% BootCI 0.01-0.04, P=0.024). Intraoperative blood pressure fluctuations are an independent risk factor for POD in elderly patients. Minimizing fluctuation, potentially through continuous rather than intermittent vasopressor administration, may improve perioperative neurocognitive outcomes.