Association between intraoperative hypotension and postoperative ICU delirium: a retrospective observational study

Postoperative delirium is a common complication associated with prolonged hospitalization, cognitive decline, and increased mortality. Intraoperative hypotension (IOH) is a potential modifiable risk factor for postoperative delirium, but previous studies have shown inconsistent results due to methodological limitations. High-risk surgical patients, particularly those with comorbidities or advanced age, may be especially vulnerable. We evaluated the association between IOH and postoperative ICU delirium within 48 h.

We conducted a single-center retrospective study of high-risk adult patients who underwent surgery under general anesthesia without cardiopulmonary bypass and were admitted to the ICU between 2017 and 2024. IOH exposure was quantified using the cumulative area where mean arterial pressure (MAP) was below 65 mmHg (hypotension area) and total time under this threshold (hypotension time). Multivariable logistic regression was used to assess the association between IOH and postoperative ICU delirium, adjusting for preoperative comorbidities, intraoperative medications, and anesthetic depth. Subgroup and interaction analyses explored effect modifiers.

Among 4798 patients, both hypotension area (OR 1.16, 95% CI 1.05-1.29, P = 0.003) and hypotension time (OR 3.42, 95% CI 1.21-9.65, P = 0.02) were significantly associated with postoperative ICU delirium within 48 h. Subgroup analyses suggested stronger associations in patients with advanced age, higher ASA-PS, inhalational anesthesia, neurosurgery, and intubation at ICU admission.

IOH was significantly associated with postoperative ICU delirium. These findings underscore the importance of vigilant blood pressure management during surgery, particularly in high-risk patients. Interventional studies are needed to confirm these results and guide preventive strategies.