Delirium in elderly critically ill patients: the value of cerebral regulation

Delirium is a common neurological complication in elderly critically ill patients, and a uniform blood pressure target may not adequately address individual cerebral perfusion requirements. This study aimed to evaluate whether cerebral regulation-targeted optimal blood pressure management (OBPM) reduces the incidence of delirium and improve clinical outcomes in this population.

This prospective, single-center, observational study was conducted at Xiangya Hospital, Central South University, from August 2023 to May 2025. A total of 119 elderly critically ill patients were enrolled, including 39 in the OBPM group and 80 in the standard of care (SOC) group. Using near-infrared spectroscopy (NIRS) and ICM+ software, the tissue oxygen reactivity index (TOx) was derived from the dynamic correlation between regional cerebral oxygen saturation (rSO₂) and mean arterial pressure (MAP) across steady-state measurements obtained during stepwise norepinephrine titration, with the optimal MAP (MAPopt) defined as the MAP value at which TOx was minimized. In the OBPM group, blood pressure was targeted within MAPopt ± 5 mmHg, while the SOC group received standard care with blood pressure maintained within the normal range and no signs of inadequate tissue perfusion. The primary outcome, delirium, was screened twice daily throughout the ICU stay using the Confusion Assessment Method for the ICU (CAM-ICU) and the incidence of delirium was determined if the patients experienced it at least once. Secondary outcomes included all-cause mortality at hospital discharge, duration of mechanical ventilation, ICU length of stay, and hospital length of stay.

The incidence of delirium was significantly lower in the OBPM group than in the SOC group (33.3% vs. 55.0%, p = 0.043), and ICU length of stay was significantly shorter [5.0 (3.0-9.0) d vs. 7.0 (4.0-11.0) d, p = 0.022]. Multivariable logistic regression showed that OBPM was independently associated with lower odds of delirium (OR = 0.409, 95% CI: 0.184-0.909, p = 0.028). Mechanical ventilation (OR = 3.500, P = 0.010), sepsis-related organ failure assessment (SOFA) score (OR = 1.139, p = 0.010), and ratio of arterial oxygen partial pressure to fraction of inspired oxygen (PaO₂/FiO₂) (OR = 0.995, p = 0.014) were also independently associated with delirium. No significant differences were observed between groups in hospital length of stay or mortality. Independent risk factors for mortality included sepsis, Acute Physiology and Chronic Health Evaluation (APACHE) II score, lactate level, and prothrombin time.

Cerebral regulation-targeted optimal blood pressure management was associated with a reduced incidence of delirium and shorter ICU stay in elderly critically ill patients, without increasing mortality. Larger multicenter randomized controlled trials are needed to confirm these findings and guide clinical implementation.