Association of blood pressure variability with short- and long-term cognitive outcomes in patients with critical illness

Blood pressure variability (BPV), a modifiable risk factor, can compromise cerebral perfusion in critically ill patients. We studied the association between BPV in the intensive care unit (ICU) and short- and long-term cognitive outcomes. All patients were ≥50 years old. The short-term cognitive end points were delirium and depressed alertness without delirium. The long-term outcome was change in the slope of longitudinal cognitive scores. Primary BPV measure was average real variability (ARV) of systolic blood pressure. Associations were assessed with multivariable multinominal logistic regression and linear mixed effects models. Of 794 patients (1130 admissions) 185 developed delirium and 274 developed depressed alertness. There was a dose-response association of 24-h systolic ARV with delirium (adjusted OR, 95% CI 2.15 per 5 mm Hg increase, 1.31–3.06, P < 0.017) and with depressed alertness (OR 1.89, 95% CI 1.18–3.03, P < 0.008). For 371 patients with available longitudinal cognitive scores, the decline in cognitive trajectory was accelerated after discharge (annual change OR −0.097, 95% CI −0.122 to −0.073). This acceleration increased with delirium (additional decline −0.132 [−0.233 to 0.030], P = 0.011). We found no significant association between BPV and post-ICU cognitive trajectory. BPV was associated with increased likelihood of delirium in the ICU. Delirium, but not BPV, was associated with long-term cognitive decline. •Blood pressure variability (BPV) may compromise brain perfusion.•Critically ill patients may have increased BPV, which is a modifiable risk factor.•BPV in ICU is associated with an increased risk for delirium and encephalopathy.•BPV is not associated with long-term cognitive impairment.•Delirium is associated with accelerated cognitive decline after ICU discharge.