Blood Pressure Variability and Acute Kidney Injury in Traumatic Intracranial Hemorrhage : A Retrospective Cohort Study Using the MIMIC-IV Database.

OBJECTIVE

Acute kidney injury (AKI) is a common and serious complication in traumatic intracranial hemorrhage (tICH), leading to worse outcomes. Blood pressure variability (BPV), beyond mean blood pressure levels, may impair end-organ perfusion and predispose to AKI. However, the relationship between BPV and AKI in tICH patients remains poorly defined. We investigated the association between BPV and AKI in patients with tICH.

METHODS

We conducted a retrospective cohort study of tICH patients from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Inclusion required ≥24 systolic and diastolic blood pressure measurements within the first 24 hours of intensive care unit admission. BPV indices, average real variability (ARV), standard deviation (SD), and coefficient of variation (CV), were calculated for both systolic (SBP) and diastolic pressures. Univariate and multivariate logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for AKI. Two adjustment schemes were applied : group 1 (age, congestive heart failure, diabetes) and group 2 (group 1 covariates + vasoactive agents, mannitol, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, hypertonic saline). Analyses were performed in the hypertensive subgroup (mean SBP ≥140 mmHg), using the same covariate adjustment schemes.

RESULTS

Among 551 patients, AKI developed in 385 (69.9%). In multivariate analysis with adjusted for all confounders, higher SBP_ARV (OR, 1.046; 95% CI, 1.004-1.095; p=0.048) and SBP_SD (OR, 1.052; 95% CI, 1.010-1.099; p=0.018) were independent predictors of AKI. In hypertensive subgroups, after adjustment for all confounders, associations were even stronger : SBP_ARV (OR, 1.285; 95% CI, 1.064-1.553; p=0.009), SBP_SD (OR, 1.203; 95% CI, 1.022-1.417; p=0.027) and SBP_CV (OR, 1.273; 95% CI, 1.012-1.601; p=0.039).

CONCLUSION

Elevated systolic BPV independently predicts AKI in tICH patients. Incorporating BPV monitoring into neurocritical care protocols may help identify high-risk patients and guide interventions to stabilize blood pressure fluctuations, potentially minimizing AKI risk.