Impact of mean arterial pressure fluctuation on mortality in critically ill patients

Objective: The purpose of this study was to investigate the association between mean arterial pressure fluctuations and mortality in critically ill patients admitted to the ICU. Design: Retrospective cohort. Setting: All adult ICUs at a tertiary care hospital. Patients: All adult patients with complete mean arterial pressure records were selected for analysis in the Multiparameter Intelligent Monitoring in Intensive Care II database. Patients in the external cohort were newly recruited adult patients in the Medical Information Mart for Intensive Care III database. Interventions: None. Measurements and Main Results: The records of 8,242 patients were extracted. Mean arterial pressure fluctuation was calculated as follows: (mean nighttime mean arterial pressure - mean daytime mean arterial pressure)/mean arterial pressure. Patients were divided into two groups according to the degree of mean arterial pressure fluctuation: group A (between -5% and 5%) and group B (<-5% and >5%). The endpoints of this study were ICU and hospital mortality. Patients in group A (n = 4,793) had higher ICU and hospital mortality than those in group B (n = 3,449; 11.1% vs 8.1%, p < 0.001 and 13.8% vs 10.1%, p < 0.001, respectively). After adjusting for other covariates, the mean arterial pressure fluctuations between -5% and 5% were significantly correlated with ICU mortality (odds ratio, 1.296; 95% CI, 1.103-1.521; p = 0.002) and hospital mortality (odds ratio, 1.323; 95% CI, 1.142-1.531; p < 0.001). This relationship remained remarkable in patients with low or high Sequential Organ Failure Assessment scores in the sensitive analysis. Furthermore, external validation on a total of 4,502 individuals revealed that patients in group A still had significantly higher ICU (p < 0.001) and hospital mortality (p < 0.001) than those in group B. Conclusions: The reduced mean arterial pressure fluctuation (within -5% and 5%) may be associated with ICU and hospital mortality in critically ill patients.