Background

We have shown that using age-adjusted admission systolic blood pressure (SBP) values (z-scores) may offer advantages in determining the associated mortality risk in a large unselected PICU population.

Objectives

We hypothesized that the SBP z-score risk profile would differ in children admitted with a primary cardiac diagnosis from the rest of the cohort.

Methods

This is a retrospective cohort study using data from 2 cardiac and 2 general PICUs from 2004-2018. We derived SBP z-scores according to the NIH Task Force definitions of normal SBP (1,2). We defined the relationship between mortality and SBP z-scores using logistic regression, adjusted for PIM-2 with the blood pressure component removed.

Results

Data from 34,745 patients were analysed (19,649 cardiac and 15,096 non-cardiac admissions). The relationship between mortality and SBP z-scores are shown in Figure 1. The relationship is U-shaped for general ICU admission, but inverse for cardiac ICU.

Conclusion

Our data show an inverse relationship between SBP z-scores and mortality in the cardiac population. The decreased risk of mortality with hypertension is potentially representative of the favourable outcome in children with good post-operative recovery of heart function. Whether manipulating blood pressure modifies the risk of death needs to be assessed in an interventional trial.

References:

(1) National Institutes of Health. The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents. Available from:https://www.nhlbi.nih.gov/files/docs/resources/heart/hbp_ped.pdf [Accessed 18/6/2018].

(2) National Institutes of Health-Task Force on Blood Pressure Control in Children. Report of the Second Task Force on Blood Pressure Control in Children-1987.Pediatrics. 1987. 79;1:1-25.