Optimal Mean Arterial Blood Pressure in Extremely Preterm Infants within the First 24 Hours of Life

Abstract

To define levels of mean arterial blood pressure (MABP) where cerebrovascular reactivity is strongest (MABPOPT) during the early transitional circulation in extremely preterm infants and to investigate the association between deviations above and below MABPOPT with intraventricular hemorrhage (IVH) and mortality. A total of 44 infants born at a median gestational age 25 (23-27) weeks with indwelling arterial catheter were studied at a median 5.5 (3.1-12.6) hours within the first 24 hours of life. Cerebrovascular reactivity (tissue oxygenation heart rate reactivity index) was estimated by the moving correlation coefficient between heart rate and near-infrared spectroscopy tissue oxygenation index. MABPOPT was defined as the MABP where tissue oxygenation heart rate reactivity index reaches minimum value. Deviations below or above MABPOPT values were calculated along with MABPOPT values during retrospective data analysis. MABPOPT was detected in all infants. The mean (SD) MABPOPT was 31.3 (±4.7) mm Hg. MABPOPT increased with increasing gestational age, R = 0.424; P = .004. Deviations below MABPOPT were greater in the IVH group (mean 2.7 mm Hg; 95% CI 2.0-3.5) compared with no-IVH (mean 1.7 mm Hg; 1.1-2.2), P = .006. In infants who died, the deviation below MABPOPT was greater (mean 3.3; 95% CI 1.9-4.8) compared with those who survived (mean 1.9 mm Hg; 95% CI 1.4-2.3), P = .015. Defining optimal MABP based on the strength of cerebrovascular reactivity within the first 24 hours of life is feasible and can provide an individualized approach to the care of extremely preterm infants. Deviations below MABPOPT were significantly associated with IVH and death.