Early postnatal hypotension is not associated with indicators of white matter damage or cerebral palsy in extremely low gestational age newborns

Abstract

Objective: To evaluate, in extremely low gestational age newborns (ELGANs), relationships between indicators of early postnatal hypotension and cranial ultrasound indicators of cerebral white matter damage imaged in the nursery and cerebral palsy diagnoses at 24 months follow-up.

Study design: The 1041 infants in this prospective study were born at <28 weeks gestation, were assessed for three indicators of hypotension in the first 24 postnatal hours, had at least one set of protocol cranial ultrasound scans and were evaluated with a structured neurological exam at 24 months corrected age. Indicators of hypotension included: (1) lowest mean arterial pressure (MAP) in the lowest quartile for gestational age; (2) treatment with a vasopressor; and (3) blood pressure lability, defined as the upper quartile of the difference between each infant's lowest and highest MAP. Outcomes included indicators of cerebral white matter damage, that is, moderate/severe ventriculomegaly or an echolucent lesion on cranial ultrasound and cerebral palsy diagnoses at 24 months gestation. Logistic regression was used to evaluate relationships among hypotension indicators and outcomes, adjusting for potential confounders.

Result: Twenty-one percent of surviving infants had a lowest blood pressure in the lowest quartile for gestational age, 24% were treated with vasopressors and 24% had labile blood pressure. Among infants with these hypotension indicators, 10% percent developed ventriculomegaly and 7% developed an echolucent lesion. At 24 months follow-up, 6% had developed quadriparesis, 4% diparesis and 2% hemiparesis. After adjusting for confounders, we found no association between indicators of hypotension, and indicators of cerebral white matter damage or a cerebral palsy diagnosis.

Conclusion: The absence of an association between indicators of hypotension and cerebral white matter damage and or cerebral palsy suggests that early hypotension may not be important in the pathogenesis of brain injury in ELGANs.

Figure 1

Sample for analyses of hypotension indicators and ultrasound lesions and cerebral palsy

Figure 2

Odds ratios (and 95% confidence intervals) of the risk of indicators of white matter damage obtained with logistic regression models that incorporate indicators of hypotension during the first 24 postnatal hours and potential confounders.* *Adjustment is made for black race, public insurance, primagravida, male sex, gestational age 23–24 weeks, birth weight Z-score < -1, multi-fetal gestation, delivery for preeclampsia or fetal indication and receipt of magnesium. A hospital strata term is included to account for the possibility that infants born at a particular hospital are more like each other than like infants born at other hospitals. §Low Q: lowest MAP recorded in the first 24 hours in the lowest quartile for gestational age ¶Vaso: treatment for hypotension with a vasopressor in the first 24 hours with any vasopressor (dopamine, dobutamine, and epinephrine) †Labile: labile blood pressure, defined as the upper quartile of the difference in the lowest and highest MAP

Figure 3

Odds ratios (and 95% confidence intervals) of the risk of cerebral palsy types obtained with logistic regression models that incorporate indicators of hypotension during the first 24 postnatal hours and potential confounders.* *Adjustment is made for black race, public insurance, primagravida, male sex, gestational age 23–24 weeks, birth weight Z-score < -1, multi-fetal gestation, delivery for preeclampsia or fetal indication and receipt of magnesium. A hospital strata term is included to account for the possibility that infants born at a particular hospital are more like each other than like infants born at other hospitals. §Low Q: lowest MAP recorded in the first 24 hours in the lowest quartile for gestational age ¶Vaso: treatment for hypotension with a vasopressor in the first 24 hours with any vasopressor (dopamine, dobutamine, and epinephrine) †Labile: labile blood pressure, defined as the upper quartile of the difference in the lowest and highest MAP