SVC Blood Flow and Outcome

SVC Blood Flow and Outcome

Low superior vena cava flow and neurodevelopment at 3 years in very preterm infants. Hunt RW, Evans N, Rieger I, et al. J Pediatr (Nov 2004); 145:588-92.

Objectives: Low superior vena cava (SVC) flow is common in the first hours after very preterm birth and has a strong association with subsequent periventricular/ intraventricular hemorrhage. We report the neurodevelopmental outcome at 3 years of age of very preterm babies who had serial echocardiographic studies, including measures of SVC flow, during the first 48 hours after birth.

Study design: A prospective observational study was performed on a cohort of 126 babies (<30 weeks), 103 of whom survived to discharge. Neurodevelopmental follow-up data, which included abnormal developmental quotient, abnormal motor score, and cerebral palsy, were available for 93% of this cohort at 3 years of age. Relations between 3-year outcome and early hemodynamic measures and clinical parameters were explored.

Results: After controlling for confounding variables, average SVC flow over the first 24 hours of life was significantly associated with the primary outcome of death or survival with any disability (P=.004) and with the secondary outcome of abnormal developmental quotient (P=.006). A greater number of low SVC flow readings during the first 24 hours was significantly related to death and adverse developmental outcome, but the individual lowest SVC flow was not, suggesting the importance of duration of low SVC flow. After adjustment, there was no significant association between average mean blood pressure over the first 24 hours and abnormal developmental outcome, whereas the proportion of mean blood pressure readings less than the gestational age showed a trend toward an association with death and any disability.

Conclusions: Low early postnatal blood flow to the upper body and brain may be one factor in the causal pathway of impaired preterm neurodevelopmental outcome.

Comments: Low SVC flow, (a measure of cerebral blood flow) during the first 24 hours is strongly associated with the development of IVH and PVL in VLBW infants. Interestingly, the IVH usually occurs after the blood flow has normalized, suggesting an ischemia-reperfusion injury. We now learn that this condition is also associated with death or survival with disability, and with abnormal neurodevelopmental outcome. The problem is that we have no data that supports the use of inotropes to reduce cerebral hypoperfusion in these infants. In fact, dopamine and dobutamine have been shown not to consistently increase cerebral perfusion as measured by SVC blood flow (See NeoNotes Vol. 3, Issue 4, 2002 (3-020)). I wonder what effect hydrocortisone has on cerebral perfusion and outcomes in VLBW infants. See NeoNotes Vol. 2, Issue 6, 2001 (2-021) for a discussion of using hydrocortisone for hypotension in premature infants. ABK.

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