Betamethasone Impairs Cerebral Blood Flow Velocities in Very Premature Infants with Severe Chronic Lung Disease

Objective

To assess betamethasone (BM) effects on the cerebral hemodynamics of neonates with severe chronic lung disease (CLD).

Study design

Intravenous BM was given once daily for 6 consecutive days to 12 infants (birth weight: 698 g [range, 650-884 g], gestational age: 25.3 weeks [range, 25-26.4 weeks]) at a postnatal age of 34 days (range, 28-36 days). Cerebral blood flow velocities (CBFVs) were recorded prospectively in the anterior cerebral artery (ACA) and the lenticulostriate artery (LSA) before, during, and after treatment, using Doppler flowmetry.

Results

The decrease in systolic and diastolic velocities was maximum on the 5th day, reaching 32% (95% confidence interval [CI], 23%-42%) and 58% (95% CI, 39%-64%) from baseline in the ACA, and 44% (95% CI, 29%-50%) and 57% (95% CI, 33%-66%) in the LSA, respectively. The resistance index (RI) increased significantly in both arteries during treatment. Return to baseline values was observed after BM was stopped. The change in velocities and RI was independent of arterial blood gas and blood pressure variations.

Conclusions

BM decreased the CBFVs of premature infants, suggesting a vasoconstrictor effect in both superficial and deep arterial vessels. Caution is recommended when BM is used to treat preterm infants with severe CLD.

Abbreviations: ACA, Anterior cerebral artery, ANOVA, Analysis of variance, BM, Betamethasone, CBFV, Cerebral blood flow velocity, CLD, Chronic lung disease, DEX, Dexamethasone, EDV, End diastolic velocity, LSA, Lenticulostriate artery, MAP, Mean airway pressure, PSV, Peak systolic velocity, RI, Resistance index, Tc, Transcutaneous