Levothyroxine replacement therapy and refractory hypotension out of transitional period in preterm infants.

BACKGROUND

Recent studies suggest that refractory hypotension from causes other than septicaemia or cardiac failure is common in extremely preterm infants even out of the transitional period. Marked response to low-dose cortisol suggests underlying adrenal insufficiency, although the exact mechanism remains unknown.

METHODS

To investigate potential triggers for and related short-term outcomes of early-onset (<Day 7) and late-onset (≥Day 7) refractory hypotension, clinical data for 70 infants <30 weeks gestation were assessed.

RESULTS

The incidence of early-onset refractory hypotension (n=7) was correlated with younger gestational ages <26 weeks (P < 0.05), whereas the incidence of late-onset refractory hypotension (n=14) was correlated with younger gestational ages and levothyroxine supplementation (P<0.05 and 0.01, respectively). The incidence of both early- and late-onset refractory hypotension was correlated with risks of short-term adverse outcomes such as prolonged mechanical ventilation and hospital stay.

CONCLUSIONS

Levothyroxine supplementation was identified as an independent variable correlated with an increased incidence of refractory hypotension out of the transitional period; as seen in hypothyroidism with Addison's disease, the immature hypothalamic-pituitary-adrenal axis may not respond properly to the increased demand for cortisol, which may precipitate premature infants into refractory hypotension. Following the administration of levothyroxine, preterm infants may have to be carefully monitored for early signs of refractory hypotension.