Is refractory hypotension in preterm infants a manifestation of early ductal shunting?

BACKGROUND: Clinicians frequently use hydrocortisone (HC) to treat vasopressor-resistant hypotension even before establishing its cause.
OBJECTIVE: To identify the etiologic factors leading to development of refractory hypotension, and to assess if patent ductus arteriosus (PDA) is associated with refractory hypotension during the first week of life. STUDY
DESIGN: The medical records of 290 consecutively born infants <or=30 weeks' gestational age (GA) were reviewed to identify the escalating need for vasopressors to maintain mean arterial blood pressure (MABP) at or above a level equal to the GA in completed weeks. Refractory hypotension was defined as MABP unresponsive to fluid boluses and high-dose vasopressors (dopamine and dobutamine at doses 20 microg/kg/min each and/or epinephrine) prompting the use of HC.
RESULTS: Eighty-nine (30.7%) of 290 infants had refractory hypotension between postnatal days 2 and 7. Infants with refractory hypotension were more likely to have a lower birth weight and GA (P<0.001), been treated with surfactant (P=0.004) and received indomethacin for a symptomatic PDA (P<0.001). To identify the etiologic factors, a univariate analysis revealed that the use of high-frequency oscillatory ventilation, presence of air leaks, PDA, sepsis, hyperkalemia and intraventricular hemorrhage (IVH) were significantly associated with refractory hypotension. However, multivariate analysis confirmed the independent association of only PDA (odds ratio (OR) 7.6, 95% confidence interval (CI) 3.3-17.7, P=0.000), severe IVH (OR 2.6, 95% CI 1.1-6.4, P=0.03) and GA (OR 0.7, 95% CI 0.6-0.8, P=0.001).
CONCLUSIONS: Evaluation for early ductal shunting and closure of the ductus, if patent, should be attempted before HC is considered in hypotensive infants with escalating needs for vasopressors.