Title : Early Postnatal Hypotension (EPH) in ELBW neonates: Complications and effects of antenatal factors
Background: The incidence of EPH in ELBW infants is 20- 45%. EPH is associated with significant mortality and morbidities in this population. There are no recent reports on the adverse outcomes of refractory and nonrefractory hypotension in ELBW infants, as compared with normotensive ELBW neonates. About 25% of hypotensive ELBW infants are refractory to the standard treatment of volume expansion and inotropes (VI) and require hydrocortisone (HC). Such neonates undergo a prolonged exposure to hypotension and VI before resolution is achieved with HC. Objective: 1.To compare normotensive ELBW infants with those who suffer from refractory (HC) and non-refractory (VI) hypotension. 2. To compare infants suffering from refractory and non-refractory hypotension, in order to identify clinical features of neonates susceptible to refractory hypotension early in course. Study Design: Retrospective case control Results: Normotensive controls (C) Vs. Hypotensive VI and HC groups: VI (n=74) Vs. C (n=124): BW, GA and receipt of ANS did not differ. In the multivariate analysis, the occurrence of gestation associated diabetes mellitus (GDM) and risks for PDA, IVH, SIP, VM and oxygen dependence at 36 postmenstrual week of life (BPD) were higher in VI. HC (n=69) Vs. C: HC recipients had lower BW, GA and receipt of ANS. After controlling for these variables, the risks for IVH, BPD, air leaks and PDA were higher in the HC group. The occurrences of SIP, NEC, VM and GDM did not differ. Hypotensive infants: HC vs. VI groups: Infants in HC group had lower BW (675 ± 121 g) and gestational age (GA, 25.1 ± 1.3 weeks) and higher mean airway pressure and oxygen requirements, all independent of antenatal steroid (ANS) exposure. The receipt of ANS (p=0.01) and occurrences of GDM, (p=0.01) were lower in HC group. ANS (OR 0.5, 95% CI 0.2–0.9, p 0.01) and GDM (OR 0.3, 95% CI 0.09–0.9, p 0.04) reduced the risk for RH, as did maternal hypertension after controlling for BW (OR 0.2, (%% CI 0.07-0.9 p =.02). HC group had higher risk for IVH (OR2.1, 95%CI1.02–4.2 p= 0.04) which declined in the multivariate analysis. A trend towards lower risk of ventriculomegaly (VM) was noted in HC group (OR 0.3, 95% CI 0.1–1.1), which became significant after controlling for BW (OR 0.2 95% CI 0.07–0.9, p 0.04). Conclusions: Hypotension treated with inotropes is associated with increased risks for SIP and VM in ELBW infants. ELBW neonates treated with hydrocortisone for refractory hypotension do not exhibit such risks. GDM decreases the occurrence of refractory hypotension in ELBW infants. ELBW infants who are ≤25 weeks of GA and unexposed to ANS and GDM are more likely to suffer from refractory hypotension and may benefit from an initial therapy with, or earlier institution of hydrocortisone. Effect of maternal hypertension in decreasing the occurrence of refractory hypotension is birth weight dependent. This, as well as the trend towards a higher risk for VM with VI therapy needs validation in future well powered studies.