Cardiovascular instability after patent ductus arteriosus ligation in preterm infants: the role of hydrocortisone
ABSTRACT Following patent ductus arteriosus (PDA) ligation, preterm infants may develop profound hypotension and respiratory failure. Prophylactic stress hydrocortisone (HC) has emerged as a therapy to prevent complications, postulating these infants do not synthesize steroids because of an immature hypothalamic-pituitary-adrenal axis. The purpose of this study was to compare outcomes in infants who received stress HC before their PDA ligations to those who did not.
A retrospective chart review was performed of infants who underwent PDA ligations at our institution's neonatal intensive care unit. Data were collected on treatment with HC, and respiratory and cardiovascular support.
Gestational age (GA) and birth weight were lower in the HC group (24 vs 25 weeks, 632 vs 790 g), but age at time of surgery was similar (26 vs 21 days). Cardiorespiratory support was comparable between the groups pre- and post-operatively. In regression models that adjusted for GA, HC treatment was not independently related to respiratory support postoperatively, but was associated with a decrease in postoperative dopamine (2.2 mcg kg(-1) min(-1); P=0.03). Respiratory support postoperatively was predicted by preoperative respiratory support. GA and age at surgery were not independently associated with outcome.
Preoperative stress HC was not associated with improved cardiorespiratory stability, regardless of GA. Further investigation is needed to identify infants who may benefit from this therapy.
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ABSTRACT: Background: Targeted milrinone treatment for low left ventricular output (LVO) reduces the incidence of acute cardiorespiratory instability following ligation of patent ductus arteriosus (PDA) in preterm infants. Despite this, some infants continue to experience postoperative deterioration. Adrenal insufficiency related to prematurity has been postulated as a possible mechanism. Objectives: To describe adrenal function in premature infants undergoing PDA ligation and to investigate its association with pre- and postoperative clinical and echocardiography-derived indices of disease severity. Methods: A retrospective cohort study was conducted over a 2-year period on infants who underwent PDA ligation and had preoperative adrenocorticotropic hormone (ACTH) stimulation. All infants were screened by echocardiography for low LVO at 1 h after surgery and treated with intravenous milrinone if LVO <200 ml/kg/min. The primary outcome evaluated was low LVO at 1 h after surgery. Secondary outcomes included hypotension and oxygenation and ventilation failure occurring within 24 h. Results: A total of 35 infants at a median gestation of 25.4 (24.5-26.4) weeks and weight at birth of 700 (600-810) g were included. Baseline median cortisol measured preoperatively was 202 (137-403) nmol/l. Following the ACTH stimulation test, 3 infants had cortisol ≤500 nmol/l while 15 had ≤750 nmol/l. There was no association seen between any cortisol value and low LVO postoperatively. Post-ACTH cortisol ≤750 nmol/l was significantly associated with hypotension (p = 0.03) and oxygenation (p = 0.04) and ventilation (p = 0.008) failure. Receiver-operator characteristic curve showed a high predictive value of post-ACTH cortisol for all clinical outcomes. Conclusions: Post-ACTH cortisol (≤750 nmol/l) may be associated with clinical indices of postoperative cardiorespiratory instability. Relative adrenal insufficiency may play a role in the etiology of post-PDA ligation hemodynamic and respiratory instability.Neonatology 04/2013; 104(1):28-33. DOI:10.1159/000350017 · 2.37 Impact Factor