Risk Factors for Postoperative Cardiopulmonary Instability Following Ligation of Patent Ductus Arteriosus in Very Low Birth Weight Infants

Purpose: Patent ductus arteriosus (PDA) is common in preterm infants, and about 30% of preterm infants undergo surgical ligation of the PDA. Cardiopulmonary instability, defined as hypotension and respiratory failure after PDA ligation, is reported to occur at a frequency of 40-50%. This study investigated the factors affecting cardiopulmonary instability after PDA ligation in preterm infants. Methods: The medical records of 45 very low birth weight (VLBW) infants who underwent PDA ligation in the neonatal intensive care unit from January 2009 to December 2013 were analyzed retrospectively. PDA ligation was only performed when medical treatment for hemodynamically significant PDA failed or was contraindicated. The cases were categorized into the hemodynamic instability (n=20) and control (n=25) groups. Results: Patients underwent ligation at the mean age of 14.3±13.3 days. There were no significant differences between groups in mortality or weaning from ventilation after PDA ligation. In the hemodynamic instability group, birth weight was significantly lower (P=0.046) and the pre-operation C-reactive protein (CRP) level was significantly higher (P=0.042) than in the control group. The use of high-frequency ventilation was higher in the hemodynamic instability group (P=0.033). There were no differences in use of inotropics, mean airway pressure at ligation, timing of ligation, or PDA size between groups. The birth weight and pre-operation CRP level at the time of ligation remained a significant risk factor for cardiopulmonary instability on multiple logistic regression analysis. Conclusion: In VLBW infants, lower birth weight and a higher pre-operation CRP level are related to unstable conditions after PDA ligation.