Respiratory and cardiovascular morbidity in the first 48 hours post surgical ligation of the patent ductus arteriosus

Background: Ligation of a patent ductus arteriosus could be associated with severe cardiorespiratory compromise in preterm infants. There is limited data on the incidence, profile and temporal profile of post-operative morbidity. Objective: To assess the incidence, profile and temporal occurrence of cardiovascular and respiratory decompensation during the first 48 hours of postoperative period. Method: Retrospective analysis of the cohort over last seven years (2002-2008) was done and charts reviewed to record demographics and haemodynamic/ventilatory indices. Respiratory decompensation was defined a priori as increase in Fractional inspired oxygen by 0.2, Mean airway pressure by 2 cm H₂O, increase in Respiratory Severity Score by 50% or increase in Ventilation Index by 50%. Cardiovascular decompensation was defined as systolic blood pressure <2 standard deviation, addition of inotrope, increase in dosage of previously started inotrope by 5 micrograms/kg/min or need for hydrocortisone. Data was plotted under 4 time epochs; 0-6, 6-12, 12-24 and 24-48 hours after surgical intervention. Results: Forty eight infants underwent duct ligation during the period. Mean gestational age and birthweight were 26.1 ± 1.3 weeks and 788 ± 181 g respectively. Respiratory decompensation was seen in 14 (29%) babies (increase in Mean airway pressure and Fractional inspired oxygen each) and 23 (48%) babies (increase in Respiratory Severity Score by 50%). Cardiovascular decompensation was seen in 14 (29%) babies (low systolic blood pressure), and 9 (19%) (addition or increased dosage of inotropes or hydrocortisone). Conclusions: Postoperative period after surgical duct ligation is oftentimes complicated by cardiorespiratory instability. Its knowledge could improve care in critically sick infants.