The Characterization of Postoperative Mechanical Respiratory Requirement in Neonates and Infants Undergoing Cardiac Surgery on Cardiopulmonary Bypass in a Single Tertiary Institution.

OBJECTIVES: Although neonates and infants undergoing cardiac surgery on cardiopulmonary bypass (CPB) are at high risk of developing perioperative morbidity and mortality, including lung injury, the intraoperative profile of lung injury in this cohort is not well-described. Given that the postoperative course of patients in the pediatric cardiac surgical arena has become increasingly expedited, the objective of this study was to characterize the profiles of postoperative mechanical ventilatory support in neonates and infants undergoing cardiac surgery on CPB and to examine the characteristics of lung mechanics and lung injury in this patient population who are potentially amendable to early postoperative recovery in a single tertiary pediatric institution.

DESIGN: A retrospective data analysis of neonates and infants who underwent cardiac surgery on cardiopulmonary bypass.

SETTING: A single-center, university teaching hospital.

PARTICIPANTS: The study included 328 neonates and infants who underwent cardiac surgery on cardiopulmonary bypass.

INTERVENTIONS: A subset of 128 patients were studied: 58 patients undergoing ventricular septal defect (VSD) repair, 36 patients undergoing complete atrioventricular canal (CAVC) repair, and 34 patients undergoing bidirectional Glenn (BDG) shunt surgery.

MEASUREMENTS AND MAIN RESULTS: Of the entire cohort, 3.7% experienced in-hospital mortality. Among all surgical procedures, VSD repair (17.7%) was the most common, followed by CAVC repair (11.0%) and BDG shunt surgery (10.4%). Of patients who underwent VSD repair, CAVC repair, and BDG shunt surgery, 65.5%, 41.7%, and 67.6% were off mechanical ventilatory support within 24 hours postoperatively, respectively. In all three of the surgical repairs, lung compliance decreased after CPB compared to pre-CPB phase. Sixty point three percent of patients with VSD repair and 77.8% of patients with CAVC repair showed a PaO2 /FI O2 (P/F) ratio of <300 after CPB. Post- CPB P/F ratios of 120 for VSD patients and 100 for CAVC patients were considered as optimal cutoff values to highly predict prolonged (>24 hours) postoperative mechanical ventilatory support. A higher volume of transfused platelets also was associated with postoperative ventilatory support ≥24 hours in patients undergoing VSD repair, CAVC repair, and BDG shunt surgery.

CONCLUSIONS: There was a high incidence of lung injury after CPB in neonates and infants, even in surgeries amendable for early recovery. Given that CPB-related factors (CPB duration, crossclamp time) and volume of transfused platelet were significantly associated with prolonged postoperative ventilatory support, the underlying cause of cardiac surgery-related lung injury can be multi-factorial.