Adult patients who require transfusion following cardiopulmonary bypass (CPB) are at increased risk of adverse outcomes including death. Such studies have been done in children as well, with similar results, but none have previously been limited to neonates. Neonates may be more likely to bleed after cardiopulmonary bypass: the fixed bypass priming volumes are proportionally larger for neonates thus causing greater dilution of clotting factors, their coagulation system is relatively immature, and their procedures can be longer and are undertaken at lower temperatures. Dr. Nina A. Guzzetta, Department of Anesthesiology, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia, and colleagues retrospectively examined the relationship of bleeding to outcome in 167 neonates who underwent complex congenital heart surgery with CPB between January 1, 2010, and December 31, 2011. The results of their analysis are presented in the article “Excessive Postoperative Bleeding and Outcomes in Neonates Undergoing Cardiopulmonary Bypass,” which was published in this month’s issue of Anesthesia & Analgesia.
Chest tube output and transfusion requirements were correlated. Patients who were more likely to bleed (all values comparing bleeding quartile ≤ 75% vs. > 75%) weighed less (3.1 vs. 3.0 kg), had longer CPB times (132 vs. 154 min), had longer aortic cross-clamp times (66 vs. 77 min), had lower lowest temperature (25°C vs. 19°C), had greater regional perfusion time (0 vs. 38 min), used deep hypothermic circulatory arrest (0 vs. 1 min), were more likely premature (8% vs. 7%), and had higher Risk Adjustment for Congenital Heart Surgery (RACHS-1) scores, indicating a more complex procedure. Postoperative outcomes were worse for neonates who bled more: time from protamine to time out of the OR was greater (89 vs. 99 min), they were ventilated longer postoperatively (73 vs. 143 min), spent more time in the ICU (7 days vs. 10 days), and 72-hour creatinine was greater (0.7 vs. 0.8 mg/dL). Outcome data was also worse for patients who bled more: the need for dialysis was greater (1% vs. 6%) as was the need for ECMO (3% vs. 11%), though in-hospital mortality was not greater. And though mortality was greater for infants who bled >75th percentile, conclusive statements regarding mortality are difficult due to the study’s small sample size and the fact the study came from a single institution.
Previous studies of children including infants had similar findings. Nonetheless, this was a well-written and researched paper and the authors have made an important contribution since the study was limited to infants at their institution.