Should intraoperative hypercapnea or hypercarbia raise concern in neonates undergoing thoracoscopic repair of diaphragmatic hernia of Bochdalek?

Better understanding of cardiopulmonary physiology in children with congenital diaphragmatic hernia of Bochdalek (CDH) has facilitated improved survival. In addition, it has allowed surgeons to employ minimally invasive techniques to their repair under conditions that might result in hypercarbia and/or recurrent pulmonary hypertension. Under institutional review board approval, the records of all neonates at a single institution who underwent thoracoscopic CDH (T-CDH) were reviewed with attention to the incidence of intraoperative hypercapnea (elevated end tidal CO(2)) or hypercarbia (increased PCO(2) by blood gas measurement) and any associated complications. From 2004 through 2007, 31 consecutive neonates, including those who had undergone extracorporeal membrane oxygenation, had T-CDH. CO(2) insufflation to 3 mm Hg was used until the viscera were reduced within the abdominal cavity. The operative technique and outcomes are described elsewhere. Preoperative analyses revealed a mean arterial PCO(2) of 53 +/- 11 torr and SaO(2) of 95 +/- 5%. The mean highest recorded intraoperative end-tidal CO(2) level was 64 +/- 13 and correlated poorly with the highest arterial PCO(2) (mean, 78 +/- 29 torr; range, 29-130). The mean lowest recorded intraoperative SaO(2) was 92 +/- 8% with only two values less than 88%. The average lowest intraoperative mean arterial blood pressure was 47 +/- 8 mm Hg (range, 34-70 mm Hg). No neonate received inhaled nitric oxide, intravenous buffer administration, or escalation of inotrope administration during the procedures nor did any experience recurrent pulmonary hypertension postoperatively. Hypercapnea and hypercarbia are common phenomena during T-CDH but do not appear to correlate with one another nor result in clinically evident recurrent pulmonary hypertension, hypoxemia, hypotension, need for support with vasoactive medications, inhaled nitric oxide, or buffering agents.