Serial blood lactate measurements predict early outcome after neonatal repair or palliation for complex congenital heart disease

Objectives: Neonates with congenital heart disease may appear hemodynamical ly stable after operation and then suddenly experience catastrophic decompe nsation. An improved means of predicting which infants will suddenly die in the early postoperative period may lead to lifesaving interventions. Studi es indicate that blood lactate level is proportional to tissue oxygen debt, but information linking lactate levels with outcome in infants after opera tion is limited. We sought to determine whether a change in lactate level o ver time was predictive of a poor outcome defined as death within the first 72 hours or the need for extracorporeal membrane oxygenation. Methods: To test this hypothesis, we studied prospectively 46 infants who w ere less than 1 month old and were undergoing complex cardiac surgical pall iation or repair. Postoperative arterial oxygen saturation, bicarbonate, an d lactate levels were recorded on admission to the intensive care unit and every 3 to 12 hours for the first 3 days. Results: Thirty-seven patients had a good outcome, and 9 patients had a poo r outcome. Mean initial lactate level was significantly greater in patients with a poor outcome (9.4 +/- 3.8 mmol/L) than in patients with a good outc ome (5.6 +/- 2.1 mmol/L; P =.03). However, an elevated initial lactate leve l of more than 6 mmol/L had a low positive predictive value (38%) for poor outcome. In contrast, a change in lactate level of 0.75 mmol/L per hour or more was associated with a poor outcome (P <.0001) and predicted a poor out come with an 89% sensitivity value, a 100% specificity value, and a 100% po sitive predictive value. Conclusions: Serial blood lactate level measurements may be an accurate pre dictor of death or the requirement for extracorporeal membrane oxygenator s upport for patients who undergo complex neonatal cardiac surgery.