Can the outcome of pediatric extracorporeal membrane oxygenation after cardiac surgery be predicted?

PURPOSE

The purpose of this study is to assess whether clinical and biochemical variables may be used to predict outcome in children treated with extracorporeal membrane oxygenation (ECMO) after cardiac surgery and to determine when to discontinue ECMO support.

METHODS

We retrospectively reviewed the medical records of 26 children treated with ECMO after cardiac surgery at our institution from October 2000 to May 2004.

RESULTS

Patients mean age was 16.4 months (range, two weeks to 144 months) and mean weight was 6.3 kg (range, 2.2-26 kg). Of the 26 children requiring ECMO support, 23 underwent biventricular repair, and 3 had single ventricle procedure. None of the single ventricle repair or the truncus arteriosus repair group survived the ECMO support. Twelve patients (46%) survived the ECMO support and were discharged from hospital. Four patients needed ECMO support after 45 min (mean) of cardiopulmonary resuscitation (CPR) time (range = 30-55 min) with 2/4 survived to discharge. All patients who survived to discharge showed no evidence of neurological deficit or disseminated intravascular coagulopathy (DIC) whereas 5 patients died following stroke, and 8 following DIC, respectively (p = 0.021 and 0.002). Renal failure developed in 8 cases (1 survivor and 7 nonsurvivors, p = 0.022). Seventeen patients (65%) required re-exploration of the mediastinum for bleeding. Length of time on ECMO, although it was longer among the nonsurvivors, was not significantly different between the survivor (74.5 hours) and nonsurvivor (118.2 hours) groups (p = 0.41). Inotrope score at ECMO initiation and serum lactate within 72 hours of ECMO were calculated and the difference between the two groups was not significantly related to survival (p = 0.29 and 0.22 respectively).

CONCLUSION

Our findings suggest patients who develop renal failure, stroke and DIC during ECMO support have a high mortality. Patients with single ventricle physiology, and repaired truncus arteriosus may benefit less from ECMO support and have an increased risk of death. Elevated levels of lactate during the first 72 hours, high inotrope score at the initiation of ECMO and long ECMO support duration (more than 3 days) are all potential variables that can be used in determining when to discontinue ECMO support.