Congenital diaphragmatic hernia, extracorporeal membrane oxygenation, and death: A spectrum of etiologies

Abstract

Extracorporeal Life Support Organization (ELSO) registry data show increased mortality in congenital diaphragmatic hernia (CDH) infants compared with other extracorporeal membrane oxygenation (ECMO) indications. To test the hypothesis that death might be related to various clinical parameters, retrospective data collection was solicited on 175 ECMO-related CDH deaths from 41 American ECMO centers (ELSO Registry 1980 through 1989). Data capture forms were received on 100 of 175 infants representing 29 of 41 centers. After review of all available material, a predominant cause of death was assigned. Other diagnoses were given secondary status. We analyzed arterial blood gas values at 6, 3, and 1 hour pre-ECMO, as well as at the time of highest recorded PO 2 (preductal and postductal) and lowest recorded PCO 2, and correlated these findings with predominant cause of death. The relationship between individual variables and cause of death was assessed by t test. Multivariate analysis was performed by using a stepwise discriminate procedure. The most common predominant causes of death were brain death (29%), pulmonary hypertension (25%), and pulmonary hypoplasia (17%). Correlation of arterial blood gas values at 6, 3, and 1 hour pre-ECMO with predominant causes of death established the following statistically significant associations ( P < .05): (1) pulmonary hypoplasia and low PO 2 at 6 hours pre-ECMO; (2) brain death and low pH at 1 hour pre-ECMO; and (3) pulmonary hypertension and high HCO 3 − at 1 hour pre-ECMO. Correlation of arterial blood gas values at a time of highest PCO 2 with predominant causes of death established the following statistically significant associations ( P < .05): (1) pulmonary hypoplasia and low PO 2; (2) brain death and low pH; and (3) pulmonary hypertension and high HCO 3 −. Nineteen infants had both preductal and postductal PO 2 data. Eight infants with a preductal PO 2 > 100 mm Hg but postductal PO 2 < 100 mm Hg had pulmonary hypertension and brain death as causes of death. No infant in this group died of pulmonary hypoplasia. The conclusions were: (1) 83% of infants studied had a cause of death that was potentially reversible; (2) no infants achieving a PO 2 > 58.1 mm Hg at 6 hours pre-ECMO or a PO 2 > 89.6 mm Hg at a time of lowest recorded PCO 2 pre-ECMO, had pulmonary hypoplasia as a predominant cause of death; (3) brain death is associated with a low pH and infants at risk should be managed appropriately; (4) sampling both preductal and postductal PO 2 is important in accurately assessing the pre-ECMO infant; and (5) association elucidated in this study may become important in defining certain management strategies and patient selection in an effort to improve mortality in ECMO-treated CDH infants.