Role of admission gas exchange measurement in predicting congenital diaphragmatic hernia survival in the era of gentle ventilation

Abstract

Background/purpose: Neonates with significant congenital diaphragmatic hernia (CDH) require cardiopulmonary support. Management has been characterized by progressive abandonment of hyperventilation. Ability to prognosticate outcomes using measures of ventilation and oxygenation with gentle ventilation remains unclear. We sought to determine whether assessment of gas exchange at the time of NICU admission is predictive of survival in this current era.

Methods: Neonates with CDH admitted to a Children's Hospital from 1995 to 2006 were evaluated for demographics, blood gas (ABG) measurements and ventilator settings for the first 48hours, and discharge outcome.

Results: One-hundred-and-nineteen CDH patients were admitted, 88 (74%) survived. Mean admission ABG pCO2 was higher in infants who died compared to survivors (86±48 versus 49±20, p≤0.001); positive predictive value (PPV) for mortality of pCO2≥80mmHg was 0.71. Mean first hour preductal oxygen saturation (preductalO2Sat) was lower in infants who died compared to survivors (81±17 versus 97±5, p<0.001); PPV for mortality of preductalO2Sat<85% was 0.82. Eleven patients met both pCO2 and preductalO2Sat criteria, and 10 (91%) died, PPV of 0.92. Within hours of admission, pCO2 and preductalO2Sat differences between survivors and nonsurvivors lost significance.

Conclusion: Admission pCO2 and preductalO2Sat may be useful in predicting survival in neonatal CDH. The differential in gas exchange between survivors and nonsurvivors loses significance with contemporary neonatal care.

Keywords: Carbon dioxide; Congenital diaphragmatic hernia; Mortality; Neonate; Oxygen saturation.