Findings associated with better survival:
(1) birthweight > 3.5 kilograms
(2) pH > 7.4
(3) arterial pH > 40 mm Hg
(4) PaCO2 < 49 mm Hg
(5) medical management sufficient for > 18 hours prior to starting ECMO
(6) gestational age > 39 weeks
Findings associated with a worse survival:
(1) birthweight < 2 kilograms
(2) arterial PaO2 < 40 mm Hg
(3) ECMO started within 12 hours
(4) gestational age < 36 weeks
Parameters used in the discriminant function:
(1) birthweight in kilograms
(2) pre-ECMO arterial pH
(3) pre-ECMO arterial PaO2 in mm Hg (torr)
discriminant function =
= (0.68 * (pH)) + (0.62 * (birthweight)) + (0.29 * PaO2))
Unfortunately the authors never gave their breakpoints for the function.
The value of the discriminant score when all favorable factors were present is > 19.1. The value for the discriminant function with factors associated with a worse survival is < 17.4.
Performance:
• The sensitivity was 62% and specificity 63%, which are poor.
• The poor performance was ascribed to factors such as diversity in the patient population and types of care provided.
• According to the authors there are no criteria that are reliable enough to predict mortality with enough certainty to refuse the care.
