Timing of lung size assessment in the prediction of survival in fetuses with diaphragmatic hernia.
OBJECTIVE
To investigate whether the prediction of postnatal outcome of fetuses with isolated congenital diaphragmatic hernia depends on the gestational age at assessment using the fetal observed to expected (O/E) lung area to head circumference ratio (LHR), by comparing the performance of the test at 22-23 weeks with that at 32-33 weeks of gestation.


METHODS
Following prenatal diagnosis of isolated diaphragmatic hernia before 22 weeks, we evaluated the O/E LHR at 22-32 weeks and again at 32-33 weeks of gestation. Only cases liveborn beyond 34 weeks of gestation and with postnatal follow-up available until discharge from the hospital were included. Regression analysis was used to examine the effect on postnatal survival of O/E LHR, gestational age at delivery, side of the diaphragmatic hernia and intrathoracic position of the liver. Wilcoxon rank test for paired samples was used to compare median O/E LHR at 22-23 weeks and 32-33 weeks, in babies who survived and in those who died. Receiver-operating characteristics (ROC) curves were constructed for the prediction of survival by O/E LHR at 22-23 weeks and at 32-33 weeks.


RESULTS
In total, 53 pairs of measurements could be assessed. Univariate logistic regression analysis demonstrated that significant predictors of survival were the presence or absence of intrathoracic herniation of the liver, the O/E LHR at 22-23 weeks and the O/E LHR at 32-33 weeks of gestation. Multivariate logistic regression analysis demonstrated that only O/E LHR at 22-23 weeks or 32-33 weeks provided significant independent prediction of survival. The median O/E LHR at 22-23 weeks was not significantly different from that at 32-23 weeks either in survivors or in babies that subsequently died in the neonatal period (P = 0.25 and P = 0.09, respectively). The area under the ROC curve for prediction of postnatal survival from the O/E LHR at 22-23 weeks was 0.789 (P < 0.001) and that for prediction from the O/E LHR at 32-33 weeks was 0.842 (P < 0.001).


CONCLUSIONS
In isolated diaphragmatic hernia, O/E LHR measurement at 22-23 weeks as well as at 32-33 weeks provides useful independent prediction of subsequent survival. The prediction of postnatal survival using O/E LHR is independent of the timing of assessment.
Jani
J
J
Fetal Medicine Units of University Hospital Gasthuisberg, Leuven, Belgium.
Nicolaides
K H
KH
Benachi
A
A
Moreno
O
O
Favre
R
R
Gratacos
E
E
Deprest
J
J
D002508:Cephalometry / Q000379:methods; D005260:Female; D005865:Gestational Age; D006257:Head / Q000000981:diagnostic imaging*; D006548:Hernia, Diaphragmatic / Q000000981:diagnostic imaging*; D006801:Humans; D007231:Infant, Newborn; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome; D011263:Pregnancy Trimester, Third; D012189:Retrospective Studies; D016019:Survival Analysis; D016216:Ultrasonography, Prenatal / Q000379:methods