Assessment of Carina Position Antenatally and Postnatally in Infants with Congenital Diaphragmatic Hernia

Objective To determine whether endotracheal tube (ETT) insertion depth should be modified in infants with congenital diaphragmatic hernia (CDH) to reduce the risk of main-stem intubation. Study design The distance from the thoracic inlet to the carina was measured antenatally by fetal magnetic resonance imaging (MRI) between 20-28 weeks' (early) and 30-34 weeks' (late) gestation in 30 infants with CDH and compared with 12 early and 36 late MRIs in control infants without CDH. Postnatal tube position was assessed by chest radiograph in the same 30 infants with CDH and compared with 20 control infants with postnatal birth depression. Results The carina position was displaced upward in fetuses and newborns with CDH. Distance from the thoracic inlet to the carina compared with controls was 1.04 +/- 0.1 cm vs 1.42 +/- 0.07 cm on early MRI (P < .05), 1.43 +/- 0.14 cm vs 1.9 +/- 0.04 cm on late MRI (P < .01), and 2.36 +/- 0.07 cm vs 3.28 +/- 0.05 cm on postnatal radiographs (P < .01). Adjusting the ETT depth by 1 cm resulted in a median distance of 1.27 cm from the tip of the ETT to the carina. Conclusion Cephalad displacement of the carina in infants with CDH may predispose them to right main-stem intubation and subsequent development of pneumothorax. We speculate that modifying the ETT insertion depth to 5.5 cm + weight in newborns born at term may prevent pneumothoraces and improve outcomes for infants with CDH.