Balloon tracheal occlusion for congenital diaphragmatic hernia: Experimental studies

Purpose: Temporary tracheal occlusion is an effective strategy to enlarge f etal lungs, but the optimal technique to accomplish occlusion is unknown. E xternal clips are effective when applied fetoscopically (Fetendo clip), but require a difficult fetal neck dissection. This study was undertaken to as sess the feasibility of intratracheal balloon occlusion, revisiting the int ernal occlusion strategy. Methods: (1) The internal diameter (ID) of human fetal trachea (53 fetuses; 14 to 41 weeks' gestation) was compared using a computer-assisted image an alyzer and sonography, ex vivo. (2) Volume to diameter relationship of the balloon (balloon configuration curve) was defined using an image analyzing computer. (3) Using the trachea of fetal sheep, pressures that break balloo n tracheal seal (seal pressure) were investigated. Results: (1) Between 16 and 41 weeks' gestation, tracheal ID (range, 0.7 to 5.4 mm) correlates significantly with gestational age. (2) Balloon volume required to achieve tracheal seal could be determined based on the tracheal growth curve and the balloon configuration curve. (3) Tracheal seal breaki ng points varied depending on the tracheal specimen tested. Conclusion: Internal tracheal occlusion using a balloon is feasible with mi nimal tracheal damage if the balloon volume is adjusted to fetal tracheal g rowth. Copyright (C) 2000 by W.B. Saunders Company.