Transbronchial biopsies in children after heart-lung transplantation. Sixty transbronchial biopsies have been performed in eight children after heart-lung transplantation. The selection of fiber-optic bronchoscope or a small (4 mm; 30 cm) rigid bronchoscope was made according to the size of endotracheal tube required at surgery. If the endotracheal tube was size 7.5 or greater, a fiber-optic bronchoscope was used, whereas if the endotracheal tube size was below 7, a rigid bronchoscope was used. For the diagnosis of lung rejection, the histology of biopsies revealed a sensitivity of 91% and specificity of 69% (similar to the result in adults). The histology also distinguished lung infection from rejection. Complications included three pneumothoraces and two clinically significant episodes of hemorrhage, one of which led to a cardiorespiratory arrest, which may have been caused by hypoxia. As a result, arterial oxygen saturation is now monitored during the procedure using a pulse oximeter. 