What is the preoperative management of CDH?
In the delivery room, once the diagnosis of CDH is suspected, mask ventilation should be avoided to prevent distention of the abdominal organs in the thorax, which would further impair oxygenation and ventilation. The tra-chea should be intubated and inflation pressures limited to less than 40 cm H2O to avoid causing a pneumothorax. A pneumothorax will most likely occur in the contralateral lung, which is where most of the gas exchange occurs. An orogastric tube should be inserted to assist in deflation of the stomach. If transfer to the neonatal intensive care unit (NICU) is delayed, an arterial and intravenous catheter should be inserted to guide therapy and for administration of pharmacologic agents. If possible, the arterial line should be placed in the right radial artery so that preductal oxygenation is measured.
Measures to both prevent further increases in PVR and promote a decrease in PVR, thereby increasing pulmonary blood flow, should be instituted. These include increased oxygenation, hypocarbia, alkalosis, avoiding sympathetic stimulation, and normothermia. Pharmacologic vasodilator therapy may be necessary. Tolazoline is most commonly used for this purpose. However, there may be systemic hypotension associated with its use and pharmacologic support of the systemic blood pressure may be necessary. Nitric oxide, a specific pulmonary vasodilator, has been used in these patients with variable results. If these meas-ures do not improve the neonate’s condition, extracorporeal membrane oxygenation (ECMO) may be utilized.