Congenital diaphragmatic hernia: a persistent problem

Vitamin A decreases the incidence and severity of nitrofen-induced congenital diaphragmatic hernia in rats

Congenital diaphragmatic hernia (CDH) is a major cause of refractory respiratory failure in the newborn. Pulmonary hypoplasia often limits survival. Vitamin A (Vit A) is an important signal for lung growth. We hypothesized that antenatal treatment with Vit A would stimulate lung growth and decrease mortality in experimental CDH induced in rats by ingestion of the herbicide nitrofen (2, 4-dichlorophenyl-p-nitrophenyl ether). Nitrofen was administered to pregnant rats on day 12 of gestation (term 22 days). Rats were assigned to five groups: three groups received one dose of oral antenatal Vit A (15,000 IU) before (day 10), concomitant with (day 12), or after (day 14) nitrofen administration; one group received only nitrofen; and a control group received vehicle (olive oil). The incidence of CDH was markedly lower in all groups receiving Vit A (day 10, 44%; day 12, 20%; and day 14, 40%) compared with the nitrofen-treated group (84%; P < 0.05). The 72-h survival was higher in all 3 Vit A-treated groups (day 10, 40%; day 12, 58%; and day 14, 70%) compared with the nitrofen-treated group (16%; P < 0.05). Lung-to-body weight ratio and radial saccular count were significantly increased by Vit A. Antenatal treatment with Vit A lowers the incidence and severity of experimental CDH and increases lung growth and maturation.

Persistent pulmonary hypertension in high-risk congenital diaphragmatic hernia patients: incidence and vasodilator therapy

Survival of congenital diaphragmatic hernia patients depends on the gravity of pulmonary hypoplasia and persistent pulmonary hypertension (PPH). Many vasoactive drugs have been used in the treatment of PPH, but often they also lower peripheral resistance, leading to a significant drop in arterial blood pressure. The incidence of PPH in 52 high-risk diaphragmatic hernia patients and the results of treatment with tolazoline and prostacyclin were evaluated in a study lasting 52 months and involving 52 patients. High-risk patients require ventilatory support within 6 hours after birth. Study parameters were alveolar-arterial oxygenation difference (AaDO2), oxygenation index (OI), and mean arterial blood pressure (MABP), measured at set times before and after administration of tolazoline or prostacyclin. Twenty-one patients had documented episodes of PPH (46%), and 18 of them died. Tolazoline did not lower AaDO2 and OI values, but MABP dropped significantly. Prostacyclin caused a significant decrease of AaDO2 and OI values without an effect on MABP. We concluded: (1) PPH presented in 46% of our patients, associated with a high mortality rate; (2) tolazoline is not an effective dilator of the pulmonary vascular bed and lowers MABP; and (3) prostacyclin is an effective pulmonary vasodilator as reflected by ventilation parameters without systemic side effects; it does not affect overall outcome but can used as a "bridge" to extracorporeal membrane oxygenation.

Augmented venous access in the problematic ECMO patient: a case report

Extracorporeal membrane oxygenation (ECMO) provides an adjunct to support of neonates with respiratory distress. The rate of venous drainage is the limiting step to the amount of arterial flow that may be generated during ECMO. We present a 3-kg, 37-week gestation female with congenital diaphragmatic hernia (CDH) whose anatomic venous drainage was insufficient to allow total extracorporeal support. The internal jugular vein was of insufficient size to allow placement of a cannula large enough to support adequate bypass flow. We established minimally acceptable flow by simultaneous caudad and cephalad catheterization of the internal vein. We performed a right lower quadrant retroperitoneal dissection and cannulated the common iliac vein when systemic pressures deteriorated at 24 hours with marginal venous drainage. After triple cannulation the bypass flows were normal. The right leg developed mild cyanosis and edema immediately following cannulation, but these changes resolved over 24 hours with elevation. The common iliac vein provides a desirable route for augmentation of venous drainage in the patient with difficult standard, or cephalad, jugular venous access for extracorporeal support.

Ventilation parameters and arterial blood gases as a prediction of hypoplasia in congenital diaphragmatic hernia

Attempts to predict the degree of pulmonary hypoplasia associated with congenital diaphragmatic hernia have been made by evaluating the ventilation parameters and the arterial blood gasses of these patients. A CO2 index as a predictor of outcome, which correlates the PaCO2 with the ventilation index, was recently proposed. However, in this study the postductal PaO2 was a better predictor of survival. And the so-called "honeymoon period" was a better indicator of the efficacy of extracorporeal membrane oxygenation (ECMO) than the CO2 index. Nineteen patients were evaluated; 11 were treated with ECMO, and eight were not considered suitable for ECMO.