Congenital diaphragmatic hernia
Congenital diaphragmatic hernia (CDH) most commonly presents as respiratory distress and cyanosis in a baby shortly after birth and is a true surgical emergency. Because the diaphragmatic malformation originates early in fetal development, the presence of intestines in the thorax inhibits lung development, resulting in the primary problem in CDH—hypoplasia of the lung parenchyma and pulmonary vasculature. CDH is often associated with other congenital problems that may affect the management of anesthesia (Table 201-1).
Table 201-1
Congenital Problems Associated with Congenital Diaphragmatic Hernia
| System | Frequency (% of Affected Neonates) | Associated Problem(s) |
| Central nervous system | 28 | Encephalopathy, hydrocephalus, spina bifida |
| Polyhydramnios, without gastrointestinal anomalies | 30 | |
| Gastrointestinal | 20 | Intestinal atresia, malrotation |
| Genitourinary | 15 | Hypospadias |
| Cardiac | 13-23 | Atrial septal defect, coarctation, tetralogy of Fallot, ventricular septal defect |
Incidence and classification
CDH occurs in about 1 in every 2500 live births. Classification is based on location of the defect, with the most common and significant being the posterior lateral aspect of the diaphragm, through the foramen of Bochdalek (80%). Left-sided hernias occur five times more often than right-sided ones. Hernias through the esophageal hiatus are generally small, with no compromise of pulmonary function, and do not usually present in the neonatal period. Figure 201-1 illustrates other sites in which hernias may be evidenced. Incomplete muscularization of the diaphragm (eventration) may occur, resulting in the development of a hernia sac. Many cases are asymptomatic, but severe cases may present identically to CDH.
