TRISOMY 21 SYNDROME DOWN SYNDROME
An additional chromosome 21—part or whole— results in the most common pattern of con-genital human malformation: Down syndrome. Characteristic abnormalities of interest to the anes-thesiologist include a short neck, irregular dentition, mental retardation, hypotonia, and a large tongue. Associated abnormalities include congenital heart disease in 40% of patients (particularly endocardial cushion defects and ventricular septal defect), sub-glottic stenosis, tracheoesophageal fistula, chronic pulmonary infections, and seizures. These neonates are often premature and small for their gestational age. Later in life many patients with Down syndrome undergo multiple procedures requiring general anesthesia.
Because of anatomic differences, these patients often have difficult airways, particularly during infancy. The size of the endotracheal tube required is typically smaller than that predicted by age. Respiratory complications such as postopera-tive stridor and apnea are common. Neck flexion during laryngoscopy and intubation may result in atlantooccipital dislocation because of the con-genital laxity of these ligaments. The possibility of associated congenital diseases must always be con-sidered. As in all pediatric patients, care must be taken to avoid air bubbles in the intravenous line because of possible right-to-left shunts and para-doxical air emboli.