Epidurals, Ethics, and Expectations: Talking Risks and Benefits in Obstetric Anesthesia

Certain infants are at risk for postanesthetic apnea. Commonly accepted risk factors include postconceptual age < 55 - 60 weeks in a formerly premature infant; age < 4 weeks in a full-term infant; pre-existing apnea; anemia (which may simply be a marker rather than a causative factor); and certain congenital neurological conditions. For this full-term 6-week-old boy, neither age-related risk criteria applies for apnea monitoring. Also, while Chiari malformation may increase apnea risk, pyloric stenosis is not generally associated with congenital neurological disease. Volatile anesthetics are eliminated faster in infants than adults due to the higher ratio of minute ventilation to functional residual capacity. Vomiting due to pyloric stenosis may lead to a hypokalemic, hypochloremic metabolic alkalosis. Over time, the pH of the cerebrospinal fluid (CSF) increases as well, mirroring changes in the serum. Since CSF alkalosis inhibits respiratory drive, babies with pyloric stenosis are at higher risk for apnea. For this reason, a period of apnea monitoring after pyloroplasty is often recommended.