Anesthetic considerations in premature birth

Premature birth still accounts for about 75% of perinatal mortality. Although great strides have been made in the care of premature babies over the past two decades, markedly decreasing mortality, the prevention of premature birth has not been greatly improved. Although tocolysis, particularly with the beta-2 agonists and magnesium sulfate, may delay birth and allow fetal maturation, it poses several risks which, if not recognized, can cause serious morbidity and even mortality. The use of these drugs and other less widely used tocolytics has important implications for the anesthesiologist. The premature infant itself is subjected to such risks as RDS, IVH, NEC, asphyxia, hypothermia, increased incidence of breech presentation, metabolic disturbances, and predisposition for trauma. To ensure safe delivery, premature babies should be delivered in a tertiary care center equipped and ready to attend to their needs. Major conduction block, particularly continuous lumbar epidural analgesia, is an ideal form of analgesia for the delivery of most premature neonates. Properly administered, it maintains maternal physiology, is not associated with drug depression in the newborn, enables a controlled, atraumatic vaginal delivery, and has little interaction with tocolytics (and indeed may protect against some of their side effects). It is ideal for a trial of labor and, if initiated early, allows for an emergency cesarean section. Continuous lumbar epidural block and subarachnoid block are both superb for elective or urgent cesarean section. However, when their use is contraindicated, inhalation analgesia for vaginal delivery or general anesthesia for cesarean section can be safely administered from the standpoint of both mother and child. Expertly administered anesthesia is not a luxury but is indeed indispensable for successful premature delivery.