Pediatric surgical patients are not merely small adults. The surgical care of children differs markedly from that of adults in many respects, including unique physiologic demands that vary according to age and development. The neonate’s physiologic development is closer to that of a fetus, while adolescents are similar to adults, and infants or children have problems unique to their chronologic and developmental age. Infants and children also suffer from congenital abnormalities and diseases not seen in adults, and their management requires an intimate understanding of the relevant embryology and pathogenesis.
The newborn infant with a surgically correctable lesion often has other disorders that threaten survival. The care of these babies—particularly the premature and small-for-gestational-age babies, has improved with the emergence of the intensive care nursery. Dramatic advances have been made in the technology of infant monitoring and respiratory support. Low-birth-weight infants can now receive ventilatory support from sophisticated infant respirators for prolonged periods in a precisely controlled microenvironment. Surfactant therapy and high-frequency ventilation has allowed a population of extremely premature infants to survive. Temperature is controlled by servoregulation, while pulse and blood pressure are continuously recorded. Ventilation is monitored by transcutaneous O2 and Co2 electrodes or by indwelling arterial catheters. The metabolic consequences of prematurity and intrauterine growth retardation are monitored by frequent measurement of glucose, calcium, electrolytes, and bilirubin in microliter quantities of blood. Nutritional requirements for growth and development can be provided by enteral or parenteral routes. This kind of specialized care of critically ill newborns requires trained personnel and specialized equipment. The care of such babies is best accomplished in designated regional centers capable of providing pediatric surgical and neonatal intensive care.
Newborn infants can be classified according to their level of maturation (weight) and development (gestational age). A normal full-term infant has a gestational age of 37-42 weeks and a body weight greater than 2500 g. The gestational age of the infant is calculated from the date of the last normal menstrual period. However, clinical assessment of gestational age by morphologic and neurologic examination of the small infant can be more accurate than calculation from the menstrual history.
Four signs may be useful in assessing gestational age. Infants less than 37 weeks’ gestational age have (1) fine fuzzy hair with thin, semitransparent skin, (2) ears that lack cartilaginous support, (3) a breast nodule less than 3 mm in diameter, and (4) few transverse creases on the balls of the feet anteriorly. In males, the testicles are incompletely descended and reside in the inguinal canal, and the scrotum is small with few rugae. In females, the labia minora are relatively enlarged and the labia majora are small.
Preterm infants are those born before 37 weeks’ gestation. Several physiologic abnormalities may coexist in ...