How is this neonate managed preoperatively?
Immediately after birth, the exposed intra-abdominal contents should be wrapped in a sterile dressing which is then kept warm and moist. Plastic coverings may also help to decrease heat and fluid loss. It is important to monitor and maintain temperature preoperatively. Preoperative preparation should include placement of an intravenous catheter for fluid replacement. An arterial catheter may be placed for frequent laboratory analysis, including measure-ments of blood glucose.
Infants are more susceptible to dehydration because of their increased metabolic rate and water losses. Insensible fluid losses are greater in infants because of their greater surface area/weight ratio and thinner skin. In addition, gastroschisis, omphalocele, pyloric stenosis, intussuscep-tion, and many other processes can cause significant elec-trolyte and fluid imbalances.
Assessment of volume status involves many variables: moistness of mucous membranes, skin turgor, weight, mean arterial pressure, capillary perfusion time, urine output, peripheral pulse quality, and heart rate. Significant fluid deficits and electrolyte imbalances should be cor-rected preoperatively. Initially a balanced salt solution should be used to increase blood volume and replace third-space losses. Fluid replacement should also include main-tenance fluids, with or without glucose, depending on blood glucose analysis. Excess glucose can be detrimental since the neonatal kidney can spill glucose easily, resulting in an osmotic diuresis. As replacement occurs, multiple parameters need to be monitored to assess hydration sta-tus, such as vital signs, urine output, clinical examination, and laboratory values.
Maintaining temperature is critical during the peri-operative period since hypothermia is a potential risk. Hypothermia causes an increase in the metabolic rate with increased oxygen consumption resulting in hypoxemia, acidosis, and possibly apnea. The neonate attempts to main-tain body temperature through nonshivering thermogenesis. This is accomplished by the metabolism of brown fat, which is more abundant in newborns than in adults. Brown fat metabolism is stimulated by norepinephrine released through sympathetic innervation in an attempt to maintain core temperature at a great metabolic cost.
The intestines are susceptible to both morphologic and functional compromise, especially in gastroschisis due to the lack of a protective peritoneal membrane and possible pre-existing fetal peritonitis. Bowel atresia is seen in about 10% of cases. Care should be taken to avoid traumatizing the exposed bowel and to avoid incarceration at the site of extrusion.
Although sepsis may occur, there is no indication for the administration of prophylactic antibiotics.
The neonate should be examined for other associated congenital anomalies, especially those involving the cardio-vascular and pulmonary system, which may affect mor-bidity and mortality. Omphalocele can be a part of the Beckwith-Wiedemann syndrome, which also includes macroglossia, gigantism, organomegaly, and symptomatic hypoglycemia. Neonates with Beckwith-Wiedemann syn-drome are known to have a difficult airway due to the macroglossia.