GASTROSCHISIS OMPHALOCELE MEDICAL CARE
Category: Pediatric Surgery
Abstract : Medical Care: • Intestinal inflammation o Intestinal inflammation may occur with either gastroschisis or ruptured omphalocele. o The eviscerated intestine may be either normal or abnormal in structure and function. The degree of abnormality depends upon the extent of the inflammatory and ischemic injury, manifested by shortened length and surface exudate (peel), which is related to
Medical Care:
• Intestinal inflammation
o Intestinal inflammation may occur with either gastroschisis or ruptured omphalocele.
o The eviscerated intestine may be either normal or abnormal in structure and function.
The degree of abnormality depends upon the extent of the inflammatory and ischemic injury, manifested by shortened length and surface exudate (peel), which is related to the composition and duration of the intestine's exposure to the amniotic fluid and fetal urine.
o Inflamed intestine is thick and edematous, the loops of bowel are matted together, and the mesentery is congested and foreshortened.
o Histologically, atrophy of the myenteric ganglion cells is seen.
o The intestine is dysmotile, with prolonged transit time and decreased absorption of carbohydrate, fat, and protein. These deleterious effects remit as the inflammation resolves, usually in 4-6 weeks. During this time, total parenteral nutrition (TPN) is required.
• Intact omphalocele
o Usually, neonates with intact omphalocele are in no distress, unless associated pulmonary hypoplasia is present.
o Examine the baby carefully to detect any associated problems, such as Beckwith-Wiedemann syndrome, chromosomal abnormalities, congenital heart disease, or other associated malformations. Give nothing by mouth (NPO) pending operative repair.
o Administer maintenance IV fluids, and cover the omphalocele sac with sterile saline-soaked gauze and with plastic wrap, using sterile technique. As an alternative, the baby's lower torso may be placed in a bowel bag. The omphalocele should be supported to avoid excessive traction to the mesentery.
o Give prophylactic antibiotics preoperatively, because of the possibility of an associated intestinal anomaly.
o Closure of a small or moderate size omphalocele usually is accomplished without difficulty.
o A ruptured omphalocele is treated like gastroschisis.
o Closure of a giant omphalocele that contains the liver can be very challenging.
• Gastroschisis
o Respiratory distress in neonates with gastroschisis may respond to gastric decompression, although endotracheal intubation may still be needed.
o Fluid, electrolyte, and heat losses must be minimized and corrected. Administer an intravenous fluid bolus (20 mL/kg LR), followed by 5% dextrose ¼ NS at 2-3 times the baby's maintenance fluid rate.
o The baby should be placed under a radiant heater, and the exposed intestines should be covered with plastic wrap and supported to avoid excessive traction on the mesentery. As an alternative, the baby's lower torso may be placed in a bowel bag.
o Insert a urinary catheter to monitor urine output and facilitate reduction of the herniated viscera by avoiding bladder distention.
o Administer antibiotics to prevent infection, since neonates have low levels of circulating immunoglobulin G (IgG).
o Place a central venous line to provide parenteral nutrition, thereby minimizing protein loss during the period of gastrointestinal dysfunction.
Surgical Care:
• Omphalocele
o Ambroise Pare, the 17th-century French surgeon, accurately described omphalocele and the dire consequences of opening the sac to attempt surgical closure. Certainly, his admonition encouraged conservative treatment, ie, squeezing the sac to effect reduction of the herniated viscera or painting the sac with escharotic agents to promote epithelization.
o The problem with this approach is that it is slow. During this time the sac may rupture, resulting in a wound infection. Even if complications do not occur, the healing of such a large wound exacts a significant metabolic and nutritional toll.
o Healing may be hastened by surgically mobilizing skin flaps sufficient to cover the omphalocele sac, thereby obtaining closure of the abdominal wall defect in a way comparable to closing a burn wound with skin grafts (Gross technique). This, however, results in the creation of a ventral hernia.
o In 1967, Schuster developed a technique that may be used in the initial treatment of a baby with a giant omphalocele or in correcting the ventral hernia created by skin flap closure. An incision is made along the skin-sac junction of the abdominal wall defect, which is enlarged in the midline. The anterior rectus fascia is exposed from the xiphoid to the pubis, and Teflon sheets are sutured to its medial edge. The Teflon sheets are then closed over the omphalocele sac and gradually tightened, approximating the rectus muscles over the abdominal viscera.
• Gastroschisis
o In 1969, Allen and Wrenn adapted Schuster's technique for treatment of gastroschisis
o Silastic sheets are sutured to the full thickness of the enlarged abdominal wall defect and closed over the eviscerated intestine, whose reduction is facilitated by stretching the abdominal musculature, emptying the stomach and bladder, and manually evacuating the colon.
o A major factor in the reduction of the extruded viscera is resolution of intestinal inflammation, which results in a change from a rigid, congealed mass of bowel to soft, pliable loops of intestine, which squeeze into the abdominal cavity.
o Too tight a closure of the abdominal wall must be avoided, for this limits excursion of the diaphragm and necessitates increased inspiratory pressure to compensate for the increase in airway resistance. In general, peak inspiratory pressures (PIPs) higher than 25 mmHg should be avoided. High-frequency oscillatory ventilation may be an alternative to conventional ventilation if intraabdominal pressures are markedly increased.
o In addition, tight closure of the abdominal cavity impedes venous return to the heart, compromising cardiac output and decreasing renal blood flow and glomerular filtration rate. Renal vein thrombosis and renal failure may ensue.
o Diminished mesenteric blood flow may facilitate the development of necrotizing enterocolitis.
o In order to avoid these problems, techniques have been developed to monitor central venous pressure (CVP), intraabdominal pressure, intravesicular pressure, and intragastric pressure (which should not exceed 20 cm of water).
Consultations:
• Neonatologists and pediatric surgeons usually care for babies with these anomalies.
• Consult with cardiology, pulmonology, gastroenterology, and genetics, as indicated.
Diet:
• Babies with omphalocele usually do not require special formulas; their intestines are typically normal, with the exception of occasional atresias, which, in the author's experience, are located in the distal ileum and are not associated with short gut.
• Babies with gastroschisis, on the other hand, typically require special elemental, crystalline amino acid, or protein hydrolysate formulas with nonlactose carbohydrate and medium-chain triglycerides because of the associated gut inflammation and resultant tendency towards substrate malabsorption and allergy.
• Babies with short gut syndrome absorb medium-chain triglycerides more readily than long-chain triglycerides; however, the latter are more valuable with regard to gut adaptation.
Activity:
• A child with a repaired giant omphalocele has an epigastric liver. In this location, the liver is more vulnerable to trauma. Avoidance of contact sports is prudent.
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