A
N OMPH A LOCELE IS ONE OF THE MOST COM MONcongenital abdominal wall anomalies requiring surgi-cal intervention in the newborn
period. The earliest documented case was in 1634. Not until the 1960s did outcomes begin to improve, however, with new sur-gical innovations, advances in neonatal intensive care, and the introduction of total parenteral nutrition.1,2 Currently,
mor-tality and morbidity are deter-mined primarily by the presence of associated structural and/or chromosomal anomalies.
An omphalocele is a midline congenital abdominal wall defect of the umbilical ring resulting in herniation of the abdominal viscera. No protective abdomi-nal muscles, fascia, or skin cover the defect; instead, a transpar-ent membranous sac covers the herniated viscera. The umbili-cal cord inserts into the mem-branous sac, and the Wharton’s jelly that covers the umbilical cord is interposed throughout the sac.1,3 This article reviews
the embryology of an omphalo-cele as well as preoperative and postoperative management and nursing care for an infant with this defect.
EMBRYOLOGY
The omphalocele generally develops early in gestation. The primitive gut is divided into the foregut, midgut, and hindgut. The foregut devel-ops into the pharynx, lower respiratory system, esophagus and stomach, duodenum, liver, biliary apparatus, and pancreas. The midgut develops into the small intestine, the cecum, the appendix, the ascending colon, and part of the transverse colon. The hindgut develops into the remainder of the transverse colon, the descending colon, the sigmoid colon, the rectum, the anal canal, and a portion of the bladder and urethra.4
Mesoderm, ectoderm, and endoderm, which arise from the embryonic disc, are the three primary germ layers from which all cells and tissues of the body develop. Between two and four weeks gestation, the embryonic disc goes through a process of infolding of the four body folds: one cephalic (cranial), one caudal (distal end), and two lateral. By week 4 of gestation, the body folds converge (except for the body stalk, or umbilical cord), completing the body closure.
Accepted for publication May 2005. Revised August 2005.
Caring for the Newborn
with an Omphalocele
Carol McNair, RN, MN, NNP
Judy Hawes, RN, MN, NNP
Heather Urquhart, RN, MEd, NNP
ABSTRACT
An omphalocele, a ventral defect of the umbilical ring resulting in herniation of the abdominal viscera, is one of the most common congenital abdominal wall defects seen in the newborn. Omphaloceles occur in 1 in 3,000 to 10,000 live births. Associated malformations such as chromosomal, cardiac, or genitourinary abnormalities are common. Postnatal management includes protection of the herniated viscera, maintenance of fluids and electrolytes, prevention of hypothermia, gastric decompression, prevention of sepsis, and maintenance of cardiorespiratory stability. A primary or staged closure approach may be used to repair the defect. Some giant omphaloceles require a skin flap or nonoperative management approach, however. Immediate postoperative complications, usually related to significant changes in intra-abdominal pressures, include compromise of interior venous blood return and hemodynamic and respiratory instability due to diaphragmatic elevation. Complications occur more frequently with giant defects. Potential short-term complications include necrotizing enterocolitis, prolonged ileus, and respiratory distress. Long-term complications include parenteral nutrition dependence, gastroesophageal reflux, parenteral nutrition– related liver disease, feeding intolerance, and neuro-developmental delay. Overall, advances in surgical therapies and nursing care have improved outcomes for infants with omphaloceles; survival rates for those with isolated omphaloceles are reported at 75 to 95 percent. Infants with associated anomalies and giant omphaloceles have the poorest outcomes.
Around the beginning of week 6 of gestation, the midgut elongates and forms a U-shaped loop, which projects into the body stalk. The body stalk eventually constricts to become the umbilical cord.5 Projection into the body stalk is known
as physiologic umbilical herniation. This midgut migration occurs because the liver and kidneys occupy most of the abdominal cavity, and space in the abdomen is inadequate for the rapidly growing midgut. The midgut, positioned in the umbilical cord, rotates 90 degrees counterclockwise around the superior mesenteric artery.4 For unknown reasons,
at about week 10 of gestation, the intestines return to the abdomen. The small intestines return first, followed by the large intestines, which complete an additional 180-degree counterclockwise rotation. After the intestines return to the abdomen, they enlarge, lengthen, fuse to the abdominal wall, and assume their final position within the abdominal cavity. The abdominal wall then closes, and the body stalk constricts to become the umbilical cord.5
An omphalocele is a central defect of the umbilical ring that causes persistent herniation of the abdominal contents, of varying severity, in the umbilical cord. The embryogen-esis is not fully understood, but three primary theories exist. First, an omphalocele may develop with a partial or complete developmental arrest or migration of the abdominal wall folds.6 Second, some authors theorize that there is ventral
extension of the body wall or persistence of the body stalk.1,7
According to the third theory, the abdominal viscera fail to return to the abdominal cavity at the end of week 10 of development after normal physiologic umbilical herniation has occurred.1,4,6,8,9
Most omphaloceles result from lateral fold defects and are centrally located on the abdominal wall. Some may develop in the epigastric (above the umbilicus) or hypogastric (below the umbilicus) abdominal wall region. An epigastric ompha-locele is thought to be a defect of the cephalic fold and may be
associated with the upper midline syndrome of pentalogy of Cantrell (cleft sternum, diaphragmatic hernia, ectopia cordis, absence of pericardium, and congenital heart defects).10
Hypogastric omphaloceles are proposed to be a defect of the caudal fold and may be associated with a lower midline syndrome such as developmental anomalies of the hindgut, bladder extrophy, colonic atresia, sacral vertebral anomalies, or meningomyelocele.1,10,11 Upper and lower midline
syn-dromes are rare.
Omphaloceles vary in size and may contain small intestine, large intestine, liver, stomach, spleen, bladder, and gonads. In approximately 50 percent of all cases, the defect contains liver.12 The abdominal wall defect can range from 4 to 12 cm
in diameter.1,11 The size of the omphalocele and
abdomi-nal cavity influence the approach to surgical management. Defects are classified by the amount of viscera herniated, from small to giant, and by the integrity of the membranous sac (ruptured or intact). Omphalocele sac rupture prior to delivery is reported in 10 to 18 percent of cases.1 Infants with
giant omphaloceles have an abdominal wall defect >5 cm in diameter. The abdominal cavity in these infants is usually small and underdeveloped due to the absence of intestinal viscera in the abdominal cavity to stimulate growth.1,6,13 EPIDEMIOLOGY AND
ASSOCIATED ANOMALIES
Epidemiologic studies have demonstrated that the inci-dence of omphalocele remains steady at 1 in 3,000 to 10,000 live births.1,3,12,14 The incidence increases to 1 in 3,000 to
4,000 births when stillbirths are included.3 Omphaloceles
are associated with advanced maternal age and are reported to occur more frequently in males than in females, at a ratio of 1.5–3:1.1,3,14,15 Associated anomalies are reported in 30 to
80 percent of cases.1,3,11 Congenital heart disease and
chro-mosomal, renal, genitourinary, facial, skeletal, and gastroin-testinal anomalies have been reported (Table 1).10,13,16
Chromosomal syndromes are reported to occur in 8 to 40 percent of omphalocele cases. Trisomies 13 and 18 are the most common chromosomal abnormalities, but the defect has also been reported in infants with trisomies 14, 15, 16, 17, and 21.1,3,11,17 In addition to the omphalocele defect,
these infants commonly have other structural anomalies. The omphalocele defect in infants with chromosomal aberrations is frequently small in size and often does not contain the liver.18,19 Beckwith-Wiedemann syndrome, an overgrowth
syndrome characterized by macrosomia, hypoglycemia, and macroglossia, occurs in 12 to 14 percent of infants with an omphalocele.1,5,20
Congenital heart defect is the most common structural abnormality identified in infants with an omphalocele. These occur in 20 to 50 percent of infants with an omphalocele, with tetralogy of Fallot and atrial septal defect being most common.1,2 Genitourinary, skeletal, and facial (i.e., cleft lip/
palate) structural defects are identified in 10–20 percent of cases.6,21,22 Nonrotation of the bowel occurs in most cases.
TABLE 1 ! Anomalies Associated with Omphalocele
Anomaly Incidence Most Common
Chromosomal 30–40% Trisomy 13 and 18
Beckwith-Wiedemann syndrome Other trisomies
Congenital heart 50% Tetralogy of Fallot Atrial septal defect Renal <10% Renal malrotations Genitourinary <10% Bladder extrophy
Cloacal extophy Facial <10% Cleft lip and palate Skeletal <10% Variety of defects
Gastrointestinal 40% Intestinal atresias, duplications, diaphragmatic hernia
Adapted from: Langer JC. 1996. Gastroschisis and omphalocele. Seminars
in Pediatric Surgery 5(2): 124–128, and Wilson RD, Johnson MP. 2004.
Congenital abdominal wall defects: An update. Fetal Diagnosis and
Chromosomal abnormalities are less frequently identified in infants with giant omphaloceles; however, these patients are at increased risk for structural anomalies such as pulmo-nary hypoplasia and congenital heart disease. In particular, risk for respiratory insufficiency is increased due to pulmo-nary hypoplasia and the presence of a small, narrow thorax.23
The developmental abnormality likely has an onset within the antenatal period. Lung volumes and functional residual capacity prior to repair of the defect have been shown to be below normal, suggesting that the pulmonary hypoplasia rep-resents an abnormality of antenatal lung growth.24,25 Theories
to explain the small thorax and pulmonary hypoplasia vary. Pulmonary hypoplasia may be a primary defect or may result from restricted lung expansion due to a small, narrow tho-racic cage.24 Low intra-abdominal pressures secondary to the
displaced abdominal viscera may modify diaphragm mobility and function, resulting in pulmonary hypoplasia and thoracic deformity. Adequate intra-abdominal pressures may be nec-essary for the thoracic cage to develop, and with displacement of the liver and other abdominal viscera in cases of omphalo-celes, intra-abdominal pressures decrease, potentially altering development of the fetal thoracic cage. Abnormalities in tho-racic and abdominal muscle development may also contribute to the small, narrow thorax observed in these patients. The rectus muscles may be displaced, pulling the ribs inward and downward and leading to a chest wall deformity. Furthermore, underdeveloped abdominal musculature related to the defect may cause scoliosis and a secondary thoracic deformity.23
These theories indicate that intrauterine lung and chest wall development depend on sufficient intra-abdominal pressures, muscle development, and diaphragm movements.
PRENATAL MANAGEMENT
Prior to the introduction of routine obstetric ultrasounds, omphaloceles were identified at birth. Most are now diag-nosed antenatally.16,23 Antenatal identification is also
facili-tated by the measurement of maternal serum α-fetoprotein (MSAFP) levels. Measurement of MSAFP is used routinely to screen for neural tube defects and chromosomal trisomies. Abnormal MSAFP results have been used to identify some other fetal abnormalities as well, including omphaloceles. α-fetoprotein (AFP) is produced by the fetal liver and gas-trointestinal tract and excreted in fetal urine and into the amniotic fluid. It then diffuses into the maternal circulation at the much lower levels found in amniotic fluid. The exposed membrane and blood vessels of an omphalocele allow AFP to be secreted into the amniotic fluid and maternal circulation, resulting in higher than normal AFP levels. The amount of AFP secreted across the membrane is directly proportional to the size of the defect.26
Elevated MSAFP levels are found in only 42 to 50 percent of omphalocele cases.3,27,28 But MSAFP combined with
ultrasound can increase defect identification by up to 80 percent.10 Prenatal detection warrants further investigation
for associated structural and/or chromosomal abnormalities.
Specifically, a fetal echocardiogram should be completed to identify congenital heart disease.10 Amniocentesis should be
considered to evaluate for chromosomal abnormalities.18 In
particular, chromosomal abnormalities should be highly sus-pected in cases where the omphalocele contains only bowel because a higher incidence of chromosomal abnormalities has been reported in these cases than in infants with omphalo-celes containing liver and bowel.29
A multidisciplinary team approach is essential for paren-tal counseling. In addition to nurses, members of the team usually include a perinatologist, neonatologist, geneticist, pediatric surgeon, and pediatric cardiologist. Prenatal detec-tion of an omphalocele and related structural and/or chro-mosomal abnormalities allows parents to consider whether to continue the pregnancy. Elective pregnancy termina-tion occurs in 29 to 51 percent of cases.14,19,30 Pregnancies
that continue require completion of serial ultrasounds to monitor fetal growth and assess sac integrity. The degree of fetal growth restriction is variable and is reported in 6 to 35 percent of cases.3,17 Delivery should occur at a tertiary level
hospital where neonatal and surgical expertise is immediately available for stabilization and optimization of postnatal care. For infants born in community hospitals, transfer to a surgi-cal tertiary care center by experienced personnel is strongly recommended.
MODE OF DELIVERY
The optimal method of delivery for infants with ompha-loceles remains controversial. With the increased frequency of antenatal detection of the defect, some advocate routine delivery of these infants by cesarean section. This recommen-dation is based on the assumption that delivery through a narrow vaginal canal could injure and impair blood supply to the abdominal contents. In addition, the exteriorized bowel may impede the delivery process, causing birth dystocia and increasing the risk of fetal compromise.
Although rare cases of liver damage and birth dystocia have been reported, however, multiple studies (primarily ret-rospective in design) have failed to demonstrate that cesarean section improves infant outcome.31–35 Furthermore, routine
cesarean section increases maternal risk by exposing the mother to an operative procedure. Enough evidence exists currently to recommend vaginal delivery for infants with smaller omphaloceles. Despite the absence of well-controlled prospective studies, however, infants with giant omphaloceles are frequently delivered by cesarean section. The rationale is to decrease the risk of (1) birth dystocia, (2) sac rupture, (3) liver contusion and hemorrhage, and (4) exposure to micro-organisms inhabiting the birth canal.2,34 Cesarean section is
also performed based on obstetric or other fetal indications. POSTNATAL MANAGEMENT
Effective postnatal care and management may influence outcomes. The goals of management include maintaining cardiorespiratory stability, protecting the herniated viscera,
managing fluids, maintaining vascular access, monitoring lab tests, maintaining normothermia, facilitating gastric decom-pression, preventing infection, and performing diagnostics.
Maintaining Cardiorespiratory Stability
The infant’s cardiorespiratory state should be assessed immediately upon birth and ventilation and cardiovascular support provided as required. Infants with giant omphalo-celes are at risk for respiratory insufficiency and therefore frequently require intubation and ventilatory support imme-diately at delivery.23,36 Those with chromosomal or other
structural anomalies may develop hemodynamic instability secondary to other associated anomalies such as congenital heart disease.
Protecting the Herniated Viscera
After delivery of the infant, the defect should be handled gently and as little as possible to avoid injury to the herni-ated viscera and the membranous sac covering the defect. Although the sac can occasionally rupture antenatally or during delivery, most infants are born with it intact.10 To
avoid accidental injury, the cord clamp should be placed away from the viscera (i.e., bowel, liver) at the distal aspect of the umbilical cord.6 The infant should be positioned to avoid
vascular compression from the weight of the defect (usually side-lying). The defect should be wrapped with sterile, warm, saline-soaked gauze and then covered with a water-tight dressing (i.e., clear plastic wrap). Alternatively, a sterile, clear bowel bag can be used to enclose the abdominal defect, legs, and torso.2,6 These interventions are to (1) minimize
insen-sible water losses by limiting heat and evaporative losses and (2) reduce the risk of infection.
Managing Fluids
Water, electrolyte, and protein losses are increased in an infant with an omphalocele, with the greatest losses occur-ring when the membranous sac coveoccur-ring it has ruptured.2,5
Intravascular fluid deficits may lead to reduced tissue per-fusion and the development of metabolic acidosis.37
Maintaining intravascular fluid volume is important in con-tinuing generalized tissue perfusion, including preservation of bowel wall perfusion. Assessment of the adequacy of intra-vascular volume involves ongoing evaluation of the heart rate, blood pressure, urine output, blood gases, electrolytes, fluid balance, and hematocrit. Measures to reduce insensible water loss include using humidified, warmed incubators instead of radiant warmers; wrapping the defect as previously described; and maintaining normothermia.38
Maintaining Vascular Access
An intravenous (IV) line should be started immediately at birth, preferably in an upper extremity.6 Upper extremities
are preferred particularly in the postoperative period because lower limb perfusion may be decreased due to increased intra-abdominal pressure and venous compression that devel-ops when the abdominal viscera are surgically returned to within the abdominal cavity.39 Enteral feedings, particularly
in cases of giant omphaloceles, are frequently delayed due to prolonged ileus; even when feedings are introduced, limited enteral tolerance may restrict the advancement of feedings.23
In these cases, adequate vascular access is important, and a peripherally inserted central catheter (PICC) or central venous line (CVL) should be considered, preferably within the first few days, for administration of fluids and total parenteral nutrition.
FIGURE 1 ! Silo placement in operating room.
Courtesy of Dr. J. Langer, Head of the Division of Pediatric General Surgery, Hospital for Sick Children, Toronto, Ontario.
FIGURE 2 ! Post–silo placement.
Courtesy of Dr. J. Langer, Head of the Division of Pediatric General Surgery, Hospital for Sick Children, Toronto, Ontario.
Monitoring Lab Tests
Assessing the adequacy of the intravascular volume and hemodynamic stability frequently includes measuring blood gases, electrolytes and fluid balance, glucose, and hematocrit levels. Frequency and specific laboratory analysis are guided primarily by clinical assessments. If Beckwith-Wiedemann syndrome is suspected, glucose levels must be monitored fre-quently because hypoglycemia often occurs with it.
Maintaining Normothermia
Increased evaporative heat losses, particularly in cases of a ruptured omphalocele, increase the risk of hypothermia.5
Hypothermia should be avoided because it may lead to vaso-constriction, decreased tissue perfusion, and increased risk for the development of metabolic acidosis.40 Overheating should
also be avoided because insensible water losses increase with hyperthermia.38 Interventions to maintain normothermia
include thoroughly drying the infant at birth to reduce evap-orative heat losses and caring for him in a warmed incubator. Humidified incubators are preferred over radiant warmers because insensible water losses are significantly reduced in this environment.2,5,38
Facilitating Gastric Decompression
A nasogastric tube of adequate caliber must be inserted promptly postdelivery and connected to intermittent wall suction to facilitate gastric drainage decompression.2,10
This reduces the risk of pulmonary aspiration of gastric secretions. In addition, gastric decompression reduces the risk of intestinal distension and impairment of bowel wall perfusion in crying infants who swallow large quanti-ties of air.2 An indwelling urinary catheter can be inserted
to reduce pressure on the herniated viscera from an over-distended bladder and to facilitate accurate assessment of urinary output.
Preventing Infection
Broad-spectrum antibiotics are routinely started at birth because the risk of infection increases with unavoidable exposure of the defect to environmental microorganisms.2,5
Routine use of infection-control practices (sterile gloves and dressings) minimizes infection risk. In anticipation of a sur-gical intervention and the risk of associated bleeding, vitamin K must be administered routinely.
Performing Diagnostics
After an infant has been stabilized, a thorough physi-cal examination should be completed and investigations arranged to evaluate for other associated anomalies. Postnatal investigations may include an echocardiogram, chest x-ray, abdominal ultrasound, and chromosome analysis. Antenatal investigations such as chromosome analysis and echocardio-grams are frequently repeated postnatally to confirm ante-natal findings.6
TREATMENT OPTIONS
The size of the defect, the capacity of the abdominal cavity, gestational age, birth weight, and the presence of associated anomalies determine the primary surgical approach. Four omphalocele treatment options are available: (1) primary closure, (2) staged closure using a silo pouch, (3) skin flap closure, and (4) a nonoperative approach that involves apply-ing topical escharotic agents to promote membrane epithe-lialization. In some cases, complex congenital heart disease may require more urgent management than the abdominal wall defect.
Primary Closure
Omphaloceles that are 5 cm or less in diameter are usually good candidates for primary closure.6 This is a single
proce-dure that closes the defective fascia in the operating room. Staged Closure
In cases of larger or giant omphaloceles, staged closure is usually indicated to avoid hemodynamic and respiratory com-plications. This technique, developed in 1967 by Schuster, continues to be the standard therapeutic approach for large defects.41 This technique involves creating a silo (“chimney”)
by covering the defect with a prosthetic Silastic sheet and then suturing it to the surrounding fascia. Compressing the silo pouch a few times a day as tolerated gradually reduces the herniated viscera. To protect the defect and to minimize contamination, the silo pouch is covered in sterile gauze until fascial closure. The pouch should be suspended from the top of the incubator or overbed warmer to prevent compression on the intestines and to allow gravity to encourage reduction into the abdominal cavity. Gentle suspension can be achieved by applying ties to the end of the silo pouch (away from any viscera) and carefully taping the ties to the top of the incu-bator or warmer. The viscera have usually been sufficiently reduced into the abdominal cavity to permit fascial closure within five to seven days (Figures 1 and 2).2,10
Skin Flap Procudure
Although the skin flap procedure was developed in the late 1800s, it was not used routinely until 1948.1 Prior to
Schuster’s development of the silo pouch technique, this was the only treatment option available for large defects. It involves mobilizing the lateral abdominal wall skin and then covering the defect with the skin flaps. Complications include skin flap necrosis, hematomas, and infection.5 A skin flap procedure is
generally performed when primary or staged closure cannot be achieved. The major disadvantage to this technique is that a large ventral hernia persists and will require later surgical repair.
Nonoperative Approach
For a large defect in the presence of prematurity, severe cardiac disease, or life-threatening chromosomal abnormali-ties, a nonoperative approach is often used. This technique
involves applying a topical drying agent to promote epithelialization of the membrane covering the defect. Several agents have been used to promote epithelialization, including 70 percent alcohol, 2 percent mercurochrome, and silver sulfadiazine (Flamazine). The principal concern with this approach is the potential for systemic absorption of the topical agent.6 Toxic mercury levels have been reported in
infants treated with mercurochrome, for example, and use of this agent is discouraged.5,42
Choice of Treatment
The surgical skin flap approach and the nonoperative topical technique assume a secondary role to primary or staged silo closure. A surgeon uses clinical judgment to deter-mine whether to attempt a primary or staged closure; objec-tive measures such as intragastric pressures, central venous pressure, and cardiac index may help the surgeon determine if primary closure can be achieved. Yaster and colleagues demonstrated in a 1988 study that intraoperatively measured intragastric pressures (IGP) >20–21 mmHg were associated with decreased cardiac output and increased central venous pressure and with the development of anuria and bowel isch-emia. These results suggest that abdominal organ blood flow is compromised when IGP is >20–21 mmHg and that safe primary closure may not then be achieved.39
POSTOPERATIVE MANAGEMENT
Complications often occur in the immediate postoperative period due to a sudden change in intra-abdominal pressure. Acute increases in intra-abdominal pressure are associ-ated with significant reductions in cardiac output, reduc-tions in regional blood flow, and increases in ventilation
requirements.2,39 Increases in intra-abdominal pressure are
more common in infants with primary closure and larger defects, secondary to decreased intra-abdominal cavity capac-ity. Tight closures may result in significantly increased intra-abdominal pressure, leading to renal, mesenteric, and inferior vena cava vascular compromise.2,6
Compression of the inferior vena cava can lead to reduced cardiac output secondary to decreased venous return. Compression of the mesenteric vessels may lead to bowel isch-emia.2,39 Reduced renal blood flow decreases the glomerular
filtration rate and impairs renal function. These changes often require aggressive fluid management in the initial postopera-tive period and frequent monitoring of intake and output, electrolytes, and hemodynamic parameters.2 Fortunately,
renal impairment is usually transient. A peripheral arterial catheter helps facilitate the close monitoring of hemodynamic status and blood sampling.
Ventilatory requirements may also be influenced by an underlying component of pulmonary hypoplasia.2,24
Respiratory insufficiency is a significant risk in tight abdom-inal wall closures because lung volumes are reduced when increased intra-abdominal pressure inhibits diaphragm movement. High-frequency oscillation (HFO), sedation, and muscle relaxation may be required to optimize mechanical ventilation in the postoperative period.
Pain management is vitally important in both the preoper-ative and the immediate postoperpreoper-ative periods. An objective pain measurement tool should be used to guide pain man-agement strategies. Preoperatively, infants with silo pouches who undergo daily reductions may need bolus opioids in addition to a baseline opioid infusion. Opioid infusions (mor-phine, fentanyl) should be titrated to manage each infant’s pain. Postoperatively, pain scores are highest in the first 72 hours, and frequent pain assessments must be completed and adequate analgesia provided.43 Various developmental care
strategies may also help in managing the infant’s pain, and other pharmacologic agents such as sedatives may optimize the infant’s comfort (Figure 3).
Feeding tolerance is often another major challenge for infants with omphaloceles. Although infants with an ompha-locele tend to have fewer difficulties tolerating feedings than those with gastroschisis, a prolonged ileus is often present, and gastrointestinal function may take several weeks to resume.2 Infants with giant omphaloceles have demonstrated
an increased frequency of longer-term oral feeding aversion.23
Once feedings have been initiated, prokinetic therapy may be beneficial for the gastrointestinal dysmotility and gastro-esophageal reflux (GER).2,23,44 Most infants are eventually
able to tolerate full feedings.21,45 NURSING IMPLICATIONS
Neonatal nurses can be instrumental in recognizing insta-bility in infants with an omphalocele. This is particularly important for patients born with associated anomalies such as congenital heart defects and for infants with giant
ompha-FIGURE 3 ! Postoperation following silo closure.
Note large ventral hernia.
Courtesy of Dr. J. Langer, Head of the Division of Pediatric General Surgery, Hospital for Sick Children, Toronto, Ontario.
loceles, who frequently present with respiratory compromise. An understanding of these associated anomalies helps the nurse anticipate potential effects on cardiorespiratory and hemodynamic stability, thus allowing for rapid identifica-tion and for initiaidentifica-tion of early intervenidentifica-tion. In addiidentifica-tion, neonatal nurses help minimize the risk of sac rupture by advocating for gentle and infrequent handling of the defect and thereby promoting protection of the sac and underly-ing viscera. Overall, nursunderly-ing goals in carunderly-ing for an infant with an omphalocele should include recognizing cardiovas-cular instability, maintaining fluid and electrolyte balance, maintaining normothermia, preventing gastric distention, promoting comfort through the use of environmental and pharmacologic measures, and promoting optimal nutrition, growth, and development. Neonatal nurses can also advo-cate for the early initiation of secure central vascular access in infants whose feedings will be delayed. This approach may promote patient comfort by reducing the number of periph-eral IV lines required and therefore the ovperiph-erall number of painful interventions. In addition, an understanding of asso-ciated anomalies and various treatment approaches enables the nurse to provide basic information and ongoing support to parents.
PARENTAL SUPPORT
Nurses must incorporate goals to meet the psychosocial needs of the family. Even though most infants with ompha-loceles are antenatally diagnosed and most parents have been informed of postnatal expectations, the postnatal experience is unique to that family. From the time of prenatal diagno-sis to discharge, parents require information, support, and compassion. For many, the prolonged hospitalization can be difficult. Tertiary care centers are generally located in large urban centers, and social workers can assist families from distant communities with living accommodations, trans-portation, and ongoing psychosocial support. Especially for families who live far away from the hospital and whose infant requires prolonged hospitalization, pictures can help parents stay connected.
Nurses are in a position to address the ongoing fears and concerns of these parents using a multidisciplinary and indi-vidualized approach. Although the initial instability of the infant often temporarily precludes holding him, for example, nurses can encourage parents to hold their infant as soon as stability is achieved. The cyclic pattern of enteral feeding pro-gression and repro-gression, although typical, can be discourag-ing for parents. Nurses can promote their inclusion in infant care needs such as diapering. Parental bonding must be a priority. Regular family meetings with members of the mul-tidisciplinary team can provide parents an opportunity to ask questions and have their fears and concerns addressed. MORBIDITY AND MORTALITY
Survival rates are influenced by underlying associated struc-tural and/or chromosomal abnormalities. A mortality rate of
80 percent has been reported for infants with omphaloceles and associated anomalies.46 The size of the defect has also
been reported as determining outcome, with a mortality rate of 25 percent in infants with giant omphaloceles and no other underlying anomalies reported in one study. Death in infants with giant omphaloceles is usually secondary to respiratory failure, infection, or total parenteral nutrition–related liver failure.23 Prognosis is favorable for infants with isolated small
omphaloceles and no associated structural or chromosomal anomalies.47 In cases of isolated omphaloceles, survival rates
range from 75 to 95 percent.1,17,23,39,48
Morbidity is also determined primarily by the presence of associated structural and chromosomal anomalies and by the size of the abdominal wall defect.3,23 Complications
associated with the omphalocele occur more frequently with giant omphaloceles. Short-term morbidities in cases of giant omphaloceles include necrotizing enterocolitis, prolonged ileus, catheter-related sepsis, wound infection, and respira-tory distress. Long-term morbidities include growth delay, ventral herniation of the defect, GER, liver failure secondary to long-term parenteral nutrition, asthma, respiratory infec-tions, and some cases of developmental delay.1,23
Feeding problems, GER, asthma, bronchomalacia, and recurrent respiratory infections have been reported in 40 to 80 percent of cases of giant omphalocele.11 Prenatal and
postnatal counseling should help prepare parents of infants with isolated giant omphaloceles for potential morbidities and for the possibilities of a prolonged hospitalization and of rehospitalizations. If complete closure of the omphalocele is not achieved in the neonatal period, multiple surgeries may be required, and full repair may take several years.
It is encouraging that, in an adult quality-of-life study published by Koivusalo and colleagues, adults who had been born with an omphalocele or gastroschisis reported a quality of life not different from that of the general popula-tion. Participants expressed cosmetic concerns related to the abdominal scar and some functional gastrointestinal disor-ders such as reflux and lactose or dairy intolerance, but these were not deemed serious problems by study participants.49 CASE STUDY
In a routine ultrasound of a 24-year-old primigravida woman at 19 weeks gestation, a large omphalocele contain-ing liver, bowel, gallbladder, and stomach was identified. Following referral to a high-risk fetal clinic, an investiga-tion for associated anomalies revealed a normal 46XY male karyotype and normal fetal echocardiogram. Parent counsel-ing included consultation with a perinatologist and pediatric surgeon to discuss results of the antenatal testing, expecta-tions, postnatal management, and outcomes. The parents decided to continue with the pregnancy.
At 38 weeks gestation, an appropriate-for-gestational-age, 3,010 gm, nondysmorphic caucasian male was delivered by elective cesarean section at a tertiary level center. Baby S’s apgars were 8 at 1 minute and 9 at 5 minutes. The infant
cried at birth but quickly developed respiratory distress and required intubation at 20 minutes of age. The defect’s mem-branous sac was intact, with intestine and liver identified within it. On gross examination, the bowel appeared pink. A complete physical examination revealed a small thorax. No other abnormalities were identified.
After the initial resuscitation and establishment of mechan-ical ventilation, the infant’s giant omphalocele was wrapped in warm, saline-moistened gauze and covered with an outer layer of dry, sterile gauze. His legs and torso were then enclosed in a clear, sterile body bag. A #10 French nasogas-tric tube was placed for ongoing gasnasogas-tric decompression. An IV was commenced in the right hand, and D10W was started. Total fluid intake was commenced at 110 ml/kg/day. Broad-spectrum antibiotics were started. Vital signs were stable, and serial glucose levels were normal. Primary closure could not be achieved, and a silo pouch was placed within the first 24 hours. A CVL for IV nutrition was established. A mor-phine infusion (40 µg/kg/hour) was initiated in conjunction with bolus morphine (0.1 mg/kg) to facilitate handling.
On day 5, Baby S’s morphine was changed to fentanyl (4 µg/kg/hour) due to rising pain scores. Daily reductions were completed, and on day 8, he returned to the operating room for fascia closure. Unfortunately, fascia closure could not be achieved, and a skin flap procedure was completed. A large ventral hernia remained. Postoperatively, ventila-tory requirements rose due to the increase in intra-abdomi-nal pressure and inhibition of diaphragm movements. Chest radiograph revealed low lung volumes.
HFO was required for the first three days postoperation. The infant’s fentanyl was increased to 7 µg/kg/hour over the immediate postoperative days to respond to rising pain scores. Respiratory status improved gradually, and extu-bation was achieved on day 35. Baby S was weaned slowly from fentanyl because of his need for high doses over a long time. After a period of prolonged ileus, continuous feedings were started on day 31, and full feedings were reached on day 51. The infant was transitioned to bolus feedings given every two hours, but attempts to advance to a three-hourly feeding schedule were initially unsuccessful due to increased tachypnea and vomiting episodes. Eventually, longer periods between feedings were tolerated. Initially, oromotor dysfunc-tion limited bottle feeding, but this improved quickly with an oral stimulation program.
After almost four months in the hospital, Baby S was dis-charged home feeding well and steadily gaining weight. At four months, his neurodevelopmental exam is normal. He is not yet pulling his legs up because the ventral hernia limits his movement. He will require ongoing occupational therapy to support motor development in the presence of his large ventral hernia. Closure of it is planned in one to two years. CONCLUSION
The care of an infant with an omphalocele can be complex. The acute preoperative and postoperative phases may be
followed by an extensive chronic recovery phase fraught with ongoing challenges. This article has provided a review of the embryology and epidemiology of the infant with an ompha-locele and a guide for prenatal, postnatal, and postoperative management. Nurses can be pivotal in meeting the needs of infants and families as they confront the challenges of recov-ery from this congenital anomaly.
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About the Authors
Carol McNair is a full-time clinical nurse specialist/neonatal nurse practitioner in the Level III NICU at The Hospital for Sick Children in Toronto, Ontario. She has particular interest in surgical and cardiac infants and pain management. She is a project director in the Research Institute at SickKids.
Judy Hawes is a full-time clinical nurse specialist/neonatal nurse practitioner in the Level III NICU at the Hospital for Sick Children in Toronto, Ontario. She has an interest in surgical infants, particularly those with necrotizing enterocolitis and short bowel syndrome.
Heather Urquhart is the coordinator for the perinatal intensive care nursing program at George Brown College. She also works part-time as a clinical nurse specialist/neonatal nurse practitioner in the Level III NICU at The Hospital for Sick Children in Toronto, Ontario.
The authors would like to thank Dr. J. Langer for his pictures and assistance in the preparation of this manuscript.
For further information, please contact: Carol McNair, RN, MN
The Hospital for Sick Children 555 University Avenue Toronto, Ontario Canada, M5G 1X8 416-813-7931
E-mail: carol.mcnair@sickkids.ca
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