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A N OMPHALOCELE IS ONE OF THE MOST COMMON congenital 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 Whartons 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.
EMBRYOLOGYThe 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
ABSTRACTAn 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.
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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 1.53:1.1,3,14,15
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 1020 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 3040% Trisomy 13 and 18Beckwith-Wiedemann
syndromeOther trisomies
Congenital heart 50% Tetralogy of FallotAtrial septal defect
Renal
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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 MANAGEMENTPrior 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 -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. -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 DELIVERYThe 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.3135 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 MANAGEMENTEffective postnatal care and management may
influence
outcomes. The goals of management include maintaining
cardiorespiratory stability, protecting the herniated viscera,
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managing fluids, maintaining vascular access, monitoring lab
tests, maintaining normothermia, facilitating gastric
decom-pression, preventing infection, and performing
diagnostics.
Maintaining Cardiorespiratory StabilityThe infants
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 VisceraAfter 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 FluidsWater, electrolyte, and protein losses are
increased in an
infant with an omphalocele, with the greatest losses occur-ring
when the membranous sac covering 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 AccessAn 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 f irst few days, for administration of f luids 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 ! Postsilo placement.
Courtesy of Dr. J. Langer, Head of the Division of Pediatric
General Surgery, Hospital for Sick Children, Toronto, Ontario.
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Monitoring Lab TestsAssessing 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 NormothermiaIncreased 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 DecompressionA 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 InfectionBroad-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 DiagnosticsAfter 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 OPTIONSThe 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 ProcudureAlthough the skin flap procedure was
developed in the
late 1800s, it was not used routinely until 1948.1 Prior to
Schusters 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 ApproachFor 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
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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 TreatmentThe surgical skin f lap 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)
>2021 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 >2021 mmHg and that
safe primary closure may not then be achieved.39
POSTOPERATIVE MANAGEMENTComplications 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 f low, 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 inf luenced 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 postoperative 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 infants 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 infants
pain, and other pharmacologic agents such as sedatives may optimize
the infants 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 IMPLICATIONSNeonatal 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.
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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
initiation of early intervention. In addition, 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, nursing goals in
caring 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 overall 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 SUPPORTNurses 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
regression, 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 MORTALITYSurvival 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 nutritionrelated 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 STUDYIn 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 Ss apgars were 8 at 1
minute and 9 at 5 minutes. The infant
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3 2 6 S E P T E M B E R / O C T O B E R 2 0 0 6 , V O L . 2 5 ,
N O . 5
N E O N A T A L N E T W O R K:FBST
cried at birth but quickly developed respiratory distress and
required intubation at 20 minutes of age. The defects 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 infants 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 gastric 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 g/kg/hour) was initiated in conjunction with bolus
morphine (0.1 mg/kg) to facilitate handling.
On day 5, Baby Ss morphine was changed to fentanyl (4 g/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
infants fentanyl was increased to 7 g/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.
CONCLUSIONThe 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.
REFERENCES 1. Cooney DR. 1998. Defects of the abdominal wall. In
Pediatric Surgery,
5th ed., ONeill JA, et al., eds. Toronto: Mosby, 10451086. 2.
Langer JC. 1996. Gastroschisis and omphalocele. Seminars in
Pediatric
Surgery 5(2): 124128. 3. Paidas MJ, Crombleholme TM, and
Robertson FM. 1994. Prenatal
diagnosis and management of the fetus with an abdominal wall
defect. Seminars in Perinatology 18(3): 196214.
4. Moore K, and Persaud T. 1998. In The Developing Human
Clinically Oriented Embryology, 6th ed., Moore K, and Persaud T,
eds. Philadelphia: WB Saunders, 273302.
5. Seashore JH. 1978. Congenital abdominal wall defects. Clinics
in Perinatology 5(1): 6177.
6. Dillon PW, and Cilley RE. 1993. Newborn surgical emergencies:
Gastrointestinal anomalies, abdominal wall defects. Pediatric
Clinics of North America 40(6): 12891314.
7. DeVries PA. 1980. The pathogenesis of gastroschisis and
omphalocele. Journal of Pediatric Surgery 15(3): 245251.
8. Rescorla FJ. 2001. Surgical emergenices in the newborn. In
Workbook in Practical Neonatology, 3rd ed., Polin RA, Yoder MC, and
Burg FD, eds. Toronto: WB Saunders, 423459.
9. Sadler T. 2000. Digestive system. In Langmans Medical
Embryology, 8th ed., OBrian P, and Sadler T, eds. Philadelphia:
Lippincott Williams & Wilkins, 270303.
10. Wilson RD, and Johnson MP. 2004. Congenital abdominal wall
defects: An update. Fetal Diagnosis and Therapy 19(5): 385398.
11. Grosfeld JL, Dawes L, and Weber TR. 1981. Congenital
abdominal wall defects: Current management and survival. Surgical
Clinics of North America 61(5): 10371049.
12. Stringel G, and Filler RM. 1979. Prognostic factors in
omphalocele and gastroschisis. Journal of Pediatric Surgery 14(5):
515519.
13. Dykes EH. 1996. Prenatal diagnosis and management of
abdominal wall defects. Seminars in Pediatric Surgery 5(2):
9094.
14. Forrester MB, and Merz RD. 1999. Epidemiology of abdominal
wall defects, Hawaii, 19861997. Teratology 60(3): 117123.
15. Calzolari E, et al. 1995. Omphalocele and gastroschisis in
Europe: A survey of 3 million births 19801990. EUROCAT Working
Group. American Journal of Medical Genetics 58(2): 187194.
16. Davidson JM, et al. 1984. Gastroschisis and omphalocele:
Prenatal diagnosis and perinatal management. Prenatal Diagnosis
4(5): 355363.
17. Heider AL, Strauss RA, and Kuller JA. 2004. Omphalocele:
Clinical outcomes in cases with normal karyotypes. American Journal
of Obstetrics and Gynecology 190(1): 135141.
18. Nyberg DA, et al. 1989. Chromosomal abnormalities in fetuses
with omphalocele. Significance of omphalocele contents. Journal of
Ultrasound Medicine 8(6): 299308.
19. Stoll C, et al. 2001. Risk factors in congenital abdominal
wall defects (omphalocele and gastroschisis): A study in a series
of 265,858 consecutive births. Annals of Genetics 44(4):
201208.
20. Elliott M, and Maher ER. 1994. Beckwith-Wiedemann syndrome.
Journal of Medical Genetics 31(7): 560564.
-
V O L . 2 5 , N O . 5 , S E P T E M B E R / O C T O B E R 2 0 0
6 3 2 7
N E O N A T A L N E T W O R K:FBST
21. Dunn JC, and Fonkalsrud EW. 1997. Improved survival of
infants with omphalocele. American Journal of Surgery 173(4):
284287.
22. Yang P, et al. 1992. Genetic-epidemiologic study of
omphalocele and gastroschisis: evidence for heterogeneity. American
Journal of Medical Genetics 44(5): 668675.
23. Biard J, et al. 2004. Prenatally diagnosed giant
omphaloceles: Short- and long-term outcomes. Prenatal Diagnosis
24(6): 434439.
24. Hershenson MB, et al. 1985. Respiratory insufficiency in
newborns with abdominal wall defects. Journal of Pediatric Surgery
20(4): 348353.
25. Laubscher B, et al. 1998. Serial lung volume measurements
during the perinatal period in infants with abdominal wall defects.
Journal of Pediatric Surgery 33(3): 497499.
26. Haddow JE, and Palomaki GE 1999. Biochemical screening for
neural tube defects and Down syndrome. In Fetal Medicine: Basic
Science and Clinical Practice, Rodeck CH, and Whittle MJ, eds.
Philadelphia: Churchill Livingstone, 373374.
27. Mann L, et al. 1984. Prenatal assessment of anterior wall
defects and their prognosis. Prenatal Diagnosis 4(6): 427431.
28. Zarzour SJ, et al. 1998. Abnormal maternal serum alpha
fetoprotein and pregnancy outcome. The Journal of Maternal-Fetal
Medicine 7(6): 304307.
29. Nicolaides KH, et al. 1992. Fetal gastro-intestinal and
abdominal wall defects: Associated malformations and chromosomal
abnormalities. Fetal Diagnostic Therapy 7(2): 102115.
30. Barisic I, et al. 2001. Evaluation of prenatal ultrasound
diagnosis of fetal abdominal wall defects by 19 European
registries. Ultrasound in Obstetrics & Gynecology 18(4):
309316.
31. How HY, et al. 2000. Is vaginal delivery preferable to
elective cesarean delivery in fetuses with a known ventral wall
defect? American Journal of Obstetrics and Gynecology 182(6):
15271534.
32. Kirk EP, and Wah RM. 1983. Obstetric management of the fetus
with omphalocele or gastroschisis: A review and report of one
hundred twelve cases. American Journal of Obstetrics and Gynecology
146(5): 512517.
33. Lewis DF, et al. 1990. Fetal gastroschisis and omphalocele:
Is cesarean section the best mode of delivery? American Journal of
Obstetrics and Gynecology 163(3): 773775.
34. Lurie S, Sherman D, and Bukovsky I. 1999. Omphalocele
delivery enigma: the best mode of delivery still remains dubious.
European Journal of Obstetrics, Gynecology, and Reproductive
Biology 82(1): 1922.
35. Moretti M, et al. 1990. The effect of mode of delivery on
the perinatal outcome in fetuses with abdominal wall defects.
American Journal of Obstetrics and Gynecology 163(3): 833837.
36. Tsakayannis DE, Zurakowski D, and Lillehei CW. 1996.
Respiratory insufficiency at birth: A predictor of mortality for
infants with omphalocele. Journal of Pediatric Surgery 31(8):
10881091.
37. Phillippart AI, Canty TG, and Filler RM. 1972. Acute fluid
volume requirements in infants with anterior abdominal wall
defects. Journal of Pediatric Surgery 7(5): 553557.
38. Bell EF, and Oh W. 1999. Fluid and electrolyte management.
In Neonatology. Pathophysiology and Management of the Newborn, 5th
ed., Avery GB, Fletcher MA, and MacDonald MG, eds. Toronto:
Lippincott Williams & Wilkins, 347349.
39. Yaster M, et al. 1988. Hemodynamic effects of primary
closure of omphalocele/gastroschisis in human newborns.
Anesthesiology 69(1): 8488.
40. Leo J, and Huether SE. 1998. Pain, temperature regulation,
sleep, and sensory function. In Pathophysiology. The Biologic Basis
for Disease in Adults and Children, 3rd ed., McCance RL, and
Huether SE, eds. Toronto: Mosby, 437.
41. Schuster SR. 1967. A new method for the staged repair of
large omphaloceles. Surgery, Gynecology & Obstetrics 125(4):
837850.
42. Stanley-Brown EG, and Frank JE. 1971. Mercury poisoning from
application to omphalocele. JAMA 216(28): 21442145.
43. McNair C, et al. 2004. Postoperative pain assessment in the
neonatal intensive care unit. Archives of Disease in Childhood.
Fetal and Neonatal Edition 89(6): 537541.
44. Beaudoin S, et al. 1995. Gastroesophageal reflux in neonates
with congenital abdominal wall defect. European Journal of
Pediatric Surgery 5(6): 323326.
45. Meller JL, Reyes HM, and Loeff DS. 1989. Gastroschisis and
omphalocele. Clinics in Perinatology 16(1): 113122.
46. Hughes MD, et al. 1989. Fetal omphalocele: Prenatal US
detection of concurrent anomalies and other predictors of outcome.
Radiology 177(3): 883884.
47. Salomon LJ, et al. 2002. Omphalocele: Beyond the size issue.
Journal of Pediatric Surgery 37(10): 15041505.
48. Fisher R, et al. 1996. Impact of antenatal diagnosis on
incidence and prognosis in abdominal wall defects. Journal of
Pediatric Surgery 31(4): 538541.
49. Koivusalo A, Lindahl H, and Rintala RJ. 2002. Morbidity and
quality of life in adult patients with a congential abdominal wall
defect: A questionnaire survey. Journal of Pediatric Surgery
37(11): 15941601.
About the AuthorsCarol 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:
[email protected]
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interested, please submit your letter of interest and curriculum
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Network2270 Northpoint ParkwaySanta Rosa, CA
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