Gastroschisis
Omphalocele
Incidence
4.5: 10,000
3: 10,000
Embryology
Anterior abdominal wall defect, umbilical cord intact and to the right of defect. No membranous sac. Usually small and large intestines
Midline abdominal wall defect. Abdominal viscera herniated through the umbilical ring into a membranous sac. Sac may include small and large intestines, liver, spleen, and other viscera
Maternal risk factors
Young maternal age, cigarette smoking
Extremes of maternal age 20< or >40 years
Associated Anomalies
2–10%
GI problems: malrotation, atresia and stenosis
1–2% with cardiac defects
35–75%
Chromosomal abnormalities (Trisomy 13, 18, 21); Associated syndromes
Up to 50% with cardiac defects
Prematurity (%)
60
33
What other anomalies are associated with omphalocele?
While gastroschisis is less likely to be associated with other syndromes or anomalies, 35–75% of neonates with omphalocele will have associated anomalies, usually related to midline defects including neural tube defects, cardiac defects, genitourinary anomalies, orofacial clefts, and diaphragmatic defects. Up to 50% of these patients may have congenital cardiac disease, including VSD, Tetralogy of Fallot, and extropia corpis. Chromosomal abnormalities are common, including trisomy 13, 18, and 21, as well as Turner Syndrome and rare chromosomal deletions. In addition to chromosomal abnormalities, several syndromes are associated with omphalocele: CHARGE syndrome, Pentalogy of Cantrell (omphalocele, diaphragmatic hernia, sternal abnormalities, ectopic cordis), amniotic band sequence, OEIS syndrome (omphalocele, exstrophy of the bladder, imperforate anus, spinal defects), Carpenter syndrome, Beckwich Wiedemann syndrome (macroglossia, giantism, hypoglycemia, omphalocele) [1, 2].
What maternal risk factors are associated with gastroschisis?
Describe the associated risk factors in neonates born with gastroschisis?
Neonates born with gastroschisis are usually premature and small for gestational age (SGA).
Risk factors associated with prematurity are associated with immature organ systems—including the respiratory, cardiovascular, and renal systems. Consequences include respiratory distress syndrome (RDS), retinopathy of prematurity (ROP), electrolyte abnormalities and sepsis.
Respiratory Distress Syndrome: Type II pneumocytes are responsible for surfactant production, but surfactant synthesis for appropriate pulmonary function is not adequate until 34–36 weeks GA. Maternal preterm betemethasone therapy 48 h prior to delivery has been shown to improve lung maturation in premature infants.
Retinopathy of Prematurity: ROP is a progressive vascular overgrowth of the retinal vessels that lead to intraocular hemorrhage associated with hyperoxia. Therefore, FiO2 should be minimized to reach a target saturation of 90–95% depending on the clinical or procedural circumstances.
Describe potential GI complications associated with gastroschisis?
Up to 25% of neonates may have associated gastrointestinal atresias, which may require emergent surgery for bowel obstruction.
Second, when the bowel is exposed to the intrauterine environment with no protective sac, it is at risk for injury. An inflammatory peel may develop and cause the bowel loops to become indistinguishable from each other. Pathology can include localized atresias to volvulus with loss of the entire midgut. Intestinal atresia or volvulus may result in intestinal obstruction, rupture, and eventually sepsis [1].
Preoperative Evaluation and Preparation
- (6)
What other studies would you request prior to proceeding with the procedure?
Important laboratory studies prior to starting the procedure would include hematocrit, type, and cross for blood products, blood glucose level and standard electrolytes as this patient is at risk for large insensible loses, electrolyte abnormalities, and blood loss during the procedure.
If time permits, a chest X-ray and an echocardiogram would be useful in ruling out cardiac defects. However, due to the unstable nature of the patient, including dusky bowel, tachycardia and hypotension, there may not be time for additional studies. Cardiac defects are rare in gastroschisis patients and physical exam may help determine the likelihood of other abnormalities.
- (7)
Are these vital signs normal for a 34-week-old premature infant?
The respiratory rate and oxygen saturation are normal for a newborn. However, the heart rate is elevated in this patient, with an upper limit of normal around 170. The blood pressure is low, even for a preterm neonate.
Traditionally, the gestational age has been used as the lower acceptable mean arterial pressure (MAP) for a preterm infant. Target MAPs for this patient should be 34 mmHg. While the there is large variation in “normal” blood pressure for neonates, neonatal literature suggests that all premature infants should have a MAP >30 mmHg. Additionally, the clinical condition should be evaluated and this patient is tachycardiac and hypotensive [4, 6]. See Table 53.2.
Table 53.2
Neonatal vital signs
Heart rate
Blood pressure
Respiratory rate
Premature
120–170
55–70/35–45
40–70
Infant
100–150
65–75/40–45
35–55
- (8)
What is the differential diagnosis for tachycardia and hypotension in a neonate with gastroschisis?
The most common causes of hypotension in neonates are hypovolemia (insensible losses or blood loss during delivery), hypoglycemia, hypothermia, sepsis, or oversedation.
The most likely cause of hypotension and tachycardia in this patient is hypovolemia. On exam the patient has decreased distal pulses and a sunken fontanelle. Neonates with gastroschisis have fluid losses that are at least 3–4 times that of a healthy newborn from insensible losses, heat, and fluid losses from the exposed bowel, and third spacing of fluid from sequestration of intestinal fluid. Maintenance fluids may be as high as 150–300 ml/kg per day to maintain normovolemia [5].
- (9)
The leak with a 3.0 uncuffed ETT is at 10 cm H2O. Would you change the ETT prior to starting the procedure? Why or why not?
The patient has a large leak with a 3.0 uncuffed ETT and the tube should be replaced with a larger ETT or a cuffed ETT. During gastroschisis repair, replacing the viscera into an underdeveloped abdominal cavity can restrict diaphragmatic excursion, compress the lungs and cause high intra-abdominal pressures. As a result, a cuffed ETT would allow the anesthesiologist to use higher peak inspiratory pressures to adequately ventilate the patient. While uncuffed ETTs were preferred historically, recent literature suggests that intubation with a low pressure, low profile cuffed ETT is preferable in cases with changing abdominal pressures.
- 10)
What vascular access would you want in this patient prior to proceeding with the procedure? Would you place umbilical lines?
This patient will need an arterial line in order to monitor hemodynamics and serial ABGs. During gastroschisis repair, large fluid requirements and returning abdominal contents to an underdeveloped cavity may cause large shifts in hemodynamics, which necessitate monitoring of arterial blood pressure. Large fluid requirements and potential for electrolyte derangement necessitate the need for serial labs and glucose levels.
This case may be done without a central venous line if time is of the essence. However, a patient with dusky bowel concerning for bowel obstruction and potential sepsis, in addition to the large fluid shifts associated with a large gastroschisis defect, may warrant a central line to monitor central venous pressure, mixed venous saturation, and deliver inotropes.
While it is possible to place umbilical lines in a patient with gastroschisis, practically these lines may be in the surgical field or become kinked or inaccurate during replacement of abdominal viscera.Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
