omphalocele and gastroschisis
TRANSCRIPT
NEONATAL EMERGENCIES-* OMPHALOCELE* GASTROSCHISIS
Speaker: Dr Bhagirath.S.N
Moderator: Dr Sarika
Omphalocele (Exomphalos) Incidence: 1 in 5000 live births
• Gut contents are normally extruded out in the 5th week of fetal life
• During this time the pleuro peritoneal cavities which are in unison get divided into thoracic and abdominal cavities by the newly formed diaphragm (around 7th week)
• around 9th week, the extruded gut contents come back into the abdominal cavity. • If there is failure on part of the gut contents to come back into the abdominal cavity in entirety, then a part of the gut remains outside.
• This mass of tissue is ensheathed by a membrane called amnion
• this membrane affords protection against both infection and loss of extracellular fluid.
• typically the umbilical cord is at the apex of the mass.
GastroschisisIncidence: 1 in 5000 live births
• Gut contents are normally extruded out in the 5th week of fetal life
• During this time the pleuro peritoneal cavities which are in unison get divided into thoracic and abdominal cavities by the newly formed diaphragm (7th week)
• around 9th week, the extruded gut contents come back into the abdominal cavity. • unlike an omphalocele, gut contents enter back in entirety at 9th week.
•owing to a disruption in blood supply from the omphalomesenteric
artery, there is ischemia and atrophy of several layers of abdominal wall
at base of the umbilical cord.
• This leads to an area of weakness in the abdominal wall.
Gastroschisis
•It is through this weakness that gut
contents pouch out later in foetal life.
There is no membrane covering the
mass and therefore no protection is
afforded against infection or loss of
extra cellular fluid.
• As the gut lies exposed (without a
membrane) it tends to irritate the
uterine lining increasing the chances
of premature delivery.
• typically the umbilical cord is at one
side of the mass
Associated congenital anomalies
•Are more with omphalocele than Gastroschisis
1. Bowel atresia
2. Imperforate anus
3. Congenital heart disease (20%)
4. Bladder exostrophy
5. Beckwith Weidman syndrome: Mental retardation, hypoglycemia,
congenital heart disease, large tongue and omphalocele
6. Other defects predominantly involving the gut such as malrotation.
Antenatal diagnosis
•Involves assessment of α fetoprotein levels which are high in
abdominal wall defects.
• Maternal Serum α fetoprotein level is also assessed but is less sensitive
than α fetoprotein from amniotic fluid.
• Levels of these markers are high in omphalocele.
• USG helps in definitive diagnosis
• USG additionally helps in picking up coexistent congenital anomalies.
Preoperative care
•Obtain I.V. access
• Assess for associated congenital anomalies
• Manage respiratory insufficiency.
• Aspirate from the nasogastric tube.
Perioperative care
1. Anticipate difficulty airway in a neonate with large tongue as in
Beckwith Wiedemann syndrome
2. IV or inhalational induction may be preferred. Rapid sequence
induction is also found to be useful.
3. Endotracheal intubation (nasal tube) and IPPV are required.
4. Maintenance with volatile anesthetic with oxygen and air.
5. If extubation is not planned for at the end of surgery then judicious
use of opoids is accepted.
6. A caudal epidural confers good post operative analgesia.
7. An arterial line is helpful in monitoring blood pressure and arterial
blood gases.
8. Since a large volume of tissue is exposed to room air, the amount of
loss in terms of fluids can be substantial and need to be replenished. 9. To this end, organ perfusion needs to be maintained at optimal levels,
especially so when the abdominal contents are compressing the inferior vena cava and compromising cardiac output.
Perioperative care
11.During surgery intra-abdominal pressure increases, lung compliance
falls, and ventilation usually becomes more difficult. Ventilatory rate
and pressure along with the FIO2 usually need to be increased. A slight
degree of head up may be helpful.
12.To summarise, the chief concerns in these surgeries are fluid loss
replacement and maintaining ventilation.
13.Fluid loss must be minimised by covering the gut contents outside the
abdominal cavity with a sterile bag containing saline.
Perioperative care
14.Fluid loss replacement is best done with balanced salt solution with
5% albumin.
15.It is best to avoid N2O to prevent further abdominal distension.
16.Adequate muscle relaxation is important to facilitate better closure of
abdominal wall, but if the defect is large then a forceful closure may
hamper circulation to bowel, Kidneys and lower limb. In fact use of
pulse oximetry to assess perfusion in the lower limb is avidly
advocated.
When to attempt a primary closure in a single sittingas opposed to multiple sittings…?
• Intragastric pressure is measured.
• If it is below 20 mm of Hg then a primary closure is done in a single
sitting.
• If it is above 20 mm of Hg then a delayed closure technique is
adopted. If closure is difficult through conventional approaches…?• A wide silo is incorporated into the abdominal wall covering the
viscera.
• Every 2-3 days the silo is reduced either bedside or on the OT table
with or without Ketamine.
• A hurried reduction impedes circulation and compromises oxygenation
• After several stages of such reduction final solution is to achieve
complete closure under general anesthesia with muscle relaxation.
• Surgery may not be an immediate solution, but probably remains the
only effective one.
Post operative care
• Coexistent pulmonary hypoplasia (especially in Omphalocele) requires
careful consideration during ventilation
Too little risks inadequate oxygenation Too much results in
barotrauma
• Better not to extubate
• Postoperative complications include
Post operative hypertension
Edema of extremities
Post operative care
• Post operative hypertension
Increased intra abdominal pressure
Decreased renal perfusion
Increased renin secretion
Activation of renin-angiotensin-aldosterone system
Hypertension
References….
Clinical Anesthesia by Paul.G.Barash6th editionP1222-1225
Miller’s Anesthesia 7th Edition, Vol 2
P1178, 1180
References….
Paediatric anaesthesiaEdited by Edward DoyleUnits 11 & 12
Smith’s Anesthesia for Infants & Children
Motoyama & DavisP 1098, 99