Anesthesia of congenital diaphragmatic hernia , for surgical repair post operative management, complications, ventilation strategy

2. Definition:
A congenital diaphragmatic hernia is a defect in
the diaphragm that occurs in utero allowing the
abdominal contents to herniate into the thorax

3. site:
CDH lesions occur more frequently on the left side, and often in a posterior
lateral location through the foramen of Bochdalek
Effect:
unilateral irreversible pulmonary hypoplasia.
In severe cases the abdominal contents will cause a mediastinal shift resulting in deleterious effects on
pulmonary development bilaterally.
Bowel compression of the developing lung causes arterial remodeling that can lead to persistent
pulmonary hypertension

4. CASE
A full-term male baby was born with respiratory distress and
cyanosis. Physical examination showed barrel chest and scaphoid
abdomen.
The breath sounds were absent in the left side of the chest;
the heart sounds were best heard in the right side of the chest.
Labored respiration, nasal flaring, and sternal retraction were found.
The baby weighed 2,800 g. Blood pressure was 60/30 mmHg; heart
rate, 160 beats per minute; respiration, 70 breaths per minute; and
temperature, 36°C (96.8°F).
Arterial blood gas analysis on room air showed the following: pH,
7.20; PaCO2, 55 mmHg; PaO2, 35 mmHg; and CO2 content, 19 mEq
per L.

5. What are the causes of hypoxemia in patients
with
CDH?
1- pulmonary vascular hypoplasia
2- Airway maldevelopment leads to reduced total number of bronchi and
alveoli at birth with resulting decreased lung compliance and decreases in both
ventilation and surface area for gas exchange.
Oxygenation is thus impaired.
3- pulmonary hypertension due to Pulmonary vascular hypoplasia causing right-
to-left shunting
through the patent ductus arteriosus, with resultant hypoxemia.

7. How do you make a diagnosis of right-to-left
shunting through the patent ductus arteriosus?
1- Clinical signs of ductal patency include murmur, tachycardia, bounding peripheral pulses with
wide pulse pressure, congestive heart failure, and unexplained metabolic acidosis.
2- Preductal (upper extremity) and postductal (lower/umbilical arteries) oxygen saturation
measurements by pulse oximetry demonstrate:
a 10% or higher gradient difference (with preductal saturation being higher).
3- The gold standard for diagnosis is with Doppler echocardiogram to demonstrate the size of the
ductal opening and the shunt and allow estimation of mean pulmonary pressure

8. What other congenital anomalies are usually
associated with CDH?
10% having a chromosome abnormality, most commonly trisomy 18 and isochromosome 12p
25% having cardiovascular malformations including: (VSD), (ASD), (TOF), and hypoplastic left
heart syndrome
28% having CNS abnormalities including neural tube defects, hydrocephalus, agenesis of corpus
callous, and sensorineural hearing loss
15% having genitourinary abnormalities including: undescended testis and hypospadias
20% having gastrointestinal malformations including: malrotation, atresia, omphalocele, and
gastroesophageal reflux

9. How would you interpret the following arterial blood gas
analyses:
pH, 7.20; PaCO2, 55 mmHg; PaO2, 35 mmHg; and CO2
content, 19 mEq per L? How would you correct them?
Mixed respiratory and metabolic acidosis with severe hypoxemia.
In this patient, the severe hypoxemia is due to the pulmonary pathology and PPH.
As alveolar PO2 decreases below a threshold of 50 mmHg at normal PCO2, ventilation increases
initially and respiratory alkalosis followers.
However, if hypoxemia is not corrected, patient fatigue results in CO2 retention and a respiratory
acidosis.
In addition, the hypoxemia results in anaerobic metabolism and a concomitant lactic acidosis.
Teatment includes:
mechanical ventilation with control of oxygenation and ventilation.
Metabolic acidosis should be corrected by administration of sodium bicarbonate and improvement of
circulation/perfusion with fluid therapy.

10. What immediate treatment should be given to improve the
newborn’s respiratory status preoperatively?
Immediate treatment should include:
1- intubation and ventilation and decompression of the intrathoracic bowel
with a nasogastric tubeand further pulmonary damage must be
2- Avoid Barotrauma by maintaining peak inspiratory pressures under 25
cm H2O and fraction of inspired oxygen (FIO2) adjusted to preductal arterial
saturations >85%.
3- pressure support ventilation,
4- high-frequency oscillatory ventilation,
5- permissive hypercarbia, and even ECMO are modes to optimize the oxygenation

11. Should CDH be repaired urgently once the diagnosis
is made and confirmed?
CDH is a surgical emergency
But the medical emergency and correction of acidosis and
fluid status has the priority.

12. What monitors would you use for this
neonate during
surgeryRespiratory
Two pulse oximeters, for preductal and postductal oxygen saturation
Capnometry
Inspiratory pressure measurement
Inspiratory oxygen concentration
Intraoperative ABG
Cardiovascular
Five-lead ECG
NIBP, Arterial line: right radial artery for preductal PaO2
(CVP) line for evaluating volume status and right ventricular performance
Thermoregulatory
Esophageal or rectal temperature probe

13. How would you induce and maintain
anesthesia?
preoperative care of the neonate is continued into the operating room
high-dose opioids and nondepolarizing muscle relaxant.
Ventilation strategies: 3Ps
permissive hypercarbia (60 to 65 mmHg),
preductal oxygen saturation of 90% to 95%,
peak pressures <25 cm H2O.
Ventilation goal Pco2= 50-65 mmhg, PH= 7.2-7.25
Volatile agents may be instituted with precaution because may decrease SVR more than PVR
right-to-left shunt.
Frequent ABG will guide changes in respiratory management and assessment of acid–base status.
Availability isotonic fluids and inotropes such as dopamine and/or dobutamine and hydrocortisone.
Avoid hypothermia PVR and right-to-left shunting.

14. Would you use nitrous oxide for anesthesia? Why?
NO
it will expand air-filled cavities (such as bowel) and potentially further
compress functioning lung tissue
it inspired oxygen concentration

15. How would you ventilate the patient?
Avoid volutrauma:
small tidal volumes
low-peak inspiratory pressures,
Adequate oxygenation:
the goal of saturations in the low to mid 90s
permissive hypercapnia:
Pco2= 50- 65 mmHg with maintenance of pH >7.25.

16. Pulmonary hypertension management:
Criteria for PH treatment:
Preductal sao2 less than 70%
Postductal Pao2 less than 40%
Echo shows PH
Treatment:
1- INO: AT 20 ppm, wean if oxygenation maintained at Fio2 less than .6
2- Catecholamines: to enhance rt and lt heart emptying after volume expansion and oxygen
carrying capacity optimization.
3- Milrinone: Rt vent dysfunction or dilatation
after load reduction after INO

17. When will you allow for operation?
1- Fio2 less than 50%
2- Normal BP for estimated GA
3- Lactate less than
4- Properative Echo improvement in PH and Lt
vent function
5- UOP more than 2mlkghr

18. The surgeon returned the intrathoracic stomach and intestine to the
peritoneal cavity and the ipsilateral lung was found to be
hypoplastic and collapsed.
The resident anesthesiologist tried to expand the collapsed lung
manually with positive airway pressure.
Five minutes after the abdomen was closed, the blood pressure
suddenly dropped from 70/40 to 30/20 mmHg, the heart rate from
150 to 80 beats per minute, and the pulse oximeter from 95% down
to 60% saturation. What would you immediately do?

19. Any sudden deterioration in blood pressure, heart rate, oxygen saturation, or
pulmonary compliance is suggestive of tension pneumothorax
How u will manage?
Auscultation of the chest, particularly the contralateral side, should be done
immediately.
If absent or diminished breath sounds confirm the diagnosis
a chest tube should be inserted immediately.
if a chest tube is not immediately available A large-bore intravenous catheter
with needle may be inserted to release the tension pneumothorax

20. If there is no pneumothorax, or if deterioration is not
improved after insertion of a chest tube, what do u
think is the cause?
inferior vena cava compression should be considered.
The abdominal cavity is often underdeveloped and unable to fully accommodate the
returned abdominal organs, which increases the intra-abdominal pressure, displaces the diaphragm
cephalad, and ultimately decreases pulmonary compliance (in the healthy lung).
desaturation, hypercarbia, and overall instability.
ttt the abdominal wound should be reopened.
A patch closure of the abdomen
or a Silo pouch is placed until growth allows safe return to the abdominal cavity.

21. At the conclusion of surgery, would you extubate
the
patient in the operating room?
No, the patient should remain intubated at the
conclusion of surgery