Congenital Diaphragmatic Hernia

Pediatric Surgery
Dr Charlie Stolar discusses key points of CDH with Dr. Todd Ponsky.  EDITED BY NICHOLAS BRUNS, MD and IAN GLENN, MD.

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In this episode, Dr. Charles Stolar from Columbia University College of Physicians and Surgeons and California Pediatric Surgery Group discusses evaluation and management of congenital diaphragmatic hernia.

 

Outline

  • Antenatal consultation
    • May be misinformed by obstetrician
    • Diagnosis usually made at the 20thweek ultrasound
      • Stomach may be seen in the same cross sectional plane as the heart
      • Usually on the left
      • May be associated congenital heart disease or central nervous system anomalies
    • Recommend spontaneous vaginal delivery. CDH alone is not an indication for C-section
    • CDH can be confused with a multicystic adenomatoid malformation or large eventration on prenatal and neonatal imaging
    • Fetal procedures at this point are experimental
    • As 10-15% of patients need ECMO, infants should be born at a facility that has ECMO capabilities
    • Prognosis
      • Instill cautious optimism to parents
      • Measurements are user-dependent and institution-specific
      • Lung-to-head ratio of limited value unless very low (<0.8)
      • Associated congenital heart disease or CNS abnormalities are perhaps the most important findings
      • 80-85% survive to teenage years
    • Antenatal corticosteroids may have most benefit in the setting of prenatal polyhydramnios
    • EXIT to ECMO
      • Difficult to identify the most severe CDH patients
      • Data are not convincing
  • Neonatal evaluation
    • Respiratory status
      • Most are intubated at birth
      • Pre- and post-ductal gradients - pulse oximeter on right arm and left foot
      • Echocardiogram
      • Chest x-ray
    • Lines/tubes
      • NG
      • Umbilical vein catheter
      • Umbilical artery catheter
  • Management of pre-ductal hypoxemia
    • Check hemoglobin and assess volume status
    • Optimize FiO2 and ventilatory pressures
      • Favor permissive hypercapnia and spontaneous ventilation
      • High rate and low pressure ventilation to prevent barotrauma
      • As pulmonary vascular resistance and compliance improves, can switch to more conventional ventilatory settings
      • No paralysis and minimal sedation
    • High-frequency oscillator ventilation (HFOV) is indicated after conventional ventilation has failed, but it is not high value as it frequently indicates that the child needs ECMO. It may have better results in preterm infants
    • Nitric oxide (NO) is of no value in CDH. May a get response initially, but then tachyphylaxis occurs
  • ECMO
    • ECMO is used selectively based pre-ductal oximetry
    • If a baby maintains pre-ductal saturation >90% with best respiratory care, then they do not need ECMO
    • Indicated for inadequate tissue perfusion despite optimal medical management
      • Ventilatory and oxygenation indices exist to assign scores
      • Oxygenation index of >40 for 4 hours is an indication
      • Consider ECMO for end organ dysfunction (anuria, depressed cardiac function, depressed neurologic function, etc.)
    • Contraindications
      • Less than 34- to 35-weeks gestation due to risk of intracranial hemorrhage and difficulty fitting the cannulas
      • Smaller infants may not have large enough vessels for the cannula
      • Irreversible condition (lung disease, neurologic disease)
        • If pCO2 > 60 or 70 or cannot adequately oxygenate pre-ductal blood with optimal ventilatory management, considered not to have enough lung to be compatible with life
      • Congenital syndromes (trisomy 13, 18)
      • Bleeding
    • V-V versus V-A ECMO
      • V-V may be great for patients with normal cardiac function that are not in extremis
      • May be difficult to cannulate vessels due to larger cannulas or from mediastinal shift
      • V-A may be used for sicker or unstable babies
    • Cannulization
      • Placement can be assisted with echocardiogram. Dr Stolar has the cardiologist do this during every ECMO cannulization
      • Passing a guide wire from the subclavian vein into the right atrium can help in putting the cannula in
      • Stay sutures are placed with three 5-0 Prolene sutures on both venotomy and arteriotomy to help open it
    • Initiation
      • May get hyperkalemia from unwashed blood
      • Tachycardia and hypertension are common as well
      • Slowly increased ECMO support over 45-90 min
      • Goal is 120-125 cc/kg/min (~80% of cardiac output)
      • Follow preductal saturations or mixed venous saturations
      • Diurese infant and follow lung compliance and urine output
    • Weaning
      • Regular cardiac echocardiograms to follow the right heart function
      • Hyperoxia test
        • Turn FiO2 up on the ventilator up to 1.0
        • If PaO2 rises, this is an indication that lungs are functioning
      • Slowly reduce rate by 1-2 cc/kg/hr
      • Ideally Dr Stolar would operate right as the baby is about to be completely weaned off
      • If you can’t wean ECMO, sometimes may be forced to operate on the child on ECMO. This is unlikely to lead to immediate improvement
    • When to withdraw ECMO due to futility
      • After 2-3 weeks this becomes a consideration if they have not improved after repair. Surgical repair may improve respiratory function by removing distended bowel from the chest, relieving mass effect
      • Usually occurs after major event such as CNS insult (i.e. cerebral hemorrhage)
      • Manage parents’ expectations
  • Surgical repair
    • Dr Stolar prefers to operate on the child when they are on modest ventilator settings, usually 2-4 days
      • Right ventricular pressure should be less than systemic pressure
    • If they require ECMO, Dr Stolar does the repair when they are about to come off of ECMO
      • If the child decompensates, this gives a safety net
      • Goal is to get off of ECMO by post-operative day 2 or 3 when the platelet clots dissolve
      • Special considerations for operating on ECMO
        • Preoperative Amicar
        • Abdominal approach
        • Patch to minimize extent of dissection
        • Jackson-Pratt to prevent hematoma accumulation
        • Chest tube to drain bleeding from mesothelial surfaces
    • In the OR, use the infant ventilator rather than the anesthesia ventilator. There is less dead space and better compliance
    • Perioperative antibiotics – Dr Stolar uses ampicillin and gentamicin
      • For a right-sided defect, it is important for the echocardiogram to note if the hepatic veins drain directly into the right atrium
      • Hepato-pulmonary fusion may occur. Do not try to separate this. It cannot be treated surgically
    • Type of approach
      • Thoracoscopy
        • Dr Stolar’s thoughts
          • Great to visualize the anatomy
          • Tension pneumothorax should be avoided in the unstable patient
          • High recurrence, up to 25%. Dr Stolar is hesitant to use thoracoscopy
        • Technique
          • Position the patient at the edge of the bed such that the surgeon is operating from behind the head pointing towards the feet
          • 3 ports: 4-mm camera and two 3-mm instruments
          • Insufflate to a peak pressure of 5-7 mm Hg
          • Reduce contents to abdomen. Reduce the spleen last or it may obstruct the defect. It also may prevent contents from herniating back into the chest
          • Resect the hernia sac
          • Use 5-cm strand of 3-0 or 4-0 Ethibond
          • Mobilizing the posterior leaflet may be difficult because it is hard to see behind the defect
          • Lateral edge may use an extracorporeal-intracorporeal rib stitch
          • Dr Stolar does not use a chest tube unless there is active bleeding, expected bleeding (ECMO) or an air leak
      • Laparotomy
        • Adequate subcostal incision
        • Rotate the liver out of the abdomen
        • Eviscerate the bowel
        • Mobilize the posterior leaflet
        • Sew from medial to lateral
          • Medial can be most challenging because there is a lack of diaphragm
          • Can take a pericardial flap to bridge a gap (upside down ‘U’ incision into the pericardium
          • Use monofilament nonabsorbable suture (PDS) so that it does not saw the tissue
        • If a patch is needed, Dr Stolar favors 1-mm Gore-Tex
          • Helpful to anchor the patch to the ribs laterally
          • Sew the patch with redundancy so that it can balloon out (not taught)
        • No need for repair of intestinal nonrotation due to increased risk of bleeding from increased dissection
      • Right-sided CDH
        • Baby is prepped for both an abdominal and thoracic approach
        • Dr Stolar starts abdominally but frequently the liver is in the way and a counter incision is needed for better vision
        • Even with a thoracotomy, a thoracoscope can be used to look to see around corners
  • Post-operative care
    • Usually patients decompensate the first day, and then improve and go home in 4-5 days
    • Common to have dysmotility in the upper GI tract (esophagus, stomach), but it is unusual to need a fundoplication
      • Upper GI series should be performed post-operatively. Will often have abnormal upper GI series, manometry, gastric emptying, etc.
      • If an anti-reflux operation is needed, should be done with a G tube and a drainage procedure (Jaboulay or Finney pyloroplasty)
      • Prokinetics are unreliable
    • Multi-disciplinary clinic
      • Includes pediatric GI, pediatric orthopedics, pediatric neurology, pediatric surgery, neuropsychiatry
      • Seen for life and followed regularly
      • Dr Stolar has had several patients with Barrett’s esophagus discovered as teenagers
      • Increased attention deficit disorders and autism
      • Asymmetric chest wall sometimes treated with Nuss procedure
      • Scoliosis can be treated with early bracing
  • Recurrences
    • Recurrences are more common on the left than the right
    • Dr Stolar has treated recurrences with thoracoscopy to be in a virgin plane, but this has just been two cases

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