Congenital Diaphragmatic Hernia (CDH)

Patient Considerations

• CDH is a developmental discontinuation of the diaphragm that allows for viscera of the abdomen to herniate into the chest. Visceral herniation occurs during the period of lung development when the pulmonary arteries and lung bronchi begin branching between the 3^rd and 16^th weeks post fertilization.

• Pathogenesis

  • The leading theories on pathogenesis of this disease are that CDH results from a failure of pleuroperitoneal folds to close or from environmental/ genetic triggers that stop the differentiation of mesenchymal cells that form the diaphragm. The most common presenting symptom of CDH is acute respiratory distress.

• Associated Anomalies

  • CDH can be isolated or part of syndromes. Isolated CDH is associated with pulmonary hypoplasia, pulmonary hypertension, intestinal malrotation, and cardiac dextroposition which occur due to the mechanical consequences of CDH. Chromosomal abnormalities are found in 10-20% of cases most commonly being 18, 13, 21. Polyhydramnios can occur due to esophageal compression and hydrops fetalis can occur due to mediastinal shift and compression of great vessels.

Case Planning

• The patient’s status and morbidity significantly affect the anesthetic plan

  • Very ill patients may present for repair while on ECMO

    • Anesthesia may or may not be involved in the care of these patients

    • Traditionally an "easier” anesthetic as ventilation and cardiac output are augmented by the ECMO support

    • Transport is VERY cumbersome

      • Coordination of transport takes significant time/effort

      • ECMO circuits may not fit in the standard transport elevator and the service elevator may be required

      • Manual ventilation is not absolutely required during ECMO

Patients who are not ECMO candidates may present with multiple support measures

• This may include

  • Oscillator/Jet Ventilation

  • Inhaled Nitric Oxide

  • Inhaled Flolan

  • Vasopressor infusions

  • NICU Cases

    • The case may be booked to be done at bedside in the NICU because the patient is "too sick to transport”

      • Managing a critically ill patient outside the OR places us at a disadvantage in the event of an emergency

        • Help is far away

        • Emergency supplies must be brought in advance

        • Unfamiliar environment

        • Charting must be done manually which distracts the providers from caring for the patient

      • Ask what makes the patient "too sick” to transport

        • Evaluate whether the risks of transport are outweighed by the benefit of being in the OR if an emergency occurs

        • Is the oscillator/jet ventilator actually required?

    • If proceeding in the NICU, plan ahead!

      • Consider asking for a second attending/provider

      • Charting

        • Paper chart v. Laptop and manually inputting data into centricity

    • Electronic charting may be easier to manage in the event of an emergency and has the benefit of being accessible for reference when planning subsequent anesthetics

      • Bring the traveling cardiac cart and line cart

      • Bring ultrasound if additional lines anticipated

      • Meds/Infusions

  • Have code drugs drawn-up in single dose syringes

    • This eliminates the need to calculate doses in an emergency

      • Consider having Epinephrine and Vasopressin infusions ordered and in-line

  • Consolidate all infusions onto a single pole to make infusion adjustment easier

• Consider having albumin pre-drawn up and ready to bolus

  • Assign emergency roles prior to procedure start

    • Make sure NICU staff knows what you need them to do ahead of time

    • Make it clear who will "run the code”

    • Discuss emergency ECMO plan

Have a readily available push line for medications

• This should be separate from the infusion line

  • NICU Intra-op

    • Positioning

      • Consider re-positioning the patient so you have easy access to the airway

        • Make sure that the ETT can be accessed and suctioned PRIOR to allowing the surgery to start

        • Have equipment for manual ventilation set-up and ready

      • Orient the patient with the head at the foot of the bed?

        • This may also help facilitate emergency ECMO cannulation

    • Respiratory

      • If the patient is on non-conventional ventilation

        • RT must be immediately available to adjust the vent if you are not comfortable doing so

• Be ready and able to manually ventilate the patient with an AMBU bag or Mapleson circuit

  • Maintenance

    • Narcotic and muscle relaxation

RED FLAG- The "Hail Mary”

• If a patient is critically ill on heroic ventilatory/vasopressor support and is not an ECMO candidate, the planned surgical intervention may be a "Hail Mary” with a high chance of peri-operative morbidity/mortality

  • Discuss with the attending surgeon to identify how "sick” the child is

  • Have a pre-defined plan for what to do if the child arrests

    • Is the child an ECMO candidate?

      • If yes, make sure perfusion is aware and that cannulation supplies are ready

      • Discuss intra-op ECMO criteria with the surgical team

  • If ECMO may be required, consider having the perfusion team prime a circuit and have it ready prior to starting an off-ECMO repair

• If there is a significant chance of peri-operative death, this should be clearly communicated to the family and all staff present

OR Case Specific or Unique Room Set-Up Requirements

• Airway

  • Patients frequently present with an existing ETT

  • Caution should be used with positive pressure ventilation

    • High risk of pneumothorax with elevated peak pressures

    • Consider permissive hypercapnia

  • Avoid Nitrous Oxide if performing a mask induction

• Drugs/Infusions

  • Consider inhaled Nitric Oxide if pulmonary hypertension is present

  • Narcotic

  • Muscle Relaxation

  • Volatile- if needed

• Monitors

  • Standard ASA monitors

  • Consider NIRS

  • Consider arterial access to monitor ABGs to assess adequacy of ventilation

• Blood Availability

  • T+C x1 unit

• PICU Bed Availability

  • These patients are frequently critically ill and present from a NICU bed

  • Ensure availability of post-op ventilation

Anesthetic Considerations

Induction

• Patients frequently present with an ETT in place

• Avoid elevated peak pressures when masking/intubating

Positioning

• Supine v. lateral

Maintenance

• Maintenance of Anesthesia

  • Hemodynamic/Physiologic goals

    • Avoid elevated peak pressures to avoid barotrauma

    • Avoid pulmonary hypertensive crisis

      • Minimize hypoxia and hypercarbia while avoiding barotrauma

    • As most of these patients are neonates the goal MAP should be the patient’s gestational age

      • Ex. A 1 day old born at 37 weeks should have a MAP of 37 or above

Emergence/Disposition

• Patients will likely return to the NICU intubated

Post-Op Pain Management

• IV narcotics

Case-Specific Complications

• Reduction of abdominal contents into the abdomen may acutely decrease venous return and impairing cardiac output

• Hypoplasia of the affected lung impairs pulmonary vascular development leading to pulmonary hypertension

  • These patients are prone to pulmonary hypertensive crisis

• Aggressive ventilation may cause barotrauma on the contralateral lung

• Any combination of the above may precipitate cardiovascular collapse