Case 60 - congential diaphragamtic hernia Flashcards

1
Q

Describe the pathophysiology of congenital diaphragamtic hernia

A
  • occurs during fetal development
  • posterolateral diaphragm defect on the Left side = most common site
  • abdominal contents hernia into pleural cavity –> impair lung development –> pulmonary hypoplasia
  • although ipsilateral side is primarily affected, contralateral lung also is abnormal:
    • decreae number of bronchi and alveoli
    • inappropriate muscularized pulm arteries

Physiologic changes

  • increase in PVR and persistent pulm HTN
    • persistent pulm HTN –> patent foramen ovale and ductus arteriosus –> hypoxia and acidosis –> further leads to patent ductus arteriosus (closes only with increase PaO2)
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2
Q

is congenital diaphramatic hernia an emergent surgery?

A

No

  • may be associated with congenital anomalies (CVS, GI, GU, craniofacial)

Initial managment

  • intubate
  • improve ventilation and oxygenation
  • once stabilized, perform surgery
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3
Q

What are the clinical features of CHD?

A

pathophys review

  • herniation of abdominal contents into thorax causing hypoplastic lungs.
  • hypoplastic lungs –> increase PVR –> persistent pulm HTN of newborn –> patent ductus arteriosus and foramen ovale –> hypoxia and acidosis (becuase reduced blood flow to lungs)

Clinical features:

  • tachypnea
  • cyanosis
  • scaphoid abdomen
  • absence of breath sounds on affected sides
  • heart sounds shifted to contralateral side
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4
Q

how is CHD diagnosed?

A

In utero

  • ultrasonography may show disease

Post-natally

  • CXR –> definitive diagnosis –> abdominal contents in thoracic cavity
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5
Q

What is the preop managment of a neonate with CHD?

A

1) AVOID bag mask ventilation
* can cause distension of abdominal organs in thorax –> compress the lungs further –> prevent futher oxygenation and ventilation

2) Tracheal intubation

3) maintain insp pressure < 40 cm H2O

  • at risk for pneumothorax of contralateral lung
    • contralateral lung affected 2/2 gas flow to path of least resistance = contralateral lung

4) insert OG tube
* decompress stomach to avoid compression of lungs
5) transfer to NICU for sabilization

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6
Q

What is the pulmonary goals for CHD patients?

A

AVOID INCREASES IN PVR

factors that increase PVR

  • Hypoxia
  • hypercarbia
  • acidosis
  • hypothermia
  • sympathetic stimulation

Other ways to decrease PVR

  • inhaled nitric oxide
  • pulmonary vasodilators
  • avoid volume overload and subsequent pulm edema
  • ECMO
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7
Q

What is permissive hypercapnia? How may this be beneficial to CHD patients?

A

Permissive hypercapnia

  • Allow PaCo2 to increase, while maintaing adequate oxygneation and acid-base balance.
    • PaCO2 can lead to resp acidosis, but you can correct pH with other measures like bicarb or THAM solution

permissive hypercapnia and CDH pts

  • goal is to avoid increase in PVR.
  • in order to decrease PaCo2, higher inspiratory pressure required to maintain ventilation –> result is barotrauma / risk of pneumothorax
  • in permissive hypercapnia, allow PaCo2 to increase, but maintain normal acid-base balance with bicarb and THAM.
  • maintain pre-ductal SaO2 > 90%
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8
Q

What are the anestheic considerations for neonates with CDH?

A

1) Avoid increases in PVR

  • hypoxia, hypercarbia, acidosis, hypothermia, symp stimulation = all increase PVR
  • adequate oxygenation
  • hyperventilation
    • continue permissive hypercapnia if employed pre-operatively
    • keep an eye on peak insp press if hyperventilating
  • Alkalosis
    • serial ABGs
  • Normothermia

2) Avoid increases in peak inspiratory pressure

  • may need higher peak inspiratory pressure to maintain adequate ventilation and oxygenatoin
    • places lungs at risk for barotrauma and pneumothorax (contralateral lung more affected)
  • consider decrease TV and increase RR –> may decrease inspiratory pressures

3) continue pharmacologic infusions (NO, pulm vasodilat)
4) avoid N20
* can cause intestinal distension –> impede abd closure

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9
Q

All of a sudden, the blood pressure starts to decrease, and neonate is progressively becoming unstable and deteroriating. What is the most likley cuaes, what do you do?

A
  • avoid high peak inspiratory pressure > 40 cm h2o
  • if neone suddenly beocmes unstable, think pneumothorax of contralateral lung
    • needle decompression
    • followed by chest tube insertion
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10
Q

Would you extubate the neonate after surgery?

A

NO

  • despite surgery fixing the defect, the PVR is not going to be normalied immedietly
  • pulm HTN may persist, and neonates will require oxygen and ventilatory support
  • the neonate still has pulmonary hypoplasia that will not change immedietly with surgery
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