cdh medical & surgical management

7/31/2019 Cdh Medical & Surgical Management

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MEDICAL & SURGICAL

MANAGEMENT


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MEDICAL MANAGEMENT


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GOAL OF TREATMENT

Because of associated persistent pulmonary

hypertension of the newborn (PPHN) and

pulmonary hypoplasia, medical therapy in

patients with congenital diaphragmatic hernia

(CDH) is directed toward optimizing

oxygenation while avoiding barotrauma.


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Delivery Room Management

If known or suspected to have congenital

diaphragmatic hernia:

place a vented orogastric tube

connect it to continuous suction to prevent bowel

distension and further lung compression

For the same reason, avoid mask ventilation

and immediately intubate the trachea.


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Mechanical ventilation strategies

targeted at avoiding high peak inspiratory

pressures and synchronizing ventilation with

the infant's respiratory effort. (Deprest et al. ClinPerinatol. Jun 2009)

In some instances, high-frequency ventilation

(HFV) may be helpful in avoiding the use of

high peak inspiratory pressures. Early use ofHFV showed 90% survival rate. (Bohn Am J RespCrit Care Med, 2002)


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PaO2concentrations greater than 50 mm Hg

typically provide for adequate oxygen delivery

at the tissue level.

Aiming for higher PaO2 concentrations may

lead to increased ventilator support and

barotrauma.

Barotrauma contributes to up to 25% of CDH

deaths.


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Similarly, infants with congenital diaphragmatichernia often have hypercarbia because ofpulmonary hypoplasia.

Whether to maintain a low PaCO2

for pulmonaryvasodilation, to allow permissive hypercapnia, orto maintain normocarbia remains controversial.

Retrospective studies suggest that gentleventilation and permissive hypercarbia with

stable hypoxemia (>80%), may be associatedwith improved survival (76%). (Boloker et al. J Ped Surg,2002)


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Alkalinization

Alkalinization was frequently used in the past

because of its ability to produce a rapid

pulmonary vasodilation.

Forced alkalosis can be accomplished either by

using hyperventilation to induce hypocarbia

or by alkali infusions.


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Alkalinization

However, benefits of alkalosis have never

been demonstrated in any prospective clinical

trial, and these therapies are considered

controversial. In addition, alkalosis may resultin undesirable side effects.

For instance, hypocarbia constricts the

cerebral vasculature and reduces cerebralblood flow.


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Alkalinization

Extreme alkalosis and hypocarbia are strongly

associated with later neurodevelopmental

deficits, including a high rate of sensorineural

hearing loss.

Previous studies indicate that the use of alkali

infusions may be associated with increased

use of ECMO and an increased use of oxygenat age 28 days (Walsh-Sukys et al. Pediatrics. Jan 2000).


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Cardiac Support

Inotropic support with dopamine, dobutamine,

or milrinone may be helpful in maintaining

adequate systemic blood pressure; dobutamine

and milrinone may be particularly helpful ifmyocardial dysfunction is present.

Epinephrine infusions may be necessary in

severe cases; low-dose epinephrine (< 0.2mcg/kg/min) may help to promote pulmonary

blood flow and improve cardiac output.


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Nitric Oxide

Nitric oxide does not reduce mortality or the

need for ECMO in infants with congenital

diaphragmatic hernia, although it may

immediately stabilize infants with criticalhypoxemia and reduce the chances of

cardiopulmonary arrest.(Fliman et al. J Pediatr. May 2006)


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Nitric Oxide

Inhaled nitric oxide should be used with

caution if ECMO is not immediately available.

New studies indicate a potential role for long-

term low-dose inhaled nitric oxide therapy inthe treatment of late or recurrent pulmonary

hypertension.


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Sedation

Sedation is an important adjunctive therapy,but the use of paralytic agents remains highlycontroversial.

Although diminished swallowing may bebeneficial, paralysis may promote:

both atelectasis of dependent lung regions andventilation-perfusion mismatch

generalized edema

decreased chest wall compliance


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Surfactant administration

Surfactant administration has also been

shown to produce a transient improvement in

oxygenation in some infants with CDH.

Preliminary reports from the CDH Study Group

showed surfactant administration may worsen

outcome. (Lally et al. J Pediatr Surg 2004)


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SURGICAL MANAGEMENT


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Theoretically, fetal surgery for congenital

diaphragmatic hernia provides an elegant

solution to the difficult problem of congenital

diaphragmatic hernia.

However, a randomized trial showed that in

utero repair did not improve survival

compared with standard therapy.(Harrison et al. NEngl J Med. Nov 2003)


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Subsequent trials of fetal intervention focused

on occluding the fetal trachea.

The fetal lung secretes fluid by active ion

transport through gestation, and this lung

fluid provides a template for lung growth.


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Occlusion of the fetal trachea traps this fluid

and stimulates lung growth, either byretention of growth factors within the lung or

stimulation of local growth factors by the

gentle distension provided by the fluid.


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Unfortunately, a randomized trial in humans

found that fetal tracheal occlusion did not

improve outcome compared with standard

treatment. (Jelin Clin Perinatol. Jun 2009)

Currently, fetal intervention is not indicated in

congenital diaphragmatic hernia, although

some groups continue to offer it on anexperimental basis.


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Until recently, specialists believed that

reduction of the herniated viscera and closure

of the diaphragmatic defect should be

emergently performed following birth.

However, a delayed surgical approach that

enables preoperative stabilization decreases

morbidity and mortality.


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This change in protocol is due to the recentunderstanding that the medical problems ofpulmonary hypoplasia and PPHN are largelyresponsible for the outcome of congenital

diaphragmatic hernia and that the severity ofthese pathophysiologies is largely predeterminedin utero.

Herniated viscera in the chest does not appear to

exacerbate the pathophysiology as long as boweldecompression with a nasogastric tube isadequate.


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Several reports indicate that circulatory stability,respiratory mechanics, and gas exchange deteriorateafter surgical repair. The ideal time to repair acongenital diaphragmatic hernia is unknown.

Some suggest that repair 24 hours after stabilization isideal, but delays of up to 7-10 days are typically welltolerated, and many surgeons now adopt thisapproach. Some surgeons prefer to operate on these

neonates when normal pulmonary artery pressure ismaintained for at least 24-48 hours based onechocardiography.


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Chest tube drainage is necessary when a tensionpneumothorax is present; however, whether routinechest drainage following surgical repair has a role iscontroversial. Some clinicians report improved survival

when chest drainage is not used. Others think that balanced intrathoracic drainage, in

which a closed gated pressure system is used tomaintain intrathoracic pressure within the normal

physiologic range, may minimize risk of pulmonaryinjury and improve respiratory mechanics.


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Approaches for surgical repair

Abdominal subcostal

Preferred because the accompanying malrotation

may be addressed if necessary, and the abdominal

wall may be left open with skin only closed or aSilastic pouch applied if abdominal pressure is

considered excessive

Thoracotomy


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Laparoscopic vs Thoracoscopic

MIS ideal for Morgagni hernias but can be

challenging because the peumoperitoneum

widens the defect. Laparoscopy for Bochdaleks has a high failure rate

and is associated with pCO2 and acidemia.

Thoracoscopy is better approach for Bochdalekhernias with recurrence of 14%. Open approach 3-

22%.(Marjorie et al, J Ped Surg, Nov 2003.)


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Small defect can be repaired primarily. Large

defect will require abdominal or thoracic

muscle flaps, or prosthetic patch (tension

free).

Synthetic patch (polytetrafluoroethylene) is

now preferred over autologous muscle

transfer or tight primary closure for largedefects.


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PROBLEM LIST


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Problem # 1

RESPIRATORY

S>

O>

A> PPHN sec to Bochdaleks Hernia P>

Dx:

Tx:


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Problem # 2

INFECTIOUS

S>

O>

A> R/O Sepsis

P>

Dx:

Tx:


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Problem # 3

FLUIDS & ELECTROLYTES

S>

O>

A> R/O Sepsis

P>

Dx:

Tx:

cdh medical & surgical management

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