Book 4, Case 3-CDH and prematurity

Question 1

Newborn at 38 weeks gestation has resp distress with nasal flaring, sternal retraction and cyanosis shortly after birth. also has a scaphoid abdomen and absent breath soundson left:
What does this result in?

Answer 1

CDH-herniation of abdominal contents into the thoracic cavity. This results inimpaired maturation of lung
tissue (leading to a decreased number of alveoli, decreased surfactant production, and
abnormal pulmonary vasculature) with subsequent impaired gas exchange,
intrapulmonary shunting, and pulmonary hypertension (the muscle mass in the
arterioles increases and they become more reactive). Pulmonary hypertension
impairs the transition from fetal circulation. The resultant extrapulmonary shunting
through the patent foramen ovale and patent ductus arteriosus leads to worsening
hypoxia, hypercarbia, and acidosis, which, in tum, further exacerbate pulmonary
hypertension, setting up a vicious cycle.

Question 2

Pt with CDH has a PAO2-PaO2 difference of 420?

Answer 2

Intrapulmonary and extrapulmonary shunting (extrapulmonary-through pFO and ductus arteriosus) intrapulmonary

Question 3

Normal A-a gradient in young adult non smoker:

Answer 3

Less than 10

Greater than 500=poor prognosis

Question 4

Initial treatment of CDH:

Answer 4

surgical intervention should be delayed until the
neonate is medically stable (the goal is to reduce the pulmonary hypertension that is
causing right-to-left shunting through the patent foramen ovale and the patent ductus
arteriosus), So…until then…
avoid positive pressure mask ventilation (can further
compromise respiratory function by distending intrathoracic viscera) and excessive
endotracheal suctioning (may result in transient hypoxemia or a decrease in Fi02); (2)
establish intravenous access; (3) provide supplemental oxygen; ( 4) intubate the neonate (awake and RSI both acceptable)
-insert naso or orogastric tube for stomach decompression. Establish ventilator settings-avoid high airway pressures.
Place appropriate monitors, sedate with opioids, give muscle relaxant
correcdt hypothermia

Question 5

If the intervention of intubating patient and correcting hypercarbia don’t work, what can you do to reduce PVR?

Answer 5

Prostaglandin E1 or nitric oxide-be careful-these can cause hypotension
Ligation of PDA to reduce shunting (could cause Right heart failure)
ECMO

Question 6

What is the goal of medical mgmt in these CDH patients, and how long does it take

Answer 6

24-48 hours if mild
7-15 days if severe
goal: preductal O2 sat with peak inspiratory pressures <25

Question 7

Mechanical ventilation guides in CDH:

Answer 7

pressures should NOT exceed 30 cm H20 due to the risk of PTX which is more likely on CONTRALATERAL side. moderate hypercapnia is sometimes allowed to avoid ventilator induced lung injury. High frequency oscillatory ventilation cdan be used

Question 8

What is high frequency oscillatory ventilation?

Answer 8

Constant distending airway prssure over small tidal volumes at high respiratory frequency

Question 9

Consider what pressor in CDH pts wiht right sided heart failure?

Answer 9

Consider milrinone

Question 10

Contraindications to ECMO in kids:

Answer 10

Intracranial hemorrhage
Congenital heart disease
Gestation <34 weeks

Question 11

Why would you avoid neck veins in kids with CDH? So then, where woudl you get access?

Answer 11

because it might be needed for ECMO, not to mention yuo already only have one good lung-do NOT cause a pTx . Umbilical or femoral–recognizing that lower extremity access may be less reliable if return of neonates viscera results in increased abdominal pressures.

Question 12

How to cannulate the umbilical vein?

Answer 12

(1) sterilize and drape the
area, (2) place caudal traction on the umbilical stump (caudal traction facilitates
insertion during umbilical vein catheterization; cephalad traction facilitates insertion
during umbilical artery catheterization), (3) carefully insert a soft catheter filled with
heparinized solution a distance that approximates the length between the insertion site
and the right atrium (the desired position for the catheter tip), (4) obtain a radiograph
to confirm proper placement at the junction of the inferior vena cava and the right
atrium, and (5) secure the catheter at the insertion site with suture, antibiotic
ointment, and a protective covering.

Question 13

If you can’t get umbilical catheter in, then can you still use it?

Answer 13

temporarily as long as its not more than 2 cm beyond abdominal surface and blood is still freely aspirated, however this will NOT allow us to monitor CVP

Question 14

Complications associated with umbilical vein catheterization?

Answer 14

infection and sepsis 
portal cirrhosis 
endocarditis 
cardiac tamponade 
Due to these complications, the catheter should be removed as soon as alternative IV Access is established

Question 15

Can you use an umbilical ARTERY catheter to give drugs?

Answer 15

It’s acceptable for emergency admin, but due to complications-exasnguination (accidental disconnection of stopcokc), vasospasm-I’d only use for BP monitoring

Question 16

What monitors would you place for CDH?

Answer 16

-a five-lead ECG (potential
congenital cardiac defects, pulmonary hypertension, right-to-left shunting);
-a right
radial arterial line (placement in the right radial artery allows for the measurement of
preductal Pa02, which more accurately reflects the level of oxygenation provided to
the brain) to closely monitor blood pressure (pulmonary hypertension, acid-base
disturbances, and potential abdominal compartment syndrome increase the risk of
hemodynamic instability) and facilitate frequent blood gas analysis

Precordial or esophagealstehoscope
esophageal or rectal temp
CVP catheter
Pre and post ductal pulse oximeters to identify increase in right to left shunting

Question 17

When does ROP not matter anymore?

What is post conceptual age?

Answer 17

44 weeks post conceptual age

Post conceptual age: AGe, plus time theyve been out

Question 18

Pathophysiology of retionopathy of prematurity?

Answer 18

vasoproliferative retinopathy that results in vasocontstriction and obliteration of retinal vessels followed by hypoxia that leads to abnormal neovascularization

Question 19

Pulse ox on right hand: 87%
Pulse ox on foot: 64%
What’s going on?
What do you do?

Answer 19

significant differential in the reading (usually > 5%) from a pulse
oximeter measuring preductal oxygen saturation (right hand) and a pulse oximeter
measuring postductal oxygen saturation (either foot), suggests either coarctation of

the aorta (a cardiac defect known to be associated with CDH) or a significant right-to-
left shunt through a patent ductus arteriosus.

Question 20

What would you do with differential in preductal and postductal saturation greater than 5%?

Answer 20

Assuming coarctation of the aorta had been ruled out and I believed
this to be secondary to increased right-to-left shunting through a patent foramen
ovale, I would: (1) administer 100% oxygen; (2) ensure adequate ventilation
(hyperventilation using low tidal volumes and a high respiratory rate may be utilized
to reduce pulmonary hypertension); (3) increase systemic vascular resistance, if
induction resulted in vasodilation and hypotension; and (4) take steps to reduce
pulmonary vascular resistance, such as inducing a respiratory alkalosis with
hyperventilation, treating any metabolic acidosis with bicarbonate, and ensuring both
normothermia and an adequate depth of anesthesia to minimize catecholamine
secretions.

Question 21

Once CDH is fixed, are you going to expand the collapesed and hypoplastic lung with positive pressure?

Answer 21

However, delivering the high airway
pressures required to expand the hypoplastic lung places the neonate at considerable
risk of pneumothorax, particularly on the contralateral side. Even a small
pneumothorax could be disastrous in this neonate who already has significantly
compromised cardiopulmonary function.

Question 22

Soon after returning the abdominal organs to the peritoneal cavity, the patient’s
blood pressure suddenly drops from 74/42 mmHg to 44/26 mmHg, and the
oxygen saturation drops to 68%. What are you going to do?

CDH

Answer 22

(1) alert the surgeon that the replacement of the baby’s
abdominal organs into the peritoneal cavity has possibly resulted in increased
abdominal pressure with subsequent compression of the inferior vena cava (leading to
reduced preload and cardiac output); (2) switch to 100% oxygen, (3) check the ECG
for an arrhythmia, (4) begin hand ventilation to check lung compliance (reduced lung
compliance would be consistent with pneumothorax), (5) auscultate the chest to
identify a pneumothorax (pneumothorax is most likely to occur on the contralateral
side and should be suspected in the setting of deteriorating oxygen saturation and
decreased lung compliance, with or without hypotension), (6) ensure proper
endotracheal tube placement, and (7) assess the surgical field for another surgical
cause of cardiopulmonary depression (other than replacing the abdominal contents
into the peritoneal cavity). If there were no pneumothorax, massive bleeding, or other
obvious cause, I would (8) ask the surgeon to relieve the abdominal pressure (the
surgeon may need to cover the wound and plan to proceed with complete closure at a
later date), (9) reduce my volatile agent, (10) administer fluids (volatile agents and
hypovolemia can exacerbate the cardiovascular effects of abdominal compartment
syndrome), and (11) proceed with complete closure at a later date.

Question 23

Are you extubating CDH patients/

Answer 23

No. Although
cardiopulmonary function often improves immediately following surgery, these
patients require intensive respiratory care and are at risk for rebound pulmonary
hypertension. Controlled ventilation reduces oxygen requirements, and helps to
prevent and treat hypoxemia, hypercarbia, and acidosis, all of which can induce or
exacerbate pulmonary hypertension.

Question 24

You are called to evaluate the neonate post op (CDH). BP is 52/30, HR is 78, and pulse ox is 62%. Wyd?

Breath sounds are also diminished bilaterally. Wyd?

Answer 24

Increase FiO2 to 100%.hand ventilate if
possible, check the ECG for arrhythmia, auscultate the chest, and ensure proper
endotracheal tube patency and placement. Assuming the ETT was properlypositioned, I would have a high suspicion for heart failure secondary to hypoxia,
pneumothorax, and/or worsening pulmonary hypertension.

Assuming proper ETT placement, I would treat this as a right-sided
pneumothorax until proven otherwise, since breath sounds were already diminished
on the left side and are now diminished on the right. Therefore, I would call for a
surgeon to emergently place a chest tube, and consider placing a 22-guage
angiocatheter into the second intercostal space, at the midclavicular line, as a
temporizing measure until a chest tube could be placed.