HFOV and PIE/CDH (Ken's Class)

Question 0

What are the complications of pulmonary hypoplasia?

Answer 0

These are lungs that have not developed normally:

• Fewer generations in the lungs
• Smaller air spaces
• Histologic immaturity
• Structural weakness. This leads to Pulmonary Interstitial Emphysema.

Question 1

Know the causes of oligohydramnos

Answer 1

Rupture of amniotic membranes.
Congenital absence of functional renal tissue
No fetal urine produced.
Post term gestation.

Question 2

What is the progression of Pulmonary Interstitial Emphysema (PIE)?

Answer 2

1) PIE is caused by immature lung tissue
2) Too much air in the interstitium leads to compression atelectasis of neighboring airways.
3) Compression atelectasis starts a vicious cycle where higher ventilator pressures are needed due to increased pulmonary resistance.
4) The increased ventilator pressures make the air leak worse.

Question 3

What is the treatment for PIE?

Answer 3

1) Gentle ventilation with permissive hypercapnea.
2) Chest tubes as necessary to prevent compression atelectasis.
3) Place bad lung down.
4) In severe cases, consider single lung ventilation
5) Use the Bunnell Life Pulse Jet High Frequency Ventilator

Question 4

What are the main problems connected with CDH?

Answer 4

• The main problem is that in severe cases there will be near or complete agenesis of at least one of the lungs.
• The hypoplastic lungs -> hypoxia -> pulmonary hypertension.

Question 5

What is the immediate treatment for CDH?

Answer 5

• Do not use a BVM. It will distend the gut in the chest and cause tension pneumothorax physiology.
• Intubate immediately. (Mechanical ventilation at low pressures)
• Place a double lumen gastric tube (decompresses gastric organs)
• Surgery

Question 6

With CDH, what should the RT anticipate?
What type of therapeutic gas should be used to treat it?
What kind of ventilators should be used for CDH?

Answer 6

Anticpate pulmonary hypertension
Treat it with nitric oxide (NO).
If the baby does not respond to NO, extra corporeal membrane oxygenation (ECMO) is used.
Use oscillatory or Jet ventilation.

Question 7

Know the nitric oxide interfaces.

Answer 7

1) Conventional ventilator
2) High frequency oscillator (HFOV)
3) High frequency jet (HFJV)
4) Nasal CPAP
5) Heated high flow nasal cannula
6) Nasal cannula

Question 8

What is the ventilator management for post-op HLHS? (Three factors)

Answer 8

1. Avoid “flooding” the pulmonary circulation
2. Maintain FiO2 at specific SpO2 target, usually 75 – 85%
3. Do not hyperinflate lungs.

Question 9

Why is prostaglandin E used in the treatment of HLHS?

Answer 9

It is given to keep the ductus arteriosus patent.

Potent vasodialator with short half-life.

Question 10

Why might the HLHS patient require sub-ambient FiO2 delivery?

Answer 10

This is done to maintain hypoxia and create enough pulmonary hypertension to keep the ducts are still patent.

Question 11

How can a baby with HLHS can survive the first few hours of life?

Answer 11

Their ducts are still patent.

Question 12

What are the indications of HFOV use?

Answer 12

Again…Think Lung Protection. Reduce the risk of volutrauma and barotrauma

• Neonates requiring inspiratory pressures greater than 22 cmH2O.
• Neonates with impending Pulmonary Interstitial Emphysema (PIE).
• When conventional ventilation fails.
• As prophylaxis in micro-premies.
• In the pediatric population: ARDS

Question 13

In HFOV, what might be happening if the amplitude:MAP ratio is high?
What is the solution?

Answer 13

If the Amplitude:MAP ratio is high (2.5:1 or 3:1), it could mean hypo-inflation and de-recruited alveoli.
Solution: Check CXR and increase MAP.

Question 14

What are the indications for HFJV use?

Answer 14

• Pulmonary Interstitial Emphysema (PIE) – Air Leak Syndrome
• Patients who fail HFOV
• Patients who suffer hemo-dynamic compromise on HFOV

Question 15

Compare and contrast HFOV and HFJV.

Answer 15

-The Bunnell has passive exhalation, unlike HFOV. It is not a “push-pull” ventilator.

Question 16

Servo pressure monitoring

Answer 16

• Servo pressure is one of the monitored parameters on the Bunnell
• Servo pressure is the driving pressure that automatically regulates flow
• Servo pressure changes with changes in lung volume and mechanics
• Servo pressure serves as an early warning indicator for the clinician

Question 17

The conventional ventilator is used in tandem with the HFJV to provide what four things?

Answer 17

• A “sigh” rate for alveolar recruitment
• FiO2
• PEEP
• Fresh Gas

Question 18

_____ works in tandem with a conventional ventilator.

Answer 18

The Bunnell Life Pulse

Question 19

How do you use the Jet to adjust PaCO2?

Answer 19

• Jet PIP – Adjust upward to decrease PaCO2

* Jet rate – Adjust downward to decrease PaCO2

Question 20

What increases servo pressure in HFJV?

Answer 20

• Improving compliance or resistance
• Increasing lung volume
• ET tube leak
• Ventilator tubing leak

Question 21

What complications are seen in HFOV?

Answer 21

• The most common complication is hyperinflation.
• Barotrauma (pneumothorax)
• Hemodynamic compromise
• NTB (Necrotizing Tracheo-Bronchitis)

Question 22

What do you have to remember about the Jet in pure ARDS?

Answer 22

Use high jet rate and high conventional rate.

Question 23

The ___ ventilator controls PCO2.

The ___ ventilator controls PO2.

Answer 23

The Jet ventilator controls PCO2

The Conventional ventilator controls PO2

Question 24

What Jet rates & conventional rates do you want to used in air leak syndromes?

Answer 24

Use lower Jet rates (diminish air trapping) and lower conventional (Sigh) rate to alleviate further leaking.

Question 25

How can high mean airway pressure affect hemodynamic stability?

Answer 25

high MAP (mean airway pressure) decreases venous return to right heart. If high MAP leads to hyperinflation, the heart can become compressed.

Question 26

What decreases Servo pressure?

Answer 26

• Worsening compliance or resistance
• Obstructed ET tube
• Tension pneumothorax
• Right mainstem intubation
• Patient needs suctioning

Question 27

How do you use the Jet to adjust PaO2?

Answer 27

CV FiO2
CV PEEP
CV “sigh” rate

Question 28

Why do you want to place an infant with PIE with the bad lung down?

Answer 28

Seal leak at affected lung.

Improve ventilation to non or less affected lung

Question 29

What calculation can you use for early detection of pediatric ARDS?

Answer 29

PF ratio
>300: ALI
>200: ARDS

Question 30

This type of CDH appears on the left side. It is posterior/lateral and most common.

Answer 30

Bochdalek

Question 31

What type of CDH appears on the right side. is less severe but connected to certain syndromes?

Answer 31

Morgagni

It is usually retrosternal and may actually be asymptomatic

Question 32

How do you make PCO2 alterations on HFOV?

Answer 32

first choice is amplitude adjustment and second choice is frequency (hertz) adjustment:

• For ventilation (pH, PCO2) management:
• Power (aka delta P or amplitude): Increasing the power will decrease the PCO2.

Question 33

How do you make oxygenation changes in HFOV?

Answer 33

MAP (Mean Airway Pressure): Increasing the MAP will recruit more alveoli and increase the PO2.

Question 34

In HFOV, increasing the hertz will increase the ___. Decreasing the hertz will decrease the ___.

Answer 34

Increasing the hertz will increase the PCO2.

Decreasing the hertz will decrease the PCO2.

Question 35

How is the Bunnell different from HFOV?

Answer 35

The Bunnell has passive exhalation, unlike HFOV. It is NOT a “push-pull” ventilator. The Bunnell uses a “patient box” that features a pinch valve that interrupts the high velocity flow at a pre-set rate – usually 420 times per minute.

Question 58

In HFOV, what might be happening if the amplitude:MAP ratio is low?
What is the solution?

Answer 58

If ratio is low (1.5:1), there could be hyperinflation. The MAP is too high and higher amplitudes will be needed to ventilate.

Solution: Check CXR, decrease MAP.