HFOV and PIE/CDH (Ken's Class) Flashcards
What are the complications of pulmonary hypoplasia?
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.
Know the causes of oligohydramnos
Rupture of amniotic membranes.
Congenital absence of functional renal tissue
No fetal urine produced.
Post term gestation.
What is the progression of Pulmonary Interstitial Emphysema (PIE)?
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.
What is the treatment for PIE?
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
What are the main problems connected with CDH?
- 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.
What is the immediate treatment for CDH?
- 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
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?
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.
Know the nitric oxide interfaces.
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
What is the ventilator management for post-op HLHS? (Three factors)
- Avoid “flooding” the pulmonary circulation
- Maintain FiO2 at specific SpO2 target, usually 75 – 85%
- Do not hyperinflate lungs.
Why is prostaglandin E used in the treatment of HLHS?
It is given to keep the ductus arteriosus patent.
Potent vasodialator with short half-life.
Why might the HLHS patient require sub-ambient FiO2 delivery?
This is done to maintain hypoxia and create enough pulmonary hypertension to keep the ducts are still patent.
How can a baby with HLHS can survive the first few hours of life?
Their ducts are still patent.
What are the indications of HFOV use?
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
In HFOV, what might be happening if the amplitude:MAP ratio is high?
What is the solution?
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.
What are the indications for HFJV use?
- Pulmonary Interstitial Emphysema (PIE) – Air Leak Syndrome
- Patients who fail HFOV
- Patients who suffer hemo-dynamic compromise on HFOV
Compare and contrast HFOV and HFJV.
-The Bunnell has passive exhalation, unlike HFOV. It is not a “push-pull” ventilator.
Servo pressure monitoring
- 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
The conventional ventilator is used in tandem with the HFJV to provide what four things?
- A “sigh” rate for alveolar recruitment
- FiO2
- PEEP
- Fresh Gas
_____ works in tandem with a conventional ventilator.
The Bunnell Life Pulse
How do you use the Jet to adjust PaCO2?
- Jet PIP – Adjust upward to decrease PaCO2
* Jet rate – Adjust downward to decrease PaCO2
What increases servo pressure in HFJV?
- Improving compliance or resistance
- Increasing lung volume
- ET tube leak
- Ventilator tubing leak
What complications are seen in HFOV?
- The most common complication is hyperinflation.
- Barotrauma (pneumothorax)
- Hemodynamic compromise
- NTB (Necrotizing Tracheo-Bronchitis)
What do you have to remember about the Jet in pure ARDS?
Use high jet rate and high conventional rate.
The ___ ventilator controls PCO2.
The ___ ventilator controls PO2.
The Jet ventilator controls PCO2
The Conventional ventilator controls PO2
What Jet rates & conventional rates do you want to used in air leak syndromes?
Use lower Jet rates (diminish air trapping) and lower conventional (Sigh) rate to alleviate further leaking.
How can high mean airway pressure affect hemodynamic stability?
high MAP (mean airway pressure) decreases venous return to right heart. If high MAP leads to hyperinflation, the heart can become compressed.
What decreases Servo pressure?
- Worsening compliance or resistance
- Obstructed ET tube
- Tension pneumothorax
- Right mainstem intubation
- Patient needs suctioning
How do you use the Jet to adjust PaO2?
CV FiO2
CV PEEP
CV “sigh” rate
Why do you want to place an infant with PIE with the bad lung down?
Seal leak at affected lung.
Improve ventilation to non or less affected lung
What calculation can you use for early detection of pediatric ARDS?
PF ratio
>300: ALI
>200: ARDS
This type of CDH appears on the left side. It is posterior/lateral and most common.
Bochdalek
What type of CDH appears on the right side. is less severe but connected to certain syndromes?
Morgagni
It is usually retrosternal and may actually be asymptomatic
How do you make PCO2 alterations on HFOV?
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.
How do you make oxygenation changes in HFOV?
MAP (Mean Airway Pressure): Increasing the MAP will recruit more alveoli and increase the PO2.
In HFOV, increasing the hertz will increase the ___. Decreasing the hertz will decrease the ___.
Increasing the hertz will increase the PCO2.
Decreasing the hertz will decrease the PCO2.
How is the Bunnell different from HFOV?
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.
In HFOV, what might be happening if the amplitude:MAP ratio is low?
What is the solution?
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.
