PPHN Flashcards
Pulmonary HTN is usually a dz of which baby?
34 wks-Term (very, very few 23-34 wks)
Hypoxia is what?
A relative deficiency of oxygen in Arterial blood
What is the OI (Oxygen Index)?
A measure of the severity of Hypoxemia
What is the calculatio for OI?
OI= FiO2 x MAP x 100 / post-ductal PaO2
It used to be that an OI of 40 or less meant what?
Now what can be considered if pt has PaO2 >50, Optimal MAP, and lung is inflated (good FRC)?
High likelihood of death
ECMO
When should you consider ECMO for your pt?
Optimal Lung Function +
Inability to Oxygenate
What % chance does he say ECMO will hurt baby?
How?
10%
Stroke, bleed, etc
Is there NNP school training for ECMO?
No, it’s OJT baby
Is PPHN a dz?
No, it’s a complication (physiology that accompanies other acute dz’s)
There are 2 PPHN’s. What are they?
- That of an acutely ill baby
2. That of the damaged, growing lung (BPD, CLD–>pulm arteries don’t grow, blood vessels damaged)
PPHN is caused by primary a primary dz process (3 types). Name them.
- Lung (MAS, RDS, pneumonia, lung hypoplasia)
- Pulmonary vascular (idiopathic)
- Cardiac dysfunction
What is the most likely cause of PPHN?
MAS
Can Trisomy 21 cause PPHN?
Yes, due to clamping down of pulmonary arteries
What b/p does PPHN refer to?
B/P in the lungs.
It does not mean when or what the cause is.
PPHN of the newborn has marked what? (3)
Pulmonary HTN
Vasolability
Hypoxemia (from extrapulmonary R->L shunting at FO or DA—skips the lung)
What is the incidence of PPHN?
2 : 1000 live births
What is the clinical presentation of PPHN
Labile hypoxemia
What are the clinical signs of PPHN?
Tachypnea, Retractions
RDS
Progressive Cyanosis
-all signs of underlying lung dz
When would you think about PPHN as your dx?
When oxygenation is out of proportion to everything else.
Can ventilate, can’t oxygenate
What are some common threads in PPHN?
- Elevated Pulmonary vascular resistance
- arteries either constricted or mal-formed - Pulmonary vasoconstriction or maldevelopment
- Altered vascular reactivity
When might we see mal-developed pulmonary arteries in a 23 wkr?
BPD, they develop their lungs in front of us.
Poor nutrition does not make good lungs
Altered vascular reactivity results in high pulmonary pressure which may lead to?
R->L shunting across FO or DA Tricuspid regurgitation (most anterior valve)
What signs will you see in an baby w/PPHN with altered vascular reactivity?
Blue baby w/Big Murmur
you will think it’s cyanotic heart dz
Is a grade 3/6 murmur common in PPHN babies?
Why or why not?
Yes
b/c the R heart has difficulty pumping into the pulmonary circulation, it flows backwards against tricuspid valve = murmur
Changes in PVR depend almost entirely on changes in what?
Vessel Radius
-it doesn’t take much change in radius to make b/p in blood vessel sky rocket.
What is the path of Fetal blood flow?
Placenta->Umb Vein->DV->RA->most through PFO->LA->LV->Aorta->Brain->RA->RV->(93% to placenta, 7% to lungs)
- kidney, bowel, skin get left overs
- less w/coarctation (that’s why it happens, less flow there in utero)
Only __% of combined CO goes to the lungs and when stressed can be __%
Where is blood sent instead?
7%
1%
To the placenta
What is the goal of blood flow during transition from R heart to the lungs?
100%
What causes hypoxia in PPHN?
What does this do?
Extrapulmonary shunt (R->L across fetal channels: FO/DA) Causes them to clamp down and send more blood to "placenta"-which is not there- and diverts blood from the lungs **they remember and repeat what they did in utero when stressed**
PPHN is a vicious cycle of?
It is set up by what?
So what’s important?
Blueness
The intrauterine environment, the more stressed->the more PPHN
A good HX!
Would you worry about giving PGE to a baby whom you don’t know is in cyanotic heart Dz or PPHN?
No, you’ll save his life
Won’t hurt him unless you can’t ventilate them (PGE can cause Apnea)
cAMP is the “ “ making vessels vasodilate
cAMP is the “boss”
Flolan is a potent what?
Vasodilator
Is Milrinone a first line drug for PPHN?
Why or why not?
No
Need to have good Systemic B/P (it causes SVR to drop)
If you are trying to differentiate PPHN, and note a difference in R. Upper extremity sat vs lower extremity sats, besides PPHN, what could this be?
Coarctation
Aortic interruption
How can you dx PPHN? (5)
Hyperoxia test Differnetial SaO2 or PaO2 Ventilation or Hyperventilation Echocardiogram Cardiac cath (rare)
What is the gold standard to dx PPHN?
Echocardiogram
What 3 organs does oxygenation in the NB depend on?
- Lungs (adequate FRC)
- Heart (pump blood to lungs)
- Pulmonary Arteries (allow blood to enter lungs)
