My Baby Is Blue and Has a Plastic Heart

[bleve]

As an EMTB I would call for ALS if I was on a bls truck that day and rapid transport to the childrens hospital or closest appropriate facility with a pediatric cardiologist. I want to say maybe blow by O2 via venturi at a low FiO2 I would be cautious

I am very interested to see the correct answer

Edited December 12, 2011 by bleve

[BEorP]

Looks like the OP hasn't had a chance to come back to give us all the final answer. From what I can tell, entity hit on it in a post earlier on:

found some info on http://emedicine.med...treatment#a1127 if anyone wants to read up on it a bit..

edit: this is too complex for my head right now so according to the above, increased O2 for these kids might not be the best thing for them because it will further decrease pulmonary vascular resistance / increase pulmonary blood flow.. so maybe it will be trying to find a balance of the correct O2 levels / not necessarily giving 100% o2?

From the link provided in that post, the key line seems to be:

"In the patient with hypoplastic left heart syndrome, decreased pulmonary vascular resistance causes increased pulmonary blood flow and an undesirable obligatory decrease in systemic blood flow."

Let's go back a bit. In most tissues, hypoxia leads to vasodilation. This makes sense, since if your tissues are hypoxic it would be good to increase the blood flow to get more oxygen to them. The exception to this is in the lungs. In areas of good oxygen supply, it makes sense to vasodilate to be able to take up more of that wonderful oxygen. In areas with poor oxygen supply, it makes sense to vasoconstrict so more blood will be directed to the areas with more oxygen to be taken up.

Now to think back to our current patient's heart for a moment. Due to the original condition, their left ventricle is no good. Thanks to the Norwood procedure, their right ventricle is pumping systemically. Normally the right ventricle only has to pump blood to the lungs, not the entire body, so it is working a lot harder. If the patient gets too much oxygen, that will get rid of the hypoxic vasoconstriction in the lungs. The vasodilation in the lungs means that there will be more flow in the lungs and essentially less blood for around the rest of the body. (I would guess that the kid would have a more difficult time compensating for this distributive issue since their right ventricle is punching above its weight to begin with.)

Someone also asked what O2 sat would be expected for a patient like this, the link above says:

"...most infants should remain in room air with acceptable oxygen saturation (pulse oximeter) in the low 70s."

In terms of actually titrating oxygen, I think this point was made but it never hurts to re-state it. As bleve suggested, a venturi is really the way to control the FiO2 that we are administering to a patient (though I don't expect that most ambulances have those). Remember that the FiO2 is the percentage of oxygen that a patient is receiving. If you are using a non-rebreather, the patient will always be breathing primarily pure oxygen from the reservoir bag so the FiO2 will be near 100%. Changing your flow rate from 15 LPM to 10 LPM (assuming the reservoir bag continues to remain inflated) will not change the FiO2.

Hopefully that helps to answer some questions for those who were left wondering. I really don't know anything more about any of this than what I've been able to read online since seeing this thread so hopefully people will jump in if I have been inaccurate in anything I've written. And hopefully when the OP has a chance they will be able to pop by and fill us all in on the final answer.

[Aussieaid]

First can you tell us whether by the child having had the Norwood procedure, do you mean the BT shunt or the Bi-directional Glenn, which by age 6 months this child should have had? This will make some difference in the treatment of the child.

After a HLHS baby has had the first operation, the BT shunt, giving oxygen no longer becomes a problem. The only blood flow to the lungs after the BT shunt (Stage I) surgery is through the shunt and you are not at risk of flooding the lungs with the size of those conduits unless for some reason they put in too large of one. If that was the case they would not have left the hospital, as it would have caused problems immediately. They usually close the PDA with this surgery as well so the body is not dependent on it.

When the child is first born with HLHS the only outflow from the heart is through the one outlet (usually) which is the Pulmonary Artery. The only significant blood flow to the body is through the PDA. Normally the lungs have a lower resistance level (PVR) than the systemic perfusion (SVR) so if you reduce the resistance in the lungs with oxygen (causes vasodilation in the lungs) you will increase the blood flow to the lungs, thereby "flooding" them and shunt the blood away from the higher pressure of the systemic circulation and the body.

With the first stage of the Norwood procedure they place a conduit from either the subclavian artery or more commonly now, directly from the single functional ventricle (RV in this case) and connect it to the Pulmonary artery. This supplies the blood flow to the lungs. The aorta and the pulmonary artery are joined together to create a neo-aorta that pumps the majority of the blood directly to the body.

As was stated, you will never achieve 100% because you are mixing arterial and venous blood in the systemic circulation. If they are lower than their "normal" oxygen saturations then they do need oxygen and there is more concern for withholding it than giving it.

The three main causes for lower saturations along with the tachycardia in this baby are possible stenosis or blockage of the conduit, sepsis or CHF. CHF in this baby is not going to cause the usual wet lungs because if the heart is not pumping hard enough it is not going to be getting enough forward flow to get blood to the rest of the body let alone to the lungs. Cardiac babies/children can turn septic in the blink of an eye from the tiniest thing and they deteriorate fast. They don't always have a fever either although the lack of one would make me think more of a cardiac problem first.

Why I asked what stage Norwood they are, is because if they have had the Glenn Procedure they could also develop Superior Vena Cava syndrome in which case sitting them upright and giving them oxygen are exactly what you would need to do. This facilitates the flow of blood into the lungs with the help of gravity and by reducing the pulmonary vascular resistance.

Treatment plan for this baby:

1. Oxygen to get their sats at least to their normal level. I would be putting on a mask or at least providing blow by as best you can.

2. IV. If they start to decompensate on you because they are septic or completely block off their shunt you need access already in place.

3. HOB elevated and keep patient as calm as possible.

4. I would be tempted to head towards the Pediatric facility and the specialized care but be ready to divert at any signs of further deterioration. A lot of adult hospitals are simply clueless with how to treat congenital defects and can sometimes do more harm then good. However I would not blame anyone for heading straight to the closest facility.

Rough guidelines for SpO2 goals with HLHS are:

Before Norwood stage I: 70's % (preferably mid 70's) (Room air to hypoxic ventilation ~ 17% FiO2 is used generally).

After Norwood: mid 70's-mid 80's

After Glenn Procedure: mid 80's to low 90's

After Fontan Procedure: Normal (>95%)