Test your PEDS critical care knowledge

[NotReady4PrimeTime, RN]

This is an offshoot of another thread that strayed far off its path.

I will be posting questions that spring from situations I see on my quaternary level PICU to test your knowledge of critical care topics that apply to children. As we know, children are not small adults and the reasons they are admitted to ICU are very different from those of adults. For example, PICUs see virtually NO life-style related comorbidities such as COPD from a 2 pack-per-day cigarette habit, cardiovascular disease from a 10 Big-Mac-per-week habit or end-stage cirrhosis from a 6-drink-per-day habit. Congenital anomalies, trauma (accidental and non-accidental), metabolic disorders, ingestions and respiratory infections are our biggest offenders.

Question #1:

Name the 4 main treatments for JET (junctional ectopic tachycardia).

[Humbled_Nurse]

janfrn:

Cool thread! I am not a PICU nurse so I have no idea what the answer is, but I enjoy reading the PICU forum because I find it very intellectually stimulating. I am a NICU nurse so I can relate to some of the topics. I would love it the NICU forum started a thread like this. Maybe Steve NNP could start one. Hint, Hint

[NotReady4PrimeTime, RN]

I'm sure no one would mind if you sat in on our little discussion, Humbled. And I can give Steve a little prod if you like. It's been a long time since I worked neonatal but there are lots of things I still remember so you may find me hanging out over there with you!

[NeoPediRN]

I'm going to have to research this one. Medication and cardioversion?

[NotReady4PrimeTime, RN]

Mmm, nope. Well, maybe partly. Cardioversion is definitely not on the list. What medication(s)?

[NeoPediRN]

Adenosine or amiodarone?

[NotReady4PrimeTime, RN]

Adenosine is used for supraventricular tachycardia. Amiodarone isn't usually needed for JET; it has a 6 week half life and JET is a short-lived condition, typically less than 72 hours. It's a side-effect of certain types of cardiac surgery where the surgery has injured the conduction system, causing the pacemaker impulses to arise in the AV junction rather than the SA node. It's usually seen in the infant and toddler population and uncommon in kids over 10 years old.

Anybody else have an idea?

[littleneoRN]

Propafenone, procainamide, or esmolol? Would you use digoxin here?

Hypothermia?

I'm out of my knowledge base here, but a girl can guess.

[NotReady4PrimeTime, RN]

Hypothermia is correct. The drugs are not, at least for post-operative JET. They may have a role in congenital JET, but the incidence of that is very low.

I won't keep you in suspense any longer. The treatments used on our unit and in many other units with CV surgical services are:

1. Sedation +/- neuromuscular blockade

2. Hypothermia

3. Magnesium sulfate

4. Overdrive pacing (atrial)

JET is a self-limiting post-operative complication of certain cardiac surgical procedures; it's also the most serious of the supraventricular dysrhythmias. The underlying cause is unknown but is thought to be related to swelling or inflammation of the tissue at the AV junction as could be seen in ASD stitch closure, high-on-the-septum VSD patch closure, AVSD repair and ToF repair. The incidence in North America is about 6% and is more often seen in younger children and those receiving dopamine infusions. It usually arises in the hours after the patient's admission to the ICU when the child is extremely vulnerable. The AV disassociation that may occur causes a significant decrease in cardiac output; the ECG will reveal a rapid rate (usually under the threshold for SVT, about 180-230) with absent P waves and the patient's hemodynamics will be deranged. CVP and left atrial pressures will be high (atria aren't emptying completely) and arterial BP will be low. Sedation is used to decrease autonomic arousal and lower the intrinsic HR. Hypothermia also slows HR and is a relatively benign treatment with few long-term effects. If the patient begins to shiver when we've gottne them cooled to around 34-35C, they will need neuromuscular blockade to minimize metabolic demand and autonomic arousal. We keep serum magnesium levels artificially at the high end of normal in an effort to avoid dysrhythmias in pretty much all of our CV surgical population so one of the first things we do is draw labs, then without waiting for the results we give a bolus of magnesium sulfate (while the CNA is tracking down the cooling blanket and setting it up :yelclap: ) of 0.1 mL/kg of the 50% solution. If these interventions are not enough the patient may need overdrive atrial pacing. This takes over control of conduction; the pacemaker is set for a higher rate than the patient's then the milli-amperage of the delivered shock and the sensitivity are tweaked until capture is maintained at the lowest possible settings. If all of these interventions fail, a bolus dose of amiodarone will be next. We rarely have to go this far, and only about 1% of the time do we need to continue with an amiodarone infusion.

So how do we know when JET has resolved? In most patients it lasts less than 3 days, but can continue for up to about a week. If sedation, cooling and highish magnesium levels have controlled it, we warm them up. If they stay in sinus rhythm, we let them wake up a bit. If they stay in sinus rhythm, then they're unlikely to revert to JET. If we've had to pace them, we'll pause the pacemaker and assess the underlying rhythm. Once we've got a stable sinus rhythm with the pacemaker off, we warm them, wake them and they're good. By the time they're ready to go to the ward, they don't need the higher mag levels and we stop treating.

Okay. Let's move away from the heart and on to the lungs.

Your patient is a 2 year old who arrives on the unit in status asthmaticus after several hours in the ED and on continuous nebulized albuterol. Which of the following would be an unusual finding?

a. HR 170

b. SpO2 91%

c. serum K+ 4.1

d. pCO2 58

[littleneoRN]

I'd expect the K+ to be a little bit lower. The continuous albuterol nebs are going to drive down your serum potassium, no?

[NotReady4PrimeTime, RN]

Anybody else have a response??

[kessadawn, BSN, RN]

I would expect a lower PCO2 from the tachypnea.