EMS Protocol of the Week - Non-Traumatic Cardiac Arrest and Severe Bradycardia (Pediatric)

Pediatric cardiac arrests are high stress scenarios in the best of times, so you can imagine how much more taxing they may be in the out-of-hospital setting, with even fewer resources. Keeping things heavily protocolled may be beneficial in these cases, giving EMS a fixed task list to complete to help work through all the chaos of the situation.

We’ve got a few key differences between the pediatric cardiac arrest protocol (which includes all arrest rhythms) and the adult counterparts we just covered. One is the increased emphasis on ventilator support and appropriate CPR at the CFR level, particularly given the heavy respiratory component of most pediatric arrests. Two is the increased priority of initiating transport at the BLS level, as opposed to many adult arrests that are often extensively worked up on the scene. And three is the high detail on defibrillation when indicated, utilizing appropriate Joules (or the lowest setting if unable to administer at the weight-based amount) and pad sizing. Medical Control Options look a little different here compared to the adult protocols, leading off with naloxone (again, considering respiratory etiologies), and following off with options for dextrose, bicarb, magnesium, or crystalloid.

Recognize that most of the paramedic interventions – and hence the calls for MCOs – will take place en route to the hospital, given how early in the protocol BLS is instructed to begin transport. But also realize that these transports can occasionally be prolonged, and they may feel excruciatingly drawn out for the paramedics sitting with the patient in the back of the ambulance, desperate for something to do. So listen closely to their presentations on the OLMC phone, give some real considerations to the meds they’re looking to give, and do what you can to work in tandem with them in those crucial minutes before they hit our ambulance bay. 

That’ll do it for this week, see you all next week, and give some love to www.nycremsco.org or the protocol binder.

Dave

Precordial Thump

Background: Who's hitting what now?

The precordial thump is a popularized emergency medicine procedure performed on medical television shows where the practitioner, slams their fist onto the patient's chest- the patient then wakes up, thanks the doctor, and is then seen walking out of the hospital. 

Of course real life is hardly as fun as it can be on television shows- or is it actually? Though I wasn't there to bear witness, I'm told of two relatively recent examples by my colleagues where they've used the technique. In one event, the patient remained in the same rhythm as they started, and in the second example, the patient was, well, thumped right out of their pulseless Vtach. This POTD is inspired by those events. When should I be considering the precordial thump? How does it work? Does it even work?

First descriptions of this procedure date back to the 1920s. The idea is to deliver enough force with a physical blow to cause coordinate cardiac depolarization, replacing the effect that the shock of defibrillation has on the heart during a shockable rhythm. There are anecdotes of patients with unstable rhythms getting "shocked" out of rhythms when the ambulance they were in ran over a pothole, converting them to sinus rhythm. Most ED physicians would tell you of the low success rates of the thump, but most also seem to know a doc, who knows a doc, with whom the precordial thump saved a life.

Indications: When a patient has a witnessed, monitored, unstable ventricular rhythm when a defibrillator is not immediately available. This namely applies to vfib and pulseless vtach. Depending on who you ask, this could done on a patient who starts decompensating before your eyes and before the defibrillator pads are attached. The blow is thought to generate about 5 joules (or maybe 10 if Q does it). Though hardly the amount of joules delivered by defibrillation, and though unlikely to cause depolarization, it can perhaps be justified if the red cart and pads are just a bit too far away.

How to do it: With the patient supine, position your hand 20-30cm above a patient's chest, and strike with the ulnar surface of your fist onto the lower 1/3 of the patient's chest (bonus points if you say "Live, Dammit!" the moment before the strike). Immediately recoil the fist post strike.

But...does it work?

A quick dive into the literature reveals....its ultimately not very effective, especially when compared to defibrillation. But as with any medical topic with poor supporting literature, the efficacy for the precordial thump are mixed. 

Many case reports, and a study by Pellis et al., showed up to 25% of patients treated with a precordial thump regained ROSC.

Other reports like Koster et al. showed that an initial precordial thump performed immediately at onset of ventricular arrhythmia only terminated the rhythm of 2 out of 153 patients.

Nehme et al showed, in a retrospective study looking at 434 patients with VF or pulseless VT, 103 were first treated with a precordial thump (followed by defibrillation if unsuccessful) and the other 325 were treated immediately with defibrillation. In the thump group, 5/103 patients achieved ROSC , and for the immediate defibrillation group 188/325 achieved ROSC. Additionally, for the thump group, 10 of the 103 shifted into a more dangerous rhythm, such as VF to asystole.

Possible side effects: Though the precordial thump is attempted in the event of an unstable, shockable rhythm, it can precipitate the opposite effect, and send the patient into a more unstable rhythm or asystole. Blunt intrathoracic trauma can also noted, including rib/sternal fractures, and if performed incorrectly, intraabdominal injury such as liver laceration from a broken xiphoid.

Conclusion: Between the precordial thump and defibrillating the patient with an unstable ventricular rhythm, don't even think: defibrillation is vastly superior. If defibrillation is available, use it every time. The precordial thump should NOT delay defibrillation and early CPR. It should NOT be used for unwitnessed out of hospital cardiac arrest. But if access to defibrillation is not immediately accessible, this is another possible tool in your arsenal. Just don't expect it to work very well.

Sources: https://www.ncbi.nlm.nih.gov/books/NBK545174/

https://canadiem.org/the-precordial-thump-good-bad-or-ugly/

https://pubmed.ncbi.nlm.nih.gov/18952350/

POTD: IV Contrast Allergy

 A prior allergic-like reaction to IV iodinated contrast is the most substantial risk factor for a recurrent reaction.

• Up to 35% of patients will experience a recurrence if no premedication prophylaxis is given

• Patients with a prior mild reaction have a very low risk < 1% chance of developing a moderate or severe reaction

 It is currently controversial weather premedicating before a contrast study prevents a recurrent allergic reaction.

• A randomized control study showed that premedication decreased the rate of allergic-like reactions in patients exposed to older high osmolar iodinated contrast. This is not directly related to the current contrast medium that is used.

• Another study was performed that looked at low-osmolar iodinated contrast which we currently use and the study showed decrease in overall rate of allergic type reactions of mild reactions but no there was no statistically significant difference for moderate or severe reactions.

Recommendations:

o   For patients with prior mild reactions (limited hives/itching, limited cutaneous edema, itchy/scratchy throat, nasal congestion, sneezing/conjunctivitis, rhinorrhea) either no premedication prophylaxis or premedication consisting only of an antihistamine prior to planned imaging study.

• Rationale for this:

  • Mild allergic reactions typically do not require medical treatment

  • Patients with mild reactions have a low risk of developing moderate or severe future reactions

  • Effectiveness of steroid prophylaxis for preventing this type of reaction is uncertain

One study actually showed that for patients with prior mild reactions they had less severe reactions when only antihistamine was administered rather than steroid + antihistamine. 

In patients with history of prior moderate or severe prior allergic-type reaction or patients with whom the severity of a prior allergic-type contrast reaction is unknown should receive oral premedication with a corticosteroid and an antihistamine beginning 12 hours prior to expected contrast administration. For patients in need of emergent imaging there are accelerated premedication protocols.

General Guidelines at MMC:

Mild Reaction: no pre-medication

Moderate Reaction: pre-medicate and/or use a different contrast agent

Severe: Do not give contrast unless there has been an attending level discussion with both the primary team and radiology attending that the benfit outweighs the risks and documentation for the reason of administration of contrast is done.

Our Policies at MMC

Adult Routine Premedication:

o   50mg Prednisone PO 13, 7, and 1 hour before administration of contrast

o   50mg diphenhydramine  IV/PO within 1 hour of the injection

Adult Faster Premedication (no evidence of efficacy at less than 4 hours)

o   200mg hydrocortisone IV every 4 hours prior to administration of IV contrast

o   50mg diphenhydramine  IV/PO within 1 hour of the injection

Pediatric Routine Premedication (

o   Prednisone 0.7mg/kg (not to exceed 50mg) PO or IV 13, 7, and.1 hour prior to administration of contrast

o   Diphenhydramine 1mg/kg IV/PO (not to exceed 50mg) within 1 hour of the injection

Pediatric Faster Premedication

o   Hydrocortisone 2mg/kg (not to exceed 200mg) IV every 4 hours prior to administration of contrast

o   Diphenhydramine 1mg/kg IV/PO (not to exceed 50mg) within 1 hour of the injection

 The minimum amount of time needed for steroids to be effective based on previous studies is administration of steroid at least 4 hours prior to administration of contrast.

 If you are every unsure the best thing to do is page our radiology colleagues and have a discussion with them. Many institutions have different protocols for premedicating patients for contrast studies so make sure to get familiar with whatever protocol the hospital has. Below is some common standard protocols used at other institutions.

Below are some other common combinations done at other institutions

Prior Mild Contrast Reaction - Premedication Protocol

Adult or Pediatric Patients > 50kg

• No premedication OR

• Premedication with antihistamine

  • Cetirizine (Zyrtec) 10mg by mouth 1 hour prior to imaging

Pediatric Patients < 50kg

• No premedication OR

• Premedication with antihistamine

  • Certerizine (Zyrtec)

    • Children 6 years and above: 10mg by mouth 1 hour prior to study

    • Children 2-5 years: 5mg by mouth 1 hour prior to imaging study

    • Children < 2 years do not use certirizine

Prior Moderate, Severe, or Unknown Severity Contrast Reaction - Premedication Protocol

Adult or Pediatric Patients > 50kg

• Premedication with corticosteroid and antihistamine

• Methylprednisolone (Solu-Medrol) 32mg by mouth 12 hours and 2 hours prior to imaging AND

• Certirizine 10mg by mouth 1 hour prior to study

Pediatric Patients < 50kg

• Premedication with corticosteroid and antihistamine

• Methylprednisolone 1mg/kg (up to 32mg)_by mouth 12 hours and 2 hours prior to imaging  AND

• Certirizine

  • Children 6 years and above: 10mg by mouth 1 hour prior to study

  • Children 2-5 years: 5mg by mouth 1 hour prior to imaging study

  • Children < 2 years do not use certirizine

IV Alternatives for Patients Who CANNOT Take Oral Medications

Adult or Pediatric Patients > 50kg

• Corticosteroid

  • Hydrocortisone 200mg IV 12 hours and 2 hours prior to imaging.

• Antihistamine

  •   Diphenhydramine 50mg IV 1 hour prior to study

Pediatric Patients < 50kg

• Methylprednisolone 1mg/kg (up to 32mg) IV 12 hours and 2 hours prior to imaging

• Diphenhydramine 1mg/kg (up to 50mg) IV 1 hour prior to study

Accelerated Premedication Protocol

Adult or Pediatric Patients > 50kg

• Premedication with corticosteroid and antihistamine

  • Hydrocortisone 200mg IV 5 given 5 hours and 1 hour prior to imaging AND

  • Benadryl 50mg IV given 1 hour prior to imaging study

Pediatric Patients < 50kg

• Premedication with corticosteroid and antihistamine

  • Methylprenisolone 1mg/kg (up to 32mg) IV 5 hours and 1 hour prior to imaging study AND

  • Diphenhydramine 1mg/kg (up to 50mg) IV 1 hour prior to imaging study

 References:

o   https://radiology.ucsf.edu/patient-care/patient-safety/contrast/iodinated#accordion-allergies-and-premedication

https://www.professionalradiology.com/media/documents/ACR%20Premedication%20for%20Contrast%20Allergies%20.pdf