Date: August 12th, 2021

Reference: Daya et al. Survival After Intravenous Versus Intraosseous Amiodarone, Lidocaine, or Placebo in Out-of-Hospital Shock-Refractory Cardiac Arrest. Circulation 2020

Guest Skeptic: Missy Carter is a PA practicing in emergency medicine in the Seattle area and an adjunct faculty member with the Tacoma Community College paramedic program. Missy is also now the director for Difficult Airway EMS course in Washington State

Case: An EMS crew arrives to your emergency department (ED) with a 58-year-old female who suffered a witnessed ventricular fibrillation (VF) out-of-hospital cardiac arrest (OHCA). They performed high-quality CPR and shocked the patient twice before giving amiodarone via intraosseous (IO). After giving hand off the medic tells you she had difficulty finding intravenous (IV) access and went straight to an IO. She wonders if she should have spent more time on scene trying to get the IV versus the tibial IO she has in place.

Background: We have covered OHCA multiple times on the SGEM. This has included the classic paper from Legend of EM Dr. Ian Stiell on BLS vs. ACLS (SGEM#64), the use of mechanical CPR (SGEM#136), and pre-hospital hypothermia (SGEM#183).

The issue of amiodarone vs lidocaine has also been covered on SGEM#162. This was the ALPS randomized control trial published in NEJM 2016. The bottom line from that SGEM critical appraisal was that neither amiodarone or lidocaine were likely to provide a clinically important benefit in adult OHCA patients with refractory VF or pulseless ventricular tachycardia.

We did do an episode on IO vs IV access for OHCA (SGEM#231). This was a critical appraisal of an observational study published in Annals of EM (Kawano et al 2018). The key result was that significantly fewer patients had a favorable neurologic outcome in the IO group compared to the IV group. However, we must be careful not to over-interpret observational data. There could have been unmeasured confounders that explained the difference between the two groups.

In recent years there has been an effort to lower the cognitive load in the pre-hospital setting and focus resources on the interventions that positively effect patient outcomes. There has been a trend to place supraglottic devices over intubation with some evidence to support this move (SGEM#247).  Another trend is to use IO access over IV access to free up pre-hospital providers to focus on more meaningful interventions.

Clinical Question: Does it matter if you give antiarrhythmic medications via IV or IO route in OHCA?

Reference: Daya et al. Survival After Intravenous Versus Intraosseous Amiodarone, Lidocaine, or Placebo in Out-of-Hospital Shock-Refractory Cardiac Arrest. Circulation 2020

* Population: Adult patients with non-traumatic out-of-hospital cardiac arrest and shock refractory ventricular fibrillation or pulseless ventricular tachycardia after one or more shocks anytime during resuscitation.

* Excluded: Patients who had already received open-label intravenous lidocaine or amiodarone during resuscitation or had known hypersensitivity to these drugs