Date: November 6th, 2019

Reference: Lascarrou et al. Targeted Temperature Management for Cardiac Arrest with Nonshockable Rhythm. NEJM Oct 2019

Guest Skeptic: Dr. Laura Melville (@lmelville535) is an emergency physician in Brooklyn, New York, is a part of the New York ACEP Research Committee, ALL NYC EM, and is the NYP-Brooklyn Methodist Resident Research Director.

Case: A 59-year-old woman comes is brought into your emergency department (ED) by EMS in cardiac arrest. She had a witnessed arrest, and CPR was initiated by bystanders. Her initial rhythm in the field was reported as pulseless electrical activity (PEA) by EMS.  The patient achieved return of spontaneous circulation (ROSC) on arrival to the ED.  You call your hyperthermia team to initiate targeted temperature management (TTM), which in your hospital means 33C for 24 hours followed by slow rewarming for 24 hours. Your senior resident asks you “should we really be cooling our patient to 33C, doesn’t the data suggest 36C is just as good? And if she was not in a shockable rhythm at arrest, will she be likely to benefit from this treatment?”  The patient’s family has separately mentioned they heard she might have a better chance of being “normal” if she gets cooled down.  What do you say?  Do you continue with the ICE Code? What do you tell the patient’s family?

Background: We have covered therapeutic hypothermia many times on the SGEM. This has been or out-of-hospital cardiac arrests (OHCA). Therapeutic hypothermia has not been demonstrated to have benefit in the pre-hospital setting (SGEM#54 and SGEM#183).

But two earlier randomized controlled trials (Hypothermia after Cardiac Arrest Study Group 2002 and Bernard et al 2002) showed benefit for good neurologic outcome when TTM was initiated in the hospital after ROSC was achieved.  In those studies, the temperature goal was 32C-34C and 33C respectively.

The SGEM covered the targeted temperature management (TTM) trial published in the NEJM. It showed cooling patients to 33C was not superior to 36C for the primary outcome (SGEM#82). The most recent time we have looked at therapeutic hypothermia was SGEM#199. This was a trial looking to see if there was a neuroprotective effect of hypothermia in patients with status epilepticus. Unfortunately, that study failed to demonstrate a benefit of therapeutic hypothermia for adult patients admitted to the ICU with convulsive status epilepticus.

It seems like TTM is a good example of an intervention that “makes sense” but doesn’t always work. There are many examples like this in the literature where something makes sense from a pathophysiologic standpoint but is not demonstrated to work when properly tested.

Clinical Question: Does therapeutic hypothermia improve survival with good neurologic outcome in patients who achieve ROSC after non-shockable cardiac arrest?

Reference: Lascarrou et al. Targeted Temperature Management for Cardiac Arrest with Nonshockable Rhythm. NEJM Oct 2019

* Population: Adults (18 years and older) with OHCA or IHCA of any cause, with non-shockable rhythm and a Glasgow Coma Scale (GCS) score of 8 or lower.

* Exclusion: No flow time of more than 10 minutes (collapse...