Wait! Wait! I Am Not Dead Yet!
This is an interesting suggestion, but one that might cause premature termination of CPR 1) in general and 2) especially in settings where venoarterial extracorporeal membrane oxygenation (VA-ECMO) is readily available. First, in general, ultrasound evidence of cardiac standstill does not perfectly predict that CPR will fail. According to a recent meta-analysis, about 10% of patients with cardiac standstill on ultrasound go on to have return of spontaneous circulation (ROSC) (2). Second, as far as we are aware, no one has studied whether patients with cardiac standstill on ultrasound could benefit from VA-ECMO. So long as chest compressions are temporizing cerebral and coronary perfusion (e.g., end-tidal CO2 > 10 mm Hg and arterial relaxation pressure > 20 mm Hg (3)), CPR may be justifiable indefinitely if VA-ECMO is readily available and the patient is eligible to receive it.
This idea has support in the latest American Heart Association guidelines on Advanced Cardiac Life Support (4). The guidelines suggest that VA-ECMO “may be considered for select patients for whom the suspected etiology of the cardiac arrest is potentially reversible.” Of course, determining whether a cause of arrest is reversible or not during active resuscitation is not always possible, so it is sensible to presume a reversible cause exists so long as the patient meets VA-ECMO eligibility criteria, especially since 10% of patients with “cardiac standstill” seem to develop ROSC during CPR.
Notably, VA-ECMO is becoming widely available in developed countries and even in remote regions of the United States thanks to the increasing mobility of ECMO teams deployed by academic medical centers (5). Furthermore, in a study conducted over a decade ago (early in the ECMO era), about one third of patients who received VA-ECMO after a prolonged course of CPR (mean, ≈50 min) survived to long-term follow-up, 95% of them without significant neurologic impairment (6).
The studies cited by Levitov et al (1) seem not to have considered VA-ECMO an option in cardiac arrest. We believe that the decision to terminate CPR should factor in both the availability of and the patient’s eligibility for VA-ECMO, among other factors. Though we agree that bedside ultrasound can be hugely helpful in identifying rapidly reversible causes of arrest, it may be hazardous to use the data to terminate CPR, especially in a world where VA-ECMO is increasingly available.
So if the heart is standing still on ultrasound, hold off on the wheel barrel! If the patient could possibly have a reversible condition, we suggest continuing CPR.