Date Published

April 13, 2017

Updated For

ALS PCS Version ALS PCS Version 5.2


Question: While enroute to the emergency department with a VSA patient, if your patient presents in shockable rhythm (either new, or still in a shockable rhythm), can we continue to shock the patient without pulling over? My understanding of the reason for stopping was because we used to use semi-automated systems, and we did not want false interpretations based on artifact. But, if we are now interpreting the rhythm, and determine that it is a shockable rhythm, not artifact while in transit, shouldn't we be shocking?

The OBHG companion document states to stop when enroute using semi-automated system, no wording on manual defibrillation.


Transporting a patient code 4 to the hospital is anything but a smooth ride. Paramedics monitor and interpret cardiac rhythms in a moving ambulance as part of their practice. This is difficult to do because motion artifact frequently occurs and this affects the interpretation of the ECG signal. There are numerous causes for artifact on the monitor. Some of these are ambulance movement, seizure activity, patient movement, and even isolated muscle contractions such as shivering or anxiety. Most defibrillator manufacturers advise, in their product manual, to avoid analyzing the rhythm while in a moving vehicle. They comment that motion artifact may affect the ECG signal, and potentially lead to false identification of either shockable or non-shockable rhythms. When you manually interpret the rhythm, you are essentially looking at the same information that the computer in semi-automated or fully automated formats would see. There are also safety concerns of delivering electricity in a moving truck, swaying side to side, sudden decelerations and bumps could render team members to be thrown into the shock zone, even if properly restrained. Safety of our paramedics, and first responders needs to be respected.

It is therefore the direction from Base Hospital to pull over and analyze the rhythm with the vehicle at rest if a paramedic thinks a critical rhythm change has occurred. This prevents movement artifact from confusing the reading of the rhythm and prevents shocking a patient when it is not indicated.



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