You are performing cpr on a victim and an assisting responder arrives. which of the following is most appropriate for the assisting responder to do first?

begin giving ventilations to the victim.
call for a change in position to assist with cpr.
check to see whether more advanced medical personnel have been called.
have the first rescuer stop cpr to allow for victim reassessment.

The most appropriate action for the assisting responder to take is to CHECK TO SEE WHETHER MORE ADVANCED MEDICAL PERSONNEL HAVE BEEN CALLED.

Explanation:

Cardiopulmonary Resuscitation (CPR) is an emergency medical technique that is often used to assist those in cardiac arrest pending the time that qualified medical personnel can attend to them. The CPR procedure is a life saving procedure that is made up of series of chest compression and ventilation, which are targeted at keeping the brain functioning pending the time that blood circulation and breathing will be restored.

if two responders are present at the emergency scene, one should perform the CPR while the other call appropriate lines to get the needed emergency medical attention. In the scenario presented in this question, the second responder has to ensure that the necessary needed medical help have been called for.