Which of the following actions should you avoid when performing CPR on someone?

Checking for a pulse too frequently during CPR can disrupt the flow of chest compressions and the overall effectiveness of the resuscitation effort. When performing CPR, the focus should be on providing continuous and effective chest compressions to maintain blood circulation until professional help arrives or the victim shows signs of recovery. Frequent pauses to check for a pulse can hinder this critical process and may lead to a decrease in the chances of survival. Instead, CPR guidelines recommend that rescuers only check for a pulse after a significant period of providing compressions and ventilations, typically after every 2 minutes in a professional setting or when an Automated External Defibrillator (AED) is available and can take over the assessment.

The other actions listed, such as using an AED, changing positions infrequently, and monitoring the breathing status, are generally important and may be necessary during CPR. Using an AED can greatly enhance the chances of survival, while consistent positioning and monitoring of breathing provide important information about the victim's condition during the resuscitation process.