Considerations for Resuscitation
If someone’s heart stops, and the First Aider is concerned they may have had respiratory symptoms, it is at the individual's discretion to perform or not perform mouth-to-mouth breaths based on personal risk threshold. It’s still important to call emergency medical services and find an AED. If the individual chooses to perform breaths, they should use a barrier device, such as a pocket mask. Performing the breaths/ventilations always creates the potential for personal infection/contamination, which can be mitigated with the use of a pocket mask with a one-way valve to help protect themselves.
Reference www.redcross.ca