As long as I safely could for as long as they are responding till they can breath on their own, relief arrives, or they are dead.
Until they start breathing again or until help arrives. Otherwise, as long as you physically can.
A breathing barrier device should be used if providing rescue breathing to minimize the risk of disease transmission.
For an Adult, if there are no signs of life, immediately go to CPR. For an Infant or Child, if there is no breathing, but a pulse start rescue breathing; 1 breath every 3 seconds.
During CPR, the chest compressions are applied; during rescue breathing there are no chest compressions used.
If your are not trained in CPR or rescue breathing then you should not be giving rescue breaths as you can injure the victim. The lay rescuer should only provide compressions at a rate of 100 compressions per minute. AHA provides courses to learn CPR/ rescue breathing which are very beneficial.
When a person has stopped breathing and can not breathe on his own, rescue breathing (or Mouth-To-Mouth Resuscitation) is given to try and saved the persons live (in addition to CPR and/or defibrilation).
Agonal breathing will not support life; rescue breathing (or CPR if no pulse) is required.
Causes of collapse for which rescue breathing may be needed are anaphylactic shock, heart attack, and poisoning.
Check to see if they have a pulse, or are breathing. If they have both, no CPR is needed. If they have a pulse but aren't breathing, you can perform rescue breathing only without chest compressions. If they do not have a pulse and aren't breathing, you perform rescue breathing and chest compressions.
If there is a pulse, then perform rescue breathing only.
Check for signs of life when performing rescue breathing on a child every 2 minutes.
You should check for signs of life every two minutes while performing rescue breathing on an adult or child