Only about one in three victims of cardiac arrest receives cardiopulmonary resuscitation from bystanders, studies suggest. Passersby might be reluctant to provide mouth-to-mouth resuscitation because they're afraid of catching a disease. Since some CPR is better than none at all, the American Heart Association's guidelines recommend that bystanders who are unwilling or unable to give rescue breaths call for help and at least start chest compressions. That helps because oxygen in the lungs can last for several minutes. Exceptions include children and drowning or electrocution victims in cardiac arrest. The heart association says they require full CPR with rescue breaths.