Hands-only cardiopulmonary resuscitation is recommended by the American Heart Association, but it may not be the best way to save lives if more sophisticated medical care is slow in coming, according to a review of recent research.

Long-term care providers have faced scrutiny for their CPR policies following the death of a woman at a Brookdale Senior Living facility in March. A 911 recording captured an employee’s refusal to give the resident CPR, launching an international debate about “do not resuscitate” orders and the effectiveness of CPR.

According to 2010 guidelines from the AHA, doing hands-only or compression-only CPR may save more lives than CPR with mouth-to-mouth resuscitation. However, this may only be true when emergency responders arrive on the scene quickly, according to University of Toronto researcher Aaron Orkin, M.D.

After reviewing 10 studies, Orkin found some evidence that mouth-to-mouth improved survival odds for people who had to wait 15 minutes or longer for an ambulance. This suggests that CPR guidelines for rural or isolated locations — or urban locations with long wait times for ambulances — should mean mouth-to-mouth, Orkin said.

The findings appear in the Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine.