In virtually all cases where a person has been involved in a diving accident, whether accidental or not, there will be an emergency breathing requirement. There are essentially two methods for delivering oxygen to the breathing airways during an emergency situation: mask inflation and face mask ventilation. Understanding the benefits and limitations of both methods is important for diving instructors and students.
Using an EPSAP or positive air pressure device, along with either a bag-type or pocket mask, can help overcome some of these difficulties and increase the survival rate of those who need emergency oxygen. The majority of people who suffer sudden resuscitation masks cardiac arrest will receive CPR from an EMS provider, even if they are not equipped with resuscitation masks or other types of masks. The reasons for this are that they are designed to give the best possible outcomes and to avoid unnecessary delays in treating life-threatening emergencies.