The First responder Airway & Compression rate Trial (FACT) Study will address basic life support (BLS) treatments administered by Emergency Medical Services (EMS) first responders to patients who suffer a sudden circulatory (pulseless) collapse, referred to as sudden out-of-hospital cardiac arrest (SCA). The investigators propose a randomized controlled trial among persons who suffer SCA to compare these two rescue breathing approaches (standard Bag Valve Mask vs i-gel) along with evaluating a more precise chest compression rate within the range of 100-120 compressions per minute during CPR. Importantly, each of these treatments fall within established resuscitation guidelines and are already administered as part of standard care in clinical practice. Thus this proposed trial will essentially be comparing one standard-of-care treatment against another standard-of-care treatment.

The study will address two primary aims:

Aim 1: To compare survival to hospital discharge between SCA patients randomized to BVM versus the i-gel for rescue breathing. The hypothesis is that treatment with i-gel will result in a higher rate of survival to hospital discharge than BVM.

Aim 2: To compare survival to hospital discharge between SCA patients randomized to chest compression rates of 100 versus 110 versus 120 per minute. The hypothesis is that treatment with 100 chest compressions per minute will result in a higher rate of survival to hospital discharge than compression rates of 110 or 120 per minute.

The First responder Airway & Compression rate Trial (FACT) Study will address basic life support (BLS) treatments administered by EMS first responders to patients who suffer a sudden circulatory (pulseless) collapse, referred to as sudden out-of-hospital cardiac arrest (SCA). The current standard of practice for first responder CPR includes chest compressions at a rate of 100-120 compressions per minute combined with rescue breathing using either a bag valve mask (BVM) or a type of oral airway called an i-gel. During rescue breathing with a BVM, a mask is attached to a breathing bag and placed over the patient's face. The BVM provides oxygen and clears carbon dioxide out of the lungs by blowing air through the patient's mouth. Alternatively, the i-gel consists of a short tube which is inserted in the back of the patient's throat. This tube blows oxygen more directly into the lungs, bypassing the mouth itself. Each of these breathing methods is considered standard of care treatment by EMS first responders. Standard of care means each method is commonly used to treat patients in cardiac arrest and is performed regularly, depending upon the community in which the cardiac arrest has occurred. The other component of CPR is chest compressions. The American Heart Association has recommended a chest compression rate during CPR of between 100-120 compressions per minute, but has not specified an ideal exact compression rate within this range. Scientific studies in both animals and clinical studies have shown that these different standard-of-care approaches to ventilation and the compression rate can produce different physiologic effects (such as the adequacy of rescue breathing and blood flow) that could impact clinical outcome. The investigators propose a randomized controlled trial among persons who suffer SCA to compare these two rescue breathing approaches along with evaluating a more precise chest compression rate within the range of 100-120 compressions per minute during CPR. Importantly, each of these treatments fall within established resuscitation guidelines and are already administered as part of standard care in clinical practice. Thus this proposed trial will essentially be comparing one standard-of-care treatment against another standard-of-care treatment.

The study will address two primary aims:

Aim 1: To compare survival to hospital discharge between SCA patients randomized to BVM versus the i-gel for rescue breathing. The hypothesis is that treatment with i-gel will result in a higher rate of survival to hospital discharge than BVM.

Aim 2: To compare survival to hospital discharge between SCA patients randomized to chest compression rates of 100 versus 110 versus 120 per minute. The hypothesis is that treatment with 100 chest compressions per minute will result in a higher rate of survival to hospital discharge than compression rates of 110 or 120 per minute.

Inclusion Criteria:

• Adults suffering out-of-hospital non-traumatic SCA in Seattle and greater King County in whom resuscitation will be attempted by first responding EMS personnel.

Exclusion Criteria:

• if advanced paramedic providers are first on-scene and have already initiated advanced life support (ALS) procedures,
• a written advance directive (do not attempt resuscitation orders),
• traumatic arrest (blunt, penetrating, burn),
• known prisoner,
• known pregnancy,
• other protected populations (pediatrics),
• pre-existing tracheostomy,
• recipients of mechanical ventilator support, or
• presence of an "opt out" bracelet to not be enrolled in clinical trials.