Pre-arrival Instructions Effect on Bystander Cardiopulmonary Resuscitation (CPR).

The City of Milwaukee and surrounding communities combine to form Milwaukee County covering 241 square miles and serving approximately 959,521 people. Milwaukee County includes 19 separate municipalities. Community demographics and other characteristics have remained largely stable for the past decade.

The study will take place in Milwaukee County from 2009 - 2013 in the communities providing Cardiopulmonary Resuscitation (CPR) pre-arrival instructions: West Allis and Oak Creek.

In Milwaukee County Basic Live Support (BLS) shall be started on all patients in cardiac arrest with the exception of victims with: decapitation; rigor mortis; evidence of tissue decomposition; dependent lividity; presence of a valid Do-Not-Resuscitate (DNR) or Physician Orders for Life-Sustaining Treatment (POLST); fire victim with full thickness burns to 90% or greater body surface area; hypothermic patients with signs of frozen tissue, rigid airway, ice formation in mouth, or chest noncompliant for Cardiopulmonary Resuscitation (CPR). The system standard is: Cardiopulmonary Resuscitation (CPR) will be provided whenever patient is pulseless; compressions at least 100/minute; hands on chest more than 75% of time; minimum compression depth of 2 inches in adults 75% of the time.

Therefore, the investigators will analyze data to assess how Cardiopulmonary Resuscitation (CPR) pre-arrival instructions may have affected the probability of receiving bystander Cardiopulmonary Resuscitation (CPR).

Inclusion criteria

• Patients 21 years old or older
• Presumed cardiac origin as indicated on the Milwaukee County Emergency Medical Services (MCEMS) report
• Non-Emergency Medical Services (EMS) witnessed arrest

Exclusion criteria

• Patients younger than 21 years old
• Patients who are "obviously dead" (decomposition, rigor mortis, decapitation, or other)
• Trauma victims, including hanging and burns
• Patients with cardiac arrests clearly of other non-cardiac origin including drug overdose, carbon monoxide poisoning, drowning, exsanguination, electrocution, asphyxia, hypoxia related to respiratory disease, cerebrovascular accident and documented terminal illness
• Patients determined to be a do-not-resuscitate (DNR) upon arrival of Emergency Medical Services (EMS) providers
• Cardiopulmonary Resuscitation (CPR) by someone other than Emergency Medical Services (EMS) who is a trained first responder or health care provider with a predetermined duty to provide care.