Residents of high-rise buildings had better survival rates from cardiac arrests if they lived on the first few floors, and survival was negligible for people living above the 16th floor, according to a study published in CMAJ (Canadian Medical Association Journal)

"As the number of high-rise buildings continues to increase and as population density rises in major urban centers, it is important to determine the effect of delays to patient care in high-rise buildings on survival after cardiac arrest," writes Ian Drennan, a paramedic with York Region Paramedic Services and a researcher with Rescu, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, with coauthors.

The further a patient with cardiac arrest is from the ground floor, the lower the survival rate. Of 8216 people who had cardiac arrests in private residences and were treated by 911-initiated first responders, 3.8% survived to be discharged from hospital. Of the 5998 (73%) people living below the 3rd floor who had cardiac arrests, 252 (4.2%) survived the arrest, but only 48 (2.6%) of the 1844 people living above the 3rd floor survived. When analyzed floor by floor, the researchers found a survival rate of only 0.9% in those living above the 16th floor (2 of 216) and no survivors (0 of 30) in those living above the 25th floor.

The researchers note that the use of automated external defibrillators (AED) was very low.

The study looked at the interval from arrival of an emergency vehicle to 911-initiated first responders reaching a patient having a cardiac arrest. Other studies, which have also shown poor survival rates, have measured response time between the call to 911 and arrival of an emergency vehicle on scene, but not the time to reach the patient.

While this study was intended to compare the rate of survival to hospital discharge for cardiac arrests that occur on higher versus lower floors of residential buildings, it also highlighted the fact that response times for 911-initiated first responders are traditionally measured from the time a call is received by the 911 dispatch center to when the first emergency vehicle arrives on the scene. But Drennan said this measure does not take into account the time required for 911-initiated first responders to reach the patient after they arrive on the scene and can begin resuscitation.

"The 911 response time, from emergency activation to arrival of first responders on scene, will remain relatively constant, so long as traffic patterns do not change; however, the time from arrival on scene to initial patient contact may increase as more of the population comes to live at or above the third floor," write the authors. "Thus, 911 response time may diminish in importance as a determinant for survival, whereas the time to patient contact may become more important in predicting who lives and who dies after out-of-hospital cardiac arrest."

The researchers outline several solutions to improve time to patient contact, such as giving 911-initiated first responders sole access to elevators for emergency service without public interference, similar to the access of firefighters during a fire; emergency alerts to building staff before arrival of the first responders; and better placement of defibrillators to increase bystander use.

The authors of a related commentary provide possible solutions to help improve survival rates, including CPR/AED training for residents of high-rise apartments, a national online registry of public-access defibrillators linked to first-responder applications, and using smartphones to activate volunteer first responders for patients with cardiac arrest.

"Singapore has a multipronged approach to address high-rise residential out-of-hospital cardiac arrests," writes Associate Professor Marcus Eng Hock Ong, Department of Emergency Medicine, Singapore General Hospital, with coauthors. "A large public campaign is currently underway to enroll residents' committees as first responders and to train one million people over the next five years."

This study received funding from the Canadian Institutes of Health Research and the Heart and Stroke Foundation of Canada.