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ACEP Now: Vol 35 – No 07 – July 2016

ILLUSTRATION/PAUL JUESTRICH; PHOTOs shutterstock.com

Case: A 49-year-old man calls 911 complaining of chest pain and then collapses while on the phone. EMS is dispatched to his high-rise apartment building where he lives on the 15th floor. The paramedics arrive and buzz his apartment but get no response. They try the superintendent’s number, but it goes to voicemail. The paramedics start buzzing apartments until someone lets them into the building. The elevator finally arrives but will not fit all their equipment, so they have to wait for a second one. They get to the apartment and knock, but there’s no answer. One of the paramedics goes back to the lobby to try the superintendent again, who answers. They proceed back to the 15th floor, gain access to the apartment, and find the man VSA (vital signs absent).

Clinical Question: Is there an association between survival of out-of-hospital cardiac arrest (OHCA) and the floor of patient contact?

Background: There are about 325,000 EMS-assessed OHCAs each year in the United States. More than two-thirds of cardiac arrests happen at a home or residence. Of those EMS-treated patients, about one-quarter have an initial shockable rhythm. Survival rate from initial care to discharge from the hospital for adults with OHCA assessed by EMS is around 6 percent.

The American Heart Association CPR & ECC Guidelines describe five steps in chain-of-survival for OHCA:

• Step 1: Recognition and activation of the emergency response system
• Step 2: Immediate high-quality CPR
• Step 3: Rapid defibrillation
• Step 4: Basic and advanced emergency medical services
• Step 5: Advanced life support and post arrest

Relevant Article: Drennan IR, Strum RP, Byers A, et al. Out-of-hospital cardiac arrest in high-rise buildings: delays to patient care and effect on survival. CMAJ. 2016;188(6):413-419.

• Population: Adults with OHCA of not-obvious cause at private locations.
  • Excluded: Children, witnessed arrests by first responders, traumatic arrests, or with another obvious cause or public location.
• Intervention (prognostic factor): On or above the 3rd floor.
• Comparison: Below the 3rd floor.
• Outcome:
  • Primary Outcome: Survival to hospital discharge.
  • Secondary Outcomes: Subgroup analyses.

Authors’ Conclusions: “In high-rise buildings, the survival rate after out-of-hospital cardiac arrest was lower for patients residing on higher floors. Interventions aimed at shortening response times to treatment of cardiac arrest in high-rise buildings may increase survival.”

Key Results: 5,998 patients with OHCA were below the 3rd floor, and 1,844 patients with OHCA were on the 3rd floor or higher. The overall survival to hospital discharge was 3.8 percent.

• The survival rate to hospital discharge for those below the 3rd floor versus those at the 3rd floor or above:
  • 4.2 percent versus 2.6 percent (odds ratio [OR] 0.70; 95 percent CI, 0.50–0.99; P=0.0002).
• Variables associated with lower rates of survival to hospital discharge included:
  • Older age (OR 0.96; 95 percent CI, 0.95–0.97).
  • Male sex (OR 0.72; 95 percent CI, 0.54–0.95).
  • Longer 911 response time (OR 0.86; 95 percent CI, 0.79–0.92).
• Variables associated with higher rates of survival to hospital discharge included:
  • Initial shockable rhythm (OR 10.68; 95 percent CI, 7.98–14.29).
  • Witnessed arrest (OR 2.93; 95 percent CI, 2.16–3.98).
• Survival rate for those above the 16th floor was 0.9 percent (2/216).
• Survival rate was 0 percent for those above the 25th floor (0/30).

EBM Commentary

• This was an observational trial, and only associations can be demonstrated, not causation. Unmeasured confounders could be responsible for the differences found in this study.
• The CPR rate was about 35 percent, but use of an automated external defibrillator (AED) was less than 1 percent. Rapid defibrillation is very important for OHCA patients with initial shockable rhythms. It’s estimated that survival goes down by 7 to 10 percent for each minute of delay to defibrillation.
• This study reports survival to discharge but not survival to discharge in good neurologic condition. This would be a more important patient-oriented outcome.

Bottom Line: To improve the chain of survival, increased bystander CPR is needed along with rapid access to AEDs and the removal of access barriers for first responders.