Abstract Body (Do not enter title and authors here): Background:
In-flight cardiac arrest (IFCA) is unique due to restricted access to equipment, healthcare providers, and isolated location in the air. This review aimed to explore the complexities surrounding IFCA on commercial flights, including the prevalence, incidence, and risk factors of IFCA and the effectiveness of automated external defibrillators (AED).

Methods/Results:
A narrative review of the literature was conducted on MEDLINE, PubMed, EMBASE, and Google Scholar. Literature searches were completed with Medical Subject Headings (MeSH), Emtree terminology, and appropriate keywords. The applied terms included “sudden cardiac arrest” OR “sudden cardiac death” OR “cardiac arrest, out of hospital” OR “cardiopulmonary resuscitation” OR “defibrillators” and a combination of “aircraft” OR “aviation”.

IFCA accounts for approximately 0.3% of all in-flight emergencies yet is responsible for up to 86% of all in-flight deaths. The most recent literature shows an overall survival rate from IFCA of 44%; with shockable and non-shockable rhythm survival at 53% and 35%, respectively. Table 1 summarizes reports of IFCA incidence and survival. The most impactful risk factors for IFCA included male sex (79%) and past cardiac history (48.5%). Age was not found to be a significant predictor of IFCA. Thought to be due to in-flight immobility and venous stasis, pulmonary embolisms are reportedly responsible for 2% of IFCA.

AEDs have been mandated on all commercial flights with at least 1 trained attendant in the US since 2004, however, they are only recommended in many parts of the world. A study analyzing the emergency medical equipment of European airlines showed that only 65% have provided an AED for their aircraft. Studies have shown a survival of IFCA to hospital admission of up to 36% in patients that received a shock from an AED compared to 6% without an AED. Even in non-shockable rhythms, 76% of AED applications were used for monitoring purposes and assisted with ongoing treatment.

Conclusion:
IFCA remains a rare yet highly fatal event that is associated with male sex, past cardiac history, and pulmonary embolism risk. Availability of AEDs and trained personnel are critical factors to treat patients presenting with IFCA.