Code Applications: Putting Your Smartphone To Work


Author: William Ford, MD (EM Resident Physician, PGY-2, NUEM) // Edited by: Joshua Zimmerman, MD (EM Resident Physician, PGY-4, NUEM)

Citation: [Peer-Reviewed, Web Publication] Ford W, Zimmerman J (2016, August 16). Code Applications: Putting Your Smartphone To Work [NUEM Blog]. Retrieved from

The patient has lost pulses.  Begin compressions.

How I feel during stress. 

Prior to my first high-level EMS arrival, my hands were shaking as I double-checked the airway equipment.  I couldn’t untangle the nasal cannula and dropped it to the ground.  This does not bode well, I thought.  EMS would be rolling the patient through the doorway in less than 3 minutes.  

My senior resident noticed my frantic triple- then quadruple-checks and put a hand on my shoulder.  “Ford, have you read the House of God?”  What the hell?  I can’t even remember my own name right now.  I might throw up.  EMS ETA in 2 minutes.  “At a cardiac arrest, the first procedure is to take your own pulse.”  I took a deep breath and counted my pulse for 15 seconds. I struggled to multiply 35 by 4, then realized that my heart rate was 140.

The lesson I learned from what would become the first of many such critical situations is that too much stress can turn simple tasks into insurmountable challenges. Yerkes and Dodson pioneered the concept that there is an optimal level of arousal for best performance.  When stimuli is lacking or is too intense, performance suffers [4].  In the previous example, I had moved too far to the right of the curve pictured below.


Kreutzer, Jeffrey S., Bruce Caplan, and John DeLuca. "Yerkes–Dodson Law." Encyclopedia of Clinical Neuropsychology. New York: Springer, 2011. 2737-738. Web.


Many experienced emergency physicians fall victim to their own confidence.  We have been there and done that and become somewhat blasé about cardiac arrests and think our practice can never fall off that curve.  However, the impact of stress on performance may readily be observed with chest compressions during CPR. Compression rates can vary widely in cardiac arrests [1], and rates that are too fast or too slow decrease the likelihood of getting return of spontaneous circulation (ROSC) [1,2]. Several small studies have shown that metronomes improve compliance with recommended compression rates [3,5,6].  By focusing the individual on a specific stimulus and reducing the cognitive load, we may be able to better target the optimal level of arousal needed to reach the ideal beats per minute.

Smartphone application use during cardiac arrest has the potential to provide what is termed cognitive offloading which is necessary for optimal care in medical emergencies. In general, cognitive offloading refers to relieving some of the active processes occurring in your brain that are contributing to a heightened (and possibly detrimental) arousal level. Some strategies that have been suggested for cognitive offloading include standardization (algorithm for cardiac arrest, crash carts), preparation (mock code), checklists (intubation checklist), and pre-made decision points/triggers ("see A, do B"). In theory, smartphone applications would provide cognitive offloading from cues, via sounds and visual guidance, to relieve the code leader of unnecessary cognitive burden. To examine this, I downloaded and used 3 different free iPhone applications in both real and simulated ACLS codes.  Specifically, I was interested in the real-life experience with metronome applications. 

 Disclaimer: I had no affiliation with the developers of these code apps and these opinions represent myself and no one else.

The Applications


Full Code Pro

This was the most versatile of the code apps but at the expense of a busy interface.  The app does allow you to program a set metronome rate for chest compressions, which was my initial goal in seeking out a code app.  It also tracks total code time, time spent performing each round of CPR, time between each shock and dose of epinephrine, as well as a multitude of other medications and code events.  The app has a different setting for each possible ACLS rhythm and keeps an activity log for every action performed.  One big disadvantage:  minimizing the app stops all actions and timers, so users must be careful not to accidentally return to the home screen during the chaos of a code.  All in all, it is the most useful for the ACLS providers who are able to keep their phone in their hand for the duration of the code and exclusively track the events via the app.  It is a useful supplement for those who may not be intimately familiar with the ACLS algorithms and need a reference for the next steps.  For those who need to get in the mix, however, the app has limited utility.


CPR Tempo

This app is considerably more user-friendly than Full Code Pro, though it offers fewer tracking options.  The interface is very familiar to anyone who has played videogames, with cooldown timers for defibrillation, rhythm checks and epinephrine dosing.  It requires simple operation, with one press to start and one to stop, has visual and audio cues, and continues to run in the background even when the app is closed.  The major downfall of this app is the shrill tone for the metronome that caused me to wince 110 times per minute.  The app has great promise but the ability to customize metronome tones would be a welcomed improvement.


Pro Metronome

The final app was originally created for musicians.  It is a simple metronome, but the beauty of the app—especially in contrast to CPR Tempo—is that there are 13 tone options including a snare drum, woodblock, and cowbell.  Unfortunately, this app is limited to regulating the rate of chest compressions and lacks the ability to track code events.  I found it the most useful for my role in code situations.  I was able to press play, put it in my pocket, and forget about it until the code ended.  So, if you are an ACLS provider who needs to be actively involved in a resuscitation, this might be a useful tool to have in your armamentarium.

The Bottom Line

Cognitive load plays a key role in our ability to perform in high stress situations. By utilizing strategies for cognitive offloading, we may be able to improve our ability to make decisions under pressure. While smart phone applications may not be the end-all and be-all for managing chaos, they may provide the necessary structure to enhance team performance. Overall, in my analysis of the smartphone code applications, it seems that each may have their own unique niche. If you are keeping track of every event in a code and are able to have your phone out at all times, the AHA Full Code Pro app is the winner.  For the rest of us, CPR Tempo has the most utility and would be the best if it just had a nicer tone.  Until that changes, Pro Metronome will be my choice for all future code situations.


  1. Abella, B. S. "Chest Compression Rates During Cardiopulmonary Resuscitation Are Suboptimal: A Prospective Study During In-Hospital Cardiac Arrest." Circulation 111.4 (2005): 428-34. Web.
  2. Idris, A. H., D. Guffey, T. P. Aufderheide, S. Brown, L. J. Morrison, P. Nichols, J. Powell, M. Daya, B. L. Bigham, D. L. Atkins, R. Berg, D. Davis, I. Stiell, G. Sopko, and G. Nichol. "Relationship Between Chest Compression Rates and Outcomes From Cardiac Arrest." Circulation125.24 (2012): 3004-012. Web.
  3. Kern, Karl B., Ronald E. Stickney, Leanne Gallison, and Robert E. Smith. "Metronome Improves Compression and Ventilation Rates during CPR on a Manikin in a Randomized Trial." Resuscitation 81.2 (2010): 206-10. Web.
  4. Kreutzer, Jeffrey S., Bruce Caplan, and John DeLuca. "Yerkes–Dodson Law." Encyclopedia of Clinical Neuropsychology. New York: Springer, 2011. 2737-738. Web.
  5. Oh, Je Hyeok, Sang Jin Lee, Sung Eun Kim, Kwang Jung Lee, Ju Won Choe, and Chan Woong Kim. "Effects of Audio Tone Guidance on Performance of CPR in Simulated Cardiac Arrest with an Advanced Airway." Resuscitation 79.2 (2008): 273-77. Web.
  6. Park, S. O., C. K. Hong, D. H. Shin, J. H. Lee, and S. Y. Hwang. "Efficacy of Metronome Sound Guidance via a Phone Speaker during Dispatcher-assisted Compression-only Cardiopulmonary Resuscitation by an Untrained Layperson: A Randomised Controlled Simulation Study Using a Manikin." Emergency Medicine Journal 30.8 (2012): 657-61. Web.