Are your CPR skills good enough to save a life?

Proper CPR is a key factor in survival from sudden cardiac arrest.1 As a trained CPR/AED responder you should focus on providing high-quality CPR in addition to defibrillation. This means:

•  Push hard (at least 2 in/5 cm depth)
•  Push fast (at least 100/min)
•  Minimize interruptions in compressions
•  Deliver quick rescue breaths

A problem facing communities that are trying to improve survival from SCA is the wide variability in the quality of CPR given by rescuers.2 CPR skills decline quickly and it may be that rescuers do not understand the important relationship of proper CPR and improved survival.3-6

Oxygenated blood: your brain needs it
When the heart stops pumping the brain loses it supply of oxygen. Without a constant supply of oxygen the brainís cells quickly die.

Effective CPR moves oxygenated blood throughout the body. This keeps the brain and other organs alive until the heart can be re-started with a defibrillator. However to be effective you need to do letter-perfect CPR.

Keep up the pressure
Pushing down increases pressure in the chest and forces blood through the body. When the chest then expands up to its resting position it creates a small negative pressure that sucks blood back into the heart. At this point the heart is loaded and is ready for the next compression. This vacuum also promotes blood flow from the brain which in turn results in less resistance to blood flow in the brain. It is this alternating positive and negative pressure from chest compressions that helps circulate blood.

Researchers have studied chest compressions and found most rescuers, including trained professionals, do not push down hard enough or fast enough. Most rescuers push less than 1.5 inches up to 70% of the time.7 Since chest compressions push only about 25% as well as a normal beating heat, you must strive to maximize the effect of chest compressions with proper technique.

Push hard and fast
Compression depth and rate are the key to effective CPR. Not only does this keep brain cells alive, it prolongs the time when a fibrillating heart is receptive to defibrillation. Push hard (at least 2 inches), push fast (at least 100 compressions per minute).

Another important point is to let the chest fully recoil after each chest compression. By allowing the chest to fully expand on the upstroke, the heart can refill with blood more completely. Delivering proper chest compressions is a lot of work.

Minimize interruptions in chest compressions
Another task to master is minimizing the time spent not doing chest compressions. Ideally you will only stop chest compressions for AED analysis and shocking and delivering quick rescue breathes. Researchers have found if you stop chest compressions the negative pressure in the chest goes down considerably. It then takes about a minute of chest compressions to build up enough pressure to circulate blood again.8 Even short pauses cause a loss of negative pressure.

Rescue breaths, if not done properly, can cause several problems. Keep rescue breaths short and with just enough volume to see the chest rise. This helps keep excess air out of the stomach which can cause vomiting. Over-ventilation also reduces return of blood to the heart. Finally, the less time you spend on rescue breaths, the more time you have for chest compressions.

Conclusion
Itís a grim fact that most SCA victims will not liveóless than 10% on average in the US. However, many SCA victims have a better chance of living with high-quality CPR and defibrillation.

The bottom line is: Push hard (at least 2 inches) and fast (at least 100/min) on the chest and minimize interruptions in chest compressions.

Defibrillation and proper CPR play a critical role in survival from sudden cardiac arrest. You have to be confident these skills in order to save a life. Keeping your CPR skills up to standard takes regular practice.

References
1. Meaney, P.A., et al., Cardiopulmonary resuscitation quality: improving cardiac resuscitation outcomes both inside and outside the hospital: a consensus statement from the American Heart Association. Circulation, 2013. 128(4): p. 417-35.

2. Varied quality of CPR among EMS, hospitals hurts survival. American Heart Association website. Accessed 3/18/15 at http://newsroom.heart.org/news/varied-quality-of-cpr-among-ems-hospitals-hurts-survival

3. Weaver FJ, Ramirez AG, Dorfman SB, Raizner AE. Trainee’s retention of cardiopulmonary resuscitation: how quickly they forget. JAMA 1979;241:901—3.

4. Woollard M, Whitfield R, Newcombe RG, Colquhoun M, Vetter N, Chamberlain D. Optimal refresher training intervals for AED and CPR skills: a randomised controlled trial. Resuscitation. 2006 Nov;71(2):237-47.

5. Chamberlain D, Smith A, Woollard M, Colquhoun M, Handley AJ, Leaves S, Kern KB. Trials of teaching methods in basic life support (3): comparison of simulated CPR performance after first training and at 6 months, with a note on the value of re-training. Resuscitation. 2002 May;53(2):179-87.

6. Berden HJ, Bierens JJ, Willems FF, Hendrick JM, Pijls NH, Knape JT. Resuscitation skills of lay public after recent training. Ann Emerg Med. 1994 May;23(5):1003-8.

7. Abella BS, Alvarado JP, Myklebust H, Edelson DP, Barry A, O’Hearn N, Vanden Hoek TL, Becker LB. Quality of Cardiopulmonary Resuscitation During In-Hospital Cardiac Arrest.  JAMA. 2005;293(3):305-310.

8. Yu T, Weil MH, Tang W, Sun S, Klouche K, Povoas H, Bisera J. Adverse outcomes of interrupted precordial compression during automated defibrillation. Circulation. 2002 Jul 16;106(3):368-72.