Posted on 08/01/2008

Cardiopulmonary Resuscitation (CPR) involves mimicking two important organs, both of which are required to sustain life. The answer lies in the very term cardiopulmonary. Cardio is derived from the Greek kardia meaning heart or hollow vessel, and pulmonary from the Latin pulmonarius (of the lungs).

Thus CPR quite literally means resuscitation through circulation and breathing. Not just compressions, but ventilations as well. I’m sure you already know how important “pumping and blowing” is— it would be hard not to with all the time and effort spent on training during the last 40 years or so. But the solution to resuscitation is not quite that simple.

How often do bystanders actually start CPR? Do they perform the technique according to American Heart Association (AHA) guidelines? Should they undergo formal training? Is it possible to hurt the victim? Is it best to get air into the lungs before starting compressions? Can you catch something from performing mouth-to-mouth? What if the victim has false teeth or vomitus blocking the airway? Maybe it would be best to wait for the EMTs…

This is an all too familiar story. Unfortunately, victims of sudden cardiac arrest (SCA) often do not survive because the witnesses are unsure and do nothing. See:

But, the victim desperately needs his circulation restored. Without CPR, he will die. Don’t worry about breaths and ratios. Just start the compressions. Immediately. But, call 9-1-1 first!

The dilemma arises in cases of choking, drowning and electrocution. Typically, in those situations the victim stopped breathing first (this is called respiratory arrest), so the lungs need to be filled with air before the circulation can be effective. Should there be two methods of CPR? How would I know which one to perform?

This is becoming more complicated the further we delve into it. Surely we should just stick to the same technique regardless of cause. “Blow AND pump.” That has been the recommended technique for many decades and has been widely taught throughout the world. The problem is that incidence of bystander CPR is unacceptably low, and SCA survival rates are tragic. Many times the people who witness SCA delay or do not commence CPR, because they are afraid. They can’t remember how many breaths or how many compressions. They forget exactly how they’re supposed to hold the head, and have trouble making a good seal with their mouth. And this delay is killing the victim. More training and better instruction might solve the problem.

Or should the technique revised? This is the real dilemma. Change a lifesaving procedure to suit the layperson, or maintain the best possible treatment and ensure it is carried out the correct way? Naturally we have professional opinions to support both proposals. Everyone agrees that compressions are necessary; the dissention appears once the discussion moves onto ventilations. Some believe the breaths can be forgone, others feel they are critical. The research has not yet provided an unequivocal answer. And the qualification as to whether emergency services should also consider changing their practices only exacerbates the issue.

Robert Swor, M.D., Clinical Associate Professor, Department of Emergency Medicine, Royal Oak William Beaumont Hospital, Michigan, finds that people who have conducted CPR training understand the most difficult part is “positioning the airway, getting a good seal, positioning the neck and giving adequate ventilations.” His research data[1] shows that “a minority of bystanders who are CPR trained actually did CPR,” indicating that “either CPR is too complicated or the situation is too emotionally charged for people to respond accordingly.” This point is supported by a study from Boston University School of Medicine[2] which shows that victims of cardiac arrest are more likely to receive CPR when the event is witnessed by bystanders unknown to the victim than if the arrest is witnessed by friends or family. Dr. Swor went on to say, “There is clearly a need to simplify how someone acts in an emergency situation,” and feels this is “the rationale behind hands-only CPR.” If you also take the EMS response time into account, then “there is a window there that the patient can probably survive without supplemental ventilations.”

Further evidence can be found in the frequently cited SOS-KANTO study group report[3]: Cardiac-only resuscitation by bystanders is the preferable approach to resuscitation for adult patients with witnessed out-of-hospital cardiac arrest, especially those with apnea, shockable rhythm, or short periods of untreated arrest. However, there was no evidence for any benefit from the addition of mouth-to-mouth ventilation in any subgroup.

Equally, there is evidence that ventilations are vital to patient outcome. Once critical patients are admitted to hospital, intubation is almost mandatory, and ensures the all important blood oxygen level remains optimal. Standard EMS protocols also require intubation in the absence of respiration.

Rudolph.W. Koster M.D., the European Resuscitation Council[4] spokesperson, believes ventilations are required. His concern is the reliance on the assumption that “…professional help will arrive within four minutes, when the oxygen in the blood is gone without ventilation.” How can a bystander be sure of the local EMS response time? Also, in a highly charged emotional situation they may not be conscious of the duration of CPR. Acknowledging the issue of bystander reluctance, Dr. Koster went on to say, “It may be true that more people will start CPR. But that does not mean that outcomes will be better….” This is an important qualification; return of spontaneous circulation (ROSC) does not guarantee survivability, (defined by hospital discharge rather than restoration of vital signs). Dr. Swor offered some surprising data on the causes of sudden cardiac arrest, that adds to the need for ventilations. Apparently, “…over the last 20 years the incidence of primary V-fib cardiac arrest keeps going down”, and so now pulmonary problems are increasingly found as the cause. It these cases mouth-to mouth is definitely warranted.

Consequently, ventilations during CPR should be considered, and anyone who successfully completes training will be inclined to follow the 30:2 compressions to ventilations ratio (2005 AHA guidelines). But does a bystander need to follow those guidelines as well? That is the question. In the meantime doing something is the best of all. Without it they die.

-Jeremy Whitehead, SCA Foundation

[1] Academic Emergency Medicine. 2006 Jun;13(6):596-601.

[2] Prehospital Emergency Care. 2003 Jul-Sep;7(3):299-302.

[3] Lancet. 2007 Mar 17;369(9565):920-6.

[4] Approximately 700,000 individuals in Europe have an episode of sudden cardiac arrest every year, about twice as many as in the United States. (Eur Heart J. 1997; 18: 1231–1248)