BehindTheMedspeak: 'New' CPR

In a nod to reality, the medical profession is finally taking a practical position on what CPR should entail when performed by bystanders without medical training, as is usually the case if it happens at all.

Long story short: Forget all the stuff they taught you about rescue breathing and focus on chest compressions — 80 to 100 a minute, forceful enough to depress the breastbone about two inches (ignore the sounds of ribs cracking — that's collateral damage and unavoidable sometimes) and so energy intensive that the average person can't do more than five minutes at a time and remain effective.

Here's Anahad O'Connor's "Really?" column from the April 3, 2007 New York Times Science section, which summarizes the emerging consensus.

The Claim: CPR Requires Mouth-to-Mouth Resuscitation

The Facts: Even people who have never been trained in cardiopulmonary resuscitation know that it involves a series of chest compressions combined with mouth-to-mouth resuscitation.

For years, scientists have questioned whether the mouth-to-mouth part was necessary, saying the focus of CPR should be on chest compression, which keeps blood flowing to vital organs after cardiac arrest.

Last month, a study of more than 4,000 cases of cardiac arrest, the largest on the subject to date, found that patients were more likely to recover without brain damage if their rescuers had focused on chest compressions alone. Published in The Lancet, the study found that 22 percent of people who received chest compressions alone survived with good neurological function, compared with 10 percent who received combination CPR.

Those findings echoed those of a study in The New England Journal of Medicine in 2000. The reason is that in most cases of cardiac arrest, the victim’s body has enough oxygen to keep organs functioning for several minutes. Mouth-to-mouth simply delivers more oxygen, while chest compressions perform the more vital task of pumping blood.

The Bottom Line: Studies suggest that in most CPR, mouth-to-mouth may not be necessary.

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Below, the abstract of the March 17, 2007 Lancet paper cited above.

Cardiopulmonary resuscitation by bystanders with chest compression only (SOS-KANTO): an observational study

Background: Mouth-to-mouth ventilation is a barrier to bystanders doing cardiopulmonary resuscitation (CPR), but few clinical studies have investigated the efficacy of bystander resuscitation by chest compressions without mouth-to-mouth ventilation (cardiac-only resuscitation).

Methods: We did a prospective, multicentre, observational study of patients who had out-of-hospital cardiac arrest. On arrival at the scene, paramedics assessed the technique of bystander resuscitation. The primary endpoint was favourable neurological outcome 30 days after cardiac arrest.

Findings: 4068 adult patients who had out-of-hospital cardiac arrest witnessed by bystanders were included; 439 (11%) received cardiac-only resuscitation from bystanders, 712 (18%) conventional CPR, and 2917 (72%) received no bystander CPR. Any resuscitation attempt was associated with a higher proportion having favourable neurological outcomes than no resuscitation (5·0% vs 2·2%, p<0·0001). Cardiac-only resuscitation resulted in a higher proportion of patients with favourable neurological outcomes than conventional CPR in patients with apnoea (6·2% vs 3·1%; p=0·0195), with shockable rhythm (19·4% vs 11·2%, p=0·041), and with resuscitation that started within 4 min of arrest (10·1% vs 5·1%, p=0·0221). However, there was no evidence for any benefit from the addition of mouth-to-mouth ventilation in any subgroup. The adjusted odds ratio for a favourable neurological outcome after cardiac-only resuscitation was 2·2 (95% CI 1·2–4·2) in patients who received any resuscitation from bystanders.

Interpretation: Cardiac-only resuscitation by bystanders is the preferable approach to resuscitation for adult patients with witnessed out-of-hospital cardiac arrest, especially those with apnoea, shockable rhythm, or short periods of untreated arrest.

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And if there's someone around not doing anything or unable/unwilling to perform chest compressions, have them lift both the victim's feet off the ground, up to the holder's waist level: that autotransfusion of 40% of the blood volume from the legs into the central circulation may be what enables CPR to succeed.