nos-trum. pronunciation: \nos'-trum\. noun. Etymology: Latin, neuter of noster our, ours.
1. a medicine of secret composition recommended by its preparer but usually without scientific proof of its effectiveness.
2. a usually questionable remedy or scheme.
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Sunday, August 1, 2010

STUDY: In CPR You Only Need To Do The Chest Compressions

No rescue breathing?  Just chest compressions for CPR?

My issue of the New England Journal of Medicine this week contains a research study that is causing a stir. 

What's called "bystander CPR" can be effective in saving lives, but the prospect of performing it generates reluctance in some people.  From the start, some don't want to get involved, but those who do face the prospect of putting their mouth over the victim's and breathing into it.

Faced with the necessity to perform rescue breathing, we immediately remember our Mom's adage, "Don't touch that, you don't know where it's been."

Under these circumstances, some victims who might have survived don't because bystanders are not willing to perform the procedure.

A group from Washington State and London decided to make sure that the breathing part was really necessary.  That is, did doing the rescue breathing along with the chest compressions (1) improve survival (as measured by leaving the hospital alive), and (2) reduce neurologic damage (that is, brain damage from the period when it was getting no oxygen)?  The patients were randomized to one technique or the other by the instructions of the dispatcher (the person you talk to when you call 911).

They found no significant difference for either result between doing compression + breathing and compression along.  That's a shocker, but we shouldn't get excited yet; we need to look at the experimental design, and the statistics.

For Onion Peelers,
Using 1941 patients randomized to two groups.  They observed no significant difference between the two groups in the proportion of patients who survived to hospital discharge (12.5% with chest compression alone and 11.0% with chest compression plus rescue breathing, P=0.31) or in the proportion who survived with a favorable neurologic outcome ...(14.4% and 11.5%, respectively; P=0.13). Prespecified subgroup analyses showed a trend toward a higher proportion of patients surviving to hospital discharge with chest compression alone as compared with chest compression plus rescue breathing for patients with a cardiac cause of arrest (15.5% vs. 12.3%, P=0.09) and for those with shockable rhythms (31.9% vs. 25.7%, P=0.09).

The primary goal of the study seems straightforward.  P-values failed to reach a significant level (<0.05).  What's interesting is when they split the patients up into two sub-groups--one with those patients who arrested because of a primary heart problem and those who had heart rhythm that could be shocked to normal--the data came very close to significantly better results with compression alone (last sentence above where the P=0.09).

Should these results be verified by repeat studies, and further work done to make sure there isn't some unknown confounding variable, it would rrrreeaalllly help in bystander CPR.  No need to touch your mouth to somebody else's.

In summary, interesting and straightforward study results.  Let's wait for more.

Doc D

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