Generally speaking, what do you get when you perform an observational study
based on registry data?
Not much.
Nevertheless, this study does pose an interesting research
question. Is intubation beneficial for
in-hospital cardiac arrest? Or should we just use other means of ventilation
and resuscitate accordingly.
To really answer this question, one would ideally like to
see a randomized trial so that confounders are equal amongst the two groups.
Otherwise we might be comparing geckos to watermelons.
This was an observational
cohort study of patients who had in-hospital cardiac arrest. The primary
outcome was survival to hospital discharge.
Of 71,615 patients who were intubated in the first 15
minutes, 60% were matched to a patient not intubated in the same minute.
Survival was lower
among patients who were intubated 16.3%
vs those not intubated 19.4% (RR=0.84; 95% CI 0.81-0.87; p<.001)
So this was a huge study with a pretty p value… so it must
be right?!
Wrong.
A few things...
You can’t overpower
bias with big numbers.
This study relied on registry
data which is notoriously of poor
quality. Garbage in, garbage out. No amount of fancy statistics can make up
for this.
Once again, this was not
a randomized trial so the groups were very likely different from the start.
The outcomes could very well be due to one group being sicker than the other. The
authors tried to correct for this confounding by some clever propensity
matching. But it must be emphasized that this is far from an exact science.
So what’s the take
home?
Probably not much.
But this study does lay the foundations for a proper randomized trial… hopefully only including geckos.
Covering:
Andersen LW, Granfeldt
A, Calloway CW, et al. Association Between Tracheal Intubation During Adult
In-Hospital Cardiac Arrest and Survival. JAMA 2017;317(5):494-506.
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