This is a fantastic study!
It is a fantastically bad study of how to perform research and come
to wrong conclusions. It is so awful it makes one’s heart sink.
These authors performed a retrospect data-base review of patients
who were intubated in their ED for traumatic brain injury. The main outcome was
the difference in mortality when patients were intubated with either rocuronium
or succinylcholine.
The results? No difference in mortality was found. Death occurred
in 23% in each group.
Not satisfied with negative results, the authors conducted a
post-hoc subgroup analysis and found that there was a difference in those with
severe TBI. If you torture the data enough, it will talk.
Wooohooo... we can
publish something!
They conclude, “in severely brain-injured patients
undergoing RSI in the ED, succinlycholine was associated with increased
mortality compared to rocurunium.”
This is totally nuts.
Regardless of the crazy analysis, all of the difference could
easily be attributed to unmeasured confounding. This was not a randomized trial;
therefore the patients given sux were very likely sicker.
Most experienced airway experts will tell you that they
reach for sux when they want very rapid intubating conditions in sicker patients as compared to
other neuromuscular blockers. Correcting for confounding (especially with a
retrospective database) is far from an perfect science.
In the end, this is a small study with a high risk of bias
that comes to unbelievable conclusions. Do we really believe a number needed to
kill of 5 for succinylcholine in severe TBI!?!
There is so much I haven’t mentioned... the crazy power
calculation, mixing association with causation, confusing subgroup analysis with
stratification, neglecting the details of biological plausibility etc.
In 2005, John Ioannidis published his famous paper, “Why
most published research findings are false.”
This study is a case in point. On so many levels, it is just
wrong.
At best, it might raise a hypothesis for prospective
testing. However, NOBODY should be changing their practice as a result of this
paper.
Covering:
Patanwala AE, Erstad BL, Roe DJ, et al. Succinylchoine is
associated with increased mortality when used for rapid sequence intubation of
severely brain injured patients in the Emergency Department. Pharmacotherapy.
2016;36(1):57-63.
(Special thanks to Dr Mark Reeves, FANZCA and Dr Ryan Radeski for providing me with some of their insights. However they take no responsibility for the terrible nature of this post.)
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