deficit between these two methods. Statistically
there were significantly more patients out of
temperature range while maintaining therapy
in the surface cooling group, and an increase in
median time spent outside targeted temperature
as well. This work further supported earlier
studies 22 that advocated the use of either surface
pads or intravascular devices for the induction
of hypothermia but strongly recommended
intravascular devices for maintaining target
temperature.
The National Institute for Health and Care
Excellence updated its advice on TTM in July
2017 to advocate the use of Arctic Sun over
conventional or intravascular cooling methods,
due to a combination of reduced risks associated
and the potential for improved outcomes.
Conclusions
TTM is an extensively researched, effective,
neuroprotective strategy with well established
guidelines; however, confusion exists about the
optimal duration and target temperature. At the
time of writing, the most up-to date research
would advocate starting TTM as soon as feasibly
possible, but not setting low temperatures (that
is, 33°C) and simply avoiding temperatures above
36°C. 17 This obviously remains at the clinician’s
discretion and temperatures between 35 and 36°C
are commonplace.
While new devices and research into this
treatment are evolving and being undertaken, it
is important to reflect on the fundamentals. First,
patient selection remains an often-overlooked
area, and the authors urge vigilance in selecting
those patients who are suitable for instigation of
TTM and screening carefully for those likely to
benefit from this therapy. To this point, if there
is doubt regarding the initial rhythm of arrest,
then TTM should be instigated and not withheld.
The clinician involved in the decision to
commence TTM must pay attention to the precise
control of temperature in all phases, and critically
in the rewarming phase where a passive,
non-controlled rise could have serious effects
on outcome.
Finally, as with most evolving medical
research, there is more work to be done,
particularly now that 36°C temperatures are
associated with equal outcomes to 33°C. Are we
ready to accept normothermia and adopt cooling
measures when we see a trend to hyperthermia?
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