Third, our review showed that non-invasive and well-tolerated
cooling modalities, such as ice packs or cold packs, wet gauze
sheets, and fan alone or in combination, could represent reasonable
alternatives since these are easily applied and readily
accessible during epidemic classic heatstroke, when a large
number of frail elderly patients are seen in the emergency room
[24-27]. Indeed, in four studies, the cooling time using these
techniques in patients with classic heatstroke was reasonably
low and the outcome was acceptable [24-27].
Fourth, this review suggested that pharmacologic treatment
(namely, dantrolene sodium as an adjunct to physical methods
to accelerate cooling) was ineffective, whereas antipyretic
agents were not properly assessed [28,29]. Antipyretics such
as aspirin and acetaminophen should be avoided because of
their potential to aggravate the coagulopathy and liver injury of
heatstroke.
Fifth, our review found no evidence for a specific endpoint
temperature at which to halt cooling. A rectal temperature of
39°C or less appeared to be safe in terms of mortality in most
of the studies, but associated long-term morbidity (particularly
neurologic) has not yet been established and further study is
required.
Hemodynamic management
Although rapid and effective cooling is the cornerstone of
treatment, the management of circulatory failure in heatstroke
is also important [12-14,16]. In an earlier study of 100 patients
with classic heatstroke, Austin and Berry [12] showed that
hypotension was associated with a mortality rate of 33% compared
with 10% in patients without hypotension. Hart and colleagues
[16] found that the necessity for supplementary
vasoactive treatment to restore blood pressure was associated
with both a high mortality rate and neurologic disability.
These observations were reinforced by a recent survey of 345
patients with classic heatstroke which demonstrated that the
use of vasoactive drugs within the first 24 hours of admission
to the ICU was independently associated with an increased
risk of death [32]. These findings established a link between
hypotension and poor outcome, suggesting that prevention
and treatment of the hemodynamic instability of heatstroke
may contribute to improved outcome.
Based on available data, the present study established the following evidence: