Matt Harmon

36 Chapter two This study is the first to provide detailed insight into temperature management of patients with spontaneous hypothermia in sepsis. The practice of rewarming remains controversial. Considering that hypothermia is associated with an increased mortality, rewarming is understandable, likely in an attempt to negate any adverse effects of hypothermia. The practice of rewarming may be further motivated by physicians’ drive to reach physiological values. A majority of respondents in our survey (62%) indicated that they rewarmed patients with hypothermic sepsis. In a recent survey among UK physicians, a majority of physicians (84%) also rewarmed patients, whereas 16% indicated that they would not rewarm septic patients below a temperature of 34°C 4 . Only 60% of respondents in this study were concerned with a body temperature of 35–36°C in this patient population. 4 Taken together, the differences in temperature management practice is indicative of a lack of clarity on this issue. The results from this survey make it clear that a robust definition of hypothermia is warranted. This would enable comparisons of incidences and outcome of rewarming practices. Clinical observational studies overwhelmingly point to hypothermia adversely effecting outcome. 1 In light of these studies, it is noteworthy that none of the respondents reported to have a protocol in place for the management of hypothermic sepsis, most probably due to lack of strong clinical evidence. The aforementioned clinical studies are observational in nature and therefore cannot infer causation between hypothermia and outcome. Moreover, there are no randomized trials studying the impact of rewarming in hypothermic septic patients. If rewarming benefits patients, it is unclear at which temperature they should be rewarmed as well as to which target temperature and how fast patients should be rewarmed. It would be interesting to see the effect that rewarming to target temperatures is in respect to outcome and specifically immune response. In vitro experiments have shown that rewarming can improve immune responses. 5 On the contrary, experimental evidence points to hypothermia being an adaptive response. 6 In hypothermic rodents with endotoxemia, thermogenic capacity is intact, arguing against hypothermia being a defect in thermogenic capacity. 7 Also, hypothermic rodents actively seek colder environments 8 and spontaneous hypothermia also improved survival in mice infected with E. coli. 9 Moreover, rewarming can potentially have adverse effects such as ischemia reperfusion injury and increased metabolism. 10 A randomized clinical trial would clarify the discrepancy between experimental studies and clinical observations. There are several limitations that apply to this study. An inherent limitation of this online survey is that we do not know the percentage of respondents or duplicates. To provide an indication of the rate of response to this survey, we have added the number of members of each contacted ESICM section, which