An evaluation of the Swiss staging model for hypothermia using hospital cases and case reports from the literature

Abstract

Background The Swiss staging model for hypothermia uses clinical indicators to stage hypothermia and guide the management of hypothermic patients. The proposed temperature range for clinical stage 1 is < 35–32 °C, for stage 2 is < 32–28 °C, for stage 3 is < 28–24 °C, and for stage 4 is below 24 °C. Our previous study using 183 case reports from the literature showed that the measured temperature only corresponded to the clinical stage in the Swiss staging model in approximately 50% of cases. This study, however, included few patients with moderate hypothermia. We aimed to expand this database by adding cases of hypothermic patients admitted to hospital to perform a more comprehensive evaluation of the staging model. Methods We retrospectively included patients aged ≥18 y admitted to hospital between 1.1.1994 and 15.7.2016 with a core temperature below 35 °C. We added the cases identified through our previously published literature review to estimate the percentage of those patients who were correctly classified and compare the theoretical with the observed temperature ranges for each clinical stage. Results We included 305 cases (122 patients from the hospital sampling and the 183 previously published). Using the theoretically derived temperature ranges for clinical stages resulted in 185/305 (61%) patients being assigned to the correct temperature range. Temperature was overestimated using the clinical stage in 55/305 cases (18%) and underestimated in 65/305 cases (21%); important overlaps in temperature existed among the four stage groups. The optimal temperature thresholds for discriminating between the four stages (32.1 °C, 27.5 °C, and 24.1 °C) were close to those proposed historically (32 °C, 28 °C, and 24 °C). Conclusions Our results provide further evidence of the relationship between the clinical state of patients and their temperature. The historical proposed temperature thresholds were almost optimal for discriminating between the different stages. Adding overlapping temperature ranges for each clinical stage might help clinicians to make appropriate decisions when using clinical signs to infer temperature. An update of the Swiss staging model for hypothermia including our methodology and findings could positively impact clinical care and future research.

CrossTalk proposal: Barometric pressure, independent of , is the forgotten parameter in altitude physiology and mountain medicine

“…While we agree that the current ascent recommendation remains relevant from a public health perspective (on most days the change in P B is negligible), it might nevertheless be prudent to update these recommendations for mountain professionals (guides, athletes, first responders), by take daily P B variation into account, and also complement it with enhanced educational strategies (Pasquier et al . ). Second, the commonly reported rather large interindividual variability in susceptibility to high altitude illness (Luks et al .…”

Multiple trauma management in mountain environments - a scoping review

“…Clinical signs of hypothermia may be unreliable when there are coexisting conditions and when minimally invasive temperature measurement is not possible [ 200 ]. If a suitable thermometer is not available, core temperature can be estimated using the Swiss staging system [ 201 ]. The ideal prehospital thermometer should be easy to handle, accurate in all environmental conditions, and able to reflect small temperature changes rapidly.…”

Clinical Relevance of Impaired Consciousness in Accidental Hypothermia: A Japanese Multicenter Retrospective Study

“…First, we performed a multicenter study with a large sample of patients, whereas most previous studies examined a small sample of patients at a single center. Moreover, although some reports have addressed the validity of the Swiss staging model [7,15], no study has directly analyzed the relationship between the level of impaired consciousness and core BT among patients with AH. Second, we evaluated patients who developed AH in urban areas, whereas previous studies typically evaluated AH occurring in cold climates, such as the Alps [16,17].…”

“…In this model, the degree of impaired consciousness and vital signs are used to estimate the core BT and triage the patient appropriately [1]. However, although the Swiss staging model is accepted worldwide, there is no high-quality evidence that the level of consciousness is valid for triage application [7]. In addition, little is known regarding appropriate factors for guiding triage in cases of AH.…”