Defining Acceptable Cold‐Water Immersion Times for the Treatment of Exertional Hyperthermia When Rectal Temperature Measurements are not Available
Bibliographic record
Abstract
Exertional hyperthermia is most effectively treated with immediate whole‐body cold‐water immersion to rapidly cool the body to the safe rectal temperature (T re ) of 38.6°C, which is the cooling limit recommended to negate any risk associated with overcooling hyperthermic individuals. However, the safe use of cold‐water immersion is reliant on real‐time measurement of T re to identify the appropriate immersion time, which is often unavailable in emergency situations. The purpose of this study was to determine appropriate immersion times for the immediate treatment of exertional hyperthermia for a range of water temperatures (2°C to 26°C) and following a treatment delay (20 min and 40 min) to guide emergency management in the absence of continuous T re measurements. Data were extracted from seven published studies (143 experimental sessions) involving 79 participants (65 males, 14 females; age: 26 ± 6 years; height: 177 ± 9 cm; weight, 76.9 ± 13.0 kg; body fat: 17.3 ± 6.9%; peak oxygen consumption: 56.9 ± 7.9 mL/kg/min). In each study, individuals rendered hyperthermic (T re 39.5–40.0°C) during exercise in the heat were treated immediately with immersion in water at 2°C, 8°C, 14°C, or 26°C. Separate study conditions assessed cold‐water immersion (2°C) following a 20 and 40 min treatment delay. From these data, receiver operating characteristics curves were used to define acceptable cooling times (time for T re to reach 38.6°C) for each condition (all p<0.05). Our analysis revealed that 9 min would be the recommended cooling time for immersion in water temperatures ranging from 2°C to 8°C (average sensitivity at 2°C: 0.84, average sensitivity at 8°C: 0.82; average specificity at 2°C: 0.82, average specificity at 8°C: 0.96). For immersion in water temperatures between 14°C and 20°C, the suggested cooling time was 10 min (average sensitivity: 0.80; average specificity: 0.76), whereas it was 14 min at 26°C (average sensitivity: 0.73; average specificity: 0.79). When the gold standard water temperature of 2°C is available, a cooling time of 11 min is recommended if immersion is delayed between 20 and 40 min (average sensitivity: 0.84; average specificity: 0.94). Our results provide the first clinical guidance to health practitioners for the emergency treatment of exertional hyperthermia using water immersion at a range of water temperatures and following a treatment delay when T re measurements are unavailable. Support or Funding Information Natural Sciences and Engineering Research Council of Canada (grant held by Dr. Glen P. Kenny). This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.005 | 0.009 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".