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Defining Acceptable Cold‐Water Immersion Times for the Treatment of Exertional Hyperthermia When Rectal Temperature Measurements are not Available
Author(s) -
Poirier Martin P.,
Notley Sean R.,
Gag Daniel,
McGinn Ryan R.,
Friesen Brian J.,
Flouris Andreas D.,
Kenny Glen P.
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.859.4
Subject(s) - immersion (mathematics) , hyperthermia , rectal temperature , medicine , heat illness , zoology , anesthesia , surgery , meteorology , mathematics , physics , pure mathematics , biology
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 .