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Eisenhauer I, April MD, Rizzo JA, Fisher AD, Maddry JK, Bebarta VS, Schauer SG. Seasonal Association With Hypothermia in Combat Trauma. Mil Med 2024; 189:2004-2008. [PMID: 38015941 DOI: 10.1093/milmed/usad451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 09/12/2023] [Accepted: 11/08/2023] [Indexed: 11/30/2023] Open
Abstract
INTRODUCTION Hypothermia increases mortality in trauma populations and frequently occurs in military casualties due to the nature of combat environments. The association between hypothermia and the time of year when injured remains unclear. We sought to determine the association between seasonal changes in temperature and hypothermia among combat casualties. MATERIALS AND METHODS This observational study was a secondary analysis of a previously described Department of Defense Trauma Registry dataset which included U.S. military and Coalition casualties who received prehospital care from January 2007 to March 2020 in Afghanistan and Iraq. We tested for associations between hypothermia (<36.2°C) and seasonal ambient temperatures by constructing multivariable logistic regression models. Summer was defined as June through August and winter as December through February. We assumed that the combat operations occurred in the area near the point of first contact with the deployed military treatment facilities. This study was determined to be exempt from Institutional Review Board oversight. RESULTS There were 5,821 that met inclusion for this study. Within the multivariable logistic regression model, we adjusted for injury severity score, mechanism of injury, and imputed transport time, finding that combat casualties were 2.28 (odds ratio, 95% confidence interval 1.93-2.69) times more likely to develop hypothermia in the winter versus summer. When using temperature as a continuous outcome, casualties had a lower emergency department temperature during the winter (parameter estimate -0.133°C, P < 0.001) after adjusting for confounders. In casualties experiencing hypothermia, mortality was higher (4% versus 1%, P < 0.001), and composite median injury severity score values were higher (10 versus 5, P < 0.001). Among hypothermic casualties, serious injuries were significantly more common (all P < 0.001) to the head (15% versus 7%), thorax (15% versus 7%), abdomen (9% versus 6%), extremities (35% versus 22%), and skin (4% versus 2%). CONCLUSIONS We found a seasonal variation in the occurrence of hypothermia in a large cohort of trauma casualties. Despite adjustment for multiple known confounders, our findings substantiate probable ambient temperature variations to trauma-induced hypothermia. Furthermore, our findings, when taken in the context of other studies on the efficacy of current hypothermia prevention and treatment strategies, support the need for better methods to mitigate hypothermia in future cold-weather operations.
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Affiliation(s)
- Ian Eisenhauer
- University of Colorado Center for Combat Medicine and Battlefield (COMBAT) Research, Aurora, CO 80045, USA
- Department of Emergency Medicine, University of Colorado School of Medicine, Aurora, CO 80045, USA
- Denver Health Residency in Emergency Medicine, Denver, CO 80204, USA
- Navy Medicine Leader and Professional Development Command, Bethesda, MD 20889, USA
| | - Michael D April
- Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
- 14th Field Hospital, Fort Stewart, GA 31314, USA
| | - Julie A Rizzo
- Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
- Brooke Army Medical Center, JBSA Fort Sam Houston, TX 78234, USA
| | - Andrew D Fisher
- Department of Surgery, University of New Mexico School of Medicine, Albuquerque, NM 87106, USA
- Texas Army National Guard, Austin, TX, USA
| | - Joseph K Maddry
- Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
- Brooke Army Medical Center, JBSA Fort Sam Houston, TX 78234, USA
- U.S. Army Institute of Surgical Research, JBSA Fort Sam Houston, TX 78234, USA
- 59th Medical Wing, JBSA Fort Sam Houston, TX 78258, USA
| | - Vikhyat S Bebarta
- University of Colorado Center for Combat Medicine and Battlefield (COMBAT) Research, Aurora, CO 80045, USA
- Department of Emergency Medicine, University of Colorado School of Medicine, Aurora, CO 80045, USA
- 59th Medical Wing, JBSA Fort Sam Houston, TX 78258, USA
| | - Steven G Schauer
- University of Colorado Center for Combat Medicine and Battlefield (COMBAT) Research, Aurora, CO 80045, USA
- Department of Emergency Medicine, University of Colorado School of Medicine, Aurora, CO 80045, USA
- Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
- Brooke Army Medical Center, JBSA Fort Sam Houston, TX 78234, USA
- U.S. Army Institute of Surgical Research, JBSA Fort Sam Houston, TX 78234, USA
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Lier M, Jebens C, Lorey-Tews A, Heyne T, Kunze-Szikszay N, Wieditz J, Bräuer A. What is the best way to keep the patient warm during technical rescue? Results from two prospective randomised controlled studies with healthy volunteers. BMC Emerg Med 2023; 23:83. [PMID: 37537546 PMCID: PMC10401780 DOI: 10.1186/s12873-023-00850-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 07/14/2023] [Indexed: 08/05/2023] Open
Abstract
BACKGROUND Accidental hypothermia is a manifest problem during the rescue of entrapped victims and results in different subsequent problems as coagulopathy and wound infection. Different warming methods are available for the preclinicial use. However, their effectiveness has hardly been evaluated. METHODS In a first step a survey among German fire brigades was performed with questions about the most used warming methods. In a second step two crossover studies were conducted. In each study two different warming method were compared with forced air warming - which is the most frequently used and highly effective warming method in operation rooms (Study A: halogen floodlight vs. forced air warming; Study B: forced air warming vs. fleece blanket). In both studies healthy volunteers (Study A: 30 volunteers, Study B: 32 volunteers) were sitting 60 min in a cold store. In the first 21 min there was no subject warming. Afterwards the different warming methods were initiated. Every 3 min parameters like skin temperature, core body temperature and cold perception on a 10-point numeric rating scale were recorded. Linear mixed models were fitted for each parameter to check for differences in temperature trajectories and cold perception with regard to the different warming methods. RESULTS One hundred fifty-one German fire brigades responded to the survey. The most frequently used warming methods were different rescue blankets (gold/silver, wool) and work light (halogen floodlights). Both studies (A and B) showed significantly (p < 0.05) higher values in mean skin temperature, mean body temperature and total body heat for the forced air warming methods compared to halogen floodlight respectively fleece blanket shortly after warming initiation. In contrast, values for the cold perception were significantly lower (less unpleasant cold perception) during the phase the forced air warming methods were used, compared to the fleece blanket or the halogen floodlight was used. CONCLUSION Forced air warming methods used under the standardised experimental setting are an effective method to keep patients warm during technical rescue. Halogen floodlight has an insufficient effect on the patient's heat preservation. In healthy subjects, fleece blankets will stop heat loss but will not correct heat that has already been lost. TRIAL REGISTRATION The studies were registered retrospectively on 14/02/2022 on the German Clinical Trials registry (DRKS) with the number DRKS00028079.
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Affiliation(s)
- Martin Lier
- Department of Anesthesiology, University Medical Center Göttingen, Robert-Koch-Strasse 40, 37075, Göttingen, Germany.
| | - Christopher Jebens
- Department of Anesthesiology, Intensive care, Emergency and Pain medicine, Asklepios Clinic Altona, Paul-Ehrlich-Strasse 1, 22763, Hamburg, Germany
| | - Annette Lorey-Tews
- Department of Anesthesiology and Intensive care medicine, Buchholz Hospital, Steinbecker Strasse 44, 21244, Buchholz in der Nordheide, Germany
| | - Tim Heyne
- Department of Anesthesiology, University Medical Center Göttingen, Robert-Koch-Strasse 40, 37075, Göttingen, Germany
| | - Nils Kunze-Szikszay
- Department of Anesthesiology, University Medical Center Göttingen, Robert-Koch-Strasse 40, 37075, Göttingen, Germany
| | - Johannes Wieditz
- Department of Anesthesiology, University Medical Center Göttingen, Robert-Koch-Strasse 40, 37075, Göttingen, Germany
- Department of Medical Statistics, University Medical Center Göttingen, Humboldtallee 32, 37073, Göttingen, Germany
| | - Anselm Bräuer
- Department of Anesthesiology, University Medical Center Göttingen, Robert-Koch-Strasse 40, 37075, Göttingen, Germany
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Wallner B, Salchner H, Isser M, Schachner T, Wiedermann FJ, Lederer W. Rescue Blankets as Multifunctional Rescue Equipment in Alpine and Wilderness Emergencies-A Narrative Review and Clinical Implications. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:12721. [PMID: 36232023 PMCID: PMC9566397 DOI: 10.3390/ijerph191912721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 09/30/2022] [Accepted: 10/01/2022] [Indexed: 06/16/2023]
Abstract
The utilization of rescue blankets in pre-hospital emergency medicine exceeds protection from hypothermia and enhanced visibility by far. In this narrative review, we focus on emphasizing the alternative applications of these fascinating multifunctional tools in the pre-hospital setting. A literature search in PubMed® and Web of ScienceTM yielded 100 results (last update was on 8 July 2022), a total number of 26 of which were included in this narrative review. Nine articles assessing alternative functions of rescue blanket were further evaluated and described in more detail. In addition, we performed various experimental and observational trials to test the functionality of rescue practice in mountain emergency medicine. Newly fabricated rescue blankets proved to possess impressive robustness. We evaluated rescue blankets in their applicability to not only protect from hypothermia, but also as practical tools to treat catastrophic hemorrhage and bleeding limbs, to perform open pneumothorax chest seals in sucking chest wounds, to prevent damage to unprotected eyes on the glacier and as alternative instruments for transportation in the inaccessible areas. Rescue blankets are important rescue equipment in alpine and wilderness emergencies with multifunctional applications, and must be part of every personal medical kit.
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Affiliation(s)
- Bernd Wallner
- Department of Anaesthesiology and Critical Care Medicine, Medical University of Innsbruck, Anichstr. 35, 6020 Innsbruck, Austria
| | - Hannah Salchner
- Department of Anaesthesiology and Critical Care Medicine, Medical University of Innsbruck, Anichstr. 35, 6020 Innsbruck, Austria
| | - Markus Isser
- Austrian Mountain Rescue Service—Tyrol, Medical Division, Florianistr. 2, 6410 Telfs, Austria
| | - Thomas Schachner
- Department of Cardiac Surgery, Medical University of Innsbruck, Anichstr. 35, 6020 Innsbruck, Austria
| | - Franz J. Wiedermann
- Department of Anaesthesiology and Critical Care Medicine, Medical University of Innsbruck, Anichstr. 35, 6020 Innsbruck, Austria
| | - Wolfgang Lederer
- Department of Anaesthesiology and Critical Care Medicine, Medical University of Innsbruck, Anichstr. 35, 6020 Innsbruck, Austria
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