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Lechner R, Beres Y, Oberst A, Bank K, Tannheimer M, Kulla M, Hossfeld B. Analysis of tourniquet pressure over military winter clothing and a short review of combat casualty care in cold weather warfare. Int J Circumpolar Health 2023; 82:2194141. [PMID: 36989123 PMCID: PMC10062217 DOI: 10.1080/22423982.2023.2194141] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023] Open
Abstract
Cold weather warfare is of increasing importance. Haemorrhage is the most common preventable cause of death in military conflicts. We analysed the pressure of the Combat Application Tourniquet® Generation 7 (CAT), the SAM® Extremity Tourniquet (SAMXT) and the SOF® Tactical Tourniquet Wide Generation 4 (SOFTT) over different military cold weather clothing setups with a leg tourniquet trainer. We conducted a selective PubMed search and supplemented this with own experiences in cold weather medicine. The CAT and the SAMXT both reached the cut off value of 180mmHg in almost all applications. The SOFTT was unable to reach the 180mmHg limit in less than 50% of all applications in some clothing setups. We outline the influence of cold during military operations by presenting differences between military and civilian cold exposure. We propose a classification of winter warfare and identify caveats and alterations of Tactical Combat Casualty Care in cold weather warfare, with a special focus on control of bleeding. The application of tourniquets over military winter clothing is successful in principle, but effectiveness may vary for different tourniquet models. Soldiers are more affected and impaired by cold than civilians. Military commanders must be made aware of medical alterations in cold weather warfare.
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Affiliation(s)
- Raimund Lechner
- Bundeswehr Hospital Ulm, Department of Anesthesiology, Intensive Care Medicine, Emergency Medicine and Pain Therapy, Ulm, Germany
| | - Yannick Beres
- Bundeswehr Hospital Ulm, Department of Anesthesiology, Intensive Care Medicine, Emergency Medicine and Pain Therapy, Ulm, Germany
| | - Amelie Oberst
- Bundeswehr Hospital Ulm, Department of Anesthesiology, Intensive Care Medicine, Emergency Medicine and Pain Therapy, Ulm, Germany
| | - Kristina Bank
- Bundeswehr Hospital Ulm, Department of Anesthesiology, Intensive Care Medicine, Emergency Medicine and Pain Therapy, Ulm, Germany
| | - Markus Tannheimer
- University Ulm, Department of Sport and Rehabilitation Medicine, Ulm, Germany
| | - Martin Kulla
- Bundeswehr Hospital Ulm, Department of Anesthesiology, Intensive Care Medicine, Emergency Medicine and Pain Therapy, Ulm, Germany
| | - Bjoern Hossfeld
- Bundeswehr Hospital Ulm, Department of Anesthesiology, Intensive Care Medicine, Emergency Medicine and Pain Therapy, Ulm, Germany
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Salmon OF, Segovia MD, Ugale CB, Smith CM. The impact of cold, hypoxia, and physical exertion on pistol accuracy and tactical performance. J Therm Biol 2023; 117:103676. [PMID: 37738801 DOI: 10.1016/j.jtherbio.2023.103676] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/31/2023] [Accepted: 08/02/2023] [Indexed: 09/24/2023]
Abstract
The purpose of this study was to examine the impact of independent cold and combined cold and hypoxic exposures on operational-specific task performance including pistol marksmanship, pistol magazine reload ability, and subjective and objective thermal indices before and after a whole-body physical exertional task. Twelve participants were exposed to Thermoneutral Normoxic (24 °C; FiO2 21%), Cold Normoxic (10 °C; FiO2 21%), and Cold Hypoxic (10 °C; FiO2 14%) conditions for 30min before performing pistol marksmanship at distances of 6.40 and 13.72m and a pistol magazine reload task before and after 3 sets of sandbag deadlifts at 50% body mass. Thermal perception and hand temperatures were collected before and after the physical exertion task. There were no significant differences in Pistol Accuracy performance at distances of 6.40 and 13.72m due to physical exertion, cold, or hypoxia. Following physical exertion, Pistol Accuracy was similar between Thermoneutral and Cold Normoxic conditions but lead to 17% and a 10% reduction in performance during the Cold Hypoxic condition, compared to Thermoneutral and Cold Normoxic conditions. There was no change in Pistol Accuracy for the Thermoneutral Normoxic condition. The pistol magazine reload task was not impacted by physical exertion, but there was a reduction in performance in Cold Normoxic 21% (4.04s) and Cold Hypoxic 16% (3.08s) conditions. Physical exertion did not impact hand temperature but did increase thermal perception scores for all conditions. These findings indicate that cold exposure reduced both tactical dexterity and pistol marksmanship, however, physical exertion may offset these deficits via an increase in thermal perception. Additionally, hypoxemia was the primary mediator of marksmanship performance in cold hypoxic environments following an acute bout of physical exertion. Thus, in cold mountainous environments, marksmen should be aware of their elevation and utilize brief episodes of physical activity to enhance their thermal state when marksmanship is a priority for operational success.
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Affiliation(s)
- Owen F Salmon
- Baylor University, Human & Environmental Physiology Laboratory, Waco, TX, USA
| | - Matt D Segovia
- Baylor University, Human & Environmental Physiology Laboratory, Waco, TX, USA
| | - Cierra B Ugale
- Baylor University, Human & Environmental Physiology Laboratory, Waco, TX, USA
| | - Cory M Smith
- Baylor University, Human & Environmental Physiology Laboratory, Waco, TX, USA.
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Seeley AD, Caldwell AR, Cahalin LP, Ahn S, Perry AC, Arwari B, Jacobs KA. Seven days of ischemic preconditioning augments hypoxic exercise ventilation and muscle oxygenation in recreationally trained males. Am J Physiol Regul Integr Comp Physiol 2022; 323:R457-R466. [PMID: 35968897 PMCID: PMC9529270 DOI: 10.1152/ajpregu.00335.2021] [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: 01/05/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 11/22/2022]
Abstract
This investigation sought to assess whether single or repeated bouts of ischemic preconditioning (IPC) could improve oxyhemoglobin saturation ([Formula: see text]) and/or attenuate reductions in muscle tissue saturation index (TSI) during submaximal hypoxic exercise. Fifteen healthy young men completed submaximal graded exercise under four experimental conditions: 1) normoxia (NORM), 2) hypoxia (HYP) [oxygen fraction of inspired air ([Formula: see text]) = 0.14, ∼3,200 m], 3) hypoxia preceded by a single session of IPC (IPC1-HYP), and 4) hypoxia preceded by seven sessions of IPC, one a day for 7 consecutive days (IPC7-HYP). IPC7-HYP heightened minute ventilation (V̇e) at 80% HYP peak cycling power output (Wpeak) (+10.47 ± 3.35 L·min-1, P = 0.006), compared with HYP, as a function of increased breathing frequency. Both IPC1-HYP (+0.17 ± 0.04 L·min-1, P < 0.001) and IPC7-HYP (+0.16 ± 0.04 L·min-1, P < 0.001) elicited greater oxygen consumption (V̇o2) across exercise intensities compared with NORM, whereas V̇o2 was unchanged with HYP alone. [Formula: see text] was unchanged by either IPC condition at any exercise intensity, yet the reduction of muscle TSI during resting hypoxic exposure was attenuated by IPC7-HYP (+9.9 ± 3.6%, P = 0.040) compared with HYP, likely as a function of reduced local oxygen extraction. Considering all exercise intensities, IPC7-HYP attenuated reductions of TSI with HYP (+6.4 ± 1.8%, P = 0.001). Seven days of IPC heightens ventilation, posing a threat to ventilatory efficiency, during high-intensity submaximal hypoxic exercise and attenuates reductions in hypoxic resting and exercise muscle oxygenation in healthy young men. A single session of IPC may be capable of modulating hypoxic ventilation; however, our present population was unable to demonstrate this with certainty.
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Affiliation(s)
- Afton D Seeley
- Department of Kinesiology and Sport Sciences, School of Education and Human Development, University of Miami, Coral Gables, Florida
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
- Oak Ridge Institute of Science and Education, Oak Ridge, Tennessee
| | - Aaron R Caldwell
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
- Oak Ridge Institute of Science and Education, Oak Ridge, Tennessee
| | - Lawrence P Cahalin
- Department of Physical Therapy, University of Miami Miller School of Medicine, Coral Gables, Florida
| | - Soyeon Ahn
- Department of Educational and Psychological Studies, School of Education and Human Development, University of Miami, Coral Gables, Florida
| | - Arlette C Perry
- Department of Kinesiology and Sport Sciences, School of Education and Human Development, University of Miami, Coral Gables, Florida
| | - Brian Arwari
- Department of Kinesiology and Sport Sciences, School of Education and Human Development, University of Miami, Coral Gables, Florida
| | - Kevin A Jacobs
- Department of Kinesiology and Sport Sciences, School of Education and Human Development, University of Miami, Coral Gables, Florida
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Paal P, Pasquier M, Darocha T, Lechner R, Kosinski S, Wallner B, Zafren K, Brugger H. Accidental Hypothermia: 2021 Update. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:501. [PMID: 35010760 PMCID: PMC8744717 DOI: 10.3390/ijerph19010501] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 12/08/2021] [Accepted: 12/09/2021] [Indexed: 12/13/2022]
Abstract
Accidental hypothermia is an unintentional drop of core temperature below 35 °C. Annually, thousands die of primary hypothermia and an unknown number die of secondary hypothermia worldwide. Hypothermia can be expected in emergency patients in the prehospital phase. Injured and intoxicated patients cool quickly even in subtropical regions. Preventive measures are important to avoid hypothermia or cooling in ill or injured patients. Diagnosis and assessment of the risk of cardiac arrest are based on clinical signs and core temperature measurement when available. Hypothermic patients with risk factors for imminent cardiac arrest (temperature < 30 °C in young and healthy patients and <32 °C in elderly persons, or patients with multiple comorbidities), ventricular dysrhythmias, or systolic blood pressure < 90 mmHg) and hypothermic patients who are already in cardiac arrest, should be transferred directly to an extracorporeal life support (ECLS) centre. If a hypothermic patient arrests, continuous cardiopulmonary resuscitation (CPR) should be performed. In hypothermic patients, the chances of survival and good neurological outcome are higher than for normothermic patients for witnessed, unwitnessed and asystolic cardiac arrest. Mechanical CPR devices should be used for prolonged rescue, if available. In severely hypothermic patients in cardiac arrest, if continuous or mechanical CPR is not possible, intermittent CPR should be used. Rewarming can be accomplished by passive and active techniques. Most often, passive and active external techniques are used. Only in patients with refractory hypothermia or cardiac arrest are internal rewarming techniques required. ECLS rewarming should be performed with extracorporeal membrane oxygenation (ECMO). A post-resuscitation care bundle should complement treatment.
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Affiliation(s)
- Peter Paal
- Department of Anesthesiology and Intensive Care Medicine, St. John of God Hospital, Paracelsus Medical University, 5020 Salzburg, Austria
- International Commission for Mountain Emergency Medicine (ICAR MedCom), 8302 Kloten, Switzerland; (M.P.); (K.Z.); (H.B.)
| | - Mathieu Pasquier
- International Commission for Mountain Emergency Medicine (ICAR MedCom), 8302 Kloten, Switzerland; (M.P.); (K.Z.); (H.B.)
- Department of Emergency Medicine, Lausanne University Hospital, 1011 Lausanne, Switzerland
| | - Tomasz Darocha
- Department of Anesthesiology and Intensive Care, Medical University of Silesia, 40-001 Katowice, Poland;
| | - Raimund Lechner
- Department of Anesthesiology, Intensive Care Medicine, Emergency Medicine and Pain Therapy, Military Hospital, 89081 Ulm, Germany;
| | - Sylweriusz Kosinski
- Faculty of Health Sciences, Jagiellonian University Medical College, 34-500 Krakow, Poland;
| | - Bernd Wallner
- Department of Anesthesiology and Critical Care Medicine, Medical University of Innsbruck, 6020 Innsbruck, Austria;
| | - Ken Zafren
- International Commission for Mountain Emergency Medicine (ICAR MedCom), 8302 Kloten, Switzerland; (M.P.); (K.Z.); (H.B.)
- Department of Emergency Medicine, Alaska Native Medical Center, Anchorage, AK 99508, USA
- Department of Emergency Medicine, Stanford University Medical Center, Stanford University, Palo Alto, CA 94304, USA
| | - Hermann Brugger
- International Commission for Mountain Emergency Medicine (ICAR MedCom), 8302 Kloten, Switzerland; (M.P.); (K.Z.); (H.B.)
- Institute of Mountain Emergency Medicine, Eurac Research, 39100 Bolzano, Italy
- Department of Anesthesiology and Intensive Care Medicine, Medical University of Innsbruck, 6020 Innsbruck, Austria
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Tannheimer M, Lechner R. Rapid ascents of Mt Everest: normobaric hypoxic preacclimatization. J Travel Med 2020; 27:5861564. [PMID: 32577764 DOI: 10.1093/jtm/taaa099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/22/2020] [Accepted: 06/11/2020] [Indexed: 11/12/2022]
Abstract
BACKGROUND Acclimatization to high altitude is time consuming. An expedition to Mt Everest (8848 m) requires roughly 8 weeks. Therefore it seems very attractive to reach the summit within 3 weeks from home, which is currently promised by some expedition tour operators. These rapid ascent expeditions are based on two main components, normobaric hypoxic training (NHT) prior to the expedition and the use of high flow supplemental oxygen (HFSO2). We attempted to assess the relative importance of these two elements. METHODS We evaluated the effect of NHT on the basis of the available information of these rapid ascent expeditions and our experiences made during an expedition to Manaslu (8163 m) where we used NHT for preacclimatization. To evaluate the effect of an increased O2 flow rate we calculated its effect at various activity levels at altitudes of 8000 m and above. RESULTS So far rapid ascents to Mt Everest have been successful. The participants carried out 8 weeks of NHT, reaching sleeping altitudes = 7100 m and spent at least 300 h in NH. At rest a flow rate of 2 l O2/min is sufficient to keep the partial pressure of inspired oxygen (PIO2) close to 50 mm Hg even at the summit. For ativities of ~80% of the maximum rate of oxygen consumption (VO2max) at the summit 6 l O2/min are required to maintain a PIO2 above 50 mm Hg. DISCUSSION NHT for preacclimatization seems to be the decisive element of the offered rapid ascent expeditions. An increased O2 flow rate of 8 l/min is not mandatory for climbing Mt Everest. CONCLUSIONS Preacclimatization using normobaric hypoxica (NH) is far more important than the use of HFSO2. We think that NHT will be widely used in the future. The most effective regimen of preacclimatization in NH, the duration of each session and the optimal FIO2 are still unclear and require further study.
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Affiliation(s)
- Markus Tannheimer
- University of Ulm, Department of Sport and Rehabilitation Medicine, Leimgrubenweg 14, 89089075 Ulm/75 Ulm, Germany
| | - Raimund Lechner
- Department of Anaesthesiology and Intensive Care, Bundeswehr Hospital Ulm, Oberer Eselsberg 40, 89081 Ulm, Germany
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