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Brearley M.,National Critical Care and Trauma Response Center
Workplace Health and Safety | Year: 2016

The common practice of workers resting in the shade to dissipate body heat can be complemented by ingestion of crushed ice or immersion in temperate water to rapidly lower core body temperature. © 2015 The Author(s). Source

Brearley M.,National Critical Care and Trauma Response Center
Journal of Military and Veterans' Health | Year: 2012

Exercise together with environmentally induced heat stroke continue to pose a problem for military operations in hot climates. A variety of cooling strategies are required by the military to mitigate the risk of heat stroke due to the variety of climates and physical workloads encountered by defence personnel, combined with their individual physical characteristics and uniforms/protective attire. This paper highlights that cooling is traditionally applied as a treatment for heat stroke rather than used to prevent its onset. Recent evidence from the field of sport science demonstrated that cold fluid consumption can act as a heat sink to blunt the rise of core body temperature. Furthermore, the addition of crushed ice to beverages substantially improves its heat storage potential, resulting in decreased core body temperature and enhanced endurance performance. While crushed ice will not be universally available in defence settings, it is a strategy that requires minimal equipment, is relatively quick to prepare, is not labour intensive and does not require the removal of a soldier's uniform. The military should therefore consider the use of crushed ice ingestion as a preventative measure against heat stroke. Source

Robertson A.G.,89 Royal Street | Griffiths E.K.,89 Royal Street | Norton I.,National Critical Care and Trauma Response Center | Weeramanthri T.S.,89 Royal Street
Travel Medicine and Infectious Disease | Year: 2011

Large scale Australian civilian medical assistance teams were first deployed overseas in 2004.The deployment of small Forward Teams in the early phase of a health disaster response allows for informed decisions on whether, and in what form, to deploy larger medical assistance teams.The prime consideration is to support the capacity of local services to respond to the specific needs of the affected population.In addition, Australian citizens caught up in large numbers in overseas disasters may need health assistance. © 2011 Elsevier Ltd. All rights reserved. Source

Walker A.,University of Canberra | Driller M.,University of Waikato | Brearley M.,National Critical Care and Trauma Response Center | Rattray B.,University of Canberra | Rattray B.,University of Canberra
Applied Physiology, Nutrition and Metabolism | Year: 2014

Firefighters are exposed to hot environments, which results in elevated core temperatures. Rapidly reducing core temperatures will likely increase safety as firefighters are redeployed to subsequent operational tasks. This study investigated the effectiveness of cold-water immersion (CWI) and iced-slush ingestion (SLUSH) to cool firefighters post-incident. Seventy-four Australian firefighters (mean } SD age: 38.9 } 9.0 years) undertook a simulated search and rescue task in a heat chamber (105 } 5 °C). Testing involved two 20-min work cycles separated by a 10-min rest period. Ambient temperature during recovery periods was 19.3 } 2.7 °C. Participants were randomly assigned one of three 15-min cooling protocols: (i) CWI, 15 °C to umbilicus; (ii) SLUSH, 7 g・kg-1 body weight; or (iii) seated rest (CONT). Core temperature and strength were measured pre-and postsimulation and directly after cooling. Mean temperatures for all groups reached 38.9 } 0.9 °C at the conclusion of the second work task. Both CWI and SLUSH delivered cooling rates in excess of CONT (0.093 and 0.092 compared with 0.058 °C・min-1) and reduced temperatures to baseline measurements within the 15-min cooling period. Grip strength was not negatively impacted by either SLUSH or CONT. CWI and SLUSH provide evidence-based alternatives to passive recovery and forearm immersion protocols currently adopted by many fire services. To maximise the likelihood of adoption, we recommend SLUSH ingestion as a practical and effective cooling strategy for post-incident cooling of firefighters in temperate regions. © 2014, Published by NRC Research Press. Source

Brearley M.B.,National Critical Care and Trauma Response Center | Heaney M.F.,Royal Darwin Hospital | Norton I.N.,National Critical Care and Trauma Response Center
Prehospital and Disaster Medicine | Year: 2013

Introduction Responses to physical activity while wearing personal protective equipment in hot laboratory conditions are well documented. However less is known of medical professionals responding to an emergency in hot field conditions in standard attire. Therefore, the purpose of this study was to assess the physiological responses of medical responders to a simulated field emergency in tropical conditions. Methods Ten subjects, all of whom were chronically heat-acclimatized health care workers, volunteered to participate in this investigation. Participants were the medical response team of a simulated field emergency conducted at the Northern Territory Emergency Services training grounds, Yarrawonga, NT, Australia. The exercise consisted of setting up a field hospital, transporting patients by stretcher to the hospital, triaging and treating the patients while dressed in standard medical response uniforms in field conditions (mean ambient temperature of 29.3°C and relative humidity of 50.3%, apparent temperature of 27.9°C) for a duration of 150 minutes. Gastrointestinal temperature was transmitted from an ingestible sensor and used as the index of core temperature. An integrated physiological monitoring device worn by each participant measured and logged heart rate, chest temperature and gastrointestinal temperature throughout the exercise. Hydration status was assessed by monitoring the change between pre- and post-exercise body mass and urine specific gravity (USG). Results Mean core body temperature rose from 37.5°C at the commencement of the exercise to peak at 37.8°C after 75 minutes. The individual peak core body temperature was 38.5°C, with three subjects exceeding 38.0°C. Subjects sweated 0.54 L per hour and consumed 0.36 L of fluid per hour, resulting in overall dehydration of 0.7% of body mass at the cessation of exercise. Physiological strain index was indicative of little to low strain. Conclusions The combination of the unseasonably mild environmental conditions and moderate work rates resulted in minimal heat storage during the simulated exercise. As a result, low sweat rates manifested in minimal dehydration. When provided with access to fluids in mild environmental conditions, chronically heat-acclimatized medical responders can meet their hydration requirements through ad libitum fluid consumption. Whether such an observation is replicated under a harsher thermal load remains to be investigated. Copyright © World Association for Disaster and Emergency Medicine 2013 2013 World Association for Disaster and Emergency Medicine. Source

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