Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 3 August 2018 doi:10.20944/preprints201808.0056.v1 Peer-reviewed version available at Int. J. Environ. Res. Public Health 2018, 15, 1962; doi:10.3390/ijerph15091962 1 Article 2 Evaluation of Novel Classification of Heat-Related 3 Illnesses: A Multicentre Observational Study (Heat 4 Stroke STUDY 2012) 5 Takahiro Yamamoto1,†, Motoki Fujita2,†, Yasutaka Oda2,*, Masaki Todani1, Toru Hifumi3, Yutaka 6 Kondo4, Junya Shimazaki5, Shinichiro Shiraishi6, Kei Hayashida7, Shoji Yokobori8, Shuhei 7 Takauji9, Masahiro Wakasugi10, Shunsuke Nakamura11, Jun Kanda12, Masaharu Yagi13, Takashi 8 Moriya14, Takashi Kawahara15, Michihiko Tonouchi16, Hiroyuki Yokota8, Yasufumi Miyake12, 9 Keiki Shimizu17, Ryosuke Tsuruta1,2 10 1 Advanced Medical Emergency and Critical Care Center, Yamaguchi University Hospital, 1-1-1 Minami- 11 Kogushi, Ube, Yamaguchi 755-8505, Japan; E-Mails: [email protected] (T.Y.); [email protected] 12 (M.T.); [email protected] (R.T.) 13 2 Department of Acute and General Medicine, Yamaguchi University Graduate School of Medicine, 1-1-1 14 Minami-Kogushi, Ube, Yamaguchi 755-8505, Japan; E-Mails: [email protected] (M.F.); yasutaka- 15 [email protected] (Y.O.) 16 3 Emergency and Critical Care medicine, St. Luke's International Hospital, 9-1 Akashi-cho, Chuo-ku, Tokyo 17 104-8560, Japan; E-Mail: [email protected] 18 4 Department of Emergency Medicine and Critical Care Medicine, Juntendo University Urayasu Hospital, 2- 19 1-1 Tomioka, Urayasu, Chiba 279-0021, Japan; E-Mail: [email protected] 20 5 Department of Traumatology and Acute Critical Medicine, Osaka University Graduate School of Medicine, 21 2-15 Yamadaoka, Suita, Osaka 565-0871, Japan; E-Mail: [email protected] 22 6 Department of Emergency and Critical Care Medicine, Aizu Chuo Hospital, 1-1 Tsuruga-machi, 23 Aizuwakamatsu, Fukushima, 965-8611, Japan; E-Mail: [email protected] 24 7 Department of Emergency and Critical Care Medicine, School of Medicine, Keio University, 35 25 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan; E-Mail: [email protected] 26 8 Department of Emergency and Critical Care Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, 27 Tokyo 113-8603, Japan; E-Mails: [email protected] (S.Y.); [email protected] (H.Y.) 28 9 Department of Emergency Medicine, Asahikawa Medical University, Midorigaoka-higashi 2-1-1-1, 29 Asahikawa, Hokkaido 078-8510 Japan; E-Mail: [email protected] 30 10 Emergency and Critical Care Center, Toyama University Hospital, 2630, Sugitani, Toyama City, Toyama 31 930-0152, Japan; E-Mail: [email protected] 32 11 Department of Emergency Medicine, Wakayama Rosai Hospital, 93-1 Kinomoto, Wakayama City, 33 Wakayama 640-8505, Japan; E-Mail: [email protected] 34 12 Department of Emergency Medicine, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, 35 Tokyo 173-8606, Japan; E-Mails: [email protected] (J.K.); [email protected] (Y.M.) 36 13 Department of Emergency and Critical Care Medicine, Urasoe General Hospital, 4-16-1 Iso, Urasoe, 37 Okinawa 901-2132, Japan; E-Mail: [email protected] 38 14 Emergency Department, Saitama Medical Center, Jichi Medical University, 1-847 Amanuma, Oomiya, 39 Saitama City, Saitama 330-8503, Japan; E-Mail: [email protected] 40 15 Japan Sport Council, 2-8-35 Kita-Aoyama, Minato-ku, Tokyo 107-0061, Japan; E-Mail: 41 [email protected] 42 16 Japan Meteorological Business Support Center, To-nen Bld, 3-17 Kanda-Nishikicho, Chiyoda-ku, Tokyo 43 101-0054, Japan; E-Mail: [email protected] 44 17 Emergency and Critical Care Center, Tokyo Metropolitan Tama Medical Centre, 2-8-29 Musashidai, Fuchu- 45 shi, Tokyo 183-8524, Japan; E-Mail: [email protected] 46 47 * Author to whom correspondence should be addressed; E-Mail: [email protected]; 48 Tel.: +81-836-22-2343; Fax: +81-836-22-2344 49 † These authors contributed equally to this work. 50 © 2018 by the author(s). Distributed under a Creative Commons CC BY license. Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 3 August 2018 doi:10.20944/preprints201808.0056.v1 Peer-reviewed version available at Int. J. Environ. Res. Public Health 2018, 15, 1962; doi:10.3390/ijerph15091962 2 of 17 51 Abstract: The Japanese Association for Acute Medicine Committee recently proposed a novel 52 classification system for the severity of heat-related illnesses. The illnesses are simply classified into 53 three stages based on symptoms and management or treatment. Stages I, II, and III broadly 54 correspond to heat cramp and syncope, heat exhaustion, and heat stroke, respectively. Our objective 55 was to examine whether this novel severity classification is useful in the diagnosis by healthcare 56 professionals of patients with severe heat-related illness and organ failure. A nationwide 57 surveillance study of heat-related illnesses was conducted between June 1 and September 30, 2012, 58 at emergency departments in Japan. Among the 2130 patients who attended 102 emergency 59 departments, the severity of their heat-related illness was recorded for 1799 patients, who were 60 included in this study. In the patients with heat cramp and syncope or heat exhaustion (but not heat 61 stroke), the blood test data (alanine aminotransferase, creatinine, blood urea nitrogen, and platelet 62 counts) for those classified as stage III were significantly higher than those of patients classified as 63 stage I or II. There were no deaths among the patients classified as stage I. This novel classification 64 may avoid underestimating the severity of heat-related illness. 65 Keywords: heat-related illness; international classification; heat cramp; syncope; heat exhaustion; 66 heat stroke; novel classification 67 68 1. Introduction 69 The international classification for heat-related illnesses, which considers heat cramp and 70 syncope, heat exhaustion, and heat stroke, has been used globally to assess the severity of heat-related 71 illnesses [1, 2]. In the international classification, heat stroke is defined as severe heat illness 72 characterized by a core temperature above 40°C and central nervous system (CNS) abnormalities. 73 Heat exhaustion is defined as a mild to moderate heat illness caused by water or salt depletion, in 74 which the core temperature may be normal, below normal, or slightly elevated (>37°C but <40°C) [1]. 75 Thus, body temperature is one index used to evaluate the severity of heat stroke in the international 76 classification. 77 The body temperatures of patients with heat-related illnesses have probably already begun to 78 decrease in response to various factors before they are transferred to hospital [3, 4], which could lead 79 to a misdiagnosis or mismanagement. Therefore, the Japanese Association for Acute Medicine 80 Committee recently proposed a novel classification system for the severity of heat-related illnesses 81 with no reference to body temperature, to avoid underestimating the illness (Supplementary Figure 82 S1) [5]. 83 ・Stage I is any minor heat-related illness, including heat cramp and syncope. The signs and 84 symptoms include dizziness, faintness, slight yawning, heavy sweating, muscle pain, and stiff 85 muscles (muscle cramps). No impaired consciousness is observed. 86 ・Stage III refers to severe conditions in a patient with hyperthermia who has been under heat 87 stress. Stage III patients show signs of brain dysfunction, such as loss of consciousness, cerebellar 88 signs, or convulsive seizures. They also display liver, kidney, or blood clotting system dysfunction 89 on blood tests. 90 ・Stage II is any heat-related illness not covered by stage I or stage III. The signs and symptoms 91 include headache, vomiting, fatigue, a sinking feeling, reduced concentration, and impaired 92 judgment. 93 In practise, stage I is a clinical condition that can be managed on site; stage II is a clinical 94 condition requiring immediate examination at a medical institution; and stage III is a clinical 95 condition requiring admission to hospital after blood sampling and assessment by medical workers 96 (and depending on the case, intensive care). It is only permissible to restrict care to first aid and 97 monitoring the patient when the stage I symptoms are gradually improving. The patient should be 98 taken to hospital immediately if stage II symptoms occur or if no improvement in stage I is observed 99 (as assessed by someone other than the patient). Stage III must be confirmed by ambulance workers 100 or by examination after arrival at hospital. Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 3 August 2018 doi:10.20944/preprints201808.0056.v1 Peer-reviewed version available at Int. J. Environ. Res. Public Health 2018, 15, 1962; doi:10.3390/ijerph15091962 3 of 17 101 Although the symptoms observed at each level of severity are commonly observed symptoms, 102 they do not always occur at the appropriate level of severity, and the illness should not be classified 103 at a different level of severity if a symptom does not occur. The clinical status (severity) of heat stroke 104 changes by the minute, depending on the timing and type of measures taken, and the condition of 105 the patient. The purpose of this severity classification is to recognize abnormalities early, to expedite 106 treatment and avoid serious consequences. 107 The novel classification broadly corresponds to the international classification (stage I, heat 108 cramp and syncope; stage II, heat exhaustion; stage III, heat stroke). However, the usefulness of the 109 novel classification in assessing the severity of heat-related illness has not been fully validated. The 110 possibility that stage III patients with organ failure, according to the novel classification, may be 111 included among patients diagnosed as having mild to moderate illness with the international 112 classification system (heat cramp and syncope, and heat exhaustion) should be considered.