热衰竭
热衰竭是较轻的中暑,可能出现非特异性症状和体征。治疗措施应着重在让患者远离热源并增加内热散发机制。措施包括去除衣物,浸湿皮肤帮助蒸发降温,同时确保出汗时不会出现体液容量不足。轻度体液容量不足通常定义为小于细胞外液容量的 5% 或小于总体重的 3%。[28]Tam N, Noakes TD. The quantification of body fluid allostasis during exercise. Sports Med. 2013;43:1289-1299.http://www.ncbi.nlm.nih.gov/pubmed/23955577?tool=bestpractice.com
低钠血症的热衰竭是特殊情况,在为热衰竭患者进行补液前应予以排除。应将所有出现重度体液容量不足、低钠血症或出现重度中枢神经系统紊乱的患者转诊至医疗机构进行进一步评估和管理。重度体液容量不足为超过细胞外液容量的 10% 或总体重的 9%。[28]Tam N, Noakes TD. The quantification of body fluid allostasis during exercise. Sports Med. 2013;43:1289-1299.http://www.ncbi.nlm.nih.gov/pubmed/23955577?tool=bestpractice.com
中暑
成年中暑患者的初始治疗应针对迅速降低体核温度。[29]Bouchama A, Dehbi M, Chaves-Carballo E. Cooling and hemodynamic management in
heatstroke: practical recommendations. Crit Care. 2007;11:R54.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2206402/http://www.ncbi.nlm.nih.gov/pubmed/17498312?tool=bestpractice.com这可能在得到明确诊断之前就地开始启动(例如通过外部降温措施)。临床观察发现预后与患者体温升高持续时间长短密切相关。如果可行,应当迅速参照 高级创伤生命支持 (ATLS) 方案对所有患者进行评估和管理。如若必要,应根据紧急医疗护理的 ABC 原则(保持气道 (A)、呼吸 (B) 和循环 (C) 顺畅)对患者实施复苏。
转诊至医疗机构后,应继续进行降温处理。降温措施可以是外部或内部;首选外部降温措施。[30]Harker J, Gibson P. Heat-stroke: a review of rapid cooling techniques. Intensive Crit Care Nurs. 1995;11:198-202.http://www.ncbi.nlm.nih.gov/pubmed/7670287?tool=bestpractice.com[31]Hadad E, Rav-Acha M, Heled Y, et al. Heat stroke: a review of cooling methods. Sports Med. 2004;34:501-511.http://www.ncbi.nlm.nih.gov/pubmed/15248787?tool=bestpractice.com
如若可行,应当给予静脉输注生理盐水。注射需 1 至 1.5 L /小时。解热药对中暑治疗无效,不应使用。[27]Hassanein T, Razack A, Gavaler JS, et al. Heatstroke: its clinical and pathological presentation, with particular attention to the liver. Am J Gastroenterol. 1992;87:1382-1389.http://www.ncbi.nlm.nih.gov/pubmed/1415091?tool=bestpractice.com丹曲林之前已在小型试验中进行过研究,此药作为当前治疗方法的辅助治疗获得了全新关注。[32]Bouchama A, Cafege A, Devol EB, et al. Ineffectiveness of dantrolene sodium in the treatment of heatstroke. Crit Care Med. 1991;19:176-180.http://www.ncbi.nlm.nih.gov/pubmed/1989755?tool=bestpractice.com[29]Bouchama A, Dehbi M, Chaves-Carballo E. Cooling and hemodynamic management in
heatstroke: practical recommendations. Crit Care. 2007;11:R54.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2206402/http://www.ncbi.nlm.nih.gov/pubmed/17498312?tool=bestpractice.com
外部降温
外部措施包括浸泡和蒸发降温。[1]Glazer JL. Management of heatstroke and heat exhaustion. Am Fam Physician. 2005;71:2133-2140.http://www.aafp.org/afp/2005/0601/p2133.htmlhttp://www.ncbi.nlm.nih.gov/pubmed/15952443?tool=bestpractice.com[30]Harker J, Gibson P. Heat-stroke: a review of rapid cooling techniques. Intensive Crit Care Nurs. 1995;11:198-202.http://www.ncbi.nlm.nih.gov/pubmed/7670287?tool=bestpractice.com[33]Newport M, Grayson A. Towards evidence-based emergency medicine: best BETs from the Manchester Royal Infirmary. BET 3: In patients with heatstroke is whole-body ice-water immersion the best cooling method? Emerg Med J. 2012;29:855-856.http://www.ncbi.nlm.nih.gov/pubmed/23038722?tool=bestpractice.com
浸泡降温
最迅速的降温方法可能是浸入冰浴、或使用降温毯同时在腋窝、腹股沟、颈部和头部放置冰袋。[34]McDermott BP, Casa DJ, Ganio MS, et al. Acute whole-body cooling for exercise-induced hyperthermia: a systematic review. J Athl Train. 2009;44:84-93.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2629045/http://www.ncbi.nlm.nih.gov/pubmed/19180223?tool=bestpractice.com[33]Newport M, Grayson A. Towards evidence-based emergency medicine: best BETs from the Manchester Royal Infirmary. BET 3: In patients with heatstroke is whole-body ice-water immersion the best cooling method? Emerg Med J. 2012;29:855-856.http://www.ncbi.nlm.nih.gov/pubmed/23038722?tool=bestpractice.com全身冷却降温方式的效果:有中等质量证据显示,在治疗劳力型体温过高时冰水浸泡的冷却效力最佳。[34]McDermott BP, Casa DJ, Ganio MS, et al. Acute whole-body cooling for exercise-induced hyperthermia: a systematic review. J Athl Train. 2009;44:84-93.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2629045/http://www.ncbi.nlm.nih.gov/pubmed/19180223?tool=bestpractice.com受试者<200名的随机对照临床试验(RCT)、受试者>200名且方法学存在缺陷的随机对照临床试验(RCT)、方法学存在缺陷的系统评价或者高质量的观察性(队列)研究。
美国运动训练治疗师协会 (National Athletic Trainers’ Association) 指南建议在冷水浸泡之前,先移除衣物/设备;[35]National Athletic Trainers' Association. Inter-Association Task Force on Exertional Heat Illnesses consensus statement. June 2003. https://www.nata.org/ (last accessed 28 September 2017).https://www.nata.org/sites/default/files/inter-association-task-force-exertional-heat-illness.pdf但是有证据显示,美国橄榄球运动员穿戴制服和衬垫浸入冷水时,也可能达到可接受的降温效率 (>0.16°C/min [>0.29°F/min])。[36]Miller KC, Long BC, Edwards J. Necessity of removing American football uniforms from humans with hyperthermia before cold-water immersion. J Athl Train. 2015;50:1240-1246.http://www.ncbi.nlm.nih.gov/pubmed/26678288?tool=bestpractice.com
冰水浴的患者经常出现后降低效应(即便患者离开冰水浴,体核温度依然持续下降)。为防止医源性体温过低,通常患者体核温度一旦达到 37.8°C (100°F) 即会让患者离开冰水浴,然而,有证据提示为防体核温度后降低,降温至 38.6°C (101.5°F) 离开冰水浴可能更安全。[1]Glazer JL. Management of heatstroke and heat exhaustion. Am Fam Physician. 2005;71:2133-2140.http://www.aafp.org/afp/2005/0601/p2133.htmlhttp://www.ncbi.nlm.nih.gov/pubmed/15952443?tool=bestpractice.com[30]Harker J, Gibson P. Heat-stroke: a review of rapid cooling techniques. Intensive Crit Care Nurs. 1995;11:198-202.http://www.ncbi.nlm.nih.gov/pubmed/7670287?tool=bestpractice.com[37]Gagnon D, Lemire BB, Casa DJ, et al. Cold-water immersion and the treatment of hyperthermia: using 38.6°C as a safe rectal temperature cooling limit. J Athl Train. 2010;45:439-444.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2938313/http://www.ncbi.nlm.nih.gov/pubmed/20831387?tool=bestpractice.com有报道降至 33°C (91.4°F) 的体温过低病例曾被成功治疗,但未进行广泛研究。[38]Hong JY, Lai YC, Chang CY, et al. Successful treatment of severe heatstroke with therapeutic hypothermia by a noninvasive external cooling system. Ann Emerg Med. 2012;59:491-493.http://www.ncbi.nlm.nih.gov/pubmed/21982153?tool=bestpractice.com医师应当注意因身体质量的隔热效应导致的假性肛门温度升高。[39]Newsham KR, Saunders JE, Nordin ES. Comparison of rectal and tympanic thermometry during exercise. South Med J. 2002;95:804-810.http://www.ncbi.nlm.nih.gov/pubmed/12190213?tool=bestpractice.com
若患者本人文化禁止暴露皮肤,浸泡可能是首选技术。
然而,因潜水反射常见,在心脏停搏和心动过缓者浸泡法则会很困难。在此类病例中,可能首选蒸发降温措施。
蒸发降温
患者皮肤暴露在45°C (113°F) 热空气经过机体,同时 用15°C (59°F) 冷水雾加速散热。经测量这项技术的降温效率为 0.31°C/min(0.5°F/min)。[30]Harker J, Gibson P. Heat-stroke: a review of rapid cooling techniques. Intensive Crit Care Nurs. 1995;11:198-202.http://www.ncbi.nlm.nih.gov/pubmed/7670287?tool=bestpractice.com
由于为浸泡患者实施心肺复苏有技术难度,年老患者或并发精神状态异常的患者可能首选蒸发降温方法。
内部降温
内部降温措施可以有效地迅速降低体温。胃、膀胱和肛门冷水灌洗全都可以实施。腹膜和胸部灌洗也可以实施,但这两项为侵入性更强的措施,所以只针对极端病例使用。尽管极少需要,心肺转流术或血浆置换同样也是有效的降温措施。[40]Raj VM, Alladin A, Pfeiffer B, et al. Therapeutic plasma exchange in the treatment of exertional heat stroke and multiorgan failure. Pediatr Nephrol. 2013;28:971-974.http://www.ncbi.nlm.nih.gov/pubmed/23338054?tool=bestpractice.com尚无数据可指导医师确定哪种情况下,内部降温措施可能优于外部降温措施。因此,在外部降温措施不适用或无效时,应当将内部降温措施作为首要降温方法使用。