Moffatt Samuel E, Mitchell S J B, Walke J L
University of Leicester Medical School, Centre for Medicine, Leicester, UK.
J R Army Med Corps. 2018 Jul;164(3):191-196. doi: 10.1136/jramc-2016-000723. Epub 2017 May 11.
Survival in exsanguinating cardiac arrest patients is poor, as is neurological outcome in survivors. Hypothermia has traditionally been seen as harmful to trauma patients and associated with increased mortality; however, there has been speculation that cooling to very low temperatures (20°C) could be used to treat haemorrhagic trauma patients by the induction of a suspended animation period through extreme cooling, which improves survival and preserves neurological function. This has been termed emergency preservation and resuscitation (EPR).
A systematic review of the literature was used to examine the evidence base behind the use of deep and profound hypothermia in haemorrhagic shock (HS). It included original research articles (human or animal) with cooling to 20°C after HS or an experimental model replicating it. Normovolaemic cardiac arrest, central nervous system injury and non-HS models were excluded.
Twenty articles using 456 animal subjects were included, in which 327 were cooled to 20°C. All studies describing good survival rates were possible using EPR and 19/20 demonstrated that EPR can preserve neurological function after prolonged periods of circulatory arrest or minimal circulatory flow. This additional period can be used for surgical intervention to arrest haemorrhage in HS that would otherwise be lethal.
The outcomes of this review have significant implications for application to human patients and the ongoing human clinical trial (EPR for Cardiac Arrest from Trauma). Current evidence suggests that hypothermia 20°C used in the form of EPR could be beneficial to the HS patient.
失血性心脏骤停患者的生存率很低，幸存者的神经功能预后也很差。传统上，低温被认为对创伤患者有害且与死亡率增加相关；然而，有人推测，将体温降至极低水平（20°C）可用于治疗出血性创伤患者，通过极端降温诱导一段假死期，从而提高生存率并保留神经功能。这被称为紧急保存与复苏（EPR）。
对文献进行系统综述，以检验在失血性休克（HS）中使用深度和极低温的证据基础。纳入在HS后将体温降至20°C的原始研究文章（人类或动物）或复制该过程的实验模型。排除正常血容量性心脏骤停、中枢神经系统损伤和非HS模型。
纳入20篇使用456只动物受试者的文章，其中327只被冷却至20°C。所有描述良好生存率的研究都可以通过EPR实现，20篇中有19篇表明EPR可在长时间循环骤停或最小循环血流后保留神经功能。这段额外的时间可用于手术干预，以阻止HS中否则将致命的出血。
本综述的结果对应用于人类患者及正在进行的人类临床试验（创伤性心脏骤停的EPR）具有重要意义。目前的证据表明，以EPR形式使用的20°C低温可能对HS患者有益。
