Martin N A, Falder S
St. Andrews Centre for Burns and Plastic Surgery, Broomfield Hospital, Chelmsford, Essex CM1 7ET, UK.
Department of Burns and Plastic Surgery, Alder Hey Children's NHS Foundation Trust, Liverpool L12 2AP, UK.
Burns. 2017 Dec;43(8):1624-1639. doi: 10.1016/j.burns.2017.04.003. Epub 2017 May 20.
Burn injury is common and depth is one measure of severity. Although the depth of burn injury is determined by many factors, the relationship between the temperature of the injurious agent and exposure duration, known as the time-temperature relationship, is widely accepted as one of the cornerstones of burn research. Moritz and Henriques first proposed this relationship in 1947 and their seminal work has been cited extensively. However, over the years, readers have misinterpreted their findings and incorporated misleading information about the time-temperature relationship into a wide range of industrial standards, burn prevention literature and medicolegal opinion.
The purpose of this paper is to present a critical review of the evidence that relates temperature and time to cell death and the depth of burn injury. These concepts are used by researchers, burn prevention strategists, burn care teams and child protection professionals involved in ascertaining how the mechanism of burning relates to the injury pattern and whether the injury is consistent with the history.
This review explores the robustness of the currently available evidence. The paper summarises the research from burn damage experimental work as well as bioheat transfer models and discusses the merits and limitations of these approaches.
There is broad agreement between in vitro and in vivo studies for superficial burns. There is clear evidence that the perception of pain in adult human skin occurs just above 43°C. When the basal layer of the epidermis reaches 44°C, burn injury occurs. For superficial dermal burns, the rate of tissue damage increases logarithmically with a linear increase in temperature. Beyond 70°C, rate of damage is so rapid that interpretation can be difficult. Depth of injury is also influenced by skin thickness, blood flow and cooling after injury. There is less clinical evidence for a time-temperature relationship for deep or subdermal burns. Bioheat transfer models are useful in research and becoming increasingly sophisticated but currently have limited practical use. Time-temperature relationships have not been established for burns in children's skin, although standards for domestic hot water suggest that the maximum temperature should be revised downward by 3-4°C to provide adequate burn protection for children.
Time-temperature relationships established for pain and superficial dermal burns in adult human skin have an extensive experimental modeling basis and reasonable clinical validation. However, time-temperature relationships for subdermal burns, full thickness burns and burn injury in children have limited clinical validation, being extrapolated from other data, and should be used with caution, particularly if presented during expert evidence.
烧伤很常见，烧伤深度是严重程度的一种衡量指标。尽管烧伤深度由多种因素决定，但致伤因子温度与暴露持续时间之间的关系，即时间 - 温度关系，被广泛认为是烧伤研究的基石之一。莫里茨和亨里克斯于1947年首次提出这种关系，他们的开创性工作被广泛引用。然而，多年来，读者误解了他们的研究结果，并将有关时间 - 温度关系的误导性信息纳入了广泛的工业标准、烧伤预防文献和法医学观点中。
本文的目的是对将温度和时间与细胞死亡及烧伤深度相关的证据进行批判性综述。这些概念被参与确定烧伤机制与损伤模式之间的关系以及损伤是否与病史相符的研究人员、烧伤预防策略制定者、烧伤护理团队和儿童保护专业人员所使用。
本综述探讨了现有证据的可靠性。本文总结了烧伤损伤实验研究以及生物热传递模型的研究，并讨论了这些方法的优缺点。
对于浅度烧伤，体外和体内研究之间存在广泛共识。有明确证据表明，成年人体皮肤在略高于43°C时会产生疼痛感觉。当表皮基底层达到44°C时，会发生烧伤。对于浅二度烧伤，组织损伤速率随温度线性升高呈对数增加。超过70°C时，损伤速率极快，难以解读。损伤深度还受皮肤厚度、血流量和伤后冷却的影响。对于深度或皮下烧伤的时间 - 温度关系，临床证据较少。生物热传递模型在研究中很有用且日益复杂，但目前实际应用有限。儿童皮肤烧伤的时间 - 温度关系尚未确立，尽管生活热水标准表明最高温度应下调3 - 4°C，以为儿童提供足够的烧伤防护。
为成年人体皮肤疼痛和浅二度烧伤建立的时间 - 温度关系有广泛的实验建模基础和合理的临床验证。然而，皮下烧伤、全层烧伤和儿童烧伤的时间 - 温度关系临床验证有限，是从其他数据推断而来，应谨慎使用，尤其是在专家证据中呈现时。
