Point of care serum lactate measurement is emerging as an adjunct to prehospital clinical assessment and has the potential to guide triage and advanced treatment decision-making. In this study we aimed to assess which factors potentially affect prehospital lactate levels. We performed a retrospective cohort study of all trauma patients attended by the Air Ambulance, Kent, Surrey & Sussex (AAKSS) between July 2017 and April 2018 in whom a pre-hospital lactate was measured. Lactate was measured before AAKSS treatments were commenced, but generally after prehospital treatment by ground ambulance crews was initiated. Primary endpoint of interest was the association of various patient- and treatment characteristics with prehospital lactate levels. During the study period, lactate was measured in 156 trauma patients. Median lactate was 3.0 [2.0–4.1] mmol/l. Patients with an elevated lactate more often had deranged indices of end organ perfusion- and oxygenation (shock index 0.80 [0.58–1.03] vs 0.61 [0.40–0.82], p < 0.001, SpO2 96 [89–100%] vs 98 [96–100%], p = 0.025). They more often suffered from head injuries (62% vs 41%, p = 0.008), and received less analgesia prior to arrival of the AAKSS team (51.6% vs 67.2%, p = 0.03). In multivariate analysis, indices of end organ perfusion- and oxygenation only explained 15% of the variation in lactate levels. Prehospital lactate levels are not solely associated with indices of end organ perfusion- and oxygenation. Injury type, treatments given on scene and many other (unmeasured) factors likely play an important role as well. This should be taken into account when lactate is used in clinical algorithms to guide prehospital triage or treatment.

中文翻译：

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创伤患者院前乳酸的决定因素：一项回顾性队列研究

护理点血清乳酸测量正在作为院前临床评估的辅助手段出现，并有可能指导分类和高级治疗决策。在这项研究中，我们旨在评估哪些因素可能会影响院前乳酸水平。我们对2017年7月至2018年4月期间在肯特，萨里和苏塞克斯航空（AAKSS）救护的所有创伤患者进行了一项回顾性队列研究，他们测量了院前乳酸水平。在开始AAKSS治疗之前，但通常在地面救护人员开始院前治疗之后，对乳酸进行了测量。关注的主要终点是各种患者和治疗特征与院前乳酸水平的关联。在研究期间，对156名创伤患者进行了乳酸测定。乳酸中位数为3.0 [2.0–4。1] mmol / l。乳酸升高的患者终末器官灌注和氧合指数紊乱（休克指数0.80 [0.58–1.03] vs 0.61 [0.40–0.82]，p <0.001，SpO2 96 [89-100％] vs 98 [96] –100％]，p = 0.025）。他们更常遭受头部受伤（62％vs 41％，p = 0.008），并且在AAKSS团队到达之前接受较少的镇痛作用（51.6％vs 67.2％，p = 0.03）。在多变量分析中，终末器官灌注和氧合指标仅解释了乳酸水平变化的15％。院前乳酸水平不仅与终末器官灌注和氧合指数相关。伤害类型，现场治疗和许多其他（无法衡量的）因素也可能起重要作用。在临床算法中使用乳酸盐指导院前分流或治疗时，应考虑到这一点。