The appropriateness of a restrictive transfusion strategy for those with active bleeding after traumatic injury remains uncertain. Given the association between tissue hypoxia and lactate levels, we hypothesized that the optimal transfusion strategy may differ based on lactate levels. This post hoc analysis of the RESTRIC trial sought to investigate the association between transfusion strategies and patient outcomes based on initial lactate levels. We performed a post hoc analysis of the RESTRIC trial, a cluster-randomized, crossover, non-inferiority multicenter trials, comparing a restrictive and liberal red blood cell transfusion strategy for adult trauma patients at risk of major bleeding. This was conducted during the initial phase of trauma resuscitation; from emergency department arrival up to 7 days after hospital admission or intensive care unit (ICU) discharge. Patients were grouped by lactate levels at emergency department arrival: low (< 2.5 mmol/L), middle (≥ 2.5 and < 4.0 mmol/L), and high (≥ 4.0 mmol/L). We compared 28 days mortality and ICU-free and ventilator-free days using multiple linear regression among groups. Of the 422 RESTRIC trial participants, 396 were analyzed, with low (n = 131), middle (n = 113), and high (n = 152) lactate. Across all lactate groups, 28 days mortality was similar between strategies. However, in the low lactate group, the restrictive approach correlated with more ICU-free (β coefficient 3.16; 95% CI 0.45 to 5.86) and ventilator-free days (β coefficient 2.72; 95% CI 0.18 to 5.26) compared to the liberal strategy. These findings persisted even after excluding patients with severe traumatic brain injury. Our results suggest that restrictive transfusion strategy might not have a significant impact on 28-day survival rates, regardless of lactate levels. However, the liberal transfusion strategy may lead to shorter ICU- and ventilator-free days for patients with low initial blood lactate levels.

中文翻译：

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初始乳酸水平和红细胞输注策略与严重创伤后结果的关联：RESTRIC 试验的事后分析

对于创伤后活动性出血的患者，限制性输血策略是否合适仍不确定。鉴于组织缺氧和乳酸水平之间的关联，我们假设最佳输血策略可能会根据乳酸水平而有所不同。RESTRIC 试验的事后分析旨在调查输血策略与基于初始乳酸水平的患者结果之间的关联。我们对 RESTRIC 试验进行了事后分析，这是一项整群随机、交叉、非劣效性多中心试验，比较了针对有大出血风险的成年创伤患者的限制性和自由性红细胞输注策略。这是在创伤复苏的初始阶段进行的；从到达急诊室起一直到入院或重症监护病房 (ICU) 出院后 7 天。患者到达急诊室时根据乳酸水平进行分组：低（< 2.5 mmol/L）、中（≥ 2.5 且< 4.0 mmol/L）和高（≥ 4.0 mmol/L）。我们使用组间多元线性回归比较了 28 天死亡率以及无 ICU 和无呼吸机天数。在 422 名 RESTRIC 试验参与者中，对 396 名参与者进行了分析，其中乳酸水平分别为低（n = 131）、中（n = 113）和高（n = 152）。在所有乳酸组中，不同策略的 28 天死亡率相似。然而，在低乳酸组中，与自由疗法相比，限制性方法与更多的无 ICU（β 系数 3.16；95% CI 0.45 至 5.86）和无呼吸机天数（β 系数 2.72；95% CI 0.18 至 5.26）相关。战略。即使排除了严重脑外伤患者后，这些发现仍然存在。我们的结果表明，无论乳酸水平如何，限制性输血策略可能不会对 28 天存活率产生显着影响。然而，自由输血策略可能会导致初始血乳酸水平较低的患者无需入住 ICU 和呼吸机的天数缩短。