[MEDSCAPE医学新闻]：AABB发布输血新指南

Medscape Medical News

Blood Transfusion Guidelines Updated by AABB

Marcia Frellick

October 12, 2016

New clinical practice guidelines from the AABB (formerly known as the American Association of Blood Banks) say that in most hemodynamically stable hospitalized adults, transfused red blood cells (RBCs) can be withheld until lower thresholds than previously recommended. In addition, RBCs can safely be given throughout their licensed dating period.

AABB（既往称为美国血库协会）发布新的临床实践指南认为，对于多数血流动力学稳定的成年住院患者，血红蛋白达到较既往推荐的阈值更低的水平时才需输注红细胞(RBCs)。另外，在特许期内的RBCs均可安全输注。

The expert panel, led by Jeffrey L. Carson, MD, from Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, published the guidelines online October 12 in JAMA. The AABB has long set standards for blood banking and transfusion practices.

由位于新泽西New Brunswick的Rutgers Robert Wood Johnson医学院Jeffrey L. Carson医生领导的专家组于2016年10月12日在JAMA杂线发表了上述指南。长期以来，AABB对于血液保存及输注行为制定标准。

The recommendation assigns two tiers of hemoglobin level transfusion triggers: 7 g/dL for hemodynamically stable adults, even those in critical care, and 8 g/dL for patients with preexisting cardiovascular disease or those undergoing cardiac or orthopedic surgery. The current hemoglobin threshold was 10 g/dL.

推荐意见设定了两个血红蛋白水平作为输血阈值：对于血流动力学稳定的成年患者（即使是ICU的患者），输血阈值为7 g/dL，对于既往有心血管疾病或接受心脏或骨科手术的患者，输血阈值为8 g/dL。目前的血红蛋白阈值为10 g/dL。

'Transfusion is a common therapeutic intervention for which there is considerable variation in clinical practice,' the authors write. 'If clinicians continue to adopt a restrictive transfusion strategy of 7 g/dL to 8 g/dL, the number of RBC transfusions would continue to decrease.'

“输血是常用的治疗措施，临床实践差异极大，”作者写到。“如果临床医生继续采取保守的输血策略(7 - 8 g/dL)，输注的RBCs数量将持续减少。”

They add, '[S]tandard practice should be to initiate a transfusion with 1 unit of blood rather than 2 units. This would have potentially important implications for the use of blood transfusions and minimize the risks of infectious and noninfectious complications,' the authors write.

他们补充到，“标准实践应当是输注一个单位而非两个单位血。这对于输血行为可能产生重要的影响，减少感染及非感染性并发症。”作者写到。

The panel analyzed the results of 31 randomized trials that included 12,587 participants. They compared restrictive thresholds, where transfusion is not advised until the hemoglobin level is 7 to 8 g/dL, with liberal thresholds, under which transfusion is indicated at 9 to 10 g/dL.

专家组分析了31项随机临床试验共12,587名患者的结果。他们比较了保守性输血阈值（血红蛋白7 - 8 g/dL时才建议输血）及自由输血阈值（血红蛋白9 - 10 g/dL即考虑输血）。

They found that restrictive thresholds across trials were not associated with higher rates of poor outcomes, 'including 30-day mortality, myocardial infarction, cerebrovascular accident, rebleeding, pneumonia, or thromboembolism.'

他们发现，保守性输血阈值并未增加不良预后的比例，“包括30天病死率，心肌梗塞，脑血管意外，再出血，肺炎或血栓栓塞。”

The evidence is not strong enough to make any recommendation for patients with acute coronary syndrome, severe thrombocytopenia, and chronic transfusion-dependent anemia.

对于急性冠脉综合征，严重血小板缺乏及输血依赖性慢性贫血患者，现有证据不足以作出任何推荐。

In an accompanying editorial, Mark H. Yazer, MD, and Darrell J. Triulzi, MD, from the Division of Transfusion Medicine, Department of Pathology, University of Pittsburgh Medical Center, Pennsylvania, write that the two-tiered approach to thresholds allows for more individualized transfusion decisions.

在同时发表的一篇述评中，来自宾州Pittsburgh大学医学中心病理科输血医学部的Mark H. Yazer及Darrell J. Triulzi医生认为，设定两个输血阈值有助于输血决策更加个体化。

They note that for patients such as those having hip replacements, functional recovery has traditionally represented the primary rationale for transfusion, which can be achieved using either a conservative or liberal hemoglobin concentration transfusion trigger strategy.

他们表示，例如，对于髋关节置换患者，传统上输血的主要目的在于促进功能恢复，采用保守或自由的血红蛋白输血阈值策略均可达到这一目的。

The decision to transfuse should not be based only on the patient's hemoglobin level, and should include other factors including availability of alternative therapies and patient preferences, the editorialists write.

输血决策不应仅仅根据患者的血红蛋白水平，而应当考虑到其他因素包括是否有其他治疗措施，以及患者的偏好等。

'That does not mean that guidelines...are without value, but rather that guidelines reflect general recommendations that apply to most patients in most situations. A major limitation of these guidelines is that they are based on hemoglobin level as the transfusion trigger,' they explain. 'Hemoglobin is a measure of the oxygen carrying capacity of blood, but does not indicate tissue oxygen delivery or the level of tissue oxygenation. Perhaps direct measurement of tissue oxygenation using noninvasive methods or plasma markers, such as base deficit, lactate, or other biomarkers, coupled with the measurement of hemoglobin level will provide a more clinically relevant indication of the need for RBC transfusion.'

“这并不意味着指南...没有意义，相反，指南反映了对于多数情况下多数患者适用的推荐意见。这些指南的主要局限性之一在于根据血红蛋白水平制定输血阈值”，他们解释到。“血红蛋白反映了血液的携氧能力，但并不反映组织的氧输送或组织氧合情况。采用无创方法或血浆标志物（如碱缺失，乳酸或其他生物标志物）直接测定组织氧合，结合血红蛋白水平测定结果，反映输注RBC的需求可能更具有临床意义。”

RBCs Safe Throughout Licensed Dating Period 在特许期内的RBCs是安全的

The guidelines also indicate that transfusing RBCs stored for any length of time within their licensed dating period is as safe as transfusing blood that has been stored 10 days or less for most stable hospitalized patients, even neonates.

指南还表明，对于多数病情稳定的住院患者（甚至包括新生儿），输注在保存期内的RBCs与保存期不足10天的血液同样安全。

The finding is important, as 100 million units of blood are donated each year, but the optimal range of storage had not been determined.

这一发现非常重要，因为每年捐献的血液超过100,000,000个单位，但适宜的储存期尚不明确。

For RBC storage, Dr Carson's team analyzed 13 randomized controlled trials that included 5515 participants randomly allocated to receive fresher blood or standard issue blood. They determined fresher blood did not improve clinical outcomes, which essentially affirms how many blood banks allocate blood in practice. Average duration of RBC storage in the United States is 17.9 days, the authors note.

关于RBC的保存，Carson医生的团队分析了13项随机对照试验，这些研究将总共5515名患者随机分为新鲜血或标准储存血组。他们发现，新鲜血并不能改善临床预后。作者表示，在美国，RBC的平均保存期为17.9天。

The editorialists conclude, 'These new guidelines from the AABB represent medicine at its best in that they are evidence based, derived from RCTs, reflect important clinical perspectives, and are definitive for conditions in which data are substantial, but provide greater flexibility for conditions in which data are less certain.'

述评人总结到：“AABB发布的新指南表明，在最好的情况下，医学应当基于来自RCT的证据，反映了重要的临床观点，对于有大量数据的情况提供确切的结论，而对资料并不明确的情况提出更加灵活的建议。”

The guidelines were updated from 2012 guidelines, which were based on fewer, smaller trials and included a high risk for bias, according to the researchers.

这一指南对2012年指南进行了更新。研究者认为，2012年指南是根据少数小样本研究结果制定的，具有很大的偏倚风险。

'During the past 4 years,' the authors write, 'the number of patients enrolled in RBC transfusion [randomized controlled trials] has more than doubled, and many studies have incorporated methods to minimize the risk of bias and enrolled populations of patients receiving frequent blood transfusions.'

“在过去4年间，”作者写到，“入选输注RBC随机对照试验的患者人数成倍增加，很多研究采取的方法减少了偏倚的风险，入选的患者为接受频繁输血的人群。”

Support for guideline development was provided by the AABB. Study coauthors report receiving support, personal fees, or stock options from Fresenius Kabi, Fenwal (a Fresenius Kabi company), Ortho Clinical Diagnostics, Octapharma, MacoPharm US, Castle Medical Inc, CSL Plasma Inc, Transfusion and Transplantation Technologies Inc, Cambium Medical Technologies, Biomet, CSL Behring, Masimo Corporation, Merck, AMAG Pharmaceuticals, Gauss Surgical, Vifor Pharma, and HbO2 Therapeutics. Dr Triulzi reported receiving grants from the National Heart, Lung, and Blood Institute and receiving personal fees for serving on an advisory board for Fresenius Kabi.

JAMA. Published online October 12, 2016