VincentJL：脓毒症血乳酸八问
CARDIOPULMONARY MONITORING
Blood lactate levels in psis: in 8 questions
Vincent, Jean-Louisa; Bakker, Janb,c,d,eAuthor Information
Current Opinion in Critical Care: June 2021 - Volume 27 - Issue 3 - p 298-302
doi: 10.1097/MCC.0000000000000824
Abstract西红柿鱼
Purpo of review Blood lactate concentrations are frequently measured in critically ill patients and have important prognostic value. Here, we review some key questions related to their clinical u in psis.
Recent findings Despite the metabolic hurdles, measuring lactate concentrations remains very informative in clinical practice. Although blood lactate levels change too slowly to reprent the only guide to resuscitation, rial lactate levels can help to define the patien
t's trajectory and encourage a review of the therapeutic strategy if they remain stable or increa over time.
离别歌词Summary Lactate concentrations respond too slowly to be ud to guide acute changes in therapy, but can help evaluate overall respon. Hyperlactatemia should not be considered as a problem in itlf, but as a warning of altered cell function（乳酸浓度反应太慢，无法用于指导治疗的急性变化，但可以帮助评估整体反应。高乳糖血症本身不应被视为一个问题，而应被视为细胞功能改变的警告）.
介绍蒲公英
要点：
∙休克患者乳酸浓度增加，并与脏器功能障碍和死亡率增加相关联
∙乳酸水平的变化是由产生与其吸收或清除的平衡决定的
∙高乳酸血症可视为细胞功能改变的预警信号微信号英文
椰肉怎么吃∙养老规划感染性休克中随着液体复苏乳酸水平下降可提示临床改善，但患者的治疗永远别依赖单一指标
∙连续乳酸监测太慢而无助于直接引导治疗的变化，但可用于整体治疗的指导。
INTRODUCTION
Measurement of blood lactate concentrations can be very uful in ptic shock, as in other forms of shock, providing a marker of altered tissue perfusion, dia verity, and
秋天的枫叶作文prognosis [1–4,5▪]. Moreover, the evaluation of rial lactate concentrations can help monitor a patient's respon to treatment. The normal blood lactate concentration is about 1 mEq/l (or mMol/l), and an increa to 1.5 mEq/l (hyperlactatemia) or above is an important alarm signal [6]. Septic shock is associated with a lactate concentration above an arbitrary value of 2 mEq/L [7].
In this article, we will provide an up-to-date review on the role of blood lactate measurement in patients with psis by providing answers to eight important questions.
Question 1: Does hyperlactatemia always reflect anaerobic metabolism in psis?
Answer: No.
各种花的含义
问题1：高乳酸血症能反映脓毒症的无氧代谢吗？
回 答：No
Under physiological conditions, lactate is a normal end-product of gluco metabolism via
two main pathways: glycolysis and oxidative phosphorylation. Glycolysis is a process that generates small amounts of adenosine triphosphate (ATP), but becau of its speed, can create significant energy. Oxidative phosphorylation is the process that involves the Krebs cycle. This is a slower process than glycolysis and requires oxygen to metabolize the pyruvate generated from gluco. In shock, including ptic shock, lack of oxygen prohibits the metabolism of pyruvate in the Krebs cycle, and anaerobic metabolism converts it to lactate via the enzyme lactate dehydrogena. Indeed, hypoxic states are characterized by inadequate oxygen supply to the cells such that supply is unable to match demand. Experimental studies, including models of endotoxin administration or bacterial psis, have clearly documented that an acute and profound reduction in global oxygen delivery (DO2) results in a decrea in oxygen uptake (VO2) and that the critical DO2 value at which this occurs is also the moment when lactate concentrations start to increa sharply.
In psis, the altered microcirculation, with incread heterogeneity of flow, further limits tissue oxygenation [8]. In cardiac surgery patients, who have similar microcirculatory cha
nges to tho en in psis, greater verity of microcirculatory impairment was associated with significantly higher blood lactate concentrations [9▪]. In patients with incread lactate production, liver dysfunction, frequently prent in patients with psis, may reduce the capacity to clear lactate, thus contribute to raid blood lactate concentrations. However, liver failure alone cannot result in hyperlactatemia [10]. The kidneys also metabolize lactate but to a much lesr extent such that renal failure does not have a major impact on blood lactate concentrations.
In addition metabolic changes in psis, such as inhibition of pyruvate dehydrogena and incread Na/K pump activity, may result in incread lactate concentrations despite the prence of adequate tissue oxygen availability. Another possible reason for incread lactate in psis is incread glycolysis, a process that is stimulated by beta-adrenergic agents and alkalemia among other caus (Table 1). Other caus of hyperlactatemia, which are less relevant to our discussion in psis, also exist. For example, metformin u can cau hyperlactatemia by interfering with oxidative phosphorylation [11▪].
If there are associated metabolic alterations, the lactate/pyruvate (L/P) ratio will be incread above the normal value of around 10/1, whereas with incread glycolysis, it is the excess pyruvate that can lead to hyperlactatemia, with an unchanged L/P ratio. Separation of hyperlactatemia into hypoxic and nonhypoxic caus bad on the L/P ratio has been attempted, but pyruvate measurements are difficult and prone to technical problems. Moreover, the two types (hypoxic and nonhypoxic) usually co-exist. Studies have shown that pyruvate concentrations and/or the L/P ratio have limited clinical u.
Question 2: Does vasoactive drug therapy contribute to incread lactate concentrations?
Answer: Yes and no.
问题2：血管活性药物能增加乳酸水平吗？
回 答：似是而非.
Catecholamines with strong beta-adrenergic activity can stimulate cellular metabolism and thereby increa lactate concentrations. This is particularly the ca with administration of epinephrine, which is now relatively uncommon. Any changes in lactate concentration associated with vasoactive drug administration would, however, only amplify the alarm signal, becau the sicker the patient, the greater the need for vasoactive agents and the higher the lactate concentrations. It would be a clinical error to overestimate this phenomenon and to assume that a patient's hyperlactatemia is solely the result of administration of adrenergic agents without an associated decrea in tissue perfusion（高估血管活性药物造成乳酸增加的情况，并认为患者的高乳酸血症仅仅是由肾上腺素给药造成而忽略组织灌注减少，这完全是一个错误）.
