Department of Intensive Care, CHIREC Hospitals, Université Libre de Bruxelles, Brussels, Belgium.
Department of Intensive Care, Fundación Valle del Lili.
Curr Opin Crit Care. 2023 Jun 1;29(3):244-251. doi: 10.1097/MCC.0000000000001046. Epub 2023 Apr 6.
To discuss the different techniques used to assess tissue oxygenation in critically ill patients.
While historically the analysis of oxygen consumption (VO2)/oxygen delivery (DO2) relationships has provided important information, methodological limitations prevent its use at bedside. PO2 measurements, while attractive, are unfortunately of limited value in the presence of microvascular blood flow heterogeneity which is observed in many critically ill conditions including sepsis. Surrogates of tissue oxygenation are hence used. Elevated lactate levels may suggest inadequate tissue oxygenation, but other sources than tissue hypoxia can also contribute to hyperlactatemia so that lactate measurements should be used in combination with other measurements of tissue oxygenation. Venous O2 saturation can be used to evaluate the adequacy of DO2 in respect to VO2, but it can be misleading normal or even high in sepsis. Measurements of Pv-aCO2 and computation of Pv-aCO2/CavO2 are very promising as physiologically sound, easy to measure, rapidly respond to therapy, and are associated with outcome. An elevated Pv-aCO2 reflects an impaired tissue perfusion while an increased Pv-aCO2/CavO2 ratio reflects tissue dysoxia.
Recent studies have highlighted the interest of surrogate measurements of tissue oxygenation and in particular PCO2 gradients.
讨论评估危重病患者组织氧合的不同技术。
虽然从历史上看，分析耗氧量（VO2）/氧输送（DO2）关系提供了重要信息，但方法学上的限制使其无法在床边使用。PO2 测量虽然很有吸引力，但在许多危重病情况下存在微血管血流异质性，这在包括脓毒症在内的许多情况下都有观察到，因此其价值有限。因此，使用组织氧合的替代指标。乳酸水平升高可能表明组织氧合不足，但除组织缺氧外，其他来源也可能导致高乳酸血症，因此乳酸测量应与其他组织氧合测量结合使用。静脉血氧饱和度可用于评估 DO2 与 VO2 的充足性，但在脓毒症中，它可能会导致正常或甚至升高的误导。Pv-aCO2 的测量和 Pv-aCO2/CavO2 的计算作为生理合理、易于测量、快速响应治疗以及与结果相关的指标非常有前途。升高的 Pv-aCO2 反映了组织灌注受损，而升高的 Pv-aCO2/CavO2 比值反映了组织缺氧。
最近的研究强调了组织氧合替代指标，特别是 PCO2 梯度的重要性。
