Department of Anaesthesiology, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands.
Hôpitaux universitaires Paris-Sud, Hôpital de Bicêtre, Service de réanimation Médicale.
Curr Opin Crit Care. 2018 Jun;24(3):181-189. doi: 10.1097/MCC.0000000000000493.
The current review attempts to demonstrate the value of several forms of carbon dioxide (CO2) gaps in resuscitation of the critically ill patient as monitor for the adequacy of the circulation, as target for fluid resuscitation and also as predictor for outcome.
Fluid resuscitation is one of the key treatments in many intensive care patients. It remains a challenge in daily practice as both a shortage and an overload in intravascular volume are potentially harmful. Many different approaches have been developed for use as target of fluid resuscitation. CO2 gaps can be used as surrogate for the adequacy of cardiac output (CO) and as marker for tissue perfusion and are therefore a potential target for resuscitation. CO2 gaps are easily measured via point-of-care analysers. We shed light on its potential use as nowadays it is not widely used in clinical practice despite its potential. Many studies were conducted on partial CO2 pressure differences or CO2 content (cCO2) differences either alone, or in combination with other markers for outcome or resuscitation adequacy. Furthermore, some studies deal with CO2 gap to O2 gap ratios as target for goal-directed fluid therapy or as marker for outcome.
CO2 gap is a sensitive marker of tissue hypoperfusion, with added value over traditional markers of tissue hypoxia in situations in which an oxygen diffusion barrier exists such as in tissue oedema and impaired microcirculation. Venous-to-arterial cCO2 or partial pressure gaps can be used to evaluate whether attempts to increase CO should be made. Considering the potential of the several forms of CO2 measurements and its ease of use via point-of-care analysers, it is recommendable to implement CO2 gaps in standard clinical practice.
本综述旨在展示几种形式的二氧化碳（CO2）差值在危重症患者复苏中的价值，包括作为循环充足性的监测指标、作为液体复苏的目标以及作为预后的预测指标。
液体复苏是许多重症监护患者的关键治疗方法之一。在实践中，这仍然是一个挑战，因为血管内容量不足和过载都可能是有害的。已经开发了许多不同的方法作为液体复苏的目标。CO2 差值可作为心输出量（CO）充足性的替代指标，也可作为组织灌注的标志物，因此是复苏的潜在目标。CO2 差值可通过即时检测分析仪轻松测量。尽管 CO2 差值具有潜在的用途，但目前尚未广泛应用于临床实践，我们将对此进行探讨。许多研究都针对部分 CO2 压力差或 CO2 含量（cCO2）差进行了研究，这些研究单独或与其他预后或复苏充足性标志物结合使用。此外，一些研究涉及 CO2 差值与 O2 差值的比值作为目标导向的液体治疗的目标或预后的标志物。
CO2 差值是组织低灌注的敏感标志物，在存在氧扩散屏障的情况下，如组织水肿和微循环受损时，其比传统的组织缺氧标志物更有价值。静脉-动脉 cCO2 或分压差值可用于评估是否应尝试增加 CO。考虑到几种形式的 CO2 测量的潜力及其通过即时检测分析仪的易用性，建议在标准临床实践中实施 CO2 差值。
