Department of Emergency Medicine, Virginia Commonwealth University Medical Center, Richmond, VA 23298, USA.
Shock. 2010 Feb;33(2):113-22. doi: 10.1097/SHK.0b013e3181b8569d.
Identification of occult shock is a major clinical problem compounded by inadequate criteria for assessing the efficacy of fluid resuscitation. We suggest that these problems may be resolved in part by understanding both the physiological mechanisms underlying oxygen debt accumulation and, more importantly, the debt repayment schedule during resuscitation. We present a simplified tutorial that incorporates the concept of the oxygen supply-delivery relationship with that of oxygen debt and show how this is relevant to the understanding of shock and resuscitation. Use of oxygen debt metrics as end points for shock have been controversial; however, much of the controversy may have been due to incomplete understanding of basic physiology of shock and semantic confusion between the various metrics proposed as end points. Here, we provide working definitions for the frequently misunderstood concepts of oxygen deficit and oxygen debt and discuss the relatively novel concept of oxygen debt repayment schedule. We introduce predictions made on the basis of data derived from animal models of hemorrhagic shock. Our calculations suggest that the amount of debt repaid in the first 2 h of resuscitation, rather than the restoration of volume per se, influences the likelihood of organ damage. Because of difficulties inherent in measuring oxygen debt in the prehospital and emergency settings, various metabolic end points such as lactate and base deficit have been proposed as surrogates. We demonstrate the heuristic value of this model in providing a predictive framework for both the optimum therapeutic time window and optimum fluid loadings before critical transitions to an irreversible shock state can occur. The model also provides an unambiguous and objective standard for quantifying the behavior of various postulated shock "markers".
隐匿性休克的识别是一个主要的临床问题，其原因是评估液体复苏疗效的标准不充分。我们认为，通过了解氧债积累的生理机制，以及更重要的是在复苏过程中氧债的偿还时间表，这些问题可能会部分得到解决。我们提出了一个简化的教程，该教程将氧的供应-输送关系的概念与氧债的概念结合起来，并展示了这如何与休克和复苏的理解相关。将氧债指标用作休克的终点一直存在争议；然而，争议的很大一部分可能是由于对休克的基本生理学理解不完整，以及对作为终点提出的各种指标的语义混淆。在这里，我们提供了对氧亏和氧债这两个经常被误解的概念的工作定义，并讨论了氧债偿还时间表这一相对较新的概念。我们根据失血性休克动物模型的数据提出了预测。我们的计算表明，复苏的前 2 小时内偿还的债务量，而不是容量的恢复本身，影响器官损伤的可能性。由于在院前和急诊环境中测量氧债存在固有困难，因此已经提出了各种代谢终点，如乳酸和碱缺乏，作为替代指标。我们展示了该模型在提供最佳治疗时间窗口和最佳液体负荷预测框架方面的启发价值，以避免发生不可逆休克状态的关键转变。该模型还为量化各种假定的休克“标志物”的行为提供了一个明确和客观的标准。
