The editorial by Green et al. [1] attempts to define ‘procedural sedation’. We acknowledge the merits of precisely defining terminology and the rigour of the Delphi method applied by the International Committee for the Advancement of Procedural Sedation (ICAPS). However, we remain concerned that their definition is inadequate. Moreover, we question the value of the term ‘procedural sedation’.

The proposed definition essentially describes ‘procedural sedation’ as provision of anxiolysis and analgesia to facilitate a procedure, without compromise of airway maintenance/protection, spontaneous ventilation or haemodynamic stability. No direct reference is made to changes in the level of consciousness. This is surprising given some degree of central nervous system depression is the essence of sedation and a clear association exists between this and the likelihood of physiological compromise. Concerningly, a footnote includes ‘deep sedation’ as being “within the purview” of the ICAPS definition. Given that the ASA identifies ‘deep sedation’ as a state associated with the potential for both inadequate ventilation and the need for interventions to maintain airway patency [2], an untenable contradiction with the proposed definition exists. Furthermore, the authors’ assertion that it is possible to reliably target a level of sedation that ensures infrequent compromise of airway, breathing and circulation is inconsistent with our clinical experience and ASA advice [2]. Depth of sedation and its associated physiological perturbations are the endpoints of a complex and not always predictable interaction between medication doses, level of stimulation (which may vary widely over the course of a procedure) and individual susceptibility (both intrinsic and secondary to superimposed pathology). The potential to over- or undershoot the targeted depth of sedation should always be viewed as not only plausible, but foreseeable.

The term ‘procedural sedation’ is also inherently problematic, distinguishing itself from other sedation states by reference to the indication for which it is performed, rather than the degree of depression of consciousness achieved. Given the variability in the degree of sedation required to avoid patient pain and distress according to the nature and stage of a procedure, ‘procedural’ seems an inadequate adjective to delineate the crucial qualification that compromise of airway, breathing or circulation should be avoided. The definition proposed by ICAPS can be more accurately described using the existing language of the ASA continuum of depth of sedation [2], where it equates to minimal or moderate sedation. Greater clarity and safety would be achieved by abandoning the term procedural sedation and simply stating that minimal or moderate sedation should be used for designated procedures, contexts or providers.

The editorial does raise two important points regarding the ASA sedation continuum. Firstly, in this classification, deep sedation is characterised by ‘purposeful responses’ to stimulation while general anaesthesia is characterised by patients being ‘unrousable’. However, an intermediate state of non-purposeful movement in response to painful stimuli exists that is not described by this continuum. Green et al. incorrectly refer to ‘monitored anaesthesia care’ as a deep level of sedation that includes “potential conversion to general anaesthesia.” Monitored anaesthesia care does not refer to a point on the depth of sedation continuum but defines, for billing purposes, an anaesthesia service associated with a particular standard of clinical oversight before, during and after a procedure [2, 3]. While deep sedation is one indication for monitored anaesthesia care, it may also be required when sedation is light or even absent [4]. Secondly, across the ASA sedation continuum, reference is made to the varying potential for compromise of airway patency but not protection. Airway protective reflexes are more likely to be preserved during light and moderate sedation than during deep sedation and general anaesthesia. The ASA sedation continuum could be enhanced by the addition of this criterion, while emphasising that due to the persistent risk of inadvertently moving beyond the intended depth of sedation [2], the need for fasting is not negated, even when lighter planes of sedation are targeted.

格林等人的社论。[ 1 ] 试图定义“程序镇静”。我们承认精确定义术语的优点和国际程序镇静促进委员会 (ICAPS) 应用的德尔菲法的严谨性。然而，我们仍然担心他们的定义不够充分。此外，我们质疑术语“程序镇静”的价值。

拟议的定义基本上将“程序镇静”描述为提供抗焦虑和镇痛以促进程序，而不损害气道维护/保护、自主通气或血流动力学稳定性。没有直接提到意识水平的变化。这是令人惊讶的，因为一定程度的中枢神经系统抑制是镇静的本质，并且这与生理妥协的可能性之间存在明显的关联。令人担忧的是，脚注包括“深度镇静”作为ICAPS 定义的“范围内”。鉴于 ASA 将“深度镇静”确定为与通气不足和需要干预以维持气道通畅的可能性相关的状态 [ 2]]，与提议的定义存在站不住脚的矛盾。此外，作者断言可以可靠地将镇静水平作为目标，以确保气道、呼吸和循环不经常受到损害，这与我们的临床经验和 ASA 建议不一致 [ 2 ]。镇静深度及其相关的生理扰动是药物剂量、刺激水平（在手术过程中可能变化很大）和个体易感性（固有和继发于叠加病理）之间复杂且并不总是可预测的相互作用的终点. 超过或低于目标镇静深度的可能性应始终被视为不仅是合理的，而且是可预见的。

术语“程序镇静”本身也存在问题，通过参考执行的适应症而不是达到的意识抑制程度将其与其他镇静状态区分开来。鉴于根据手术的性质和阶段，避免患者疼痛和痛苦所需的镇静程度的可变性，“程序”似乎不足以描述应避免损害气道、呼吸或循环的关键限定条件。ICAPS 提出的定义可以使用 ASA 镇静深度连续体的现有语言更准确地描述 [ 2]]，相当于轻度或中度镇静。放弃程序镇静一词并简单说明应将最低或中度镇静用于指定的程序、背景或提供者，将实现更大的清晰度和安全性。

社论确实提出了关于 ASA 镇静连续体的两个重要点。首先，在该分类中，深度镇静的特征在于对刺激的“有目的的反应”，而全身麻醉的特征在于患者“无法唤醒”。然而，存在响应疼痛刺激的无目的运动的中间状态，该连续统未描述。格林等人。错误地将“监测麻醉护理”称为深度镇静，包括“可能转换为全身麻醉”。受监控的麻醉护理不是指镇静连续体的深度，而是为了计费目的，定义了与手术前、手术中和手术后特定临床监督标准相关的麻醉服务 [ 2, 3]]。虽然深度镇静是监测麻醉护理的一种适应症，但在镇静较轻或什至没有镇静时，也可能需要使用深度镇静 [ 4 ]。其次，在整个 ASA 镇静连续体中，提到了影响气道通畅而不是保护的不同可能性。与深度镇静和全身麻醉相比，在轻度和中度镇静期间更可能保留气道保护性反射。ASA 镇静连续性可通过添加此标准得到增强，同时强调由于无意中超出预期镇静深度的持续风险 [ 2 ]，即使镇静程度较轻，也不会取消禁食的必要性有针对性。