Parekh Ankit
Division of Pulmonary, Critical Care and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
Curr Opin Pulm Med. 2024 Nov 1;30(6):600-606. doi: 10.1097/MCP.0000000000001122. Epub 2024 Sep 17.
Obstructive sleep apnea (OSA) is a common chronic condition that affects over a billion people worldwide and is associated with adverse cardio- and cerebrovascular consequences. Currently, the go-to clinical measure that determines the presence and severity of OSA is the apnea-hypopnea index (AHI). The AHI captures the frequency of respiratory events due to changes in ventilation that are associated with either oxygen desaturations or arousal from sleep. The AHI is poorly correlated to adverse outcomes in OSA with poor prognostic ability. To overcome the limitations of AHI and perhaps driven by the ease of acquisition, several studies have suggested characterizing nocturnal hypoxia in OSA, termed as "hypoxic burden". The purpose of this review is to focus on the hypoxic burden in OSA, its various definitions, and its utility in moving OSA diagnosis beyond the AHI.
Several measures and definitions of hypoxic burden have been proposed and studied that show promise in overcoming limitations of AHI and also have a greater prognostic ability than AHI. More recently, area-based measures that attempt to characterize the depth and duration of oxygen desaturations, i.e., nocturnal hypoxia in OSA, have been shown to better relate to incident cardiovascular disease than AHI. In this review, we delve into the evidence for these novel area-based metrics and also delve into the pathophysiological concepts underlying nocturnal hypoxia while cautioning the reader on interpretation of the recent findings relating hypoxic burden to adverse outcomes in OSA.
In this review on hypoxic burden, we focus on the need that has driven the sudden influx of studies assessing hypoxic burden for various outcomes of OSA, its underlying pathophysiology, the various definitions, and clinical relevance. We hope that the reader can appreciate the nuances underlying hypoxic burden in OSA and suggest the need for a cohesive framework for moving beyond the AHI with hypoxic burden.
阻塞性睡眠呼吸暂停（OSA）是一种常见的慢性疾病，全球有超过10亿人受其影响，并与不良的心脑血管后果相关。目前，用于确定OSA的存在和严重程度的主要临床指标是呼吸暂停低通气指数（AHI）。AHI反映了与氧饱和度下降或睡眠中觉醒相关的通气变化导致的呼吸事件频率。AHI与OSA的不良结局相关性较差，预后能力不足。为了克服AHI的局限性，可能也是受获取数据便捷性的驱动，多项研究建议对OSA中的夜间低氧血症进行特征化描述，即“低氧负荷”。本综述的目的是聚焦于OSA中的低氧负荷、其各种定义以及在超越AHI进行OSA诊断方面的效用。
已经提出并研究了几种低氧负荷的测量方法和定义，这些方法在克服AHI的局限性方面显示出前景，并且比AHI具有更强的预后能力。最近，试图描述氧饱和度下降的深度和持续时间（即OSA中的夜间低氧血症）的基于面积的测量方法已被证明比AHI与心血管疾病的发生更相关。在本综述中，我们深入探讨了这些新颖的基于面积的指标的证据，也深入探讨了夜间低氧血症背后的病理生理概念，同时提醒读者对低氧负荷与OSA不良结局相关的最新发现进行解读时需谨慎。
在本关于低氧负荷的综述中，我们关注了促使评估低氧负荷对OSA各种结局影响的研究突然大量涌现的需求、其潜在的病理生理学、各种定义以及临床相关性。我们希望读者能够理解OSA中低氧负荷背后的细微差别，并认识到需要一个连贯的框架来超越AHI并纳入低氧负荷。
