Comparison of Drug-Induced Sleep Endoscopy and Natural Sleep Endoscopy in the Assessment of Upper Airway Pathophysiology During Sleep: Protocol and Study Design.

Karlien Van Den Bossche,Olivier M Vanderveken,Johan Verbraecken,Marc Willemen,Sara Op De Beeck,Andrew Wellman,Eli Van De Perck,Elahe Kazemeini,Daniel Vena

doi:10.3389/fneur.2021.768973

Abstract

Study Objectives: Obstructive sleep apnea (OSA) is increasingly recognized as a complex and heterogenous disorder. As a result, a “one-size-fits-all” management approach should be avoided. Therefore, evaluation of pathophysiological endotyping in OSA patients is emphasized, with upper airway collapse during sleep as one of the main features. To assess the site(s) and pattern(s) of upper airway collapse, natural sleep endoscopy (NSE) is defined as the gold standard. As NSE is labor-intensive and time-consuming, it is not feasible in routine practice. Instead, drug-induced sleep endoscopy (DISE) is the most frequently used technique and can be considered as the clinical standard. Flow shape and snoring analysis are non-invasive measurement techniques, yet are still evolving. Although DISE is used as the clinical alternative to assess upper airway collapse, associations between DISE and NSE observations, and associated flow and snoring signals, have not been quantified satisfactorily. In the current project we aim to compare upper airway collapse identified in patients with OSA using endoscopic techniques as well as flow shape analysis and analysis of tracheal snoring sounds between natural and drug-induced sleep.Methods: This study is a blinded prospective comparative multicenter cohort study. The study population will consist of adult patients with a recent diagnosis of OSA. Eligible patients will undergo a polysomnography (PSG) with NSE overnight and a DISE within 3 months. During DISE the upper airway is assessed under sedation by an experienced ear, nose, throat (ENT) surgeon using a flexible fiberoptic endoscope in the operating theater. In contrast to DISE, NSE is performed during natural sleep using a pediatric bronchoscope. During research DISE and NSE, the standard set-up is expanded with additional PSG measurements, including gold standard flow and analysis of tracheal snoring sounds.Conclusions: This project will be one of the first studies to formally compare collapse patterns during natural and drug-induced sleep. Moreover, this will be, to the authors' best knowledge, the first comparative research in airflow shape and tracheal snoring sounds analysis between DISE and NSE. These novel and non-invasive diagnostic methods studying upper airway mechanics during sleep will be simultaneously validated against DISE and NSE.Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT04729478.

Highlights

Obstructive sleep apnea (OSA) is a highly prevalent disorder affecting almost one billion individuals worldwide [1]
The PALM concept combines these pathophysiological traits on a three-point scale, enabling categorization of patients into three categories: PALM scale 1 consists of patients with a high collapsible upper airway, necessitating a major anatomic intervention
PALM scale 2 includes patients with a moderate collapsibility who are candidates for an anatomic or nonanatomic intervention or a combination of both according to the other OSA traits, and PALM scale 3 is constituted of patients with predominantly non-anatomic traits and overall a less severe OSA [6]

Summary

Introduction

Obstructive sleep apnea (OSA) is a highly prevalent disorder affecting almost one billion individuals worldwide [1]. This entity can be best described as a heterogenous condition with recurrent upper airway collapse provoking nocturnal breathing cessation [2]. Non-anatomical traits are important contributors to OSA pathogenesis, including an ineffective pharyngeal muscle response during sleep, an oversensitive ventilatory control system (i.e., high loop gain), and a low arousal threshold [6]. The PALM concept combines these pathophysiological traits on a three-point scale (passive critical closing pressure, arousal threshold, loop gain, and muscle responsiveness), enabling categorization of patients into three categories: PALM scale 1 consists of patients with a high collapsible upper airway, necessitating a major anatomic intervention. This research project will focus on the anatomical OSA traits, with a particular focus on the site of upper airway collapse

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