Clinical Study
High-Flow Nasal Cannula and Mandibular Advancement Bite
Block Decrease Hypoxic Events during Sedative
Esophagogastroduodenoscopy: A Randomized Clinical Trial
Wei-Nung Teng ,
1,2
Chien-Kun Ting ,
1
Yu-Tzu Wang ,
2
Ming-Chih Hou,
3
Wen-Kuei Chang,
1
Mei-Yung Tsou,
1
Huihua Chiang ,
2
and Chun-Li Lin
2
1
Department of Anaesthesiology, Taipei Veterans General Hospital, Taipei City 11217, Taiwan
2
Department of Biomedical Engineering, National Yang-Ming University, Taipei City 11221, Taiwan
3
Department of Medicine, Taipei Veterans General Hospital, Taipei City 11217, Taiwan
Correspondence should be addressed to Huihua Chiang; hkchiang@ym.edu.tw and Chun-Li Lin; cllin2@ym.edu.tw
Received 13 May 2019; Revised 21 June 2019; Accepted 4 July 2019; Published 16 July 2019
Academic Editor: Hideo Inaba
Copyright © 2019 Wei-Nung Teng et al. Tis is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
During sedated endoscopic examinations, upper airway obstruction occurs. Nasal breathing ofen shifs to oral breathing during
open mouth esophagogastroduodenoscopy (EGD). High-fow nasal cannula (HFNC) which delivers humidifed 100% oxygen at 30
L min
-1
may prevent hypoxemia. A mandibular advancement (MA) bite block with oxygen inlet directed to both mouth and nose
may prevent airway obstruction during sedated EGD. Te purpose of this study was to evaluate the efcacy of these airway devices
versus standard management. One hundred and eighty-nine patients were assessed for eligibility. One hundred and ffy-three were
enrolled. Tis study randomly assigned eligible patients to three arms: the standard bite block and standard nasal cannula, HFNC,
and MA bite block groups. EGD was performed afer anaesthetic induction. Te primary endpoint was the oxygen desaturation
area under curve at 90% (AUC
Desat
). Te secondary endpoints were percentage of patients with hypoxic, upper airway obstruction,
and apnoeic and rescue events. One hundred and ffy-three patients were enrolled. AUCdesat was signifcantly lower for HFNC
and MA bite blocks versus the standard management (p= 0.019). Te HFNC reduced hypoxic events by 18% despite similar airway
obstruction and apnoeic events as standard group. Te MA bite block reduced hypoxic events by 12% and airway obstructions by
32%. Te HFNC and MA groups both showed a 16% and 14% reduction in the number of patients who received rescue intervention,
respectively, compared to the standard group. Te HFNC and MA bite block may both reduce degree and duration of hypoxemia.
HFNC may decrease hypoxemic events while maintaining nasal patency is crucial during sedative EGD. Te MA bite block may
prevent airway obstruction and decrease the need for rescue intervention.
1. Introduction
Te safety of sedation during esophagogastroduodenostomy
(EGD) has long been a concern [1–3]. At least half of
endoscopic procedures today are performed under moni-
tored anaesthesia targeting deep sedation [4, 5]. Te goal
of sedation during endoscopy is to reduce patient pain and
anxiety and ultimately provide better quality examination
and follow-up [6]. Sedation using common medications
such as midazolam, opioids, and propofol causes respiratory
depression, hypoventilation, and subsequent hypoxemia [7].
Airway management is crucial during deep sedation, since
desaturation is noted in up to 60% of patients [8] and as high
as 95% of patients have diferent degrees of airway obstruc-
tion [9]. During deep sedation, the laryngeal muscle loses
tone, causing partial or complete upper airway obstruction
[10]. Te breathing pattern also changes from mainly nasal
breathing of an awake patient to mainly oral breathing of a
mouth-open sedated patient [11]. Trained personnel manage
the airway by chin-lif, jaw thrust, insertion of nasal airway,
or bag-mask ventilation [12]. Serious complications such as
cardiopulmonary distress, hypotension, bradycardia, or the
need for intubation may occur if the airway is not properly
treated [13].
Hindawi
BioMed Research International
Volume 2019, Article ID 4206795, 7 pages
https://doi.org/10.1155/2019/4206795