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Global Translational Medicine New neck examination for sleep apnea

apneas are usually worse due to the normal REM paralysis (Windows 10 operating system) and scored the next day
of striate muscles. Although assessment of breathing under by Registered Polysomnographic Technicians (RPsgT)
anesthesia with manual pressure applied on the throat using the above published AASM criteria. The NPSG
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has been proposed, this is virtually the only provocative data of interest were the AHI, along with sleep continuity
test available for SDB and is not practical for most patients. measurements.

The rationale for the present study was to examine if 2.2. Method 1
a rapid, simple, and non-invasive stress test of airway
collapse could be devised for use by any physician in the Note that the DGT rating scale presupposes relatively
course of a general physical examination. For maximum normal waking airflow in the collapsible airway. Conditions
utility, it was crucial that it should be executed without the such as excessive bronchial secretions, allergic reactions,
use of specialized equipment and with the patient awake. acute asthma, or uncontrollable coughing would invalidate
Such a test could potentially produce a graded rating scale the test. The DGT was performed using the following
to predict airway collapsibility in sleep, perhaps performing procedures:
better than the above demographic, morphometric, or • Patient sits in an upright position, with mouth closed
questionnaire methods. This daytime test would need to (unless nose is completely obstructed, in which case
be validated against NPSG. Our solution was a simple the mouth can be open a few millimeters). The patient
“gagging test” that uses mild standardized pressure against is instructed to begin a moderately deep inspiration.
the anterior neck of the patient while they are seated and The examiner applies thumb pressure to the patient’s
performing a moderately deep inspiration. neck just after the inspiration commences.
• The “fingerprint” part of the examiner’s thumb is
This study was approved by the Research Ethics Board of applied to the anterior mid-line of the patient’s neck,
the University of Ottawa Institute of Mental Health Research immediately above the thyroid cartilage, with the
at the Royal Ottawa Hospital (approval no.: 200620). fingers loosely cupping the patient’s neck.

2. Materials and methods • A thumb press with a force of 3 Newtons is applied
to the anterior neck. This force was not measured
2.1. Materials with any engineering devices; rather, a clinical

This study included 224 sequential referrals, usually by approximation to the desired 3-Newton force was
their general practitioner, to a sleep disorders clinic at a made as follows: the single examiner (first author)
university-affiliated hospital in a large Canadian urban practiced lifting a 300-gram weight with a string tied
center. The presenting complaint was either disturbed to his thumb. Subjectively, this force was found to be
sleep or suspected sleep apnea. similar to compressing by 1 cm the side of a 20 cm tall
thin-walled single-use water bottle, which was used to
At the consultation visit, patients completed the practice the maneuver.
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Epworth Sleepiness Scale (ESS) and had BMI calculated • The direction of thumb force starts from the position
from their measured height and weight. The same above the thyroid cartilage but is then angled vertically
examining physician (the first author) assessed all patients, and posteriorly at about 45 degrees, aiming toward
to reduce error variance. At the ear-nose-throat portion the skull vertex. The intended purpose of the force
of the physical examination, the physician recorded the is to provoke airway collapse between the base of the
FTS and MM scales, then filled out a rating of airway tongue and the posterior oropharynx.
sounds – the Douglass gagging test (DGT) – as described • Even in a slim normal female, this force causes nil to
in section 2.2. No specialized equipment was used for the minimal airway obstruction noise. In contrast, even
examination. Since the DGT and all examination data heavy male sleep apnea patients with thick necks
were collected before the NPSG, this study was double- were noted to experience severe to complete airway
blind with respect to the apnea-hypopnea index (AHI) obstruction (nil breath sounds) during this mild
measured on the NPSG. challenge to airway patency.
All patients then underwent a standard NPSG using
procedures and methods promulgated by the American 2.3. Method 2
Academy of Sleep Medicine (AASM), which includes To assess airway collapsibility, airway sounds while throat
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regular assessments of technician inter-rater reliability. The pressure is applied during inspiration are rated on the
16-channel NPSG was recorded using the Embla Sandman DGT, a 5-point scale (0 – 4):
Elite sleep-diagnostic hardware and software system. Sleep • 0 = Nil audible airflow;
waveforms and SDB were recorded on computer disk • 1 = Minimal but discernable sounds of airflow;

Volume 3 Issue 4 (2024) 3 doi: 10.36922/gtm.4548