Page 32 - Portuguese Journal - SPORL - Vol 61. Nº1

apnea/hypopnea index (AHI) in the supine The present study aimed to systematically
position relative to the non-supine position . compare the prevalence of P-OSAS in adult
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Although it is one of the earliest definitions, it patients diagnosed with OSAS based on the
continues to be one of the most widely used different definitions and to identify the main
in several centers. More recently, Levendowski factors independently associated with P-OSAS
et al. introduced the definition of P-OSAS and exclusive P-OSAS (eP-OSAS).
as an AHI in the supine position which is at
least 1.5 times higher than the AHI in the Materials and Methods
non-supine position . In 2015, Frank et al., in This retrospective study was conducted by
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an attempt to better identify candidates for analyzing the records of type 3 polysomnography
positional therapy, developed the Amsterdam (PSG) between January 2020 and December
Positional OSA Classification (APOC), which 2021 in the Otorhinolaryngology Department
recommends the diagnosis of OSAS by the of the Garcia de Orta Hospital - Integrated
American Academy of Sleep Medicine (AASM) Responsibility Center.
criteria and at least 10% of time in the best and PSG records of patients aged 18 years or older,
worst sleep positions. P-OSAS includes three with total recording time greater than 4
categories: APOC I when the AHI in the best hours and AHI greater than or equal to 5 were
sleep position is less than 5; APOC II when the evaluated. Patients with a nasal flow signal of
AHI in the best sleep position is of less severity less than 85% of the total time or with position
than in the worst sleep position; and APOC III sensor failures were excluded.
when the AHI is at least 40 and there is at least A NOX T3® device with six channels was
a 25% reduction in the best sleep position . used for all PSGs: nasal flow sensor, pulse
4,5
The prevalence of P-OSAS is estimated to oximetry, thoracic and abdominal bands,
be between 53% and 77.4% among all OSAS position sensor, and microphone. The tracings
patients, and the variability may be due to obtained were automatically analyzed using
the study design, patient ethnicity, and use the Noxturnal software from Nox Medical®
of different definitions of P-OSAS. Patients and manually reviewed according to the
with P-OSAS have predominantly mild to 2018 AASM criteria . Apnea was defined as a
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moderate OSAS and are mostly younger men, decrease of at least 90% in the nasal flow sensor
with a lower body mass index (BMI ), fewer and hypopnea was defined as a decrease of at
symptoms, fewer comorbidities, smaller neck least 30% in the nasal flow sensor associated
and abdominal circumference, and lower with oxygen desaturation of at least 3%, both
scores in the Berlin, STOP-BANG and Epworth lasting 10 seconds or longer. The following
Sleepiness Scale questionnaires compared to variables were analyzed: age, sex, BMI , time
patients with non-positional OSAS . The main in the supine and non-supine positions, AHI,
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mechanism underlying P-OSAS is probably AHI in the supine and non-supine positions,
a combination of inadequate upper airway oxygen desaturation index (ODI), ODI in the
geometry, with an increased likelihood of supine and non-supine positions, total mean
collapse, reduced lung volume, and failure of desaturation drop (MDD) in the supine and
compensation by the airway dilator muscles . non-supine positions, snoring, and snoring in
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Although continuous positive airway pressure the supine and non-supine positions. P-OSAS
(CPAP) therapy remains the gold standard was characterized using the APOC criteria,
of treatment for OSAS, patient compliance and eP-OSAS was defined as APOC I. This is
remains relatively low . In this context, the because according to Cartwright's criteria,
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identification of patients with P-OSAS is of the lack of indication of minimum time in the
decisive clinical importance because they can various sleep positions can easily generate false
benefit from therapy with the new generation positives, i.e., patients who sleep more than
of positioners . 90% of the night in the supine position, with
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32 Portuguese Journal of Otorhinolaryngology - Head and Neck Surgery