P099 Physiological phenotypes of obstructive sleep apnoea (OSA) in Pacific Islanders and equally obese Caucasians

Abstract Background Pacific islanders (PI) have a high prevalence of severe OSA, attributed to obesity. Ethnic differences in mechanisms contributing to OSA have been reported. We compared physiological polysomnography characteristics in obese PI and Caucasian (C) patients with OSA. Methods Retrospective polysomnography (PSG) studies from a tertiary hospital sleep laboratory were identified for PI and age, gender and BMI matched C patients (BMI>30 kgm²). All PSGs were rescored by a single scorer, and pharyngeal collapsibility (Vpassive), upper airway muscle compensation (Vcomp), arousal threshold (AT), [all expressed as percentage of steady-state breathing (Veupnea)], and loop gain (LG) were determined non-invasively via established/validated techniques. Progress to date 14 PI [8 female] and 29 C [15 female] were identified. There were no differences in age [52.2±17.0 PI; 52.5±13.3 C years], BMI [46.9±7.7 PI; 48.2±10.1 C kgm²] or AHI (35.6 [17.9–77.5] PI; 41.2 [20.9–83.6] C events/hour) (mean±SD or median[IQR]; all p>0.4; paired t-test or Wilcoxon signed rank). There were no significant differences in Vpassive (88.8 [88.4–97.1] PI; 91.8 [44.4–95.8]C %Veupnea; p=0.38), Vcomp (1.2 [-12.0–9.2] PI; 5.8 [-1.9–9.6] C %Veupnea; p=0.30), AT (131.4 [110.5–140.8] PI; 126.1 [110.4–180.7] C %Veupnea; p=0.67) or LG (0.6±0.1 PI; 0.7±0.3 C; p=0.23). Intended outcome and impact In a small cohort of PI and age, gender and BMI matched C with OSA, upper airway obstructive event frequency was the same and there were no differences in physiological phenotypes, suggesting similar mechanisms contribute to OSA severity in both groups. Confirmation of these findings in a larger cohort is ongoing.

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P019 Obstructive sleep apnoea endotypes in people with multiple sclerosis

SLEEP Advances ◽

10.1093/sleepadvances/zpab014.067 ◽

2021 ◽

Vol 2 (Supplement_1) ◽

pp. A27-A28

Author(s):

S Carter ◽

H Hensen ◽

A Krishnan ◽

A Chiang ◽

J Carberry ◽

...

Keyword(s):

Multiple Sclerosis ◽

Obstructive Sleep Apnoea ◽

Group Analysis ◽

Respiratory Control ◽

Upper Airway ◽

Sleep Apnoea ◽

Loop Gain ◽

Male Predominance ◽

Arousal Threshold ◽

Obstructive Sleep

Abstract Purpose Obstructive sleep apnoea (OSA) is common in people with multiple sclerosis (MS) despite a lack of typical risk factors for OSA in people with MS such as obesity and male predominance. Therefore, underlying factors other than sex and obesity may be particularly important in the pathogenesis of OSA in people with MS. Thus, the primary aim of this study was to determine the relative contributions of OSA endotypes in people with MS and compare this to matched controls with OSA only. Methods Eleven people with MS and OSA (MS-OSA group) (apnoea-hypopnoea index [AHI]>5events/h) and eleven controls matched for OSA severity, age and sex without MS (OSA group) were studied. Participants underwent a detailed overnight polysomnography with an epiglottic pressure catheter and genioglossus intramuscular electrodes to allow for quantification of pathophysiological contributors to OSA. This included the respiratory arousal threshold, genioglossus muscle responsiveness, respiratory loop gain and upper airway collapsibility. Results Measures of the four primary OSA endotypes were not different between the MS-OSA and OSA groups (e.g. NREM respiratory arousal threshold -27±15 vs. -23±8 cmH2O respectively, p=0.24). Within group analysis indicated higher loop gain in non-obese MS-OSA participants compared to obese MS-OSA participants (0.53±0.11 vs. 0.37±0.11, p=0.04). Conclusions Overall, OSA endotypes are similar between MS-OSA participants and matched OSA controls. However, within the MS-OSA group, non-obese participants have higher loop gain (unstable respiratory control) compared to obese participants. Thus, unstable respiratory control may play an important role in OSA pathogenesis in many people with MS.

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Morphine alters respiratory control but not other key obstructive sleep apnoea phenotypes: a randomised trial

European Respiratory Journal ◽

10.1183/13993003.01344-2019 ◽

2020 ◽

Vol 55 (6) ◽

pp. 1901344

Author(s):

Rodrigo T. Martins ◽

Jayne C. Carberry ◽

David Wang ◽

Luke Rowsell ◽

Ronald R. Grunstein ◽

...

Keyword(s):

Upper Airway ◽

Sleep Apnoea ◽

Loop Gain ◽

Ventilatory Control ◽

Pharyngeal Muscle ◽

Arousal Threshold ◽

Ventilatory Responses ◽

Obstructive Sleep ◽

Airway Collapsibility ◽

Upper Airway Collapsibility

Accidental opioid-related deaths are increasing. These often occur during sleep. Opioids such as morphine may worsen obstructive sleep apnoea (OSA). Thus, people with OSA may be at greater risk of harm from morphine. Possible mechanisms include respiratory depression and reductions in drive to the pharyngeal muscles to increase upper airway collapsibility. However, the effects of morphine on the four key phenotypic causes of OSA (upper airway collapsibility (pharyngeal critical closure pressure; Pcrit), pharyngeal muscle responsiveness, respiratory arousal threshold and ventilatory control (loop gain) during sleep) are unknown.21 males with OSA (apnoea–hypopnoea index range 7–67 events·h−1) were studied on two nights (1-week washout) according to a double-blind, randomised, cross-over design (ACTRN12613000858796). Participants received 40 mg of MS-Contin on one visit and placebo on the other. Brief reductions in continuous positive airway pressure (CPAP) from the therapeutic level were delivered to induce airflow limitation during non-rapid eye movement (REM) sleep to quantify the four phenotypic traits. Carbon dioxide was delivered via nasal mask on therapeutic CPAP to quantify hypercapnic ventilatory responses during non-REM sleep.Compared to placebo, 40 mg of morphine did not change Pcrit (−0.1±2.4 versus −0.4±2.2 cmH2O, p=0.58), genioglossus muscle responsiveness (−2.2 (−0.87 to −5.4) versus −1.2 (−0.3 to −3.5) μV·cmH2O−1, p=0.22) or arousal threshold (−16.7±6.8 versus −15.4±6.0 cmH2O, p=0.41), but did reduce loop gain (−10.1±2.6 versus −4.4±2.1, p=0.04) and hypercapnic ventilatory responses (7.3±1.2 versus 6.1±1.5 L·min−1, p=0.006).Concordant with recent clinical findings, 40 mg of MS-Contin does not systematically impair airway collapsibility, pharyngeal muscle responsiveness or the arousal threshold in moderately severe OSA patients. However, consistent with blunted chemosensitivity, ventilatory control is altered.

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O023 Impact of weight loss of OSA pathophysiology

SLEEP Advances ◽

10.1093/sleepadvances/zpab014.022 ◽

2021 ◽

Vol 2 (Supplement_1) ◽

pp. A10-A11

Author(s):

A Wong ◽

S Landry ◽

K Yang ◽

S Joosten ◽

L Thomson ◽

...

Keyword(s):

Weight Loss ◽

Upper Airway ◽

Sleep Apnoea ◽

Loop Gain ◽

Arousal Threshold ◽

Post Surgery ◽

Obstructive Sleep ◽

Airway Collapsibility ◽

Upper Airway Collapsibility ◽

The Impact

Abstract Introduction Obesity is a major risk factor for developing obstructive sleep apnoea (OSA), however, the underlying mechanisms are not fully understood. We aimed to assess the impact of weight loss on all OSA endotypes (i.e. upper airway collapsibility, muscle compensation, respiratory arousal threshold, and loop gain). Methods We analysed data from 40 OSA patients (collated from 3 centres) who underwent bariatric surgery. Demographics and clinical polysomnograms (PSG) were performed at baseline and at between 6–18 months post-surgery. OSA endotypes were measured during sleep using non-invasive endotyping methods (derived from clinical PSG). Results Participants lost 28±14 kg and had a post-surgery reduction in the AHI of 19.6 (Interquartile range[IQR] -9.8 to -35.4) events/hr [from baseline 39.9 (24.3 to 65.6) events/hr to 17.0 (9.9 to 33.3) events/hr]. Following surgical weight loss, there was significant improvement in collapsibility (∆6.2 [IQR -1.4 to 13]%Veupnoea, p<0.0001), as well as significant reduction in loop gain and arousal threshold (∆-0.06 [-0.17 to 0.009], p<0.001 and ∆-13.7 [-24.8 to -1.8]%Veupnoea, p<0.001 respectively). There was no significant change in muscle compensation. Conclusion Our findings suggest that weight loss improves upper airway collapsibility and reduces loop gain and the arousal threshold, providing novel insights about the mechanisms by which obesity causes OSA. Further analysis is underway to determine whether knowledge of the baseline OSA endotypes (in isolation and/or in combination) can predict which individuals will have a response to weight loss alone.

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Omission of polysomnography in treatment of snoring: common reasons and medico-legal implications

The Journal of Laryngology & Otology ◽

10.1258/0022215001906273 ◽

2000 ◽

Vol 114 (7) ◽

pp. 519-521 ◽

Cited By ~ 4

Author(s):

Y. H. Goh ◽

D. K. S. Choy

Keyword(s):

Upper Airway ◽

Clinical History ◽

Tertiary Hospital ◽

Sleep Apnoea ◽

Obstructive Sleep Apnoea Syndrome ◽

Upper Airway Resistance Syndrome ◽

Asian Patients ◽

Legal Implications ◽

Obstructive Sleep ◽

Number Of Patients

Although polysomnography (PSG) is an important investigation in the treatment of snorers, it was observed that a large number of patients did not have pre-operative PSG assessment in a tertiary hospital in Singapore. Of the 118 Asian patients who underwent surgery for snoring from January 1997 to December 1998, 36 (30.5 per cent) of patients did not have pre-operative PSG and only 21 (17.8 per cent) of patients had post-operative PSG. In this cohort, 43 (36.4 per cent) patients presented with snoring as their only complaint and not associated with symptoms indicative of obstructive sleep apnoea syndrome (OSAS). Thirty-one of these ‘simple snorers’ underwent sleep studies with the following outcome: two (6.5 per cent) true simple snorers, two (6.5 per cent) upper airway resistance syndrome, nine (29 per cent) mild OSAS, seven (22.6 per cent) moderate OSAS and 11 (35.5 per cent) severe OSAS. Our study showed that without the aid of PSG, it would be difficult to predict the severity of sleep apnoea based on clinical history alone. In an increasingly litigation-conscious society such as Singapore, there is therefore little justification in omitting PSG in the treatment of snoring. The common reasons for omission of preoperative PSG and the medico-legal implications are also discussed.

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Changes in the calibre of the upper airway and the surrounding structures after maxillomandibular advancement for obstructive sleep apnoea

British Journal of Oral and Maxillofacial Surgery ◽

10.1016/j.bjoms.2014.02.006 ◽

2014 ◽

Vol 52 (5) ◽

pp. 445-451 ◽

Cited By ~ 32

Author(s):

Yuh-Jia Hsieh ◽

Yu-Fang Liao ◽

Ning-Hung Chen ◽

Yu-Ray Chen

Keyword(s):

Obstructive Sleep Apnoea ◽

Upper Airway ◽

Sleep Apnoea ◽

Maxillomandibular Advancement ◽

Obstructive Sleep

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High prevalence of peripheral arterial disease in patients with obstructive sleep apnoea

Clinical Research in Cardiology ◽

10.1007/s00392-015-0834-3 ◽

2015 ◽

Vol 104 (9) ◽

pp. 719-726 ◽

Cited By ~ 25

Author(s):

C. A. Schaefer ◽

L. Adam ◽

J. Weisser-Thomas ◽

S. Pingel ◽

G. Vogel ◽

...

Keyword(s):

Peripheral Arterial Disease ◽

Obstructive Sleep Apnoea ◽

Arterial Disease ◽

Sleep Apnoea ◽

Obstructive Sleep ◽

High Prevalence ◽

Peripheral Arterial

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Desipramine improves upper airway collapsibility and reduces OSA severity in patients with minimal muscle compensation

European Respiratory Journal ◽

10.1183/13993003.00823-2016 ◽

2016 ◽

Vol 48 (5) ◽

pp. 1340-1350 ◽

Cited By ~ 40

Author(s):

Luigi Taranto-Montemurro ◽

Scott A. Sands ◽

Bradley A. Edwards ◽

Ali Azarbarzin ◽

Melania Marques ◽

...

Keyword(s):

Crossover Trial ◽

Positive Airway Pressure ◽

Upper Airway ◽

Sleep Apnoea ◽

Double Blind ◽

Healthy Humans ◽

Dilator Muscle ◽

Obstructive Sleep ◽

Airway Collapsibility ◽

Upper Airway Collapsibility

We recently demonstrated that desipramine reduces the sleep-related loss of upper airway dilator muscle activity and reduces pharyngeal collapsibility in healthy humans without obstructive sleep apnoea (OSA). The aim of the present physiological study was to determine the effects of desipramine on upper airway collapsibility and apnoea–hypopnea index (AHI) in OSA patients.A placebo-controlled, double-blind, randomised crossover trial in 14 OSA patients was performed. Participants received treatment or placebo in randomised order before sleep. Pharyngeal collapsibility (critical collapsing pressure of the upper airway (Pcrit)) and ventilation under both passive (V′0,passive) and active (V′0,active) upper airway muscle conditions were evaluated with continuous positive airway pressure (CPAP) manipulation. AHI was quantified off CPAP.Desipramine reduced activePcrit(median (interquartile range) −5.2 (4.3) cmH2O on desipramineversus−1.9 (2.7) cmH2O on placebo; p=0.049) but not passivePcrit(−2.2 (3.4)versus−0.7 (2.1) cmH2O; p=0.135). A greater reduction in AHI occurred in those with minimal muscle compensation (defined asV′0,active−V′0,passive) on placebo (r=0.71, p=0.009). The reduction in AHI was driven by the improvement in muscle compensation (r=0.72, p=0.009).In OSA patients, noradrenergic stimulation with desipramine improves pharyngeal collapsibility and may be an effective treatment in patients with minimal upper airway muscle compensation.

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Volume-pressure properties of the upper airway in normal subjects and patients with obstructive sleep apnoea

Respirology ◽

10.1046/j.1440-1843.1999.00149.x ◽

1999 ◽

Vol 4 (1) ◽

pp. 69-75 ◽

Cited By ~ 2

Author(s):

Denan Wu ◽

Wataru Hida ◽

Yoshihiro Kikuchi ◽

Shinichi Okabe ◽

Hajime Kurosawa ◽

...

Keyword(s):

Obstructive Sleep Apnoea ◽

Upper Airway ◽

Normal Subjects ◽

Sleep Apnoea ◽

Obstructive Sleep

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Association of Snoring Characteristics with Predominant Site of Collapse of Upper Airway in Obstructive Sleep Apnoea Patients

SLEEP ◽

10.1093/sleep/zsab176 ◽

2021 ◽

Author(s):

Arun Sebastian ◽

Peter A Cistulli ◽

Gary Cohen ◽

Philip de Chazal

Keyword(s):

Acoustic Analysis ◽

Audio Signal ◽

Upper Airway ◽

Lateral Wall ◽

Sleep Apnoea ◽

Machine Learning Algorithms ◽

Classification Model ◽

Individual Site ◽

Obstructive Sleep ◽

The Individual

Abstract Study objectives Acoustic analysis of isolated events and snoring by previous researchers suggests a correlation between individual acoustic features and individual site of collapse events. In this study, we hypothesised that multi-parameter evaluation of snore sounds during natural sleep would provide a robust prediction of the predominant site of airway collapse. Methods The audio signals of 58 OSA patients were recorded simultaneously with full night polysomnography. The site of collapse was determined by manual analysis of the shape of the airflow signal during hypopnoea events and corresponding audio signal segments containing snore were manually extracted and processed. Machine learning algorithms were developed to automatically annotate the site of collapse of each hypopnoea event into three classes (lateral wall, palate and tongue-base). The predominant site of collapse for a sleep period was determined from the individual hypopnoea annotations and compared to the manually determined annotations. This was a retrospective study that used cross-validation to estimate performance. Results Cluster analysis showed that the data fits well in two clusters with a mean silhouette coefficient of 0.79 and an accuracy of 68% for classifying tongue/non-tongue collapse. A classification model using linear discriminants achieved an overall accuracy of 81% for discriminating tongue/non-tongue predominant site of collapse and accuracy of 64% for all site of collapse classes. Conclusions Our results reveal that the snore signal during hypopnoea can provide information regarding the predominant site of collapse in the upper airway. Therefore, the audio signal recorded during sleep could potentially be used as a new tool in identifying the predominant site of collapse and consequently improving the treatment selection and outcome.

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