scholarly journals Evidence for expiratory flow limitation of extrathoracic origin in patients with obstructive sleep apnoea

Thorax ◽  
2002 ◽  
Vol 57 (5) ◽  
pp. 423-428 ◽  
Author(s):  
E Verin
Keyword(s):  
Obstructive Sleep Apnoea ◽  
Sleep Apnoea ◽  
Flow Limitation ◽  
Expiratory Flow Limitation ◽  
Obstructive Sleep ◽  
Expiratory Flow

scholarly journals Palatal prolapse as a signature of expiratory flow limitation and inspiratory palatal collapse in patients with obstructive sleep apnoea

2018 ◽  
Vol 51 (2) ◽  
pp. 1701419 ◽  
Author(s):  
Ali Azarbarzin ◽  
Scott A. Sands ◽  
Melania Marques ◽  
Pedro R. Genta ◽  
Luigi Taranto-Montemurro ◽  
...  
Keyword(s):  
Obstructive Sleep Apnoea ◽  
Sleep Apnoea ◽  
Flow Limitation ◽  
Sleep Endoscopy ◽  
Expiratory Flow Limitation ◽  
Patient Level ◽  
Obstructive Sleep ◽  
Expiratory Flow ◽  
Nasal Pressure ◽  
Lateral Walls

In some individuals with obstructive sleep apnoea (OSA), the palate prolapses into the velopharynx during expiration, limiting airflow through the nose or shunting it out of the mouth. We hypothesised that this phenomenon causes expiratory flow limitation (EFL) and is associated with inspiratory “isolated” palatal collapse. We also wanted to provide a robust noninvasive means to identify this mechanism of obstruction.Using natural sleep endoscopy, 1211 breaths from 22 OSA patients were scored as having or not having palatal prolapse. The patient-level site of collapse (tongue-related, isolated palate, pharyngeal lateral walls and epiglottis) was also characterised. EFL was quantified using expiratory resistance at maximal epiglottic pressure. A noninvasive EFL index (EFLI) was developed to detect the presence of palatal prolapse and EFL using the flow signal alone. In addition, the validity of using nasal pressure was assessed.A cut-off value of EFLI >0.8 detected the presence of palatal prolapse and EFL with an accuracy of >95% and 82%, respectively. The proportion of breaths with palatal prolapse predicted isolated inspiratory palatal collapse with 90% accuracy.This study demonstrates that expiratory palatal prolapse can be quantified noninvasively, is associated with EFL and predicts the presence of inspiratory isolated palatal collapse.

Inspiratory flow limitation in obstructive sleep apnoea patients

2004 ◽  
Vol 106 (6) ◽  
pp. 563-565 ◽  
Author(s):  
Ramon FARRÉ
Keyword(s):  
Pilot Study ◽  
Airway Obstruction ◽  
Sleep Disorder ◽  
Obstructive Sleep Apnoea ◽  
Upper Airway ◽  
Sleep Apnoea ◽  
Obstructive Sleep Apnoea Syndrome ◽  
Bench Test ◽  
Flow Limitation ◽  
Obstructive Sleep

Patients suffering from the obstructive sleep apnoea syndrome (OSAS) experience nocturnal episodes of upper airway obstruction resulting in recurrent oxygen desaturations and arousals. Methods to quantify the nocturnal obstructive events are of interest for characterizing this prevalent sleep disorder. In a study published in this issue of Clinical Science, Bloch and co-workers propose the computation of a new index for objectively quantifying the degree of flow limitation in patients with OSAS. The results obtained in a bench test and in a pilot study in patients suggest that the flow limitation index proposed may help to better characterize the disturbed breathing events undergone by patients with OSAS.

scholarly journals P088 Presence versus absence of flow limitation during stable breathing in patients with obstructive sleep apnoea

2021 ◽  
Vol 2 (Supplement_1) ◽  
pp. A49-A50
Author(s):  
D Mann ◽  
T Georgeson ◽  
S Landry ◽  
A Azarbarzin ◽  
D Vena ◽  
...  
Keyword(s):  
Obstructive Sleep Apnoea ◽  
Phenotypic Variability ◽  
Sleep Apnoea ◽  
Flow Limitation ◽  
Sleep Study ◽  
Respiratory Events ◽  
Obstructive Sleep ◽  
Ventilatory Drive ◽  
Clinical Scoring ◽  
Nasal Pressure

Abstract Introduction Flow limitation is the distinguishing characteristic of obstructive sleep apnoea. Critically, periods of flow limitation can occur without overt reductions in airflow (e.g. disproportionate increase in ventilatory drive vs. achieved ventilation), however, such periods are ignored by clinical scoring. Here we investigate flow limitation during so-called “stable breathing”, i.e. periods of sleep without scored events, by applying our recently-validated model to estimate flow limitation from the airflow signal. Methods Flow limitation was visually-scored (N=117,871 breaths) from N=40 participants attending an overnight sleep study for suspected sleep apnoea. Scoring was aided by physiological signals (e.g. intra-oesophageal diaphragm EMG). Model flow limitation classification used features extracted from the pneumotach signal (cross-validated accuracy=92.4%). We applied this method to investigate the occurrence of flow limitation during stable breathing, defined as periods of sleep >3 min duration without scored arousals or respiratory events. Results Model predicted flow limitation frequency was strongly correlated with visual scoring (R²=0.84 p<0.001). The median flow limitation frequency during stable breathing ranged from 8–91%, with an overall median of 59% (IQR 37%-75%). Flow limitation frequency during stable breathing was only modestly associated with the apnoea-hypopnea index (R²=0.12 p<0.05). Discussion Flow limitation occurs surprisingly frequently during stable breathing. While some individuals achieve stable breathing with minimal flow limitation, others demonstrate substantial flow limitation. Heterogeneity in frequency of flow limitation (within and between individuals) may provide further insights into emergent phenotypic variability within sleep disordered breathing. Finally, this model performed similarly in nasal pressure (88.2% accuracy), indicating potential application to clinical studies.

Mechanisms of inspiratory and expiratory flow limitations during obstructive sleep apnoea

2006 ◽  
Vol 39 ◽  
pp. S442
Author(s):  
R. Fodil ◽  
C. Croce ◽  
F. Lofaso ◽  
B. Louis ◽  
D. Isabey
Keyword(s):  
Obstructive Sleep Apnoea ◽  
Sleep Apnoea ◽  
Obstructive Sleep ◽  
Expiratory Flow

scholarly journals P111 Respiratory Flow Limitation in the absence of Obstructive Sleep Apnoea responds to CPAP therapy

Thorax ◽  
2015 ◽  
Vol 70 (Suppl 3) ◽  
pp. A131.1-A131
Author(s):  
B Chakrabarti ◽  
S Emegbo ◽  
S Craig ◽  
J Heseltine ◽  
T Wright ◽  
...  
Keyword(s):  
Obstructive Sleep Apnoea ◽  
Sleep Apnoea ◽  
Flow Limitation ◽  
Cpap Therapy ◽  
Respiratory Flow ◽  
Obstructive Sleep
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