Flow limitation as a noninvasive assessment of residual upper-airway resistance during continuous positive airway pressure therapy of obstructive sleep apnea.

Condos, Rany; Norman, Robert G.; Krishnasamy, Ilangkovan; Peduzzi, Norah; Goldring, Roberta M.; Rapoport, David M.

doi:10.1164/ajrccm.150.2.8049832

Cited by 229 publications

(168 citation statements)

References 18 publications

Supporting

Mentioning

155

Contrasting

Unclassified

Order By: Relevance

“…It should also be borne in mind that some hysteresis exists in the pressure required to suppress respiratory events. This has been demonstrated with inspiratory flow limitation, which requires about 2 cmH 2 O more to be eliminated during upwards titration of CPAP than the pressure at which it disappears during downwards titration [12].…”

Section: P Lévy J-l Pepinmentioning

confidence: 98%

“…An additional approach that has been proposed is to use oesophageal pressure monitoring to titrate the level of CPAP to the pressure which minimizes intrathoracic pressure swings indicative of high resistance, thus correcting any elevated upper airway obstruction. A similar but noninvasive method is to use the inspiratory flow contour (flow limitation) to effect the CPAP titration [12]. Most, if not all the signals mentioned above are poorly standardized in terms of techniques of measurement and reference values.…”

Section: P Lévy J-l Pepinmentioning

confidence: 99%

“…Variability in hypopnoea detection has already been mentioned and is probably critical during an "on-line" procedure such as manual titration. Arousal detection is an even more complex issue as both the criteria used [13] and the normal values [14] inspiratory flow limitation may be recognized from flow contour but this is undoubtedly more easily and accurately done automatically by a specific algorithm than by visual inspection [8,12]. On the other hand, the titration should not be performed only by increasing the pressure.…”

Section: P Lévy J-l Pepinmentioning

confidence: 99%

See 2 more Smart Citations

Auto-CPAP: an effective and low-cost procedure in the management of OSAS?

Lévy¹,

Pépin²

1998

Eur Respir J

View full text Add to dashboard Cite

Section: P Lévy J-l Pepinmentioning

confidence: 98%

Section: P Lévy J-l Pepinmentioning

confidence: 99%

Section: P Lévy J-l Pepinmentioning

confidence: 99%

See 1 more Smart Citation

Auto-CPAP: an effective and low-cost procedure in the management of OSAS?

Lévy¹,

Pépin²

1998

Eur Respir J

View full text Add to dashboard Cite

“…Second, esophageal manometry was not used to monitor inspiratory effort and assess for the presence of IFL. We could nevertheless rely on the inspiratory flow contour to distinguish flow-limited from non-flow-limited breaths, because the inspiratory plateau remains a well-validated index of inspiratory airflow limitation (34,35) during natural sleep. Third, we recognized that arousal could confound the assessment of flow responses and designed the experimental protocol and analytic approaches to minimize this possibility.…”

Section: Limitationsmentioning

confidence: 99%

Acute Upper Airway Responses to Hypoglossal Nerve Stimulation during Sleep in Obstructive Sleep Apnea

Schwartz

Barnes

Hillman

et al. 2012

Am J Respir Crit Care Med

View full text Add to dashboard Cite

Rationale: Hypoglossal nerve stimulation (HGNS) recruits lingual muscles, reduces pharyngeal collapsibility, and treats sleep apnea. Objectives: We hypothesized that graded increases in HGNS relieve pharyngeal obstruction progressively during sleep. Methods: Responses were examined in 30 patients with sleep apnea who were implanted with an HGNS system. Current (milliampere) was increased stepwise during non-REM sleep. Frequency and pulse width were fixed. At each current level, stimulation was applied on alternating breaths, and responses in maximal inspiratory airflow (V I max) and inspiratory airflow limitation (IFL) were assessed. Pharyngeal responses to HGNS were characterized by the current levels at which V I max first increased and peaked (flow capture and peak flow thresholds), and by the V I max increase from flow capture to peak (DV I max). Measurements and Main Results: HGNS produced linear increases in V I max from unstimulated levels at flow capture to peak flow thresholds (215 6 21 to 509 6 37 ml/s; mean 6 SE; P , 0.001) with increasing current from 1.05 6 0.09 to 1.46 6 0.11 mA. V I max increased in all patients and IFL was abolished in 57% of patients (non-IFL subgroup). In the non-IFL compared with IFL subgroup, the flow response slope was greater (1241 6 199 vs. 674 6 166 ml/s/mA; P , 0.05) and the stimulation amplitude at peak flow was lower (1.23 6 0.10 vs. 1.80 6 0.20 mA; P , 0.05) without differences in peak flow. Conclusions: HGNS produced marked dose-related increases in airflow without arousing patients from sleep. Increases in airflow were of sufficient magnitude to eliminate IFL in most patients and IFL and non-IFL subgroups achieved normal or near-normal levels of flow, suggesting potential HGNS efficacy across a broad range of sleep apnea severity.Keywords: obstructive sleep apnea; electrical hypoglossal nerve stimulation; pharynx; upper airway; titration Obstructive sleep apnea is characterized by recurrent episodes of upper airway obstruction during sleep (1). Airflow obstruction is thought to result from decreases in pharyngeal neuromuscular activity at sleep onset (2). These episodes lead to intermittent hypoxemia and recurrent arousals from sleep, accounting for the long-term neurocognitive (3, 4), metabolic (5), and cardiovascular (6) sequelae of this disorder. Nasal continuous positive airway pressure remains the mainstay of treatment for moderate to severe obstructive sleep apnea (7). Difficulties adhering to therapy can limit its effectiveness in the home setting (8, 9), and alternatives have been generally less effective in relieving upper airway obstruction during sleep (10-12).Hypoglossal nerve stimulation (HGNS) has been piloted as treatment for obstructive sleep apnea (13). Implantable HGNS systems have been developed to stimulate the hypoglossal nerve during inspiration, and recruit the lingual musculature, leading to decreases in pharyngeal collapsibility during sleep (14-17). Motor activity protrudes the tongue, and mitigates airflow obstruction during sleep (18,19)....

show abstract

“…Some stop when there are no further arterial oxygen desaturations, some when there is no further snoring, and some, using a pneumotachometer to measure the shape of the inspiratory flow-time curve, also aim to minimize silent inspiratory airflow limitation. The latter has been shown [21] to indicate the presence of high upper airway resistance and large oesophageal pressure swings, which can lead to repetitive arousals in the absence of apnoeas and hypopnoeas [22]. The AutoSet ™ system detects and quantifies the degree of flattening of the inspiratory flow-time curve and sets the pressure accordingly [17,18].…”

Section: Pressure Requirementmentioning

confidence: 99%

Influence of moderate alcohol consumption on obstructive sleep apnoea with and without AutoSet nasal CPAP therapy

Teschler¹,

Berthon-Jones²,

Wessendorf³

et al. 1996

Eur Respir J

View full text Add to dashboard Cite

I In nf fl lu ue en nc ce e o of f m mo od de er ra at te e a al lc co oh ho ol l c co on ns su um mp pt ti io on n o on n o ob bs st tr ru uc ct ti iv ve e s sl le ee ep p a ap pn no oe ea a w wi it th h a an nd d w wi it th ho ou ut t A Au ut to oS Se et t " " n na as sa al l C CP PA AP P t th he er ra ap py y Fourteen adult males with untreated OSAS but without heart or lung disease were studied (age 53±9 yrs, body mass index (BMI) 33±5 kg·m -2 (mean±SD). The subjects underwent overnight polysomnography on four occasions: control, alcohol, CPAP, and alcohol + CPAP. On the alcohol nights, the subjects drank 1.5 mL·kg -1 body weight (BW) vodka (40% alcohol by volume) (blood alcohol with and without CPAP 0.45±0.1 and 0.47±0.2 mg·mL -1 (mean±SD)). On the CPAP nights, the pressure required to prevent apnoea, snoring, and silent inspiratory airflow limitation was determined using an autotitrating nasal CPAP system (ResCare AutoSet™). Alcohol and control nights were performed in random order.Without CPAP, alcohol produced a small non-significant decrease in the percentage of rapid eye movement (REM) sleep (control 11±2 vs alcohol 8±1% (mean±SEM)), but with CPAP there was no such effect (control 15±2 vs 17±2%; CPAP×alcohol interaction p=0.015). With CPAP, slow-wave sleep in the first 2 h increased slightly with alcohol (control 39±6 vs alcohol 51±4%; p=0.004). Arousal index without CPAP increased slightly with alcohol (control 43±5 vs alcohol 49±6 events·h -1 ; p=0.02). There was little or no effect of alcohol on other sleep stages, arousal index, apnoea index, apnoea/hypopnoea index, mean or longest event duration, mean or worst arterial oxygen saturation, with or without CPAP, either for the full night or for the first 2 h. There was no change in the pressure requirement for CPAP (full night: control 11.9±0.9 vs alcohol 12.5±0.9 cmH 2 O; first 2 h: 10.9±0.6 vs 11.1±0.8 cmH 2 O).Moderate alcohol intake (in the form of vodka) has little effect on breathing or saturation during sleep in subjects with mild-to-severe obstructive sleep apnoea, and no effect on the pressure required for continuous positive airway pressure in order to prevent apnoea, snoring, and flow limitation. These results cannot be extrapolated to other doses or forms of alcohol, or to subjects with concurrent heart or lung disease.

show abstract

Flow limitation as a noninvasive assessment of residual upper-airway resistance during continuous positive airway pressure therapy of obstructive sleep apnea.

Cited by 229 publications

References 18 publications

Auto-CPAP: an effective and low-cost procedure in the management of OSAS?

Auto-CPAP: an effective and low-cost procedure in the management of OSAS?

Acute Upper Airway Responses to Hypoglossal Nerve Stimulation during Sleep in Obstructive Sleep Apnea

Influence of moderate alcohol consumption on obstructive sleep apnoea with and without AutoSet nasal CPAP therapy

Contact Info

Product

Resources

About