Effect of positive nasal pressure on upper airway pressure-flow relationships

Schwartz, Alan R.; Smith, P. L.; Wise, R.A.; Bankman, Isaac N.; Permutt, Solbert

doi:10.1152/jappl.1989.66.4.1626

Cited by 105 publications

(72 citation statements)

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“…As current was increased to 2 mA (middle panel) maximal inspiratory airflow (V I max) increased during the stimulated compared with unstimulated breaths. Nevertheless, inspiration remained flow-limited, as evidenced by an early peak in inspiratory airflow followed by a roll-off and plateauing of inspiratory flow later in inspiration (indicative of "negative effort dependence," a recognized phenomenon in collapsible biologic conduits) (25,26). When the stimulus intensity was increased to 2.5 mA, V I max increased further, and inspiratory airflow no longer plateaued, indicating the flow limitation had been abolished.…”

Section: Single Breath Stimulation Airflow Responsesmentioning

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

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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)....

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Section: Single Breath Stimulation Airflow Responsesmentioning

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

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“…The prevalence of snoring is high; 25-50% of middle-aged males are estimated to snore regularly [3,6]. Male sex, obesity, alcohol, sedatives, smoking and nasal obstruction are generally believed to be causative factors in the pathogenesis of snoring [3,[7][8][9][10].…”

mentioning

confidence: 99%

The role of the nose in the pathogenesis of obstructive sleep apnoea and snoring

Kohler¹,

Bloch²,

Stradling³

2007

European Respiratory Journal

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Data from observational studies suggest that nasal obstruction contributes to the pathogenesis of snoring and obstructive sleep apnoea (OSA). To define more accurately the relationship between snoring, OSA and nasal obstruction, the current authors have summarised the literature on epidemiological and physiological studies, and performed a systematic review of randomised controlled trials in which the effects of treating nasal obstruction on snoring and OSA were investigated.Searches of bibliographical databases revealed nine trials with randomised controlled design. External nasal dilators were used in five studies, topically applied steroids in one, nasal decongestants in two, and surgical treatment in one study.Data from studies using nasal dilators, intranasal steroids and decongestants to relieve nasal congestion showed beneficial effects on sleep architecture, but only minor improvement of OSA symptoms or severity. Snoring seemed to be reduced by nasal dilators. Nasal surgery also had minimal impact on OSA symptoms.In conclusion, chronic nasal obstruction seems to play a minor role in the pathogenesis of obstructive sleep apnoea, and seems to be of some relevance in the origin of snoring. The impact of treating nasal obstruction in patients with snoring and obstructive sleep apnoea on long-term outcome remains to be defined through randomised controlled trials of medical and surgical therapies.

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“…Several studies have shown that the mechanical properties of UA in children and adults with OSAS can be predicted by the behaviour of a collapsible tube described as a Starling resistor [21][22][23][24]. Therefore, this model was used to study the response of APAP devices to mechanical behaviour of the UA.…”

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confidence: 99%

Bench testing of auto-adjusting positive airway pressure devices

Abdenbi¹

2004

European Respiratory Journal

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Continuous positive airway pressure devices are routinely used to treat sleep breathing disorders. Automated devices that adjust the therapeutic pressure have recently been proposed. The utility of such devices is still controversial, as rigorous clinical comparisons are difficult to perform as a result of patient and device differences.The current authors studied automated devices in a respiratory model that was able to mimic upper airway mechanics and to interact with pressure adjustment in a closed loop. Five auto-adjusted devices were submitted to this model, in order to determine their ability to detect respiratory events and adjust pressure accordingly.All apnoeas were suppressed, whilst the reaction to repetitive hypopnoeas was dependent on the airflow shape. In some devices, repetitive hypopnoeas were changed to flow limitation. Artificial snoring caused a pressure increase in four devices, and constant mask leak was not systematically compensated. Only one device did not raise pressure in response to central apnoeas with opened upper airways. These findings show that, in some devices, event classification failed and normal airflow was not fully restored, resulting in elevated residual event indices.In conclusion, this model is useful in order to reproducibly compare diagnostic and therapeutic capacities of commercial devices as a first step, before costly clinical studies.

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Effect of positive nasal pressure on upper airway pressure-flow relationships

Cited by 105 publications

References 0 publications

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

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

The role of the nose in the pathogenesis of obstructive sleep apnoea and snoring

Bench testing of auto-adjusting positive airway pressure devices

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