Influence of gender on upper airway mechanics: upper  airway resistance and Pcrit

Rowley, James A.; Zhou, Xusong S.; Vergine, Isabelle; Shkoukani, Mahdi A.; Badr, M. Safwan

doi:10.1152/jappl.2001.91.5.2248

Cited by 105 publications

(68 citation statements)

References 28 publications

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“…By design, the normal pharyngeal airway collapsed at a pressure of −13 cm H 2 O during sleep based on the work of Schwartz et al, 18 although a range of values have been reported in the literature. [29][30][31][32] As can be seen in the figures, progressively more negative airway pressures were necessary to occlude the pharyngeal airway for all three of the experimental conditions. The effect was most pronounced for mandibular advancement (Pclose = −21 cm H 2 O), but less so for palatal resection (Pclose = −18 cm H 2 O) or palatal stiffening (Pclose = −17 cm H 2 O).…”

Section: Resultsmentioning

confidence: 99%

The Impact of Anatomic Manipulations on Pharyngeal Collapse

Huang

White

Malhotra

2005

Chest

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Obstructive sleep apnea (OSA) is a common disease with important neurocognitive and cardiovascular sequelae. Existing therapies are unsatisfactory, leading investigators to seek alternative forms of anatomic manipulation to influence pharyngeal mechanics. We have developed a two-dimensional computational model of the normal human upper airway based on signal averaging of MRI. Using the finite element method, we can perform various anatomic perturbations on the structure in order to assess the impact of these manipulations on pharyngeal mechanics and collapse. By design, the normal sleeping upper airway model collapses at −13 cm H 2 O. This closing pressure becomes more negative (ie, less collapsible) when we perform mandibular advancement (−21 cm H 2 O), palatal resection (−18 cm H 2 O), or palatal stiffening (−17 cm H 2 O). Where clinical data are available in the literature, the results of our model correspond reasonably well. Furthermore, our model provides information regarding the site of obstruction and provides hypotheses for clinical studies that can be undertaken in the future (eg, combination therapies). We believe that, in the future, finite element modeling will provide a useful tool to help advance our understanding of OSA and its response to various therapies. Keywords breathing; computational model; lung; MRI; obstructive sleep apnea; pharyngeal collapse Obstructive sleep apnea (OSA) is an important disorder due to both its high prevalence and its well-established sequelae. 1,2 Although effective therapies exist for sleep apnea, [3][4][5][6] investigators continue to seek alternative methods to manipulate pharyngeal mechanics/ anatomy with the ultimate goal of improving currently available therapeutic modalities. [3][4][5][6][7][8] Various different methods of manipulating pharyngeal mechanics have been used to treat snoring in individuals with largely normal upper airway anatomy and to treat sleep apnea in those with a compromised pharyngeal lumen. These methods include weight loss, oral appliances, and upper airway surgery. 9-11 However, these techniques have also been problematic due to variable efficacy and minimal ability to predict therapeutic response. A number of investigators have attempted to determine which patients are most likely to respond to treatment, but without great success. [12][13][14][15][16] We believe that improvements in our Our group has been involved in the development of a computational model to better understand the behavior of the human upper airway. 17 We have used finite element analysis, which is a mathematical technique to quantitatively analyze the behavior of a given mechanical structure. We have previously published our two-dimensional model that uses anatomically correct structure from MRI of normal human subjects. 17 With this model, we have used the critical closing pressure (Pcrit) as our outcome measure to assess the collapsibility of the upper airway. 18 Using finite element analysis, we sought to determine the impact of mandibular advancement, pa...

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Section: Resultsmentioning

confidence: 99%

The Impact of Anatomic Manipulations on Pharyngeal Collapse

Huang

White

Malhotra

2005

Chest

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“…Flow limitation was defined as a plateau in flow despite ≥1 cmH 2 O decrease in the supraglottic pressure. Inspiratory flow limitation (IFL) has been previously described in detail by our laboratory (Rowley et al 2001;Aboubakr et al 2001;Shkoukani et al 2002, Mansour et al 2002.…”

Section: Discussionmentioning

confidence: 99%

Long-term facilitation of genioglossus activity is present in normal humans during NREM sleep

Chowdhuri

Pierchala

Aboubakr

et al. 2008

Respiratory Physiology & Neurobiology

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Episodic hypoxia (EH) is followed by increased ventilatory motor output in the recovery period indicative of long-term facilitation (LTF). We hypothesized that episodic hypoxia evokes LTF of genioglossus (GG) muscle activity in humans during non-rapid eye movement sleep (NREM) sleep. We studied 12 normal non-flow limited humans during stable NREM sleep. We induced 10 brief (3 minute) episodes of isocapnic hypoxia followed by 5 minutes of room air. Measurements were obtained during control, hypoxia, and at 5, 10, 20, 30 and 40 minutes of recovery, respectively, for minute ventilation (V̇I), supraglottic pressure (P SG ), upper airway resistance (R UA ) and phasic GG electromyogram (EMG GG ). In addition, sham studies were conducted on room air. During hypoxia there was a significant increase in phasic EMG GG (202.7±24.1% of control, p<0.01) and in V̇I (123.0 ±3.3% of control, p<0.05); however, only phasic EMG GG demonstrated a significant persistent increase throughout recovery (198.9±30.9%, 203.6±29.9% and 205.4±26.4% of control, at 5, 10, and 20 minutes of recovery, respectively, p<0.01). In multivariate regression analysis, age and phasic EMG GG activity during hypoxia were significant predictors of EMG GG at recovery 20 minutes. No significant changes in any of the measured parameters were noted during sham studies. Conclusion: 1) EH elicits LTF of GG in normal non-flow limited humans during NREM sleep, without ventilatory or mechanical LTF. 2) GG activity during the recovery period correlates with the magnitude of GG activation during hypoxia, and inversely with age.

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“…1 The reasons for age being an influence on AHI in only certain age ranges are unclear. Several studies of the influence of age on upper airway mechanics and control of breathing do not show an aging effect [36][37][38][39] and of those that do, the decrement in function is present in an older age group, not younger.…”

Section: Potential Mechanismsmentioning

confidence: 97%

The Influence of Race on the Severity of Sleep Disordered Breathing

Pranathiageswaran

Badr

Severson

et al. 2013

Journal of Clinical Sleep Medicine

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Background: Studies have indicated that the prevalence of obstructive sleep apnea-hypopnea syndrome (OSAHS) is similar between white and African American patients, but it is unclear if there are differences in the severity of OSAHS. We hypothesized that in patients with diagnosed OSAHS, African Americans would have higher apnea-hypopnea index (AHI) and higher mortality than white individuals. Methods: We analyzed a prospectively collected database of 512 patients studied between July 1996 through February 1999. Inclusion criteria included age ≥ 18 y, AHI ≥ 5/h, and full-night PSG. Statistical analysis was performed to determine the association between race and AHI while controlling for the effect of confounders and effect modifi ers, which included gender, age, body mass index, and comorbidities.

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Influence of gender on upper airway mechanics: upper airway resistance and Pcrit

Cited by 105 publications

References 28 publications

The Impact of Anatomic Manipulations on Pharyngeal Collapse

The Impact of Anatomic Manipulations on Pharyngeal Collapse

Long-term facilitation of genioglossus activity is present in normal humans during NREM sleep

The Influence of Race on the Severity of Sleep Disordered Breathing

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