Predicting critical closing pressure in children with obstructive sleep apnea using fluid structure interaction simulations

Author(s):  
Goutham Mylavarapu ◽  
Ephraim Gutmark ◽  
Sally Shott ◽  
Robert J. Fleck ◽  
Mohamed Mahmoud ◽  
...  

Surgical treatment of obstructive sleep apnea (OSA) in children requires knowledge of upper airway dynamics, including the closing pressure (Pcrit), a measure of airway collapsibility. We applied a Flow-Structure Interaction (FSI) computational model to estimate Pcrit in patient-specific upper airway models obtained from magnetic resonance imaging (MRI) scans. We sought to examine the agreement between measured and estimated Pcrit from FSI models in children with Down syndrome. We hypothesized that the estimated Pcrit would accurately reflect measured Pcrit during sleep and therefore reflect the severity of OSA as measured by the obstructive apnea hypopnea index (AHI). All participants (n=41) underwent polysomnography and sedated sleep MRI scans. We used Bland Altman Plots to examine the agreement between measured and estimated Pcrit. We determined associations between estimated Pcrit and OSA severity, as measured by AHI, using regression models. The agreement between passive and estimated Pcrit showed a fixed bias of -1.31 (CI=-2.78, 0.15) and a non-significant proportional bias. A weaker agreement with active Pcrit was observed. A model including AHI, gender, an interaction term for AHI and gender and neck circumference explained the largest variation (R2 = 0.61) in the relationship between AHI and estimated Pcrit. (P <0.0001). Overlap between the areas of the airway with lowest stiffness, and areas of collapse on dynamic MRI, was 77.4%±30% for the nasopharyngeal region and 78.6%±33% for the retroglossal region. The agreement between measured and estimated Pcrit and the significant association with AHI supports the validity of Pcrit estimates from the FSI model.

ORL ◽  
2021 ◽  
pp. 1-8
Author(s):  
Lifeng Li ◽  
Demin Han ◽  
Hongrui Zang ◽  
Nyall R. London

<b><i>Objective:</i></b> The purpose of this study was to evaluate the effects of nasal surgery on airflow characteristics in patients with obstructive sleep apnea (OSA) by comparing the alterations of airflow characteristics within the nasal and palatopharyngeal cavities. <b><i>Methods:</i></b> Thirty patients with OSA and nasal obstruction who underwent nasal surgery were enrolled. A pre- and postoperative 3-dimensional model was constructed, and alterations of airflow characteristics were assessed using the method of computational fluid dynamics. The other subjective and objective clinical indices were also assessed. <b><i>Results:</i></b> By comparison with the preoperative value, all postoperative subjective symptoms statistically improved (<i>p</i> &#x3c; 0.05), while the Apnea-Hypopnea Index (AHI) changed little (<i>p</i> = 0.492); the postoperative airflow velocity and pressure in both nasal and palatopharyngeal cavities, nasal and palatopharyngeal pressure differences, and total upper airway resistance statistically decreased (all <i>p</i> &#x3c; 0.01). A significant difference was derived for correlation between the alteration of simulation metrics with subjective improvements (<i>p</i> &#x3c; 0.05), except with the AHI (<i>p</i> &#x3e; 0.05). <b><i>Conclusion:</i></b> Nasal surgery can decrease the total resistance of the upper airway and increase the nasal airflow volume and subjective sleep quality in patients with OSA and nasal obstruction. The altered airflow characteristics might contribute to the postoperative reduction of pharyngeal collapse in a subset of OSA patients.


SLEEP ◽  
2020 ◽  
Vol 43 (10) ◽  
Author(s):  
Amal M Osman ◽  
Benjamin K Tong ◽  
Shane A Landry ◽  
Bradley A Edwards ◽  
Simon A Joosten ◽  
...  

Abstract Study Objectives Quantification of upper airway collapsibility in obstructive sleep apnea (OSA) could help inform targeted therapy decisions. However, current techniques are clinically impractical. The primary aim of this study was to assess if a simple, novel technique could be implemented as part of a continuous positive airway pressure (CPAP) titration study to assess pharyngeal collapsibility. Methods A total of 35 participants (15 female) with OSA (mean ± SD apnea–hypopnea index = 35 ± 19 events/h) were studied. Participants first completed a simple clinical intervention during a routine CPAP titration, where CPAP was transiently turned off from the therapeutic pressure for ≤5 breaths/efforts on ≥5 occasions during stable non-rapid eye movement (non-REM) sleep for quantitative assessment of airflow responses (%peak inspiratory flow [PIF] from preceding 5 breaths). Participants then underwent an overnight physiology study to determine the pharyngeal critical closing pressure (Pcrit) and repeat transient drops to zero CPAP to assess airflow response reproducibility. Results Mean PIF of breaths 3–5 during zero CPAP on the simple clinical intervention versus the physiology night were similar (34 ± 29% vs. 28 ± 30% on therapeutic CPAP, p = 0.2; range 0%–90% vs. 0%–95%). Pcrit was −1.0 ± 2.5 cmH2O (range −6 to 5 cmH2O). Mean PIF during zero CPAP on the simple clinical intervention and the physiology night correlated with Pcrit (r = −0.7 and −0.9, respectively, p &lt; 0.0001). Receiver operating characteristic curve analysis indicated significant diagnostic utility for the simple intervention to predict Pcrit &lt; −2 and &lt; 0 cmH2O (AUC = 0.81 and 0.92), respectively. Conclusions A simple CPAP intervention can successfully discriminate between patients with and without mild to moderately collapsible pharyngeal airways. This scalable approach may help select individuals most likely to respond to non-CPAP therapies.


2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Fernando Espinoza-Cuadros ◽  
Rubén Fernández-Pozo ◽  
Doroteo T. Toledano ◽  
José D. Alcázar-Ramírez ◽  
Eduardo López-Gonzalo ◽  
...  

Obstructive sleep apnea (OSA) is a common sleep disorder characterized by recurring breathing pauses during sleep caused by a blockage of the upper airway (UA). OSA is generally diagnosed through a costly procedure requiring an overnight stay of the patient at the hospital. This has led to proposing less costly procedures based on the analysis of patients’ facial images and voice recordings to help in OSA detection and severity assessment. In this paper we investigate the use of both image and speech processing to estimate the apnea-hypopnea index, AHI (which describes the severity of the condition), over a population of 285 male Spanish subjects suspected to suffer from OSA and referred to a Sleep Disorders Unit. Photographs and voice recordings were collected in a supervised but not highly controlled way trying to test a scenario close to an OSA assessment application running on a mobile device (i.e., smartphones or tablets). Spectral information in speech utterances is modeled by a state-of-the-art low-dimensional acoustic representation, called i-vector. A set of local craniofacial features related to OSA are extracted from images after detecting facial landmarks using Active Appearance Models (AAMs). Support vector regression (SVR) is applied on facial features and i-vectors to estimate the AHI.


2019 ◽  
Vol 24 (01) ◽  
pp. e107-e111 ◽  
Author(s):  
José Antonio Pinto ◽  
Luciana Balester Mello de Godoy ◽  
Heloisa dos Santos Sobreira Nunes ◽  
Kelly Elia Abdo ◽  
Gabriella Spinola Jahic ◽  
...  

Abstract Introduction Obstructive sleep apnea syndrome (OSAS) is a multifactorial disease characterized by episodes of partial or complete collapse during sleep of different regions of the upper airway. Surgery for OSAS evolved with the introduction of different techniques, considering new surgical concept of reconstruction of the upper airway. Objective To retrospectively evaluate the effectiveness of a new approach aimed at reducing pharyngeal collapse by combining two surgical techniques: lateral and expansion pharyngoplasty. Methods We reviewed the medical records of 38 patients with OSAS undergoing lateral/expansion pharyngoplasty from January 2012 to December 2016. The following data were collected: patient age, gender, and pre- and postoperative body mass index (BMI), Epworth sleepiness scale (ESS) scores, snoring visual analogue scale (VAS) scores, and polysomnography (PSG) results. Results The PSG results showed a significant reduction in the apnea/hypopnea index (AHI) from 22.4 ± 27.3 events/h preoperatively to 13.6 ± 17.9 events/h postoperatively (p = 0.009), with postoperative AHI reduction greater than 50% in 63.2% of the patients. There was also a significant reduction in the microarousal index (19.5 ± 22.6 vs 11.0 ± 13.4 events/h; p = 0.001) and in the minimum oxygen saturation (82.6 ± 10.3 vs 86.9 ± 11.1; p = 0.007). Conclusions Lateral-expansion pharyngoplasty represents a new surgical strategy for the treatment of OSAS in patients with palatal collapse by combining two different techniques: lateral and expansion pharyngoplasty. The two techniques, performed as a one-stage procedure, led to improvements in excessive daytime sleepiness, snoring, and PSG respiratory parameters by acting on lateral and retropalatal collapse, producing favorable results with good applicability in otolaryngology clinical practice.


2019 ◽  
Vol 105 (3) ◽  
pp. e23-e31 ◽  
Author(s):  
Matteo Parolin ◽  
Francesca Dassie ◽  
Luigi Alessio ◽  
Alexandra Wennberg ◽  
Marco Rossato ◽  
...  

Abstract Background Obstructive sleep apnea (OSA) is a common disorder characterized by upper airway collapse requiring nocturnal ventilatory assistance. Multiple studies have investigated the relationship between acromegaly and OSA, reporting discordant results. Aim To conduct a meta-analysis on the risk for OSA in acromegaly, and in particular to assess the role of disease activity and the effect of treatments. Methods and Study Selection A search through literature databases retrieved 21 articles for a total of 24 studies (n = 734). Selected outcomes were OSA prevalence and apnea-hypopnea index (AHI) in studies comparing acromegalic patients with active (ACT) vs inactive (INACT) disease and pretreatment and posttreatment measures. Factors used for moderator and meta-regression analysis included the percentage of patients with severe OSA, patient sex, age, body mass index, levels of insulin-like growth factor 1, disease duration and follow-up, and therapy. Results OSA prevalence was similar in patients with acromegaly who had ACT and INACT disease (ES = −0.16; 95% CI, −0.47 to 0.15; number of studies [k] = 10; P = 0.32). In addition, AHI was similar in ACT and INACT acromegaly patients (ES = −0.03; 95% CI, −0.49 to 0.43; k = 6; P = 0.89). When AHI was compared before and after treatment in patients with acromegaly (median follow-up of 6 months), a significant improvement was observed after treatment (ES = −0.36; 95% CI, −0.49 to −0.23; k = 10; P &lt; 0.0001). In moderator analysis, the percentage of patients with severe OSA in the populations significantly influenced the difference in OSA prevalence (P = 0.038) and AHI (P = 0.04) in ACT vs INACT patients. Conclusion Prevalence of OSA and AHI is similar in ACT and INACT patients in cross-sectional studies. However, when AHI was measured longitudinally before and after treatment, a significant improvement was observed after treatment.


SLEEP ◽  
2019 ◽  
Vol 42 (7) ◽  
Author(s):  
Amal M Osman ◽  
Jayne C Carberry ◽  
Peter G R Burke ◽  
Barbara Toson ◽  
Ronald R Grunstein ◽  
...  

AbstractStudy ObjectivesA collapsible or crowded pharyngeal airway is the main cause of obstructive sleep apnea (OSA). However, quantification of airway collapsibility during sleep (Pcrit) is not clinically feasible. The primary aim of this study was to compare upper airway collapsibility using a simple wakefulness test with Pcrit during sleep.MethodsParticipants with OSA were instrumented with a nasal mask, pneumotachograph and two pressure sensors, one at the choanae (PCHO), the other just above the epiglottis (PEPI). Approximately 60 brief (250 ms) pulses of negative airway pressure (~ –12 cmH2O at the mask) were delivered in early inspiration during wakefulness to measure the upper airway collapsibility index (UACI). Transient reductions in the continuous positive airway pressure (CPAP) holding pressure were then performed during sleep to determine Pcrit. In a subset of participants, the optimal number of replicate trials required to calculate the UACI was assessed.ResultsThe UACI (39 ± 24 mean ± SD; range = 0%–87%) and Pcrit (–0.11 ± 2.5; range: –4 to +5 cmH2O) were quantified in 34 middle-aged people (9 female) with varying OSA severity (apnea–hypopnea index range = 5–92 events/h). The UACI at a mask pressure of approximately –12 cmH2O positively correlated with Pcrit (r = 0.8; p < 0.001) and could be quantified reliably with as few as 10 replicate trials. The UACI performed well at discriminating individuals with subatmospheric Pcrit values [receiver operating characteristic curve analysis area under the curve = 0.9 (0.8–1), p < 0.001].ConclusionsThese findings indicate that a simple wakefulness test may be useful to estimate the extent of upper airway anatomical impairment during sleep in people with OSA to direct targeted non-CPAP therapies for OSA.


1996 ◽  
Vol 81 (6) ◽  
pp. 2618-2626 ◽  
Author(s):  
S. J. Cala ◽  
P. Sliwinski ◽  
M. G. Cosio ◽  
R. J. Kimoff

Cala, S. J., P. Sliwinski, M. G. Cosio, and R. J. Kimoff.Effect of topical upper airway anesthesia on apnea duration through the night in obstructive sleep apnea. J. Appl. Physiol. 81(6): 2618–2626, 1996.—It has previously been reported that the duration of obstructive apneas increases from the beginning to the end of the night (M. Charbonneau, J. M. Marin, A. Olha, R. J. Kimoff, R. D. Levy, and M. Cosio. Chest 106: 1695–1701, 1994). The purpose of this study was to test the hypothesis that stimulation of upper airway (UA) sensory receptors during obstructed inspiratory efforts contributes to arousal and apnea termination and that a progressive attenuation of this mechanism through the night contributes to apnea lengthening. We studied seven patients (six men, one woman) with severe obstructive sleep apnea (apnea-hypopnea index = 93 ± 26 events/h) during two consecutive nights of polysomnographic monitoring. On one night (random order), we performed topical UA anesthesia with 0.2% tetracaine and on the control night, sham anesthesia. We measured apnea duration, esophageal pressure (Pes) during apneas, and apneic O2 desaturation. Consistent with previous findings, apnea duration, number of efforts per apnea, and peak Pes at end apnea increased from the beginning to the end of the control nights. UA anesthesia produced a significant increase in apnea duration at the beginning of the night but no change in apnea length at the end of the night. Peak Pes and the rate of increase in Pes during the anesthesia nights were greater than during control nights, but the rate of increase in Pes was similar for the beginning and end of the control and anesthesia nights. These findings suggest that UA sensory receptors play a role in mediating apnea termination at the beginning of the night but that the contribution of these receptors diminishes as the night progresses such that greater inspiratory efforts are required to trigger arousal, leading to apnea prolongation.


2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Seda Beyhan Sagmen ◽  
Sevda Cömert

Abstract Background Obstructive sleep apnea is a condition characterized by the complete or partial obstruction of the upper airway during sleep. This study aimed to compare the clinical and polysomnographic characteristics of our obstructive sleep apnea patients according to their positional and non-positional features. Results Two hundred eighty patients were included in the study. One hundred two patients (36.43%) were female, while 178 patients (63.57%) were male. While 88 (31.43%) of these patients were defined as positional patients, 192 (68.57%) were defined as non-positional patients. The mean age of the positional patients (46.78 ± 9.66) was lower than the mean age of the non-positional patients (50.90 ± 10.96) (p 0.001). Similarly, the mean body mass index of the positional patients (29.39 ± 3.80) was lower than the mean body mass index of the non-positional patients (33.30 ± 6.45) (p < 0.001). Neck circumference values of the positional patients (40.36 ± 2.65) were lower compared to the non-positional patients (43.32 ± 2.54) (p < 0.001). Sleep values were compared based on the presence of positional sleep apnea. In the positional patients, sleep duration, sleep efficiency (percentage), duration of stage N3, minimum, and mean saturation values were found to be higher compared to the non-positional patients, while nightlong apnea hypopnea index, apnea index, percentage of sleep time with oxygen saturation below 90%, oxygen desaturation index, mean heart rate, and periodic limb movement index values were found to be lower (p < 0.05). The rate of severe sleep apnea (7.95%) in the positional patients was lower than the non-positional patients (53.65%) (p < 0.001). Conclusion In the light of these data, positional OSA is a very important condition presented in 31.43% of OSA patients and it was determined that these patients were younger, had less body mass index, and shorter neck circumference. The rate of severe disease was found to be lower in positional OSA patients


SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A340-A340
Author(s):  
A Bandyopadhyay ◽  
K N Kaneshiro ◽  
M Camacho

Abstract Introduction OSA affects 2-4% of children and untreated OSA can have adverse behavior and quality of life outcomes. 40% of children can have residual obstructive sleep apnea (OSA)despite first line treatment (adenotonsillectomy). Alternative modalities of treatment for OSA are limited. Myofunctional therapy comprises of exercises targeting upper airway muscles that can improve facial growth and have been shown to treat OSA in adults. There is paucity of data on the role of myofunctional therapy (MT) in children. The objective of this study was to systematically review the literature for articles evaluating myofunctional therapy (MT) as treatment for OSA in children and to perform a meta-analysis on the polysomnographic and mouth breathing data. Methods Medline, Embase, CINAHL, Scopus, Web of Science and Cochrane were searched from inception through October 1st, 2019. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement was followed. Results Eight studies (91 patients) reported polysomnography and/or mouth breathing outcomes. The pre- and post-MT apnea hypopnea indices (AHI) decreased from a mean ± standard deviation (M ± SD) of 3.75± 3.14/h to 2.08 ± 2.48/h, mean difference (MD) -1.6 [95% confidence interval (CI) -2.42, -0.78], P =0.0001. Mean oxygen saturations improved from 96.03 ± 1.1% to 96.67 ± 0.95%, MD 0.42 (95% CI 0.21, 0.63), P &lt;0.0001. Lowest oxygen saturations improved from 86.6 ± 7.3% to 90.94 ± 3.05%, MD 1.01 (95% CI 0.25, 1.77), P = 0.009. Mouth breathing decreased in all three studies reporting subjective outcomes. Conclusion Current literature demonstrates that myofunctional therapy decreases apnea-hypopnea index by approximately 45% in children with mild obstructive sleep apnea. Mean oxygen saturations, lowest oxygen saturations and mouth breathing outcomes improved in children. Myofunctional therapy could serve as an adjunct to other obstructive sleep apnea treatments. Support None


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