Determinants Of Obstructive Sleep Apnea Research Articles

0833 Identifying Clinical Determinants of Obstructive Sleep Apnea in Children with Sickle Cell Disease

0833 Identifying Clinical Determinants of Obstructive Sleep Apnea in Children with Sickle Cell Disease

Determinants of awake oropharyngeal volume reduction between sitting and supine positions in children evaluated for snoring.

Pharyngeal collapsibility is a major determinant of obstructive sleep apnea (OSA) pathophysiology, but its anatomical predictors in children are largely unknown. We hypothesised that anatomical (tonsillar hypertrophy, narrow palate, nasal obstruction, dental/skeletal malocclusion, obesity) and OSA-related (apnea-hypopnea index, AHI) parameters could be related to a measure of awake pharyngeal collapsibility. We performed acoustic pharyngometry in children evaluated for suspected OSA, allowing us to measure the reduction of oropharyngeal volume in supine versus sitting position normalised for the volume in supine position (ΔV%), a measure of pharyngeal collapsibility. In addition to polysomnography and a clinical examination (anatomical parameters), acoustic rhinometry was used to assess nasal obstruction. A total of 188 snoring children were included, 118 (63%) of whom were obese and 74 (39%) of whom had moderate to severe OSA (AHI ≥5/h). The median (25th-75th percentiles) ΔV% in the whole population was 20.1% (4.7; 43.3). ΔV% was independently and positively associated with AHI (p=0.023), z-score of BMI (p=0.001), tonsillar hypertrophy (p=0.007), narrow palate (p=0.035), and African (p < 0.001) ancestry. By contrast, ΔV% was not modified by dental or skeletal malocclusion, Friedman palate position class or nasopharyngeal obstruction. Tonsillar hypertrophy, obesity, narrow palate and African ancestry are independently associated with an increase in pharyngeal collapsibility in snoring children, thus increasing the risk of OSA. Increased pharyngeal compliance in African children may explain the increased risk of residual OSA after adenotonsillectomy observed in this population.

Prevalence and determinant of obstructive sleep apnea in patients attending primary health care centers in ministry of health and international medical center in Jeddah, 2018

Introduction: Obstructive sleep apnea (OSA) is a clinical disorder that requires early detection and intervention. This study aimed to assess the prevalence and determinants of OSA amongst patients attending the primary health care centers (PHCCs) in Ministry of Health (MOH) and the Family Medicine Department at International Medical Center (IMC) in Jeddah, thereby determining the high risk-population and highlight the impact of such sleep disorder. Materials and Methods: A cross-sectional survey was conducted to adult subjects attending the general clinics in the five PHCCs in Ministry of Health (MOH) and the Family Medicine Department at International Medical Center (IMC) in Jeddah, Saudi Arabia. Shapiro-wilk was used to determine the normal distribution of the sample. The STOP-BANG questionnaire and Epworth sleepiness scale (ESS) were given in validated English and Arabic version. Collected data were entered and analyzed using IBM SPSS, version 24 (IBM Corp, Armonk, NY). Results: Based from STOP-BANG analysis, the mean score was found to be 2.57, indicating that the majority of the adults under study were at low to moderate risk of having OSA. The mean score for patients who have moderate to high risk for OSA was found to be 3.97. Factors such as age, male gender, hypertension and BMI >35 were found to be significantly associated with OSA. Conclusion: The result of STOP-BANG and Epworth sleepiness scale analysis showed that most of the adult persons were at low risk of acquiring obstructive sleep apnea and experienced less daytime sleepiness. This study concludes that factors such as age, male gender, hypertension and body mass index (BMI) were found to be significantly associated with OSA. Screening techniques such as STOP-BANG and ESS were found to be an important and useful technique in assessing the prevalence of OSA. Keywords: Obstructive sleep apnea, Prevalence, Determinant, Primary health care center, STOP-BANG, ESS.

Therapeutic CPAP Level Predicts Upper Airway Collapsibility in Patients With Obstructive Sleep Apnea.

Upper airway collapsibility is a key determinant of obstructive sleep apnea (OSA) which can influence the efficacy of certain non-continuous positive airway pressure (CPAP) treatments for OSA. However, there is no simple way to measure this variable clinically. The present study aimed to develop a clinically implementable tool to evaluate the collapsibility of a patient's upper airway. Collapsibility, as characterized by the passive pharyngeal critical closing pressure (Pcrit), was measured in 46 patients with OSA. Associations were investigated between Pcrit and data extracted from patient history and routine polysomnography, including CPAP titration. Therapeutic CPAP level, demonstrated the strongest relationship to Pcrit (r2=0.51, p < .001) of all the variables investigated including apnea-hypopnea index, body mass index, sex, and age. Patients with a mildly collapsible upper airway (Pcrit ≤ -2 cmH2O) had a lower therapeutic CPAP level (6.2 ± 0.6 vs. 10.3 ± 0.4 cmH2O, p < .001) compared to patients with more severe collapsibility (Pcrit > -2 cmH2O). A therapeutic CPAP level ≤8.0 cmH2O was sensitive (89%) and specific (84%) for detecting a mildly collapsible upper airway. When applied to the independent validation data set (n = 74), this threshold maintained high specificity (91%) but reduced sensitivity (75%). Our data demonstrate that a patient's therapeutic CPAP requirement shares a strong predictive relationship with their Pcrit and may be used to accurately differentiate OSA patients with mild airway collapsibility from those with moderate-to-severe collapsibility. Although this relationship needs to be confirmed prospectively, our findings may provide clinicians with better understanding of an individual patient's OSA phenotype, which ultimately could assist in determining which patients are most likely to respond to non-CPAP therapies.

Enhanced upper-airway muscle responsiveness is a distinct feature of overweight/obese individuals without sleep apnea.

Body habitus is a major determinant of obstructive sleep apnea (OSA). However, many individuals do not have OSA despite being overweight/obese (body mass index > 25 kg/m(2)) for reasons that are not fully elucidated. To determine the key physiologic traits (upper-airway anatomy/collapsibility, upper-airway muscle responsiveness, chemoreflex control of ventilation, arousability from sleep) responsible for the absence of OSA in overweight/obese individuals. We compared key physiologic traits in 18 overweight/obese subjects without apnea (apnea-hypopnea index < 15 events per hour) with 25 overweight/obese matched patients with OSA (apnea-hypopnea index ≥ 15 events per hour) and 11 normal-weight nonapneic control subjects. Traits were measured by repeatedly lowering continuous positive airway pressure to subtherapeutic levels for 3 minutes during non-REM sleep. Overweight/obese subjects without apnea exhibited a less collapsible airway than overweight/obese patients with apnea (critical closing pressure: -3.7 ± 1.9 vs. 0.6 ± 1.2 cm H2O; P = 0.003; mean ± 95% confidence interval), but a more collapsible airway relative to normal-weight control subjects (-8.8 ± 3.1 cm H2O; P < 0.001). Notably, overweight/obese subjects without apnea exhibited a threefold greater upper-airway muscle responsiveness than both overweight/obese patients with apnea (Δgenioglossus EMG/Δepiglottic pressure: -0.49 [-0.22 to -0.79] vs. -0.15 [-0.09 to -0.22] %max/cm H2O; P = 0.008; mean [95% confidence interval]) and normal-weight control subjects (-0.16 [-0.04 to -0.30] %max/cm H2O; P = 0.02). Loop gain was elevated (more negative) in both overweight/obese groups and normal-weight control subjects (P = 0.02). Model-based analysis demonstrated that overweight/obese individuals without apnea rely on both more favorable anatomy and collapsibility and enhanced upper-airway dilator muscle responses to avoid OSA. Overweight/obese individuals without apnea have a moderately compromised upper-airway structure that is mitigated by highly responsive upper-airway dilator muscles to avoid OSA. Elucidating the mechanisms underlying enhanced muscle responses in this population may provide clues for novel OSA interventions.

Sleep Analysis of Patients With Nocturia and Benign Prostatic Obstruction

To analyze the timing of nocturia during sleep and its effect on sleep quality using the polysomnography (PSG) findings from patients with benign prostatic obstruction. From August 2009 to August 2010, 20 patients diagnosed with benign prostatic obstruction were enrolled in the present study. The sleep evaluation was performed by PSG. The Epworth index was used to evaluate the sleepiness of the patients. The effect of nocturia on sleep quality is evaluated by sleep efficacy, total sleep time, and rapid eye movement sleep duration, calculated from the hypnograms derived from the polysomnograms. The mean age, total International Prostate Symptom Score, nocturia frequency on International Prostate Symptom Score, and frequency of nocturia recorded during PSG was 60.4 ± 8.5 years (range 44-74), 19.3 ± 4.9 (range 10-28), 3.5 ± 1.05 (range 2-5), and 1.35 ± 1.2 (range 0-4), respectively. In 6 patients (30%), the Epworth sleepiness score was pathologic (score >8). Nocturia correlated positively with increased daytime sleepiness, however it did not correlate with sleep efficacy or total sleep time. These parameters were affected by the apnea-hypopnea index, the major determinant of obstructive sleep apnea. Of the 20 patients, 14 (70%) experienced nocturia during PSG, and in these patients, we recorded 23 nocturia episodes that mostly occurred in the superficial sleep stage (16 [70%] of 23). Only 7 nocturia episodes (30%) occurred in the deep sleep stage. The sleep quality of patients with deep sleep nocturia did not differ from that of patients with superficial sleep nocturia. The results of our study have shown that nocturia predominantly occurs during the superficial sleep or rapid eye movement stage and is related to increased daytime sleepiness in patients with benign prostatic obstruction. The timing and frequency of nocturia had no significant affect on sleep quality; however, the presence of obstructive sleep apnea negatively interfered with these parameters.

Analysis of anatomical and functional determinants of obstructive sleep apnea

Craniofacial abnormalities have an important role in the occurrence of obstructive sleep apnea (OSA) and may be particularly significant in Asian patients, although obesity and functional abnormalities such as reduced lung volume and increased airway resistance also may be important. We conducted simultaneous analyses of their interrelationships to evaluate the relative contributions of obesity, craniofacial structure, pulmonary function, and airway resistance to the severity of Japanese OSA because there are little data in this area. A cross-sectional observational study was performed on 134 consecutive Japanese male patients. A sleep study, lateral cephalometry, pulmonary function tests, and impulse oscillometry (IOS) were performed on all patients. Age, body mass index (BMI), position of the hyoid bone, and proximal airway resistance on IOS (R20) were significantly related to the apnea/hypopnea index (AHI) (p < 0.05) in multiple regression analysis. Subgroup analysis showed that, for moderate-to-severe OSA (AHI ≥ 15 events/h), neck circumference and R20 were predominantly related to AHI, whereas for non-to-mild OSA (AHI < 15 events/h), age and expiratory reserve volume were the predominant determinants. In obese subjects (BMI ≥ 25kg/m(2)), alveolar-arterial oxygen tension difference, position of the hyoid bone, and R20 were significantly associated with AHI, whereas age alone was a significant factor in nonobese subjects (BMI < 25kg/m(2)). Aside from age and obesity, anatomical and functional abnormalities are significantly related to the severity of Japanese OSA. Predominant determinants of AHI differed depending on the severity of OSA or the magnitude of obesity.

Regional Fat Distribution and Sleep Apnea: Sex Makes a Difference

Regional Fat Distribution and Sleep Apnea: Sex Makes a Difference

Neurotrophins and Tonsillar Hypertrophy in Children With Obstructive Sleep Apnea

Enlarged adenotonsillar tissue (AT) is a major determinant of obstructive sleep apnea (OSA) severity in children; however, mechanisms of AT proliferation are poorly understood. We hypothesized that early exposure to respiratory syncytial virus (RSV) may modify AT proliferation through up-regulation of nerve growth factor (NGF)-neurokinin 1 (NK1) receptor dependent pathways. AT harvested from 34 children with OSA and 25 children with recurrent tonsillitis (RI) were examined for mRNA expression of multiple growth factors and their receptors. In addition, NK1 receptor expression and location, and substance P tissue concentrations were compared in AT from OSA and RI children. NGF mRNA and its high-affinity tyrosine kinase receptor (trkA) expression were selectively increased in OSA (p<0.001). NK1 receptor mRNA and protein expression were also enhanced in OSA (p<0.01), and substance P concentrations in OSA patients were higher than in RI (p<0.0001). AT from OSA children exhibit distinct differences in the expression of NGF and trkA receptors, NK1 receptors, and substance P. The homology between these changes and those observed in the lower airways following RSV infection suggests that RSV may have induced neuro-immunomodulatory changes within AT, predisposing them to increased proliferation, and ultimately contribute to emergence of OSA.