• Tuberculosis and Respiratory Diseases
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• v.67 no.3
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• pp.183-190
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• 2009

Background: Repeated arousals during sleep have been known to be associated with excessive daytime sleepiness and cardiovascular complications. We investigated the relationship between arousal indices and clinical parameters. Methods: We retrospectively reviewed medical records of 41 patients who performed polysomnography for a diagnosis of obstructive sleep apnea syndrome. We defined total arousal index (TAI) as the number of arousals per hour and respiratory arousal index (RAI) as the number of arousals associated with apnea or hypopnea per hour. Results: There were significant positive correlations between arousal indices and apnea-hypopnea index (AHI) (RAI vs. AHI, r=0.958, p<0.001; TAI vs. AHI, r=0.840, p<0.001). RAI and mean oxygen saturation showed a significant negative correlation with each other (r=-0.460, p=0.002). TAI revealed a significant positive correlation with mean systolic blood pressure (MSBP) and mean diastolic blood pressure (MDBP) (TAI vs. MSBP, r=0.389, p=0.014; TAI vs. MDBP, r=0.373, p=0.019). There was no significant correlation between arousal indices and parameters of sleepiness. RAI had a significant positive correlation with body mass index (BMI) and neck circumference (NC) (RAI vs. BMI, r=0.371, p=0.017; RAI vs. NC, r=0.444, p=0.004). When partial correlation analysis was performed to adjust for other variables, there was significant correlation between RAI and AHI (r=0.935, p<0.001). Conclusion: This study shows that respiratory arousal index could be a useful index reflecting of severity of obstructive sleep apnea syndrome. Arousal during sleep would be concerned in the development of cardiovascular complication of obstructive sleep apnea. And some anthropometric factors would contribute to the development of arousals during sleep. Further studies are needed to clarify any cause-effect relationship.

• Sleep Medicine and Psychophysiology
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• v.13 no.2
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• pp.52-58
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• 2006

Objectives: Continuous positive airway pressure (CPAP) is effective in the treatment of obstructive sleep apnea syndrome (OSAS), but the major limitation of CPAP may be poor compliance. The aims of the study were to investigate the compliance and side effects of CPAP, and to evaluate the efficacy of CPAP in patients with OSAS. Methods: This study enrolled 106 patients with OSAS who took the CPAP treatment. The severity of daytime sleepiness was measured using Epworth Sleepiness Scale (ESS), and sleep quality and depressive symptoms were assessed by Pittsburgh Sleep Quality Index (PSQI) and Beck Depression Inventory (BDI), respectively. Results: During 29 months of the study period, 41.5% of patients were using CPAP and 38.7% of patients stopped using it. Compared to non-compliant patients, compliant patients had a higher PSQI score and obstructive apnea index. Among non-compliant patients, 51.2% of them stopped using CPAP within 1months. 85.7% of non-compliant patients were discomforted by the CPAP, but much more nasopharyngeal symptoms were reported in the compliant group. ESS (p<0.01), PSQI (p<0.01) and BMI (p<0.01) were reduced significantly after CPAP treatment but not BDI (p=0.86). Conclusions: We concluded that CPAP can reduce the daytime sleepiness, nocturnal sleep disturbance, and body mass index. To increase the compliance of CPAP, we suggest that some education and support are needed at the early stage of the CPAP treatment.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.201-209
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• 2014

Obstructive sleep apnea syndrome(OSAS) is a respiratory disease caused by partial or complete obstruction of the upper airway during sleep. In this paper, we proposed the optical flow method to analyze the upper airway dynamic changes during respiration for children with OSAS and control subjects. We compared the absolute value of difference between inspiration and expiration for airway area analysis method and optical flow method for 5 children with OSAS and 6 control subjects. From the statistical analysis, airway area analysis method and optical flow method are statistically significant at the 0.1 (p value is 0.0977) and 0.01 (p value is 0.0011) significance level respectively. From this simulations, the optical flow method could provide more accurate information to diagnose the OSAS patients than the traditional airway area analysis method.

• Tuberculosis and Respiratory Diseases
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• v.47 no.2
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• pp.218-230
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• 1999

Background: Craniofacial anatomic abnormalities related to structural narrowing of the upper airway have been reported in patients with obstructive sleep apnea syndrome. In this study, we evaluated the craniofacial anatomic characteristics of Korean patients with obstructive sleep apnea syndrome, and the role of cephalometric analysis in the prediction of abnormal breathing during sleep. Methods: Thirty-nine patients with obstructive sleep apnea syndrome(OSAS), 39 simple snorers(simple snorers) and 20 controls(control) had cephalometric analysis using the technique of Riley et al, and underwent standardized polysomnographic recordings. Different variables, including sex, body mass index, cephalometric and polysomnographic data, were statistically analyzed. Results: Pm-UPW and V-LPW distances were significantly shorter in OSAS when compared with simple snorers or control. PAS in simple snorers was shorter than in control. ANS-Gn distance in OSAS was significantly longer than in control. PNS-P distance in OSAS or simple snorers was significantly longer than in control. MP-H distance in OSAS was significantly longer than in simple snorers or control and MP-H distance in simple snorers was also longer than in control. NL/Pm-P angle in OSAS was lesser than in control. MP-H distance in OSAS or in the combined groups of OSAS and simple snorers was significantly correlated with apneahypopnea index(AHI). PNS-P distance in the combined groups of OSAS and simple snorers was correlated with AHI. In male of all subjects, body mass index was significantly correlated with PNS-P or MP-H distance. Conclusion: Cephalometric analysis can be useful tool in determining the craniofacial anatomic abnormalities in patients with obstructive sleep apnea syndrome. Cephalometric parameters, especially MP-H distance, can be useful for predicting frequency of narrowing or obstruction of upper airway during sleep.

• Tuberculosis and Respiratory Diseases
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• v.42 no.1
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• pp.84-92
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• 1995

Background: Nasal applied continuous positive airway pressure(CPAP) is a highly effective method of treatment for obstructive sleep apnea syndrome. More than a decade of accumulated experience with this treatment modality confirmed that it is unquestionably the medical treatment of choice for patients with obstructive sleep apnea syndrome. However it takes long time to reach optimal CPAP pressure. To save the time to reach optimal pressure, it is necessary to clarify the time to reach optimal pressure for treatment of obstructive sleep apnea syndrome. Method: CPAP pressure is titrated during an overnight study according to a standardized protocol. Just before the presleep bio-calibration procedures, the technician applies the nasal mask and switches on the clinical CPAP unit. Initial positive for pressure is typically 3.0 centimeters of water pressure. After sleep onset, the technician gradually increases the pressure until sleep-disordered breathing events disappear or become minimal. The pressure must maintain maximal airway patency during both NREM and REM sleep to be considered effective. Before recommending a final pressure setting, sleep recording and oximetry data are reviewed by an American Board of Sleep Medicine certified Sleep Specialist and a Registrered Polysomnographic Technologist. Results: We examined the time required to reach optimal pressure during routine CPAP titration in 127 consecutively evaluated individuals diagnosed with sleep-disordered breathing. Results indicate that 33% of patients required more than four hours to attain satisfactory titration. This indicates that a four-hour session is marginally enough time, at best, to determine a proper CPAP pressure setting. Moreover, 60 of 127 patients required further adjustment after optimal pressure was reached. These additional pressure trials were needed to confirm that higher pressures were not superior for eliminating sleep-disordered breathing events. Conclusions: The data presented underscore the logistical difficulty of titrating CPAP during split-night studies without modifying the titration procedure. Futhermore, the time needed to reach optimal pressure makes it improbable that proper CPAP titration can be performed during a 2-3 hour nap study.

• Sleep Medicine and Psychophysiology
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• v.6 no.2
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• pp.110-115
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• 1999

Objectives: To investigate the effect of mandibular repasitioning device on airway sige and airway collapsibility in patients with obstructive sleep apnea syndrome(OSAS). Methods: Cine CT with polysomnographic monitoring was performed during sleep in nine(OSAS) patients before and after manibular repositioning device(MRD) application. Axial CT images were obtained in five upper airway levels(retropalatal-high, retroalatal-low, retroglossal, epiglottis, and hypopharynx levels). In each airway level, one axial CT image was obtained during sleep apnea period and 10 serial axial CT images were scanned every 1 second during normal sleep breathing. After wearing MRD, all CT images were obtained by the same method. The cross-sectional areas of airway were measured by automatic tracing method. The changes of minimum airway size and maximum airway size after MRD were evaluated. The airway collapsibility was calculaed before and after MRD. Results: During sleep apnea, the airway of retropalatal-low level was the most frequently narrowest site. During normal sleep breahing the minimum airway size was increased significantly after MRD at retropalatal-low level(p=0.011). The mean airway collapsibility was the highest at retropalatal-low level. MRD decreased the airway collapsibility significantly at retropalatal-low level(p=0.021) and epiglottis level(p=0.038). Conclusions: The enlargement of the minimum airway size and decreased airway collapsibility may be the therapeutic mechanism of MRD in obstructive sleep apnea.

• Tuberculosis and Respiratory Diseases
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• v.40 no.5
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• pp.501-508
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• 1993

Background: Sleep apnea syndrome is a common disorder which is estimated to affect about 1~4% of adult male population. And if untreated, sleep apnea can cause significant sequelae, such as hypertension, nocturnal cardiac arrhythmia, daytime hypersomnolence, and cognitive impairment. Various kinds of treatment for obstructive sleep apnea (OSA) have been developed. Among them nasal CPAP, first introduced by Sullivan et al in 1981, has received widespread interest and acclaim as a treatment of OSA, and is currently recommended as first-line treatment for OSA. We evaluated the effect of nasal CPAP in OSA and the side effects of nasal CPAP hindering patients from using nasal CPAP. Methods: We performed sleep studies in 20 OSA patients at 2 consecutive nights; baseline night at first day and CPAP night at second day. We compared apnea index, lowest oxygen concentration during apnea, maximal apnea time, and total apnea duration per total sleep time before and after CPAP. We also evaluated the side effects of CPAP with inquiry to the patients. Results: 1) Apnea index was significantly decreased after CPAP in 17 out of 20 OSA patients (85%) and increased in 3 patients (15%). 2) Average apnea index was significantly decreased after CPAP ($34.1{\pm}18.9/h{\rightarrow}15.4{\pm}10.3/h$, p<0.01). 3) Total apnea duration per total sleep time was also significantly decreased after CPAP ($28.5{\pm}16.0%{\rightarrow}11.9{\pm}9.3%$, p<0.05). 4) The lowest oxygen satuation and maximal apnea time were not significantly changed after CPAP. 5) The most frequent side effect of nasal CPAP was mask discomfort (80%), and the next was drying of nasal passages (65%). Conclusion: Nasal CPAP is an effective treatment for OSA. Futher studies should be concentrated on long term follow up of nasal CPAP for its therapeutic effects and the study of methods to enhance patients' compliance.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.3
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• pp.463-469
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• 1996

Sonoring is caused by the repeated obstructions of versatile upper air way structure during sleep and is known as a kind of disease entity varing from simple snoring to obstructive sleep apnea syndrome(OSAS) which can cause serious cardiopulmonary complications due to its hypoxic pathophysiology. It has been reported that over 30% of middle-aged person have the problems of snoring and its accompanied symptomes and signs. Cephalometric measurements, frequently used to measure sella-nasion-subspinale(SNA) and sella-nasion-supramentale(SNB) angles, can provide the informations about the posterior airway space(PAS), the mandibular plane(MP) and the position of hyoid bone. These informations are useful in determining the therapeutic modalities of the snoring and OSAS patients. However, with conventional routine upright position, it does not represent the actual images of obstructive mechanism during sleep but only show the images of awaken normal upper airway anatomy. Therefore we have taken dual images of a routine upright lateral and a supine cephalometric view to compare both.

• Sleep Medicine and Psychophysiology
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• v.15 no.2
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• pp.82-86
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• 2008

Objectives: Obstructive sleep apnea syndrome (OSAS) not only causes respiratory disturbances during sleep but also decreases the quality of nocturnal sleep through sleep fragmentation and sleep structure change. We aimed at comparing the changes in sleep fragmentation and structure between baseline (diagnostic) nocturnal polysomnography (NPSG) and nCPAP (nasal continuous positive airway pressure) titration trial. Methods: One hundred and three patients with a baseline night of respiratory disturbance index (RDI) of 5 or greater and reduced RDI score during nCPAP titration night were retrospectively selected for the study. Sleep fragementation and sleep structure between baseline NPSG and the NPSG during nCPAP titration were compared. Sleep fragmentation index (SFI) was defined as the total number of awakenings and shifts to stage 1 sleep divided by the total sleep time in hour. SFI and other polysomnographic parameters were statistically compared between the two nights. Results: SFI during baseline NPSG and nCPAP titration nights were $29.0{\pm}13.8$ and $15.2{\pm}8.8$, respectively, indicating a significant SFI decrease during nCPAP titration (t=9.7, p<0.01). SFI showed significant negative correlations with sleep efficiency (r=-0.60, p<0.01) and total sleep time (r=-0.45, p<0.01) and a positive correlation with RDI (r=0.28, p<0.01). Conclusion: Use of nCPAP, even during the titration, significantly decreases sleep fragmentation and improves sleep structure in OSAS patients. We suggest that SFI may be utilized as a measure of assessing OSAS severity and nCPAP efficacy.

• The Journal of the Korean dental association
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• v.44 no.6 s.445
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• pp.350-358
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• 2006