• 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.

• Tuberculosis and Respiratory Diseases
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• v.47 no.6
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• pp.824-835
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• 1999

Background: Sleep-related breathing disorders are commonly found in patients with chronic renal failure and particularly, sleep apnea may have an influence on the long-term mortality rates in these patients. Maintenance hemodialysis is the mainstay of medical measures for correcting the metabolic derangements of chronic renal failure but it is uncertain whether it may alleviate sleep disorders including sleep apnea. Methods: Forty seven patients on maintenance hemodialysis were surveyed with the sleep questionnaire about their clinical symptoms related to sleep disorders. Among them, 15 patients underwent the polysomnography and their blood levels of urea nitrogen, creatinine, electrolytes and the arterial blood gases in the nights before and following hemodialysis were measured. Results: Forty(85.1%) of the 47 patients complained of the symptoms associated with sleep-wake cycle disturbances, 55.3% experienced snoring and 27.7% reported witnessed apneas. The duration of REM sleep increased significantly in the nights after hemodialysis compared to the nights without hemodialysis(p<0.05) and the percentage of total sleep time comprising NREM sleep decreased significantly in the nights following hemodialysis compared to the nights before hemodialysis(p<0.05). The percentage of total sleep time consisting of the stage 1 and 2 NREM sleep showed the trend for a decrease in the nights after hemodialysis(p=0.051), while the percentage of total sleep time comprising the stage 3 and 4 NREM sleep did not change between nights. The obstructive sleep apnea was more predominant type than the central one in both nights and there were no differences in the apnea index and the apnea-hypopnea index between the nights. The decrease in the blood level of urea nitrogen, creatinine, potassium and phosphorus was observed after hemodialysis(p<0.05), but the differences of parameters measured during polysomnography between the nights did not correlate with the changes of biochemical factors obtained on the two nights. Arterial blood gas analysis showed that pH was significantly greater in the nights after hemodialysis than in the nights before hemodialysis(p<0.05), but there were no correlations between the parameters examined during polysomnography and the parameters of arterial blood gas analysis(p<0.05). Conclusion: These results suggest that chronic renal failure is an important systemic disorder which is strongly associated with sleep disorders. Maintenance hemodialysis, although it is a widely accepted measure to treat chronic renal failure, did not significantly modulate the sleep architecture and the severity of sleep apnea. Thus, taking the patients with chronic renal failure into account, it is advisable to try not only to find a substantial way for correcting metabolic derangements but also to consider the institution of more effective treatments for sleep disorders.

• Sleep Medicine and Psychophysiology
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• v.15 no.2
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• pp.94-99
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• 2008

The most common cause of obstructive sleep apnea syndrome (OSAS) in childhood is adenotonsillar hypertrophy. Adenotonsillectomy improves the symptoms quite well in most cases. However, some patients could experience the OSAS again after adenotonsillectomy, who might have several risk factors such as incomplete operation, misdiagnosis, combined anatomical malformation, sinusitis or chronic allergic rhinitis, obesity, initial severe OSAS, and early onset OSAS. We report a case of 11-year-old obese boy who presented with snoring for several years. He was obese with body mass index (BMI) of $26.3kg/m^2$ and also found to have fatty liver by ultrasonogram. Initial polysomnography (PSG) showed that he met the criteria of severe OSAS with the apnea-hypopnea index (AHI) of 70.5. He underwent adenotonsillectomy and symptoms improved immediately. Four months later symptoms were relieved with AHI of 0, but 1 year after the adenotonsillectomy he started to complain snoring again and the subsequent PSG results showed that OSAS has relapsed with AHI of 43. Paranasal sinus X-ray and physical examination showed sinusitis and re-growth of adenoid. Obesity was proved not to be a contributing factor because his BMI decreased to normal range ($23.1kg/m^2$) after diet control and regular exercise. Also, liver transaminase was normalized and fatty liver was disappeared on follow-up abdominal ultrasonogram. After treatment of sinusitis, symptoms were relieved with decreased AHI (8.5). This case suggests that simple adenotonsillectomy might not be the end of OSAS treatment in childhood. Patients who had adenotonsillectomy should be followed by subsequent PSG if symptoms recur. It is also important to be aware of risk factors in the recurrent OSAS for the proper intervention according to the cause.

• Korean Journal of Clinical Laboratory Science
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• v.39 no.3
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• pp.264-270
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• 2007

Obstructive sleep apnea syndrome (OSAS) is defined by sleep apnea with decreased oxygen saturation, excessive snoring with daytime sleepiness, and frequent awakening during the night time sleep. The present study was performed to investigate how apnea-hypopnea, that possibly causes breathing disturbance during sleep, can affect sleep pattern in patients with OSAS. We included 115 patients (92 men, 23 women) who underwent a polysomnography from January 2006 to May 2007. As the frequency of sleep apnea-hypopnea increases, the proportion of non-rapid eye movement (REM) sleep (p<0.001), and stage I sleep (p<0.001) increased, while that of stage II sleep (p<0.001), stage III and IV sleep (p<0.01), and REM sleep (p<0.05) decreased. Furthermore, sleep apnea-hypopnea was closely correlated with REM sleep (r=0.314, p<0.001), stage I sleep (r=0.719, p<0.001), stage II sleep (p=-0.342, p<0.05), stage III and IV sleep (r=-0.414, p<0.001), and REM sleep (r=-0.342, p<0.05). Stage I sleep could account for the 51% of the variance of apnea-hyponea. Our study shows sleep apnea-hypopnea affects sleep pattern in pattern with OSAS significantly, and the change of stage I sleep is the most important factor in estimating the disturbance of sleep pattern.

• Sleep Medicine and Psychophysiology
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• v.24 no.1
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• pp.32-37
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• 2017

Objectives: A supine sleep position increases sleep apneas compared to non-supine positions in obstructive sleep apnea syndrome (OSAS). However, supine position time (SPT) is not highly associated with apnea-hypopnea index (AHI) in OSAS. We evaluated the correlation among sleep-related variables and SPT in OSAS. Methods: A total of 365 men with OSAS were enrolled in this study. We analyzed how SPT was correlated with demographic data, sleep structure-related variables, OSAS-related variables and heart rate variability (HRV). Multiple linear regression analysis was conducted to investigate the factors that affected SPT. Results: SPT had the most significant correlation with total sleep time (TST ; r = 0.443, p < 0.001), followed by sleep efficiency (SE ; r = 0.300, p < 0.001). Snoring time (r = 0.238, p < 0.001), time at < 90% SpO2 (r = 0.188, p < 0.001), apnea-hypopnea index (AHI ; r = 0.180, p = 0.001) and oxygen desaturation index (ODI ; r = 0.149, p = 0.004) were significantly correlated with SPT. Multiple regression analysis revealed that TST (t = 7.781, p < 0.001), snoring time (t = 3.794, p < 0.001), AHI (t = 3.768, p < 0.001) and NN50 count (t = 1.993, p = 0.047) were associated with SPT. Conclusion: SPT was more highly associated with sleep structure-related parameters than OSAS-related variables. SPT was correlated with TST, SE, AHI, snoring time and NN50 count. This suggests that SPT is likely to be determined by sleep structure, HRV and the severity of OSAS.

• Clinical and Experimental Pediatrics
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• v.46 no.11
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• pp.1073-1079
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• 2003

Purpose : Recently there has been a decrease in ventilator care rate and duration of very low birth weight infants(VLBWI) in Fatima Hospital. The aims of this study were to survey the frequency and duration of ventilation in VLBWI and to develop a non-invasive neonatal intensive care unit (NICU) policy. Methods : We performed a retrospective study of 284 newborn of infants less than 1,500 gm admitted to NICU and discharged from January 1998 to December 2001. Patients were intubated or applied continuous positive airway pressure(CPAP) via nasal prong immediately after presenting signs of respiratory distress. We analyzed epidemiologic data to study the changes in ventilator care rate, duration and outcome of ventilator care groups. Results : Of 284 newborn infants, 146 required invasive management, such as endotracheal intubation and assisted ventilation. The characteristics, the severity of clinical symptoms and laboratory findings in ventilator care groups at birth showed no significant differences. The annual proportion of infants requiring assisted ventilation decreased according to increasing gestational age. The median duration of ventilation decreased markedly from 6.0 days in 1998 to 2.7 days in 2001. Final complications and outcomes in ventilator care groups showed no significant differences. Conclusion : Our study shows a significant reduction in the invasiveness of the treatment of VLBW infants, which was not associated with an increased mortality or morbidity. A non-invasive strategy for the VLBW infant with minimal to moderate respiratory distress after birth in NICU is better than immediate invasive management. Non-invasive nasal CPAP is a simpler and safer method than invasive assisted ventilation.

• Sleep Medicine and Psychophysiology
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• v.19 no.2
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• pp.68-76
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• 2012

Objectives: Sleep disorders cause changes of autonomic nervous system (ANS) which affect cardiovascular system. Primary insomnia (PI) makes acceleration of sympathetic nervous system (SNS) tone by sleep deficiency and arousal. Obstructive sleep apnea syndrome (OSAS) sets off SNS by frequent arousals and hypoxemias during sleep. We aimed to compare the changes of heart rate variability (HRV) indices induced by insomnia or sleep apnea to analyze for ANS how much to be affected by PI or OSAS. Methods: Total 315 subjects carried out nocturnal polysomnography (NPSG) were categorized into 4 groups - PI, mild, moderate and severe OSAS. Severity of OSAS was determined by apnea-hypopnea index (AHI). Then we selected 110 subjects considering age, sex and valance of each group's size [Group 1 : PI (mean age=$41.50{\pm}13.16$ yrs, AHI <5, n=20), Group 2 : mild OSAS (mean age=$43.67{\pm}12.11$ yrs, AHI 5-15, n=30), Group 3 : moderate OSAS (mean age $44.93{\pm}12.38$ yrs, AHI 16-30, n=30), Group 4 : severe OSAS (mean age=$45.87{\pm}12.44$ yrs, AHI >30, n=30)]. Comparison of HRV indices among the four groups was performed with ANCOVA (adjusted for age and body mass index) and Sidak post-hoc test. Results: We found statistically significant differences in HRV indices between severe OSAS group and the other groups (PI, mild OSAS and moderate OSAS). And there were no significant differences in HRV indices among PI, mild and moderate OSAS group. In HRV indices of PI and severe OSAS group showing the most prominent difference in the group comparisons, average RR interval were $991.1{\pm}27.1$ and $875.8{\pm}22.0$ ms (p=0.016), standard deviation of NN interval (SDNN) was $85.4{\pm}6.6$ and $112.8{\pm}5.4$ ms (p=0.022), SDNN index was $57.5{\pm}5.2$ and $87.6{\pm}4.2$ (p<0.001), total power was $11,893.5{\pm}1,359.9$ and $18,097.0{\pm}1,107.2ms^2$(p=0.008), very low frequency (VLF) was $7,534.8{\pm}1,120.1$ and $11,883.8{\pm}912.0ms^2$ (p=0.035), low frequency (LF) was $2,724.2{\pm}327.8$ and $4,351.6{\pm}266.9ms^2$(p=0.003). Conclusions: VLF and LF which were correlated with SNS tone showed more increased differences between severe OSAS group and PI group than other group comparisons. We could suggest that severe OSAS group was more influential to increased SNS activity than PI group.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.4
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• pp.377-388
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• 2020

The aim of this study was to evaluate the association between various predicting tools and Apnea-Hypopnea Index (AHI) to identify children with sleep disordered breathing (SDB). From 5 to 10 years old who came for orthodontic counseling, 61 children, whom had lateral cephalograms, pediatric sleep questionnaire (PSQ) records, and portable sleep monitoring results, were included in this study. A total of 17 measurements (11 distances and 6 angles) were made on lateral cephalograms. The measurements of lateral cephalograms, PSQ scales and portable sleep monitoring results were statistically analyzed. 49 of 61 (80%) patients showed AHI > 1, which suspected to have SDB and their mean AHI was 2.75. In this study, adenoid size (A/N ratio), position of the hyoid bone from mandibular plane, gonial angle, and PSQ scale were related to a higher risk of pediatric SDB. Also, oxygen desaturation index (ODI) and snoring time from sleep monitoring results were statistically significant in children with SDB using Mann-Whitney test (p < 0.05). In conclusion, evaluation of hyoid bone position, adenoidal hypertrophy, gonial angle in lateral cephalogram, and PSQ scale was important to screen out potential SDB, especially in children with frequent snoring.

• Sleep Medicine and Psychophysiology
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• v.23 no.1
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• pp.16-24
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• 2016

Background and Objectives: Obstructive sleep apnea (OSA) is often undiagnosed but is an important risk factor affecting the health of an individual. The level of awareness of the illness among patients with OSA is low and is not correlated with severity of the illness. This study was conducted to compare awareness of OSA symptoms and illness between patients with OSA and simple snorers. Materials and Methods: Two hundred eighty-two patients who were suspected of having OSA participated in this study. All subjects underwent overnight polysomnography. Those with an apnea-hypopnea index (AHI) ${\geq}5$ were classified as the OSA group, while those with an AHI < 5 were classified as the simple snoring group. A sleep questionnaire, which included items on awareness of the illness, OSA, and sleep symptoms, was administered to all subjects and their bed-partners. Results: Simple snorers were much more aware of their symptoms such as snoring, irregular breathing, and apnea than were patients with OSA. Bed-partners of simple snorers were also more aware of the participants' sleep symptoms than were partners of patients with OSA. However, the duration of OSA symptoms was longer in the OSA group. In the correlation analysis, the level of awareness of OSA symptoms was negatively correlated with AHI, age, body mass index, and Epworth Sleepiness Scale score. Among the sleep questionnaire and polysomnography results, only Pittsburgh Sleep Quality Index was positively correlated with level of awareness of OSA symptoms. The minority of the respondents had heard about the treatment methods of continuous positive airway pressure and oral appliance and preferred them as treatment options. Conclusion: This study suggests that simple snorers are more aware of their symptoms than are patients with OSA. A higher severity of OSA, represented by a higher AHI, is correlated with lower awareness of one's OSA symptoms.

• Korean Journal of Clinical Laboratory Science
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• v.38 no.3
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• pp.212-217
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• 2006

Obstructive sleep apena syndrome (OSAS) is accompanied by the following symptoms: apnea caused by upper respiratory tract obstruction while sleeping, repetitive lowering of $SpO_2$, severely affected excessive daytime sleepiness (EDS), suffocation/frequent awakeness while sleeping, daytime lethargy, and lack of concentration. OSAS was investigated with sex, age, body weight, body mass index (BMI), neck circumference and snoring sound as clinical characteristics and the anticipating factors of OSAS were studied in relation with the apnea-hypopnea index (AHI). The subjects were 42 people (male 34/female 8) who visited the clinic due to snoring and had polysomnography evaluation. AHI was differenciated into normal (less than 0~5/hr), mild (5~15/hr), moderate (15~30/hr) and severe (more than 30/hr). As the apnea-hypopnea index (AHI) gets higher, the snoring sound was louder (p<0.01), neck circumference was thicker (p<0.05) and also there were relative correlations with body weight (p<0.01), body mass index (p<0.05), snoring sound (p<0.01) and neck circumference (p<0.01). Since the snoring sound and neck circumference explained 32.8% of the AHI distribution, if the patient was severely snoring or had a thick neck circumference due to obesity, the apnea-hypopnea index showed a predisposition to the obstructive sleep apnea syndrome.