Blood Pressure Regulation and Hypertension in Obstructive Sleep Apnea Syndrome: A Historical Perspective.

In obstructive sleep apnea syndrome (OSAS), an underlying disease of secondary hypertension, repeated episodes of asphyxia due to obstructive sleep apnea (OSA), followed by arousal, lead to various cardiovascular consequences. Using a canine model of OSAS, it was found that a single load of OSA caused an abrupt increase in blood pressure (BP) (Apnea Surge in seconds), while multiple OSA episodes occurring nightly for 1-3 months led to a sustained elevation of BP during both nighttime and daytime. Epidemiological studies on 24-hour ambulatory BP measurements revealed that some hypertensive patients experienced elevated BP in the early morning (Morning Surge), which could be intensified by OSAS. The resonance of Apnea Surge in seconds and Morning Surge increases the risk of organ damage, triggers the cardiovascular events, and adversely affects the prognosis of hypertensive patients with OSAS.For ameliorating these risks, OSA should be treated with positive airway pressure properly.

Assessment of cognitive function and sleep-wake rhythms in community-dwelling older adults.

Disruption of the circadian rhythm and sleep-wake cycles is a consequence of aging and is associated with the cognitive decline and many neurodegenerative conditions. We investigated the bedtime, wake-up time, sleep timing (midpoint between bedtime and wake-up time), and sleep timing standard deviation (SD) using the actigraphy among 80 consecutive volunteers aged ≥ 60 years. Global cognitive function and executive function of detailed cognitive domains were evaluated using the mini-mental state examination (MMSE) and Wisconsin card sorting test (WCST) and subjective daytime sleepiness was assessed using the Epworth Sleepiness Scale (ESS). The category achievement (CA), total errors (TE), perseverative errors of Nelson (PEN), non-perseverative errors (NPE), and difficulties in maintaining set (DMS) on the WCST were significantly correlated with sleep timing SD (CA: r = - 0.276, p = 0.013, TE: r = 0.311, p = 0.005, PEN: r = 0.241, p = 0.032, NPE: r = 0.250, p = 0.025, DMS: r = 0.235, p = 0.036), but not with the MMSE score. Multiple regression analyses with the stepwise forward selection method including age, ESS score, bedtime, sleep timing, and sleep timing SD, revealed that the ESS score, and sleep timing SD were significant factors related to CA on the WCST (ESS score: ß = - 0.322, p = 0.004; sleep timing SD: ß = - 0.250, p = 0.022). Assessment of sleep-wake rhythms, daytime sleepiness, and cognitive function using the MMSE and WCST is valuable for the prediction of cognitive decline in the geriatric population.

Association of sleep-wake rhythm and sleep quality with endothelial function in young adults.

Objective: The environment in modern society could disturb the sleep-wake rhythm. We aimed to study the association of sleep-wake rhythm with endothelial function and sleep quality. Material and Methods: Thirty-one healthy university students (mean age: 20.4±1.8 years) were enrolled. The endothelial function was evaluated with the percent endothelium-dependent flow-mediated dilation of the brachial artery [%FMD: (maximum diameter - baseline diameter)/baseline diameter x 100] using the high-resolution ultrasonography. We also measured the total sleep time (TST), sleep effciency, and the standard deviation (SD) of sleep timing (midpoint between bedtime and wake-up time) using the actigraphy. The irregular sleep-wake rhythm was defined as having the shift of bedtime or wake-up time for two hours or longer. Results: The %FMD and sleep efficiency were significantly lower in the irregular group than regular group (%FMD: 6.1±2.4 vs. 10.9±2.3, p<0.001, sleep effciency: 92.2±5.8 vs. 95.9±2.8%, p=0.027), whereas there was no significant difference in %FMD between the two groups of TST <6 hours and TST ≥6 hours. The %FMD was significantly correlated with SD of sleep timing (r=-0.481, p=0.006). Multiple regression analyses, including age, sex, TST, sleep effciency, and SD of sleep timing revealed that the SD of sleep timing was a significant factor associated with %FMD (ß=-0.454, p=0.017). Conclusion: Our findings suggest that the irregular sleep-wake rhythm and poor sleep quality could have adverse effects on endothelial function in young adults.

Effects of long sleep time and irregular sleep-wake rhythm on cognitive function in older people.

Sleep disturbances and cognitive decline are common in older adults. We aimed to investigate the effects of the total sleep time (TST) and sleep-wake rhythm on executive function and working memory in older adults. In 63 older participants, we measured the TST, wake after sleep onset (WASO), and sleep timing (midpoint between bedtime and wake-up time) using actigraphy. Executive function was evaluated with the trail making test B (TMT-B) and Wisconsin card sorting test (WCST). The number of back task (N-back task) was used to measure working memory. Participants with a TST ≥ 8 h had a significantly lower percentage of correct answers (% correct) on the 1-back task than those with a TST < 8 h. The % correct on the 1-back task was significantly correlated with the TST, WASO, and sleep timing. Multiple regression analyses revealed that the TST and sleep timing were significant factors of the % correct on the 1-back task. The TMT-B score was significantly correlated with the sleep timing. Category achievement on the WCST was significantly correlated with the standard deviation of the sleep timing. Therefore, a long sleep time and an irregular sleep-wake rhythm could have adverse effects on executive function and working memory in older people.

Sleep fragmentation and working memory in healthy adults.

INTRODUCTION: Sleep is essential for performing cognitive function in humans. We have hypothesized that sleep fragmentation compared to sleep efficiency may have a negative impact on the working memory. MATERIAL AND METHODS: Twenty-eight healthy adults (18 males and 10 females; mean age 27.8±15.5 years) were enrolled in this study. We measured the total sleep time (TST), sleep efficiency, %stage wakefulness (W), %stage rapid eye movement (REM), %stage N1, %stage N2, %stage N3, wake after sleep onset (WASO), and arousal index using polysomnography. Working memory, executive function, and sustained attention of three domains of cognitive function were evaluated with the number of back task (N-back task), Wisconsin card sorting test (WCST), and continuous performance test-identical pairs (CPT-IP), respectively. RESULTS: The percentage of correct answers on the 2-back task was significantly correlated with %stage REM, %stage N1, and %stage N2 (%stage REM: r=0.505, p=0.006; %stage N1: r=-0.637, p<0.001; %stage N2: r=0.670, p<0.001), and multiple regression analysis including the stepwise forward selection method revealed that %stage N2 was the most significant factor (%stage N2: ß=0.670, p<0.001). The percentage of correct answers on the 2-back task was also significantly correlated with TST, sleep efficiency, WASO, and arousal index (TST: r=0.492, p=0.008; sleep efficiency: r=0.622, p<0.001; WASO: r=-0.721, p<0.001; arousal index: r=-0.656, p<0.001), and WASO was the significant factor (ß=-2.086, p=0.007). The WCST category achievement and CPT-IP d-prime score were correlated with none of the sleep variables. CONCLUSION: Increased WASO and a decrease in %stage N2 were associated with worse working memory.

Clinical indication of nasal surgery for the CPAP intolerance in obstructive sleep apnea with nasal obstruction.

OBJECTIVE: The role of isolated nasal surgery for obstructive sleep apnea (OSA) patients with nasal obstruction, especially for an intolerance for continuous positive airway pressure (CPAP), is unclear. The aim of this study was to assess the effects of surgery for OSA patients with symptomatic nasal obstruction and CPAP intolerance. METHOD: Retrospectve comparative study.1037 OSA patients with apnea-hypopnea index (AHI) ≥ 20 were enrolled. Case-control study was performed between the male apnea patients undergoing nasal surgery: surgery group (n = 43) and the pair-matched apnea patients for age, sex, body mass index, and race: control group (n = 43). The surgery group suffering from nasal obstruction could not use continuous positive airway pressure, and the CPAP group free from nasal obstruction could use it successfully. RESULTS: In surgery group, surgery significantly decreased the nasal resistance and Epworth sleepiness scale scores without changing the AHI. Surgery significantly increased the nadir of oxygen saturation and shortened the apnea-hypopnea duration. Although all of the surgery group failed to use positive airway pressure preoperatively, the 40 patients of the 43 CPAP intolerance patients were able to use CPAP postoperatively. The resting three patients were cured OSA or changed the treatment to oral appliance(OA). For both groups, the cutoff nasal resistance for differentiating the failure of positive airway pressure and its success was 0.31 Pa/cm3/s. CONCLUSION: Isolated nasal surgery is effective for an intolerance of positive airway pressure in sleep apnea with nasal obstruction presumably by decreasing nasal resistance.

Effects of sleep-disordered breathing and hypertension on cognitive function in elderly adults.

Purpose: The prevalence of sleep-disordered breathing (SDB) increases with aging. SDB is a risk of hypertension, and both might lead to cognitive decline. However, the role of SDB and hypertension on the pathogenesis of age-related cognitive decline remains unclear. We examined the effects of these two diseases on cognitive function in elderly adults.Methods: Fifty-two elderly individuals (mean age, 69.6 ± 4.0 years) free from impairment in daily living activities participated in this study. Apnea/hypopnea index (AHI) and minimum oxygen saturation (SpO2) were assessed using a portable home monitoring device. We evaluated excessive daytime sleepiness with the Epworth sleepiness scale (ESS). Cognitive performance was assessed using the Wisconsin card sorting test (WCST), continuous performance test-Identical pairs (CPT-IP), and N-back task. Hypertension and diabetes mellitus were evaluated via questionnaire and blood pressure value.Results: The WCST category achievement was significantly lower in participants with minimum SpO2 <90% than those with minimum SpO2 ≥90%. The percentage of correct answer on the 0- and 1-back tasks was significantly lower in the hypertensives than normotensives. Minimum SpO2 was correlated with category achievement on the WCST. Multiple regression analysis including age, sex, body mass index, AHI, minimum SpO2, ESS, hypertension, and diabetes mellitus revealed that hypertension was the most significant factor for percentage correct answers on the 0- and 1-back tasks. There were no significant correlations between body mass index, ESS or diabetes mellitus and the parameters of WCST, CPT-IP, or N-back tasks.Conclusion: In elderly adults, nocturnal hypoxia and hypertension had a negative effect on cognitive function.

Very low frequency component of heart rate variability as a marker for therapeutic efficacy in patients with obstructive sleep apnea: Preliminary study.

BACKGROUND: Although positive airway pressure (PAP) therapy is effective for treating obstructive sleep apnea (OSA), some patients with severe OSA are intolerable to this treatment, which may lead to an increase in the mortality and morbidity of cardiovascular diseases. We investigated the relationship between heart rate variability (HRV) and sleep parameters during natural sleep and treatment of patients with OSA. MATERIALS AND METHODS: This was the cross-sectional observation study. Patients were 17 males with severe OSA who were unable to accept continuous PAP. Standard polysomnography was performed for two consecutive nights, i.e., during natural sleep and following night with bilevel PAP (BiPAP) treatment. Time-dependent responses of the amplitudes of low frequency (LF), very low frequency (VLF), and high frequency components of HRV were assessed with the technique of complex demodulation. RESULTS: Apnea-hypopnea index, oxygen desaturation time, and percentage of stage 1 sleep were significantly reduced, whereas the percentages of rapid eye movement and stages 3 + 4 sleep were increased, by BiPAP treatment. Therapy also reduced the amplitudes of VLF and LF components of HRV. Difference in amplitudes of VLF during natural sleep and treatment with BiPAP was significantly correlated with difference in percentages of stage 1 and stages 3 + 4 sleep. CONCLUSION: Therapy-induced amelioration of OSA and sleep quality was accompanied by decrease in the amplitudes of VLF components of HRV. The VLF component may thus reflect physiological changes in both autonomic activity and sleep structure and serve as an objective marker for therapeutic efficacy in patients with severe OSA.

Nonsustained ventricular tachycardia does not affect the prognosis of neuromuscular diseases: A preliminary and retrospective study.

BACKGROUND: Nonsustained ventricular tachycardia (NSVT) is sometimes observed in patients with neuromuscular diseases (NMDs). The aim of this study was to assess the role of NSVT in the survival prognosis of NMD patients. METHODS: We retrospectively analyzed the patients with NMDs who had undergone Holter ECG recordings at a single center between February and August 2012. Sixty-eight patients were enrolled in this study. The 5 year follow-up was assessed according to the cumulative event-free rate. RESULTS: Twenty-one patients died during the follow-up, seven of whom died by cardiac death. The Kaplan-Meier survival curve that compared the patients with NSVT and those without NSVT indicated the NSVT was not related to the rate of all causes of death or cardiac death in those patients with NMDs. The survival curve was not significantly changed after the adjustment by age and ejection fraction. CONCLUSION: No significant correlations between NSVT and the prognosis in patients with NMDs were found.

Influence of sleep duration on cortical oxygenation in elderly individuals.

AIM: Short sleep duration is a risk factor for cardiovascular diseases. Cerebral blood flow and its regulation are affected by pathological conditions commonly observed in the elderly population, such as dementia, atherosclerosis, diabetes mellitus (DM), stroke, and hypertension. The purpose of this study was to examine the influence of sleep duration on cortical oxygenated hemoglobin (OxyHb) using near-infrared spectroscopy (NIRS). METHODS: Seventy-three individuals (age, 70.1 ± 3.9 years, 51 men and 22 women) participated in this study. Cortical OxyHb levels were measured with NIRS. We evaluated age, body mass index (BMI), smoking status, alcohol intake, sleep duration, hypertension, DM, and hyperlipidemia using a questionnaire. Blood pressure was measured using plethysmography. RESULTS: Peak OxyHb and area under the NIRS curve significantly decreased in participants with sleep duration <7 h compared with those with sleep duration ≥7 h (0.136 ± 0.212 mM·mm vs 0.378 ± 0.342 mM·mm, P = 0.001; 112.0 ± 243.6 vs 331.7 ± 428.7, P = 0.012, respectively). Sleep duration was significantly correlated with peak OxyHb level and area under the NIRS curve (r = 0.378, P = 0.001; r = 0.285, P = 0.015, respectively). Multiple regression analysis, including age, BMI, sex, smoking status, alcohol intake, sleep duration, hypertension, DM, and hyperlipidemia revealed that sleep duration was the only significant independent factor associated with peak OxyHb and area under the NIRS curve (ß = 0.343, P = 0.004; ß = 0.244, P = 0.049, respectively), and smoking status was independently correlated with time to the peak OxyHb (ß = -0.319, P = 0.009). CONCLUSION: Sleep duration may be an important factor that influences cortical oxygenation in the elderly population.

Blunted cyclic variation of heart rate predicts mortality risk in post-myocardial infarction, end-stage renal disease, and chronic heart failure patients.

AIMS: Cyclic variation of heart rate (CVHR) associated with sleep-disordered breathing is thought to reflect cardiac autonomic responses to apnoeic/hypoxic stress. We examined whether blunted CVHR observed in ambulatory ECG could predict the mortality risk. METHODS AND RESULTS: CVHR in night-time Holter ECG was detected by an automated algorithm, and the prognostic relationships of the frequency (FCV) and amplitude (ACV) of CVHR were examined in 717 patients after myocardial infarction (post-MI 1, 6% mortality, median follow-up 25 months). The predictive power was prospectively validated in three independent cohorts: a second group of 220 post-MI patients (post-MI 2, 25.5% mortality, follow-up 45 months); 299 patients with end-stage renal disease on chronic haemodialysis (ESRD, 28.1% mortality, follow-up 85 months); and 100 patients with chronic heart failure (CHF, 35% mortality, follow-up 38 months). Although CVHR was observed in ≥96% of the patients in all cohorts, FCV did not predict mortality in any cohort. In contrast, decreased ACV was a powerful predictor of mortality in the post-MI 1 cohort (hazard ratio [95% CI] per 1 ln [ms] decrement, 2.9 [2.2-3.7], P < 0.001). This prognostic relationship was validated in the post-MI 2 (1.8 [1.4-2.2], P < 0.001), ESRD (1.5 [1.3-1.8], P < 0.001), and CHF (1.4 [1.1-1.8], P = 0.02) cohorts. The prognostic value of ACV was independent of age, gender, diabetes, ß-blocker therapy, left ventricular ejection fraction, sleep-time mean R-R interval, and FCV. CONCLUSION: Blunted CVHR detected by decreased ACV in a night-time Holter ECG predicts increased mortality risk in post-MI, ESRD, and CHF patients.

Preoperative management of deteriorating mitral regurgitation and heart failure with continuous positive airway pressure.

A 75-year-old Japanese woman with acute mitral valve prolapse and regurgitation, that developed one month previously, suffered from intractably progressive congestive heart failure (CHF). However, the emergent surgery was declined, and pharmacological treatment was discontinued due to hypotension and malignant arrhythmia. She was treated with 5-8 cmH2O of continuous positive airway pressure (CPAP) to manage CHF and Cheyne-Stokes respiration during the preoperative period of five weeks, after which plastic surgery of the mitral valve was successfully performed. CPAP can be an effective non-pharmacological treatment for CHF, unloading the left ventricle hydrostatically in order to reduce mitral regurgitation and improve oxygenation.

Relationship between adenoid size and severity of obstructive sleep apnea in preschool children.

OBJECTIVE: To investigate the contributions of adenoid and tonsil sizes to obstructive sleep apnea syndrome (OSAS) in normal-weight children in two age categories: preschool and schoolchildren. METHODS: Fifty-eight normal-weight (body mass index z-score<2) symptomatic children with OSAS (apnea-hypopnea index ≥ 2) were evaluated. The patients were divided into two age categories: preschool (age<6; n=33) and schoolchildren (age ≥ 6; n=25). Polysomnographic findings and adenoid and tonsil sizes were compared. The relative contributions of body mass index and adenoid and tonsil sizes were also investigated with a regression analysis. RESULTS: Adenoid grade and apnea index correlated significantly in preschool children (r=0.45, p<0.01). On regression analysis, adenoid grade was a significant predictor of the apnea index in preschool children. The influence of adenoid hypertrophy decreased from preschool to schoolchildren. Tonsil size had little influence on the apnea index in either group. CONCLUSION: Adenoid hypertrophy was a major contributor to OSAS in normal-weight preschool children. The upper airway morphology of younger children with OSAS differed from that of older children with OSAS.

Children with severe or moderate obstructive sleep apnoea syndrome show a high incidence of persistence after adenotonsillectomy.

CONCLUSION: Persistent obstructive sleep apnoea syndrome (OSAS) occurs in approximately 20% of normal-weight children after adenotonsillectomy (T&A) and, in nearly 70% of them, it is caused by adenoid regrowth. Patients with severe or moderate OSAS showed a high incidence of persistent disease even after T&A. Allergic disease, severity and large adenoid size are associated with adenoid regrowth and persistent disease. OBJECTIVES: To investigate factors contributing to persistent OSAS and adenoid regrowth after T&A in normal-weight children. METHODS: This was a prospective, observational study at a single institute and involved 49 normal-weight children with severe or moderate OSAS (apnoea-hypopnoea index, AHI, ≥ 5) who underwent T&A. Background information, nasal endoscopic data and pre- and postoperative polysomnographic data were collected. A third polysomnography (PSG) was performed 1.5 year postoperatively in children who subsequently developed symptoms of sleep disturbance. RESULTS: Thirteen children (27%, 13/49) were symptomatic 1.5 years after T&A. Allergic rhinitis (38.5% vs 11.1%, p = 0.03) and allergic disease (69.2% vs 30.6%, p = 0.02) were seen more frequently in these children. A third PSG confirmed persistent disease (AHI ≥ 5) in nine children (18.4%, 9/49). Six children (12.2%, 6/49) were diagnosed as having adenoid regrowth and three (6.1%, 3/49) underwent revision adenoidectomy.

Continuous positive airway pressure intolerance associated with elevated nasal resistance is possible mechanism of complex sleep apnea syndrome.

PURPOSE: Complex sleep apnea syndrome (CompSAS) is diagnosed after an elimination of obstructive events with continuous positive airway pressure (CPAP), when a central apnea index ≥5/h or Cheyne-Stokes respiration pattern emerges in patients with obstructive sleep apnea syndrome (OSAS). However, the pathophysiology of CompSAS remains controversial. METHODS: Of the 281 patients with suspected OSAS, all of whom underwent polysomnography conducted at Nagoya University Hospital, we enrolled 52 patients with apnea-hypopnea index ≥15/h (age 51.4 ± 13.3 years). The polysomnographic findings, left ventricular ejection fraction (LVEF), and nasal resistance were compared between the CompSAS patients and OSAS patients. RESULTS: Forty-three patients were diagnosed with OSAS and nine patients with central sleep apnea syndrome by natural sleep PSG. Furthermore, 43 OSAS patients were classified into the OSAS patients (OSAS group, n = 38) and the CompSAS patients (CompSAS group, n = 5) by the night on CPAP PSG. The nasal resistance was significantly higher in CompSAS group than in OSAS group (0.30 ± 0.10 vs. 0.19 ± 0.07 Pa/cm(3)/s, P = 0.004). The arousal index, percentage of stage 1 sleep, and oxygen desaturation index were significantly decreased, and the percentage of stage REM sleep was significantly increased in the OSAS group with the initial CPAP treatment, but not in the CompSAS group. In addition, the patients with CompSAS showed normal LVEF. CONCLUSION: CPAP intolerance secondary to an elevated nasal resistance might relate to frequent arousals, which could presumably contribute to an increase in central sleep apnea. Further evaluation in a large study is needed to clarify the mechanism of CompSAS.

Pathogenetic role of increased nasal resistance in obese patients with obstructive sleep apnea syndrome.

BACKGROUND: The role of increased nasal resistance in obstructive sleep apnea syndrome (OSAS) remains controversial. The aim of this study was to examine the pathogenetic role of nasal obstruction in obese patients with OSAS. METHODS: Patients with OSAS (n = 125) at a university hospital were divided into three groups according to body mass index (BMI): nonobese (BMI < 25 kg/m(2)), mildly obese (25 kg/m(2) < or = BMI < 30 kg/m(2)), and obese (BMI > or = 30 kg/m(2)). The subjects underwent nasopharyngoscopy, measurement of nasal resistance, and polysomnography. RESULTS: We studied 42 nonobese, 47 mildly obese, and 36 obese patients with OSAS. Among the obese, but not the nonobese and mildly obese patients, we found significant correlations between the oxygen desaturation index (ODI) and bilateral nasal resistance (BNR; r = 0.412; p = 0.013), between the ODI and unilateral higher nasal resistance (UHNR; r = 0.413; p = 0.012), and between the apnea index and UHNR (r = 0.334; p = 0.046). Multiple regression analysis incorporating all patients showed that BMI (p < 0.001) and BNR (p = 0.033) were independently related to the ODI. CONCLUSION: In obese patients with OSAS, increased nasal resistance could play an important pathogenetic role in hypoxemic apnea.

Pharyngeal morphology: a determinant of successful nasal surgery for sleep apnea.

OBJECTIVES/HYPOTHESIS: To estimate the effectiveness of nasal surgery on the occurrence of sleep apnea, and to analyze the pharyngeal morphology of apnea patients whose sleep-disordered breathing was ameliorated postoperatively. STUDY DESIGN: Prospective study. METHODS: Thirty-five consecutive patients with apnea and nasal obstruction underwent polysomnography and a morphological examination of the upper airway before and after nasal surgery, which included septoplasty, inferior turbinectomy, and/or functional endoscopic sinus surgery. RESULTS: Sleep apnea was significantly ameliorated in only eight patients. The postoperative reduction in the apnea-hypopnea index tended to be lower in those with a low-positioned soft palate, reflected in an elevated modified Mallampati score, and a narrow retroglossal space. Neither swollen tonsils nor narrow fauces affected the surgical outcome. Regression analysis showed that the modified Mallampati score (P < .05) and the retroglossal space (P < .05) were significant predictors of postoperative improvement in the apnea-hypopnea index. CONCLUSIONS: Among sleep apnea patients suffering from nasal obstruction, nasal surgery is effective in those with a high-positioned soft palate and/or a wide retroglossal space.

Morphological examination of upper airway in obstructive sleep apnea.

OBJECTIVES: An aim of this study was to assess the predictive power of an otorhinolaryngological examination of the upper airway to identify risk factors of obstructive sleep apnea syndrome (OSAS) in the patients. METHODS: We examined 141 consecutive patients with OSAS. The morphological features were assessed by the designated otorhinolaryngologist while the subjects were sitting relaxedly with tidal breathing. The bilateral nasal resistance was measured using the active anterior rhinomanometry during daytime wakefulness. RESULTS: The body mass index (BMI), fauces's narrowness, neck circumference, lowest oxygen saturation, tonsil size and modified Mallampati grade (MMP) showed the statistically significant correlations with the apnea-hypopnea index (AHI) of an index of apnoeseverity, however, the age, Epworth sleepiness scale (ESS), nasal resistance and retroglossal space were not significantly associated with the AHI. CONCLUSIONS: The upper airway morphology significantly associated with AHI are fauces's narrowness, tonsil size, and MMP, but not nasal resistance and retroglossal space.

Significance of a screening device (Apnomonitor 5) for sleep apnea syndrome.

OBJECTIVES: The objective was to evaluate the significance of a portable sleep-monitoring device (Apnomonitor 5, Chest Co., Tokyo, Japan) to diagnose sleep apnea syndrome (SAS). METHODS: The Apnomonitor 5 comprised an oronasal thermistor, a pulse oximeter, chest and abdominal belts to monitor the circumferences of the chest and abdomen, a microphone to monitor tracheal sound, a position detector, and an integrative unit. This screening device was commercially available and it had been used to diagnose SAS in our country. Twenty-two consecutive adults who attended Inazawa City Hospital who were suspected for SAS were prospectively enrolled and they undertook the standard polysomnography (PSG) and Apnomonitor 5 simultaneously. The designated polysomnographers analyzed the records of the PSG and Apnomonitor 5. These sleep and respiratory parameters of the devices were compared, the results of which were double-checked by the designated sleep specialist. RESULTS: The apnea-hypopnea index (AHI), apnea index, total number of apnea, and oxygen desaturation index obtained by the PSG and Apnomonitor 5 correlated significantly, whereas the averaged sleep time, total number of hypopnea, hypopnea index, and nadir oxygen saturation differed between the devices. The sensitivity of the Apnomonitor 5 versus PSG was 95% in the SAS patients with the AHI> or =15. CONCLUSIONS: The Apnomonitor 5 can be a sensitive and useful screening device for SAS especially in patients with the AHI> or =15.