Effectiveness of high-flow nasal cannula on pulmonary rehabilitation in subjects with chronic respiratory failure.

BACKGROUND: The effects of exercise training using both high fraction of inspired oxygen (FIO2) and high flow oxygen delivered through a high-flow nasal cannula (HFNC) on exercise capacity in patients with chronic respiratory failure (CRF) receiving long-term oxygen therapy (LTOT) are unknown. METHODS: In this randomized study, 32 patients with CRF receiving LTOT were assigned to undergo 4 weeks of exercise training on a cycle ergometer using an HFNC (flow: 50 L/min) with a FIO2 of 1.0 (HFNC group; n = 16) or ordinary supplemental oxygen via a nasal cannula (flow: 6 L/min) (oxygen group; n = 16). A 6-min walking test and a constant-load test were performed before and after 4 weeks of exercise training. RESULTS: Following 4 weeks of exercise training, change in the 6-min walking distance was significantly greater in the HFNC than in the oxygen group (55.2 ± 69.6 m vs. -0.5 ± 87.3 m; p = 0.04). However, there was no significant difference between the two groups in the degree of improvement in the duration of the constant-load exercise test after exercise training. CONCLUSIONS: Considering the effect on daily activities (e.g., walking), exercise training using both high FIO2 and high flow through an HFNC is a potentially superior exercise training modality for patients with CRF receiving LTOT. Clinical Trial Registration - http://www. CLINICALTRIALS: gov. Unique identifier: NCT02804243.

Low Levels of PaO2 after Long-term Noninvasive Ventilation are a Poor Prognostic Factor in Patients with Restrictive Thoracic Disease.

Objective The effects of partial pressure of arterial oxygen (PaO2) after introducing long-term noninvasive ventilation (NIV) on the prognosis of patients with restrictive thoracic disease and chronic respiratory failure are not exactly known. Methods Data from 141 patients with restrictive thoracic disease under long-term nocturnal NIV were retrospectively examined. We divided the patients into 2 groups according to the daytime PaO2 value while breathing spontaneously with prescribed oxygen at 12 months after introducing NIV: PaO2≥80 Torr group (n=76) and PaO2<80 Torr group (n=65). Results During the 4-year follow-up, the mortality was significantly higher in the PaO2<80 Torr group than in the PaO2≥80 Torr group (50.8% vs. 32.9%, p=0.03). Independent factors associated with the 4-year mortality after introducing NIV determined by a multivariate logistic regression analysis were a low body mass index [odds ratio (OR) 0.87; 95% confidence interval (CI) 0.77 to 0.97; p=0.01], assisted mode with NIV (OR 4.11; 95% CI, 1.79 to 9.45; p=0.0009), hospitalization during the first year of introducing NIV (OR 1.72; 95% CI, 1.06 to 2.79; p=0.03), and daytime PaO2<80 Torr at 12 months after introducing NIV (OR 2.30; 95% CI, 1.03 to 5.10; p=0.04). Conclusion A low daytime PaO2 at 12 months after introducing NIV was an independent risk factor for mortality. Keeping the daytime PaO2≥80 Torr through the adjustment of the nocturnal NIV settings or increased diurnal supplemental oxygen may help improve the prognosis in patients with restrictive thoracic disease who are under NIV.

The Importance of Stabilizing PaCO2 during Long-term Non-invasive Ventilation in Subjects with COPD.

OBJECTIVE: In subjects with chronic obstructive pulmonary disease (COPD), the effect of partial pressure of CO2 (PaCO2) alterations during long-term non-invasive ventilation (NIV) on continuance remains uncertain. We herein investigated the utility of PaCO2 stability during long-term NIV as a prognostic outcome. METHODS: We retrospectively assessed data from 54 subjects with COPD who received long-term NIV. The annual alteration in PaCO2 during NIV was determined using a simple linear regression method for each subject who had at least two 6-month intervals of PaCO2 data. Annual alterations in PaCO2 during long-term NIV and probable confounders were examined, and long-term NIV discontinuation was the major outcome. RESULTS: Data from 37 subjects who met the criteria were analyzed. PaCO2 during long-term NIV increased slightly in 19 subjects (group 1, <2 mm Hg/y), and increased greatly in 18 subjects (group 2, >2 mmHg/y). In the multivariate modality model, smaller annual alterations in PaCO2 (p=0.009) and lower PaCO2 6 months after the start of long-term NIV (6 m-PaCO2) (p=0.03) were associated with a significantly higher probability of continuing NIV. The 2- and 5-year probabilities of continuing NIV were 89% and 66% for group 1 and 78% and 32% for group 2, respectively. CONCLUSION: A lower 6 m-PaCO2 and a lower annual alteration of PaCO2 during long-term NIV are significant predictive variables for patients with COPD.

The importance of controlling PaCO2 throughout long-term noninvasive ventilation.

BACKGROUND: The significance of changes in P(aCO2) during long-term noninvasive ventilation (NIV) on prognosis remains unclear. We aimed to clarify whether stabilizing P(aCO2) during NIV had a favorable prognostic effect. METHODS: Data from 190 subjects with restrictive thoracic disease and who received long-term NIV were studied retrospectively. The annual change in P(aCO2) during NIV was determined using a simple linear regression method for each subject who had at least 4 6-month intervals of P(aCO2) data. Annual changes in P(aCO2) during long-term NIV and possible confounders were analyzed with discontinuation of long-term NIV as the main outcome. RESULTS: One hundred and twenty-five subjects who had > 4 6-month intervals of P(aCO2) data were included in the study. P(aCO2) during long-term NIV decreased in 41 subjects (group 1; < 0 mm Hg/y), increased slightly in 42 subjects (group 2; between 0 and 1.85 mm Hg/y), and increased significantly in 42 subjects (group 3; > 1.85 mm Hg/y). Smaller annual changes in P(aCO2) (P < .001) and a control ventilator mode (P = .008) were associated with a significantly higher probability of continuing NIV, compared with decreased P(aCO2) 3-6 months after the start of long-term NIV (P = .11). The 10-y probability of continuing NIV was 69% in group 1, 39% in group 2, and 12% in group 3. CONCLUSIONS: A decrease in the annual change of P(aCO2) during long-term NIV was shown to be a significantly prognostically favorable factor. Efforts to reduce P(aCO2) should be made if P(aCO2) increases at a greater rate during long-term NIV.

Associations among chronic obstructive pulmonary disease and sleep-disordered breathing in an urban male working population in Japan.

BACKGROUND: There are few reports about sleep disturbances in patients with chronic obstructive pulmonary disease (COPD) in Asian countries. OBJECTIVES: To investigate the associations between sleep-disordered breathing (SDB) with hypoxemia and sleep quality, including sleep duration, in patients with COPD, we measured SDB and sleep quality including the objective sleep duration determined by an actigraph and portable monitoring. METHODS: A cross-sectional epidemiological health survey of 303 male employees (means ± SD: age 43.9 ± 8.2 years; BMI 24.0 ± 3.1) was conducted. Sleep quality was measured using the Epworth Sleepiness Scale (ESS) and the Pittsburgh Sleep Quality Index (PSQI). A respiratory disturbance index (RDI) ≥5 indicated SDB. RESULTS: Nineteen subjects (6.3%) had COPD. Among these, 11 (3.6%) had COPD with SDB (overlap syndrome). Sleep duration, ESS, and PSQI scores were not significantly different between COPD patients and normal control subjects. However, COPD patients had significantly longer sleep latency (p = 0.019), a lower sleep efficiency (p = 0.017), and a higher sleep fragmentation index (p = 0.041) and average activity (p = 0.0097) during sleep than control subjects. They also had a significantly higher RDI and more severe desaturation during sleep than control subjects (p < 0.01). The differences remained after adjustment for age and BMI but disappeared following adjustment for RDI. CONCLUSIONS: COPD patients with even mild-to-moderate airflow limitations had nocturnal desaturation and RDI-related impaired sleep quality without significant symptoms.

Association between sleep apnea, sleep duration, and serum lipid profile in an urban, male, working population in Japan.

BACKGROUND: Dyslipidemia is often comorbid with obstructive sleep apnea (OSA), but few population-based studies have investigated their relationship. Short sleep duration is associated with hypertension and diabetes; however, its association with dyslipidemia is not well known. We investigated relationships among OSA, sleep duration, and the lipid profile in a community-based study. METHODS: We measured the respiratory disturbance index (RDI) and sleep duration by a type 3 portable device and actigraph in 275 men in a Japanese company. Fasting blood parameters were obtained from periodic inspection data. RESULTS: According to Japanese criteria, 143 subjects had dyslipidemia. Percent sleep time of oxygen saturation as measured by pulse oximetry (SpO2) < 90% and prevalence of severe OSA were greater and sleep duration and mean SpO2 during sleep were lower in subjects with dyslipidemia than in those without. Univariate analysis showed that the RDI was positively correlated with serum triglyceride (TG) levels (ρ = 0.20, P < .01), and sleep duration was negatively correlated with serum total cholesterol (TC) levels (γ = -0.13, P = .03) and serum low-density lipoprotein cholesterol levels (γ = -0.12, P = .04). Stepwise multiple regression analysis revealed that TG was correlated with RDI (ß = 0.14, P = .02), BMI (ß = 0.20, P < .01), and alcohol intake (ß = 0.20, P < .01), and that TC was correlated with sleep duration (ß = -0.13, P = .03), age (ß = 0.15, P = .02), and waist/hip ratio (ß = 0.15, P = .02). CONCLUSIONS: Short sleep duration was associated with TC levels and RDI was positively associated with TG levels among working-aged men in an urban Japanese company. Correcting the status of OSA and/or short sleep duration might improve the lipid profile and cardiovascular consequences.

Relationships of decreased lung function with metabolic syndrome and obstructive sleep apnea in Japanese males.

OBJECTIVE: Decreased lung function as assessed by forced vital capacity (FVC) and forced expiratory volume in one second (FEV(1)) is shown to be associated with cardiovascular morbidity and mortality. Although the underlying mechanisms for this association remain unknown, metabolic syndrome and obstructive sleep apnea (OSA) may have a role. We analyzed the relationships between metabolic syndrome and OSA in a cross-sectional health survey of middle-aged male employees. METHODS: In this secondary analysis, we re-analyzed the relationships of lung function determined by spirometry with metabolic syndrome and OSA based on the respiratory disturbance index (RDI) with a type 3 portable monitor. RESULTS: We analyzed 273 subjects. Independent of age, body mass index (BMI) and smoking, quartiles for lower FVC and FEV(1) were associated with a higher risk of metabolic syndrome compared with quartiles for the highest FVC and FEV(1), respectively. A similar trend was observed regarding the risk associated with waist circumference, and in FVC cases, dyslipidemia. The risk of hyperglycemia was significantly higher in quartiles for the second lowest FVC and FEV(1) than in quartiles for the highest FVC and FEV(1), respectively. A significant trend for an increase in RDI was observed in accordance with quartiles for lower FVC, but not FEV(1). CONCLUSION: There was a significant relationship between lung function impairment and metabolic syndrome through mainly abdominal obesity, partially through hyperglycemia, and also through dyslipidemia, but only with respect to restrictive lung function. Restrictive lung function was also related to OSA. This epidemiologic evidence may indicate underlying mechanisms between decreased lung function and cardiovascular risk.

Differences in relationships among sleep apnoea, glucose level, sleep duration and sleepiness between persons with and without type 2 diabetes.

Obstructive sleep apnoea is common in patients with diabetes. Recently, it was reported that short sleep duration and sleepiness had deleterious effects on glucose metabolism. Thereafter, several reports showed relationships between glucose metabolism and obstructive sleep apnoea, sleep duration or sleepiness. But the interrelationships among those factors based on recent epidemiological data have not been examined. We analysed data on 275 male employees (age, 44±8years; body mass index, 23.9±3.1kg m(-2) ) who underwent a cross-sectional health examination in Japan. We measured fasting plasma glucose, sleep duration using a sleep diary and an actigraph for 7days, and respiratory disturbance index with a type 3 portable monitor for two nights. Fifty-four subjects (19.6%) had impaired glucose metabolism, with 21 having diabetes. Of those 21 (body mass index, 25.9±3.8kgm(-2) ), 17 (81.0%) had obstructive sleep apnoea (respiratory disturbance index≥5). Regarding the severity of obstructive sleep apnoea, 10, four and three had mild, moderate and severe obstructive sleep apnoea, respectively. The prevalence of obstructive sleep apnoea was greater in those with than without diabetes (P=0.037). Multiple regression analyses showed that the respiratory disturbance index independently related to fasting plasma glucose only in the diabetic subjects. In patients with diabetes, after adjustment for age, waist circumference, etc. sleep fragmentation had a greater correlation with fasting plasma glucose than sleep duration, but without significance (P=0.10). Because the prevalence of obstructive sleep apnoea is extremely high in patients with diabetes, sufficient sleep duration with treatment for obstructive sleep apnoea, which ameliorates sleep fragmentation, might improve fasting plasma glucose.

[Pneumonitis induced by rifampicin].

An 86-year-old male with pulmonary tuberculosis developed fever, rash, and interstitial pneumonia 3 weeks after the beginning of treatment with isoniazid (INH), rifampicin (RFP), and ethambutol (EB). Chest CT showed new infiltration shadows that were diffuse bilateral ground-glass opacities mixed with dense consolidation and septal thickening, accompanied by a small amount of pleural effusion. Drug-induced pneumonitis was suspected, and therefore the antituberculous regimen was discontinued. The radiologic findings and symptoms improved promptly. A provocation trial with RFP lead to fever, diarrhea, and rash. Therefore, RFP was considered to be the causative drug. INH and EB were reintroduced without any recurrence of the symptoms. Clinicians should be aware not only of paradoxical reactions but also of drug-induced pneumonitis, when a new pulmonary infiltrate develops in the course of tuberculosis treatment.

PaCO2 six months after the initiation of long-term noninvasive ventilation in patients with COPD.

BACKGROUND AND OBJECTIVE: The appropriate target level for PaCO(2) after the introduction of long-term noninvasive positive pressure ventilation (NPPV) in patients with COPD remains uncertain, and therefore must be tested. METHODS: Data on 54 patients with COPD receiving long-term domiciliary NPPV were examined retrospectively. PaCO(2) a few months after NPPV and potential confounders were analyzed with discontinuation of long-term NPPV as the primary outcome. The differences in annual hospitalization rates due to respiratory deterioration between those from 1 year before to 2 years after initiation of NPPV were compared according to the PaCO(2) measured at 6 months after NPPV (6-mo PaCO(2)). RESULTS: 6-mo PaCO(2) seemed to be most related to continuation of NPPV (p=0.019). Patients with 6-mo PaCO(2) of less than 60 mmHg had maintained a significantly lower PaCO(2) value 6 to 24 months after NPPV (p=0.04) and had a significantly higher continuation rate of NPPV (p=0.03) than those with a 6-mo PaCO(2) of 60 mmHg or more. Annual hospitalization rates due to respiratory deterioration were not associated with the 6-mo PaCO(2) level, but fatal hospitalization rates during the first year of NPPV were significantly correlated with relatively high 6-mo PaCO(2) (p=0.008). CONCLUSION: A relatively low 6-mo PaCO(2) value was predictive of long-term use of NPPV. The target values of 6-mo PaCO(2) may, therefore, be less than 60 mmHg in COPD patients with extremely severe hypercapnia, although more prospective studies are needed.

Effects of the presence of hypertension on the relationship between obstructive sleep apnoea and sleepiness.

Obstructive sleep apnoea (OSA) plays a significant role in increasing blood pressure. Significant decreases were reported in blood pressure of hypertensive OSA patients with sleepiness who underwent continuous positive airway pressure (CPAP) treatment, but not in non-sleepy hypertensive OSA patients. More recently, however, significant decreases in blood pressure in non-sleepy hypertensive OSA patients following CPAP were shown. Effects of sleepiness on hypertension in OSA patients have been investigated, but not the effects of hypertension on sleepiness in OSA patients. We investigated the relationships between hypertension and sleepiness in patients with OSA. We analysed data on 275 middle-aged male subjects from a cross-sectional epidemiological health survey. We measured blood pressure and sleep duration objectively using an actigraph for 7 days and the respiratory disturbance index (RDI) with a type 3 portable device for 2 nights, and assessed sleepiness using the Epworth Sleepiness Scale (ESS). The RDI correlated significantly with ESS scores in the 88 hypertensive subjects (r = 0.33, P = 0.0024), but not in the 187 non-hypertensive subjects (r = -0.01, P = 0.91). Short sleep duration correlated significantly with ESS scores in both groups. Both the RDI and short sleep duration were related independently to sleepiness in only hypertensive subjects. Furthermore, the RDI was related negatively significantly to sleep duration in hypertensive subjects. Although short sleep duration was related significantly to sleepiness in both groups, hypertension may be important for the sleepiness in OSA patients. Detailed mechanisms of the difference in the relationship between sleepiness and the severity of OSA with or without hypertension should be studied further.

[A case of squamous cell lung carcinoma with gastric metastasis diagnosed by gastroendoscopic biopsy].

A 59-year-old man was referred to our hospital due to of a right pulmonary hilar mass shadow found on a chest X-ray film in October 2008. Bronchoscopy and transbronchial biopsy at that time revealed squamous cell carcinoma. The clinical stage was IIIB (T4N2M0). He was readmitted 2 months later because of appetite loss and severe anemia. An abdominal CT scan showed thickening of the stomach wall. Gastroendoscopy showed a submucosal tumor with central depression in the middle body of the stomach. We histologically confirmed that the gastric lesion was metastasis from the squamous cell lung carcinoma. Here we report a rare case of squamous cell lung carcinoma with gastric metastasis diagnosed by gastroendoscopic biopsy while the patient was alive.

Importance of the PaCO(2) from 3 to 6 months after initiation of long-term non-invasive ventilation.

BACKGROUND: The level at which arterial carbon dioxide tension (PaCO(2)) a few months after introduction of long-term non-invasive positive pressure ventilation (NPPV) is associated with a favorable prognosis remains uncertain. METHODS: Data on 184 post-tuberculosis patients with chronic restrictive ventilatory failure who were receiving long-term domiciliary NPPV were examined retrospectively. Average PaCO(2) 3-6 months after NPPV (3- to 6-mo PaCO(2)) and potential confounders were analyzed with discontinuation of long-term NPPV as the primary outcome. The effects of 3- to 6-mo PaCO(2) on annual hospitalization rates due to respiratory deterioration from 1 year before to 3 years after the initiation of NPPV were examined. The effect of the difference between the PaCO(2) value at the start of NPPV (0-mo PaCO(2)) and the PaCO(2) value 3- to 6-mo later (d-PaCO(2)) on continuation rates for NPPV was also assessed in patients who initiated NPPV while in a chronic state. RESULTS: Patients with relatively low 3- to 6-mo PaCO(2) values maintained a relatively low PaCO(2) 6-36 months after NPPV (p < 0.0001) and had significantly better continuation rates (p < 0.03) and lower hospitalization rates from the 1st to 3rd year of NPPV (p = 0.008, 0.049, 0.009, respectively) than those with higher levels. The 0-mo PaCO(2) (p = 0.26) or d-PaCO(2) (p = 0.86) had no predictive value. CONCLUSION: A relatively low 3- to 6-mo PaCO(2) value was predictive of long-term use of NPPV. The target values for 3- to 6-mo PaCO(2) may, therefore, be less than 60 mmHg in post-tuberculosis patients, although more studies are needed.

Associations between obstructive sleep apnea, metabolic syndrome, and sleep duration, as measured with an actigraph, in an urban male working population in Japan.

BACKGROUND: Severe obstructive sleep apnea (OSA), metabolic syndrome (Mets) and short sleep duration are all risk factors for cardiovascular events. There has been no report which has investigated this relationship in an age- and BMI-matched population-based study. The prevalence of OSA in Mets subjects has not been established, although the converse (i.e., the prevalence of Mets in OSA subjects) has been investigated several times. METHODS: This home cardiorespiratory (type 3) sleep study, using an actigraph, was conducted in 275 males working for an urban company. Retrospective measurements of fasting blood parameters were obtained from the company's periodical inspection data. The mean duration between the sleep study and the measurement of blood parameters was 213 days. RESULTS: Although there was a significant relationship between OSA severity and the prevalence of Mets (P < 0.001), the association between severity and Mets was not significant after adjustments were made for age and BMI. Severe OSA was 7.8 times as likely to be present in subjects with Mets (16.2% of all 68 Mets subjects) as those without (2.4% of 207 non-Mets) (P < 0.001). Subject with severe OSA had a significantly short sleep duration (P < 0.05). Sleep duration in Mets subjects was also significantly shorter than in those without (P < 0.05). CONCLUSIONS: Although increased BMI and age both had a significant effect on the prevalence of OSA in patients with Mets, one of 6 subjects with Mets, but only one of 40 without Mets had severe OSA in an urban male population in Japan. Physicians should take into account this high prevalence of severe OSA in patients with Mets. Sleep duration should be taken into consideration as an important factor in studies investigating the prevalence of severe OSA and Mets.

Importance of ventilator mode in long-term noninvasive positive pressure ventilation.

BACKGROUND: Long-term noninvasive positive pressure ventilation (NPPV) is associated with an excellent survival rate, especially in post-tuberculosis patients. Nothing is currently known on which method of ventilatory support is associated with a better continuation of long-term NPPV, which itself might lead to longer survival. METHODS: One hundred and eighty four post-tuberculosis patients, who started NPPV at the Kyoto University Hospital group and the National Tokyo Hospital from June 1990 to August 2007, were examined retrospectively. Ventilator mode (an assisted mode or a pure controlled mode) and potential confounders were examined with the discontinuation of NPPV as the primary outcome. RESULTS: Patients treated with a pure controlled mode had significantly better continuation rates (hazard ratio, 3.09; 95% confidential interval, 1.75-5.47; p=0.0001) and better survival rates (Log-rank test; p=0.0031) than those treated with an assisted mode. Female gender and no pulmonary lesions were also associated with a significantly better probability of continuing NPPV. The five- and ten-year probabilities of continuing NPPV for 106 patients with a pure controlled mode were 68.3% and 41.4%, respectively, while those for 76 patients with an assisted mode were 46.7% and 12.7%, respectively. CONCLUSIONS: Patients treated with pure controlled ventilation had significantly better continuation rates and survival rates than those treated with assisted ventilation. Prospective randomized controlled trials are needed to verify the effectiveness of a pure controlled mode in patients with not only restrictive thoracic disease but also other diseases including chronic obstructive pulmonary disease.

Acylated ghrelin level in patients with OSA before and after nasal CPAP treatment.

BACKGROUND AND OBJECTIVE: Patients with newly diagnosed OSA have been reported to have recent weight gain prior to diagnosis. Ghrelin stimulates food intake and increases weight gain. Plasma ghrelin is decreased in obese and increased in lean individuals. Of the two circulating forms of ghrelin, acylated and unacylated, the former is thought to be essential for the biological activity of ghrelin. METHODS: The plasma levels of the two forms of ghrelin were measured in 21 OSA patients (with a mean of 46.2 sleep-disordered events/h) before and after 1 month of nasal CPAP (nCPAP) treatment, and were compared with those in 14 untreated OSA patients and 13 individuals without OSA. RESULTS: The BMI was significantly higher in the 21 OSA patients than in the non-OSA group as were the baseline acylated (11.4 +/- 5.86 vs 7.19 +/- 3.80 fmol/mL, P = 0.03) and unacylated (84.2 +/- 50.6 vs 48.3 +/- 23.2 fmol/mL, P = 0.02) ghrelin levels. The total ghrelin level was positively correlated with the number of sleep-disordered breathings (P = 0.002). After 1 month of nCPAP treatment, the acylated ghrelin level significantly decreased (P = 0.02) while the unacylated ghrelin level did not (P = 0.09). CONCLUSIONS: Treatment of OSA may play an important role in the management of obesity in these patients by reducing the acylated ghrelin level.

Sleep-disordered breathing in the usual lifestyle setting as detected with home monitoring in a population of working men in Japan.

STUDY OBJECTIVES: To examine (1) the prevalence of home-monitored sleep-disordered breathing (SDB) and obstructive sleep apnea syndrome in a Japanese working population and (2) whether home monitoring with a type 3 portable monitor and actigraphy can produce reliable data to analyze SDB in usual lifestyles. METHODS: A cross-sectional survey using a self-administered questionnaire was conducted on a group of employees at a wholesale company in Osaka, Japan. Examinations by physicians and by sleep monitoring were also performed. Unattended home cardiorespiratory (type 3) sleep studies with actigraphy were conducted for 2 nights to diagnose SDB in 322 subjects. From the baseline questionnaires and sleep diaries, participants were assessed to follow their usual lifestyles during the study (e.g., time in bed, alcohol intake). RESULTS: Of 466 Japanese male employees, 396 responded to the questionnaire survey (85.0%). Results from 322 male employees aged 23 to 59 (43.8 +/- 8.4 years) were analyzed. Respiratory disturbance index (RDI), calculated from the type 3 portable monitors and actigraphy, was highly reliable with an intraclass correlation of 0.98 for interscorer reliability and with an intraclass correlation of 0.95 for night-to-night reliability. Prevalence of mild (5 < or = RDI < 15), moderate (15 < or = RDI < 30) and severe (RDI < or = 30) SDB in this population were 37.4%, 15.7%, and 6.6%, respectively. The prevalence of obstructive sleep apnea syndrome (RDI > or = 5 and Epworth Sleepiness Scale score > 10) was 17.6%. CONCLUSIONS: The prevalence of moderate to severe SDB (RDI > or = 15) was 22.3% in this Japanese male working population aged 23 to 59, measured in participant's usual life settings. Unattended home monitoring with type 3 portable monitors and actigraphy was highly reliable and may be suitable for analyzing SDB in the usual lifestyle setting.

Plasma thioredoxin, a novel oxidative stress marker, in patients with obstructive sleep apnea before and after nasal continuous positive airway pressure.

Obstructive sleep apnea (OSA) is associated with increased cardiovascular mortality, and oxidative stress was suggested to play an important role. We hypothesized that the plasma TRX level, a novel oxidative stress marker, is elevated in OSA patients. Plasma TRX and adiponectin levels, which are significantly associated with cardiovascular mortality, were measured in 41 patients with severe OSA before (n = 41) and after (n = 27) nasal continuous positive airway pressure therapy (nCPAP) for 1 month and in 12 subjects without OSA (non-OSA group). The TRX level was significantly higher (p = 0.02) and the adiponectin level was significantly lower (p = 0.02) in the OSA group than in the non-OSA group. After 1 month of nCPAP (n = 27), the TRX level significantly decreased (p = 0.03), and the adiponectin level significantly increased (p = 0.03). Among the 14 patients with untreated OSA, the TRX and adiponectin levels did not significantly change over a 1-month interval. Among the 53 (41 OSA + 12 non-OSA) subjects, the TRX level was positively correlated with the respiratory disturbance index (p = 0.001) and percentage of time with SaO(2) <90% (p = 0.0002). The adiponectin level, but not the TRX level, was correlated with the BMI (n = 53; p = 0.02). Plasma TRX may be a unique marker for evaluating oxidative stress and monitoring the effectiveness of nCPAP in OSA patients.

Falls in blood pressure in patients with obstructive sleep apnoea after long-term nasal continuous positive airway pressure treatment.

OBJECTIVES: Effective treatment of obstructive sleep apnoea (OSA) with nasal continuous positive airway pressure (nCPAP) lowers blood pressure (BP). The long-term effects of nCPAP treatment on BP in OSA patients are not well known. The time period of such treatment sufficient to lower BP in OSA patients is also not known. We investigated compliance with long-term nCPAP therapy and its effects on BP. METHODS: This observational study involved 66 OSA patients [59 men, seven women; mean age, 51 (48-54) years; body mass index (BMI), 28.7 (27.7-29.7) kg/m; apnoea and hypopnoea, 50.3 (45.6-55.0)/h; 95% confidence intervals]. BP and BMI were measured before the study and at two checkpoints after usage of nCPAP [620 (552-688) and 1071 (1000-1143) days]. RESULTS: The different times between the first and second checkpoints for detecting objective compliance were 17 (4-30) min (P = 0.003). Diastolic BP decreased by 5.9 (3.1-8.7) mmHg after 600 days nCPAP treatment and by 4.6 (2.0-7.2) mmHg after 1000 days (P = 0.0006). Systolic BP and BMI did not change significantly. Usage of nCPAP treatment for a daily average of 3 h was needed to achieve a significant decrease in diastolic BP [7.4 (4.3-10.6) mmHg, P < 0.0001]. Diastolic BP of normotensive OSA patients did not change significantly by nCPAP treatment, but that of hypertensive OSA patients decreased significantly within 1 month-3 years of nCPAP treatment whether or not medication was used. CONCLUSIONS: In patients with severe OSA, the use of nCPAP for a daily average of 3 h would be sufficient to decrease the diastolic BP of hypertensive OSA patients.