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Objective The effects of partial pressure of arterial oxygen (PaO 2 ) 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 PaO 2 value while breathing spontaneously with prescribed oxygen at 12 months after introducing NIV: PaO 2 ≥80 Torr group (n=76) and PaO 2 <80 Torr group (n=65). Results During the 4-year follow-up, the mortality was significantly higher in the PaO 2 <80 Torr group than in the PaO 2 ≥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 PaO 2 <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 PaO 2 at 12 months after introducing NIV was an independent risk factor for mortality. Keeping the daytime PaO 2 ≥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.

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.

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.

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.