Respiratory and Metabolic Responses as Determinants of Exercise Endurance Time in Constant-load Exercise Test in Healthy Adult Volunteers : A Prospective Cross-sectional Study

Article信州医学雑誌 69(6) : 355-362(2021)departmental bulletin pape

Questionnaire Survey about Disaster Preparation for Users of Long-term Oxygen Therapy

Article信州医学雑誌 67(6): 407-416(2019)journal articl

Relationship between Sympathetic Nerve Activity Evaluated by Pulse Rate Variability and Blood Pressure Early in the Morning in Sleep Disordered Breathing

Article信州医学雑誌 67(4): 241-251(2019)journal articl

Instability of parasympathetic nerve function evaluated by instantaneous time-frequency analysis in patients with obstructive sleep apnea

The purpose was to determine whether the instability of parasympathetic nerve (PN) function is associated with fragmentation of sleep and the instability can be improved by CPAP treatment in obstructive sleep apnea (OSA). Fifty-three OSA and 50 non-OSA subjects were examined by full-PSG and pulse rate variability (PRV) was recorded simultaneously using a photoplethysmograph and evaluated by instantaneous time-frequency analysis using the complex demodulation method. PN and sympathetic nerve (SN) activity were assessed by the mean high-frequency (HF) amplitude and ratio of low-frequency (LF) and HF amplitude (LF/ HF ratio), respectively. Furthermore, the shift in central frequency (CF) of the main HF peak over time was monitored continuously. The relative times over which the same main HF peak was sustained for at least 20 s and 5 min in total recording time (%HF20s and % HF5min) were considered as markers of PN stability. Twenty-two of 53 patients with OSA also examined under the treatment with continuous positive airway pressure (CPAP). A significant increase in mean LF/ HF ratio and decrease in HF amplitude were observed in severe OSA. Furthermore, both % HF20s and % HF5min were significantly decreased not only in mild-to-moderate OSA but also in severe OSA, and % HF20s was the strongest independent determinant for arousal index. Treatment with CPAP significantly decreased the LH/HF ratio and increased both % HF20s and % HF5min. These findings suggest that the stability of PN function is impaired by arousal due to repeated apnea and hypopnea in OSA, and that CPAP therapy improves SN activity and PN dysfunction.ArticleSLEEP AND BIOLOGICAL RHYTHMS.16(3):323-330(2018)journal articl

Efficacy of tiotropium and indacaterol monotherapy and their combination on dynamic lung hyperinflation in COPD: a random open-label crossover study

Background and objective: The difference in efficacy of long-acting muscarinic antagonists (LAMAs) and long-acting beta(2)-agonists (LABAs) for dynamic lung hyperinflation (DLH) in COPD is unclear. The purpose of this study was to elucidate the difference in efficacy of LAMA and LABA alone and the combination thereof for DLH. Subjects and methods: Thirty stable patients were enrolled and randomly divided into two groups following baseline measurements. One group was treated with 5 mu g tiotropium (Respimat inhaler) for 4 weeks following a 4-week treatment with 150 mu g indacaterol, while the other group was treated with indacaterol for 4 weeks following a 4-week treatment with tiotropium. For both groups, these treatments were followed by a combination of the two drugs for 4 weeks. Pulmonary function tests, including DLH evaluated by metronome-paced incremental hyperventilation and exercise tolerance evaluated by the shuttle-walk test, were performed at the end of each treatment period. Results: In total, 23 patients completed this study. Both tiotropium and indacaterol alone significantly increased forced expiratory volume in 1 second, exercise tolerance, and improved health status. Tiotropium significantly improved DLH, but indacaterol did not. The combination therapy resulted in further improvements in lung function and exercise tolerance, but not in DLH. Conclusion: The efficacy of tiotropium in inhibiting DLH following metronome-paced incremental hyperventilation may be superior to that of 150 mu g indacaterol, although the effects on airflow obstruction were the same, and the combination therapy showed further improvement in airflow obstruction, but not in DLH.ArticleINTERNATIONAL JOURNAL OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE.12:3195-3201(2017)journal articl

Sputum eosinophilia can predict responsiveness to inhaled corticosteroid treatment in patients with overlap syndrome of COPD and asthma

Background: Chronic obstructive pulmonary disease (COPD) and asthma may overlap and converge in older people (overlap syndrome). It was hypothesized that patients with overlap syndrome may have different clinical characteristics such as sputum eosinophilia, and better responsiveness to treatment with inhaled corticosteroid (ICS). Methods: Sixty-three patients with stable COPD (forced expiratory volume in 1 second [FEV1] <= 80%) underwent pulmonary function tests, including reversibility of airflow limitation, arterial blood gas analysis, analysis of inflammatory cells in induced sputum, and chest high-resolution computed tomography. The inclusion criteria for COPD patients with asthmatic symptoms included having asthmatic symptoms such as episodic breathlessness, wheezing, cough, and chest tightness worsening at night or in the early morning (COPD with asthma group). The clinical features of COPD patients with asthmatic symptoms were compared with those of COPD patients without asthmatic symptoms (COPD without asthma group). Results: The increases in FEV1 in response to treatment with ICS were significantly higher in the COPD with asthma group. The peripheral eosinophil counts and sputum eosinophil counts were significantly higher. The prevalence of patients with bronchial wall thickening on chest high-resolution computed tomography was significantly higher. A significant correlation was observed between the increases in FEV1 in response to treatment with ICS and sputum eosinophil counts, and between the increases in FEV1 in response to treatment with ICS and the grade of bronchial wall thickening. Receiver operating characteristic curve analysis revealed 82.4% sensitivity and 84.8% specificity of sputum eosinophil count for detecting COPD with asthma, using 2.5% as the cutoff value. Conclusion: COPD patients with asthmatic symptoms had some clinical features. ICS should be considered earlier as a potential treatment in such patients. High sputum eosinophil counts and bronchial wall thickening on chest high-resolution computed tomography might therefore be a good predictor of response to ICS.ArticleINTERNATIONAL JOURNAL OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE. 7:283-289 (2012)journal articl

Annual changes in pulmonary function in combined pulmonary fibrosis and emphysema: Over a 5-year follow-up

Background: Combined pulmonary fibrosis and emphysema (CPFE) is a unique disorder that has been previously described, and the distinct features of CPFE in comparison with chronic obstructive pulmonary disease (COPD) have been reported. However, the yearly dynamics of pulmonary function parameters in CPFE patients compared with those in COPD patients have not yet been reported. Methods: We retrospectively enrolled patients with CPFE and COPD who had undergone pulmonary function tests more than five times during a follow-up period of more than five years. The baseline clinical characteristics and the annual changes in pulmonary function during the follow-up period in 16 stable CPFE patients were compared with those in 19 stable COPD patients. Annual changes in pulmonary function were estimated from linear regressions, with assumptions for time-dependency and linearity. We analyzed the time-dependent fluctuations in pulmonary function for the two disorders. Results: Annual decreases in VC and FVC in the CPFE group were significantly higher than those in the COPD group. Annual decrease in FEV1/FVC in the COPD group was significantly higher than in the CPFE group. During the follow-up period, FEV1/FVC in the CPFE group appeared to improve because of annual decrease in FVC. Annual decreases in DLco and DLco/VA in the CPFE group were significantly higher than those in the COPD group. Conclusion: This is the first report showing the yearly dynamics of pulmonary function parameters in CPFE patients compared with those in COPD patients during a follow-up period of more than five years. This study revealed that the physiologic consequences of CPFE including the rate of progression of pulmonary function impairment were different from those of COPD. (C) 2013 Elsevier Ltd. All rights reserved.ArticleRESPIRATORY MEDICINE. 107(12):1986-1992 (2013)journal articl

Additive efficacy of short-acting bronchodilators on dynamic hyperinflation and exercise tolerance in stable COPD patients treated with long-acting bronchodilators

The purpose of this study was to clarify the additive efficacy of short-acting beta(2)-agonists (SABA) or muscarinic antagonists (SAMA) on dynamic hyperinflation and exercise tolerance in patients with chronic obstructive pulmonary disease (COPD) who had been treated with long-acting bronchodilators. Thirty-two patients with stable COPD who had been treated with long-acting bronchodilators, including long-acting muscarinic antagonists (LAMA), were examined by pulmonary function tests, dynamic hyperinflation evaluated by the method of step-wise metronome-paced incremental hyperventilation, and the incremental shuttle walking test before and after inhalation of SABA or SAMA. The additive efficacy of the two drugs was analyzed. Inhalation of SABA and SAMA improved airflow limitation and dynamic hyperinflation in stable COPD patients who had been treated with LAMA. Inhalation of SABA decreased respiratory resistance and the difference in respiratory resistance at 5 Hz and 20 Hz. On the whole, the additive efficacy of SABA on airflow limitation and dynamic hyperinflation was superior to that of SAMA. Furthermore, inhalation of SABA resulted in relief of breathlessness during exercise and significant improvement in exercise capacity. Inhalation of SABA resulted in significant improvement in exercise tolerance, which may have been due to improvement in dynamic hyperinflation. Single use of SABA before exercise, in addition to regular treatment with LAMA, may therefore be useful in stable COPD patients.ArticleRESPIRATORY MEDICINE. 107(3):394-400 (2013)journal articl

Clinical Characteristics and Predictors of Mortality in Patients with Combined Pulmonary Fibrosis and Emphysema Syndrome and Lung Cancer

Rationale: We performed this retrospective study to clarify the clinical characteristics, survival and mortality predictors in patients with combined pulmonary fibrosis and emphysema (CPFE) and lung cancer. Methods: We retrospectively reviewed the medical records of a total of 123 patients with lung cancer, as confirmed according to histological or cytological examinations. Based on the findings of chest CT, the patients were categorized into four groups: LC+normal (n=70); LC+emphysema (n=26); LC+fibrosis (n=10); LC+CPFE (n=17). The clinical characteristics and survival of the LC+CPFE group were compared with those of the other groups. In addition, mortality predictors were evaluated in the LC+CPFE group. Results: The proportion of females was significantly higher in the LC+normal group than in the LC+CPFE and LC+emphysema groups. Significantly more patients were diagnosed with squamous cell carcinoma in the LC+CPFE group than in the LC+normal group. The proportion of patients whose primary mass was located in “nonsubpleural” areas was significantly higher in patients with CPFE who also had lung cancer in the upper lobe than in those with CPFE who also had lung cancer in the other sites. There were significant differences in survival between the LC+normal group and the other groups, whereas there were no significant differences in survival among the LC+emphysema, LC+fibrosis and LC+CPFE groups. In the LC+CPFE group, the patients with a high level of serum KL-6 at diagnosis and upper lobe lung cancer demonstrated a high risk of death. A high level of serum KL-6 at diagnosis was also independently associated with a high risk of death. Conclusions: Patients with CPFE and lung cancer may have distinct clinical characteristics. Strict follow-up is required in patients with CPFE and lung cancer whose serum KL-6 level at diagnosis is higher than the normal range and/or the primary mass of lung cancer is located in the upper lobe.ArticleJournal of Pulmonary and Respiratory Medicine.5(3):263(2015)journal articl