Examination of the inspiratory flow rates of COPD patients in Japanese medical facilities

UNLABELLED: Chronic obstructive pulmonary disease (COPD) is treated primarily with inhalation therapy. However, as many COPD patients are elderly, whether or not patients inhale dry powder at an adequate inspiratory flow rate requires investigation. We therefore conducted a multicenter investigation of the effects of height, body weight, age, disease severity, and other factors on inspiratory flow rate in COPD patients. METHODS: We measured inspiratory flow rates and forced expiratory volume in the first second (FEV1) with the In-Check Dial (Clement Clarke) fitted with a discus adapter in 175 COPD patients of 40 years old and over (mean age 71.3, men 89.1%, women 10.9%). RESULTS: A total of 98.9% of the patients had an inspiratory flow rate exceeding 30L/minute. Two patients had a rate of 30L/minute or less. The mean inspiratory flow rate was 98 +/- 30L/minute overall, 104 +/- 27L/minute in mild COPD, 109 +/- 28L/minute in moderate COPD, 91 +/- 26L/minute in severe COPD, 71 +/- 24L/minute in very severe COPD, and 83 +/- 28L/minute in patients 75 years and older. Inspiratory flow rates significantly correlated with body mass index and FEV1. CONCLUSION: Most elderly patients with COPD maintained a sufficient inspiratory flow rate when inhaling dry powder.