Fig 1.
A double-blind, crossover, randomized controlled trial comparing Program A, including 4 weeks of usual PR followed by 8 weeks of PR under FiO2 0.3, with Program B, including 4 weeks of usual PR followed by 8 weeks of PR under FiO2 0.5. The washout period was set for 12 weeks or more. Abbreviations: 6MWD, Six-Minute Walk Distance; CAT, COPD Assessment Test; mMRC, Modified Medical Research Council Dyspnea Scale; LFT, Lung function tests; PR, pulmonary rehabilitation.
Fig 2.
An example of an adverse event caused by hypocapnia.
(A) O2 loading (Flow rate 40 L/m). Stretching and Resistance training begins. (B) Stretching and resistance training completed. (C) Aerobic exercise begins. (D) Aerobic exercise completed. (a) During aerobic exercise, CO₂ levels were low. Seventeen minutes and 30 seconds after the start of the treadmill, the patient complained of dizziness, and the exercise was stopped. (b) CO₂ levels decreased further after exercise cessation. The subject continued to report dizziness.
Table 1.
Patient characteristics.
Fig 3.
Changes in six-min walk distance (6MWD) and COPD assessment (CAT) score by O2-supplemented pulmonary rehabilitation (PR).
(A) Program A or B, including PR with O2 supplementation (FiO2 0.3 or 0.5, respectively), did not significantly increase 6MWD (n = 6). (B) The Δ6MWD for Program B, including FiO2 0.5 PR, indicated a decrease from baseline performance (n = 6). (C) Program A or B, including PR with O2 supplementation (FiO2 0.3 or 0.5, respectively), significantly decreased CAT score (n = 6). (D) The decrease in CAT score after Program A, including FiO2 0.3 PR, was larger than that after Program B, including FiO2 0.5 PR (n = 6). *: p < 0.05, Line graph: ♦Mean. Colors represent each subject.
Fig 4.
Changes in quadriceps muscle power by O2-supplemented pulmonary rehabilitation (PR).
(A) Program A or B, including PR with O2 supplementation (FiO2 0.3 or 0.5, respectively), significantly increased rt quadriceps muscle power (n = 6). (B) O2-supplemented PR increased rt quadriceps muscle power in a dose-dependent manner (n = 6). (C) Program A or B, including PR with O2 supplementation (FiO2 0.3 or 0.5, respectively), significantly increased lt quadriceps muscle power (n = 6). (D) O2-supplemented PR increased lt quadriceps muscle power in a dose dependent manner (n = 6). (E) Program A or B, including PR with O2 supplementation (FiO2 0.3 or 0.5, respectively), significantly increased (rt or lt) quadriceps muscle power (n = 12 from 6 patients). (F) O2-supplemented PR increased (rt or lt) quadriceps muscle power in a dose-dependent manner (n = 12 from 6 patients). *: p < 0.05, **: p < 0.01, Line graph: ♦Mean. Colors represent each subject.
Fig 5.
Changes in lower leg circumference by O2-supplemented pulmonary rehabilitation (PR).
(A) Program A or B, including PR with O2 supplementation (FiO2 0.3 or 0.5, respectively), significantly increased rt lower leg circumference (n = 6). (B) O2-supplemented PR increased rt lower leg circumference in a dose-dependent manner (n = 6). (C) Program A or B, including PR with O2 supplementation (FiO2 0.3 or 0.5, respectively), significantly increased lt lower leg circumference (n = 6). (D) O2-supplemented PR increased lt lower leg circumference in a dose-dependent manner (n = 6). (E) Program A or B, including PR with O2 supplementation (FiO2 0.3 or 0.5, respectively), significantly increased rt and lt lower leg circumference (n = 12 from 6 patients). (F) O2-supplemented PR increased rt and lt lower leg circumference in a dose-dependent manner (n = 12 from 6 patients). **: p < 0.01, ***: p < 0.001, Line graph: ♦Mean. Colors represent each subject.
Fig 6.
Changes in muscle mass by O2-supplemented pulmonary rehabilitation (PR).
(A) Program A or B, including PR with O2 supplementation (FiO2 0.3 or 0.5, respectively), significantly increased trunk muscle mass (n = 6). (B) O2-supplemented PR increased trunk muscle mass in a dose-dependent manner (n = 6). (C) Program A or B, including PR with O2 supplementation (FiO2 0.3 or 0.5, respectively), significantly increased rt leg muscle mass (n = 6). (D) O2-supplemented PR increased rt leg muscle mass in a dose-dependent manner (n = 6). (E) Program A or B, including PR with O2 supplementation (FiO2 0.3 or 0.5, respectively), significantly increased rt and lt leg muscle mass (n = 12 from 6 patients). (F) O2-supplemented PR dose-dependently increased (rt and left) leg muscle mass (n = 12 from 6 patients). *: p < 0.05, **: p < 0.01, Line graph: ♦Mean. Colors represent each subject.
Table 2.
Conventional items and the sample size required to demonstrate the differences in rehabilitation achievements between FiO2 0.5 and FiO2 0.3 oxygen-supplemented pulmonary rehabilitation (PR) for patients with chronic obstructive pulmonary disease (COPD).
Table 3.
Candidates of new items and the sample size required to demonstrate the differences in rehabilitation achievements between FiO2 0.5 and FiO2 0.3 oxygen-supplemented pulmonary rehabilitation (PR) for patients with chronic obstructive pulmonary disease (COPD).