Jun Horie

Electrically stimulated ventilation feedback improves the ventilation pattern in patients with COPD

[Purpose] We aimed to determine the effects of ventilation feedback using electrical stimulation on ventilation pattern during exercise in patients with chronic obstructive pulmonary disease (COPD), and develop new rehabilitation methods. [Subjects] This randomized double-blind placebo-controlled trial included 24 patients with COPD. [Methods] Phasic electrical stimulation during expiration (PESE) or a placebo was given to all the cases. Minute ventilation (VE), tidal volume (TV), respiratory rate (RR), expiratory time (Te), total respiratory time (Ttot), dead-space gas volume to tidal gas volume (VD/VT), oxygen uptake (VO2), carbon dioxide output (VCO2), Borg scale (Borg), and percutaneous oxygen saturation (SpO2) during rest and exercise were assessed. [Results] The placebo group showed no obvious change in ventilation measurements at rest or during exercise. However, in the PESE group, TV, Te, and Ttot significantly increased, while RR and VD/VT significantly decreased during exercise compared with the baseline measurements. Borg scores, SpO2, VO2, or VCO2 did not differ significantly. [Conclusion] PESE improves the ventilation pattern during rest and exercise. Furthermore, PESE does not increase VO2, which may indicate an increased workload. Biofeedback may contribute to PESE effects. Stimulation applied during expiration may evoke sensations increasing prolonged expiration awareness, facilitating prolongation.

Surface electromyography activity of the rectus abdominis, internal oblique, and external oblique muscles during forced expiration in healthy adults

We aimed to characterize rectus abdominis, internal oblique, and external oblique muscle activity in healthy adults under expiratory resistance using surface electromyography. We randomly assigned 42 healthy adult subjects to 3 groups: 30%, 20%, and 10% maximal expiratory intraoral pressure (PEmax). After measuring 100% PEmax and muscle activity during 100% PEmax, the activity and maximum voluntary contraction of each muscle during the assigned experimental condition were measured. At 100% PEmax, the external oblique (p<0.01) and internal oblique (p<0.01) showed significantly elevated activity compared with the rectus abdominis muscle. Furthermore, at 20% and 30% PEmax, the external oblique (p<0.05 and<0.01, respectively) and the internal oblique (p<0.05 and<0.01, respectively) showed significantly elevated activity compared with the rectus abdominis muscle. At 10% PEmax, no significant differences were observed in muscle activity. Although we observed no significant difference between 10% and 20% PEmax, activity during 30% PEmax was significantly greater than during 20% PEmax (external oblique: p<0.05; internal oblique: p<0.01). The abdominal oblique muscles are the most active during forced expiration. Moreover, 30% PEmax is the minimum intensity required to achieve significant, albeit very slight, muscle activity during expiratory resistance.

Changes in exercise tolerance and quality of life are unrelated in lung cancer survivors who undergo video-assisted thoracic surgery

[Purpose] The associations between changes in respiratory function, exercise tolerance, and quality of life (QOL) in patients with lung cancer who undergo lobectomy using video-assisted thoracoscopic surgery (VATS) are unclear. This study aimed to investigate the relationships between exercise tolerance and QOL in patients who underwent VATS. [Subjects and Methods] Thirty-six patients with lung cancer were followed for 3 months after VATS. Patients were evaluated before and 1, 4, and 12 weeks after surgery. Respiratory function, grip strength, and knee extension strength, as well as the results of timed up and go, 6-minute walk, and cardiopulmonary exercise tests, were evaluated using the 36-item short-form health survey. Longitudinal changes in physical performance and QOL were analyzed, as was the relationship between the change in physical function and QOL. [Results] The physical and social aspects of QOL significantly decreased at week 4 post-surgery, but recovered to pre-surgical levels by week 12. In contrast, physical (non-respiratory) function recovered to pre-surgical levels by week 4. There was no correlation between the percentages of change in QOL and those related to physical function. [Conclusion] Our preliminary study highlights the fact that early recovery of physical function is possible after VATS, but does not necessarily correlate with early QOL recovery. It is therefore necessary to perform perioperative interventions to promptly restore QOL after surgery.