Performance enhancement in chronic obstructive pulmonary disease

Effects of Pressure Support Ventilation May Be Lost at High Exercise Intensities in People with COPD

Pressure support ventilation (PSV) may be used for exercise training in chronic obstructive pulmonary disease (COPD), but its acute effect on maximum exercise capacity is not fully known. The objective of this study was to evaluate the effect of 10 cm H₂O PSV and a fixed PSV level titrated to patient comfort at rest on maximum exercise workload (WLmax), breathing pattern and metabolic parameters during a symptom-limited incremental bicycle test in individuals with COPD. Eleven individuals with COPD (forced expiratory volume in one second: 49 ± 16%; age: 64 ± 7 years) performed three exercise tests: without a ventilator, with 10 cm H₂O of PSV and with a fixed level titrated to comfort at rest, using a SERVO-i ventilator. Tests were performed in randomized order and at least 48 hours apart. The WLmax, breathing pattern, metabolic parameters, and mouth pressure (Pmo) were compared using repeated measures analysis of variance. Mean PSV during titration was 8.2 ± 4.5 cm H₂O. There was no difference in the WLmax achieved during the three tests. At rest, PSV increased the tidal volume, minute ventilation, and mean inspiratory flow with a lower end-tidal CO₂; this was not sustained at peak exercise. Pmo decreased progressively (decreased unloading) with PSV at workloads close to peak, suggesting the ventilator was unable to keep up with the increased ventilatory demand at high workloads. In conclusion, with a Servo-i ventilator, 10 cm H₂O of PSV and a fixed level of PSV established by titration to comfort at rest, is ineffective for the purpose of achieving higher exercise workloads as the acute physiological effects may not be sustained at peak exercise.

The Impact of Pre-Dialytic Endurance Training on Nutritional Status and Quality of Life in Stable Hemodialysis Patients (Sawada Study)

BACKGROUND

Protein-energy malnutrition and decreased quality of life (QOL) are common in hemodialysis (HD) patients. Although several studies have proved that regular exercise has beneficial effects, few control studies have shown the effects of exercise training on the nutritional status and QOL in HD patients.

METHODS

Fifty-five HD patients were recruited, and 22 of them were trained to exercise on an ergometer prior to dialysis three times a week for one year. Serum albumin levels, creatinine generation rate (CGR), and the Short Form 36 were assessed as outcome measures.

RESULTS

The serum albumin levels and CGR increased in the training group compared with baseline. The QOL scores also increased in half of the physical health and mental health dimensions in the training group.

CONCLUSION

These observations suggest that low-dose, long-term pre-dialytic endurance training might reverse the poor clinical outcome by improving the nutritional status and QOL in HD patients.