The effect of long-acting dual bronchodilator therapy on exercise tolerance, dynamic hyperinflation, and dead space during constant work rate exercise in COPD

Fixed-intensity exercise tests to measure exertional dyspnoea in chronic heart and lung populations: a systematic review

INTRODUCTION

Exertional dyspnoea is the primary diagnostic symptom for chronic cardiopulmonary disease populations. Whilst a number of exercise tests are used, there remains no gold standard clinical measure of exertional dyspnoea. The aim of this review was to comprehensively describe and evaluate all types of fixed-intensity exercise tests used to assess exertional dyspnoea in chronic cardiopulmonary populations and, where possible, report the reliability and responsiveness of the tests.

METHODS

A systematic search of five electronic databases identified papers that examined 1) fixed-intensity exercise tests and measured exertional dyspnoea, 2) chronic cardiopulmonary populations, 3) exertional dyspnoea reported at isotime or upon completion of fixed-duration exercise tests, and 4) published in English.

RESULTS

Searches identified 8785 papers. 123 papers were included, covering exercise tests using a variety of fixed-intensity protocols. Three modes were identified, as follows: 1) cycling (n=87), 2) walking (n=31) and 3) other (step test (n=8) and arm exercise (n=2)). Most studies (98%) were performed on chronic respiratory disease patients. Nearly all studies (88%) used an incremental exercise test. 34% of studies used a fixed duration for the exercise test, with the remaining 66% using an exhaustion protocol recording exertional dyspnoea at isotime. Exertional dyspnoea was measured using the Borg scale (89%). 7% of studies reported reliability. Most studies (72%) examined the change in exertional dyspnoea in response to different interventions.

CONCLUSION

Considerable methodological variety of fixed-intensity exercise tests exists to assess exertional dyspnoea and most test protocols require incremental exercise tests. There does not appear to be a simple, universal test for measuring exertional dyspnoea in the clinical setting.

Exercise capacity and physical activity in COPD patients treated with a LAMA/LABA combination: a systematic review and meta-analysis

BACKGROUND

Persistent airflow limitation and dyspnoea may reduce chronic obstructive pulmonary disease (COPD) patients exercise capacity and physical activity, undermining their physical status and quality of life. Long-acting muscarinic antagonists and long-acting beta-2 agonists (LAMA/LABA) combinations are amongst moderate-to-severe COPD recommended treatments. This article analyses LAMA/LABA combinations effect on COPD patients exercise capacity and physical activity outcomes.

METHODS

A systematic review and meta-analysis of double-blind randomized controlled trials comparing LAMA/LABA combinations against monotherapy or placebo was conducted.

RESULTS

Seventeen articles were identified (N = 4041 patients). In endurance shuttle walk test and constant work rate cycle ergometry, LAMA/LABA combinations obtained better results than placebo, but not monotherapy, whereas in 6-min walking test, results favoured LAMA/LABA over monotherapy (four studies), but not over placebo (one study). Moreover, LAMA/LABA combinations obtained better results than placebo in number of steps per day, reduction in percentage of inactive patients and daily activity-related energy expenditure, and better than monotherapy when measuring time spent on ≥ 1.0-1.5, ≥ 2.0 and ≥ 3.0 metabolic equivalents of task activities.

CONCLUSIONS

LAMA/LABA combinations in COPD patients provided better results than monotherapy or placebo in most exercise capacity and physical activity outcomes.

Effect of induced acute metabolic alkalosis on the V̇E/V̇CO2 response to exercise in healthy adults

We tested the hypothesis that increasing the respiratory control systems' arterial PCO₂ equilibrium point via induced acute metabolic alkalosis by ingestion of sodium bicarbonate (NaHCO₃, 0.3 g/kg) would decrease the ventilatory equivalent for CO₂ (V̇_E/V̇CO₂) at its lowest point ("nadir") during constant-load cycle exercise testing performed at 80 % of peak power output in 18 healthy young adults. Compared to the sodium chloride (4 g) control condition, ingestion of NaHCO₃: increased arterialized venous pH, HCO₃- and PCO₂ at rest by 0.05 ± 0.01 units (mean ± SE), 6.4 ± 0.4 mEq/L and 4.3 ± 0.7 mmHg, respectively (all p < 0.0001); and decreased the V̇_E/V̇CO₂ nadir during exercise by 9.4 % (p < 0.0001) secondary to a 4.7 ± 1.8 L/min decrease in V̇_E (p = 0.019). In conclusion, induced acute metabolic alkalosis by ingestion of NaHCO₃ decreased the V̇_E/V̇CO₂ response to strenuous exercise in healthy adults.