Effect of Maximal Oxygen Pulse on Patients with Chronic Obstructive Pulmonary Disease*

Objective This study evaluated the effect of maximal oxygen pulse (O2Pmax) on patients with chronic obstructive pulmonary disease (COPD) and confirmed the predictive effect on acute exacerbations of COPD (AECOPD).Methods This retrospective study included 91 participants who underwent cardiopulmonary exercise testing (CPET), lung function testing, a dyspnea scale assessment, and a 3-year follow-up. The participants were divided into two groups according to the O2Pmax value. Exercise capacity, ventilatory conditions, gas exchange efficiency, and dyspnea symptoms were compared, and the correlations between O2Pmax and these indices were evaluated. The ability of O2Pmax to predict AECOPD was examined.Results Exercise capacity, ventilatory conditions, and gas exchange efficiency were lower, and dyspnea symptom scores were higher in the impaired O2Pmax group (P < 0.05). O2Pmax was positively correlated with forced vital capacity (FVC)%, forced expiratory volume in 1 sec (FEV1)%, FEV1/FVC%, anaerobic threshold (AT), work rate (WR)%, aximal oxygen uptake (V?O2max)%, V?O2/kgmax, V?O2/kgmax%, WRAT, WRmax, V?O2AT, V?O2max, and V?Emax, and was negatively correlated with EqCO2AT, and EqCO2max (P < 0.05). Most importantly, O2Pmax could be used to predict AECOPD, and the best cut-off value was 89.5% (area under the curve, 0.739; 95% CI, 0.609-0.869).Conclusion O2Pmax reflected exercise capacity, ventilation capacity, gas exchange capacity, and dyspnea symptoms in patients with COPD and may be an independent predictor of AECOPD.