Pulmonary Rehabilitation in Patients with COPD (2)
Patients with functional limitations due to COPD were selected from the outpatient clinic. The characteristics of the patients are shown in Table 1. All patients had moderate to severe airflow obstruction without significant changes after inhalation of broncho-dilators. flovent inhaler
In all of them, a ventilatory limitation of the exercise capacity was established by means of a maximal bicycle ergometer test. All patients stopped the exercise test because of dyspnea and muscle fatigue of the legs.
The ventilatory limitation was defined as a normal resting arterial PcOj that rose during progressive exercise. This may indicate an insufficiency of the respiratory muscles to maintain an adequate ventilation during the higher metabolic rate of exercise. As the alveolar-arterial oxygen pressure difference (P[A-2]OJ increases with 1.5 to 2 kPa during progressive exercise in normal subjects, an additional selection criterion was that the P(A-a)02 did not increase by more than 2 kPa at maximal exercise. In this way, patients were excluded who had severe lowering of the arterial Po, due to ventilation-perfusion mismatching, or with diffusion or shunt phenomena during exercise. There were no other limitations of the exercise capacity in these patients, such as cardiovascular or neuromuscular problems.