Subjects varied as to how many practice runs were required before the test was considered technically acceptable. When subjects failed either to match the preset ventilatory controls or to generate the required opening pressure, they came off the mouthpiece, effectively terminating the test. Pressure at the airway opening was measured with a differential pressure transducer (Validyne MCI). Inspiratory flow was measured with a pneumota-chygraph (Fleisch HP 47304A) in series with the inspiratory port. Inspiratory flow was integrated (Gould Integrator Amplifier 134615-70) to display Vt. All variables were recorded on a 16-channel strip chart recorder (Gould ES 1000). The SaOa was monitored with a pulse oximeter (Ohmeda Biox 3700) and was maintained at or above 90 percent throughout the test with the administration of supplemental oxygen as necessary. buy ventolin inhalers
Our clinical test of exercise tolerance was the 6-minute walking test performed under circumstances of maximum encouragement in the hospital corridor. The total distance walked was recorded. The baseline performance was established from the best of three tests performed at the same time each day.” The ABGs were measured both before and after therapy at the same time of the day (late afternoon) while patients breathed room air without ventilatory support.