Study design (if review, criteria of inclusion for studies)
Prospective, controlled, subject-blinded study.
Participants
Pulmonary function laboratory at the VA Palo Alto Health Care System.
Interventions
Thirty-six subjects, including 12 healthy volunteers, 12 subjects with CF, and 12 subjects with COPD were studied.
Outcome measures
Studies of dynamic lung function and PIFR without and with varying resistances were obtained at a single laboratory visit.
Main results
Dynamic lung function and PIFR varied inversely with the resistive load for all patient groups and did not correlate with the disease severity, as indicated by FEV1 of percent predicted. The average subjective comfort rating for any given resistive load was similar for subjects with CF and COPD.
Authors' conclusions
These results support the conclusion that subjects with stable CF and COPD of varying severity can comfortably generate the necessary flow rates to operate new and currently available DPIs over a wide range of inspiratory resistances.