title: Inspiratory flow rate and dynamic lung function in cystic fibrosis and chronic obstructive lung diseases.
abstract: OBJECTIVE
  The peak inspiratory flow rates (PIFRs) generated by cystic fibrosis (CF) and COPD patients through a range of clinically relevant resistances have not yet been reported (to our knowledge). The objectives of this study were to (1) explore a relevant range of resistive loads and address whether patients with stable CF and COPD can generate the PIFR sufficient to disperse dry-powder inhalants (DPI) and (2) determine whether the optimal inspiratory flow rate effective for delivery of aerosolized pharmacologic therapeutic agents can be attained with a comfort rating acceptable to subjects.
  
  
  METHODS
  Prospective, controlled, subject-blinded study.
  
  
  METHODS
  Pulmonary function laboratory at the VA Palo Alto Health Care System.
  
  
  METHODS
  Thirty-six subjects, including 12 healthy volunteers, 12 subjects with CF, and 12 subjects with COPD were studied.
  
  
  METHODS
  Studies of dynamic lung function and PIFR without and with varying resistances were obtained at a single laboratory visit.
  
  
  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.
  
  
  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.
authors.affiliation: Department of Medicine, VA Palo Alto Health Care System, CA 94304, USA. sarinas@icon.palo-alto.med.va.gov
authors.forename: P S
authors.initials: PS
authors.lastname: Sarinas
authors.forename: T E
authors.initials: TE
authors.lastname: Robinson
authors.forename: A R
authors.initials: AR
authors.lastname: Clark
authors.forename: J
authors.initials: J
authors.lastname: Canfield
authors.forename: R K
authors.initials: RK
authors.lastname: Chitkara
authors.forename: R B
authors.initials: RB
authors.lastname: Fick
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000403:Airway Resistance; D003550:Cystic Fibrosis / Q000503:physiopathology*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007320:Inspiratory Capacity; D008168:Lung / Q000503:physiopathology*; D008173:Lung Diseases, Obstructive / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012720:Severity of Illness Index