title: Effect of inhaled salbutamol on dynamic intrinsic positive end-expiratory pressure in spontaneously breathing patients with stable severe chronic obstructive pulmonary disease.
abstract: BACKGROUND
  The objective was to determine the effect of inhaled salbutamol on PEEPi dyn in spontaneously breathing patients with stable severe chronic obstructive pulmonary disease (COPD).
  
  
  METHODS
  Eleven patients with COPD were studied (mean age: 63 years, average FEV1 0.71 +/- 0.31 L). The patients were evaluated before and after inhaling 400 pg of salbutamol. Spirometry, slow vital capacity, breathing pattern, and PEEPi dyn pre- and post-bronchodilator administration were performed. PEEPi dyn was measured as the difference in esophageal pressure between the onset of inspiratory effort and the point of zero flow.
  
  
  RESULTS
  Pre-BD PEEPi dyn fell on average by 56% after inhalation of salbutamol (1.89 +/- 1.24 cm H2O to 0.83 +/- 0.81 cm H2O, p<0.001). This was accompanied by bronchodilation and a reduction of air trapping (FEV1: 0.71 +/- 0.31 L to 0.91 +/- 0.35 L, p<0.001; IC: 1.5 +/- 0.53 L to 1.94 +/- 0.56 L, p<0.001). A significant positive correlation between deltaPEEPi dyn, deltaFEV1 (r=0.64, p<0.05), and deltaIC (r=0.69, p<0.05) was observed. The breathing pattern did not change significantly after bronchodilation. Stepwise multiple regression analysis of pre-BD spirometric and breathing pattern parameters selected IC and Ti/Ttot as the strongest predictors of pre-BD PEEPi dyn (p=0.039 and 0.006, respectively).
  
  
  CONCLUSIONS
  The inhalation of 400 microg of salbutamol produced bronchodilation, reduction of air trapping, and a decrease in PEEPi dyn in spontaneously breathing patients with stable severe COPD.
authors.affiliation: Pulmonary Laboratory, Hospital Alemán, Buenos Aires, Argentina. cnigro@intramed.net
authors.forename: Carlos Alberto
authors.initials: CA
authors.lastname: Nigro
authors.forename: Jorge Ernesto
authors.initials: JE
authors.lastname: Prieto
authors.forename: María Mercedes
authors.initials: MM
authors.lastname: Kleinert
authors.forename: Edgardo Edmundo
authors.initials: EE
authors.lastname: Rhodius
mesh_terms: D000280:Administration, Inhalation; D000368:Aged; D000420:Albuterol / Q000008:administration & dosage*; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy*; D012119:Respiration / Q000187:drug effects
chemical_list: D001993:Bronchodilator Agents; D000420:Albuterol