title: Diagnostic accuracy of metronome-paced tachypnea to detect dynamic hyperinflation.
abstract: BACKGROUND
  This prospective study was carried out to investigate if metronome-paced tachypnea (MPT) can serve as an accurate diagnostic tool to identify patients with chronic obstructive pulmonary disease (COPD) who are susceptible to develop dynamic hyperinflation during exercise. Commonly, this is assessed by measuring change in inspiratory capacity (IC) during cardiopulmonary exercise testing (CPET), which, however, is complex and laborious.
  
  
  METHODS
  Fifty-three patients with COPD (FEV(1) 58 ± 22%pred) and 20 age-matched healthy subjects were characterized by lung function testing and performed CPET (reference standard) and MPT. The repeatability coefficient of IC (10·2%) was used as cut-off to classify subjects as hyperinflators during CPET. Subsequently, dynamic hyperinflation was measured after MPT. With receiver operating characteristic analysis, the optimal cut-off for MPT-induced dynamic hyperinflation was determined and sensitivity and specificity of MPT to identify hyperinflators were evaluated.
  
  
  RESULTS
  With 10·2% decrease in IC as cut-off for CPET-induced dynamic hyperinflation, the optimal cut-off for MPT was 11·1% decrease in IC. Using these cut-offs, MPT had a sensitivity of 85% and specificity of 85% to identify the subjects who hyperinflated during CPET.
  
  
  CONCLUSIONS
  The MPT test shows good overall accuracy to identify subjects who are susceptible to develop dynamic hyperinflation during CPET. Before considering the use of MPT as a screening tool for dynamic hyperinflation in COPD, sensitivity and specificity need further evaluation.
authors.affiliation: Radboud University Nijmegen Medical Centre, of Pulmonary Diseases, Nijmegen, The Netherlands. A.Lahaije@LONG.umcn.nl
authors.forename: Anke J M C
authors.initials: AJ
authors.lastname: Lahaije
authors.forename: Laura M
authors.initials: LM
authors.lastname: Willems
authors.forename: Hieronymus W H
authors.initials: HW
authors.lastname: van Hees
authors.forename: P N Richard
authors.initials: PN
authors.lastname: Dekhuijzen
authors.forename: Hanneke A C
authors.initials: HA
authors.lastname: van Helvoort
authors.forename: Yvonne F
authors.initials: YF
authors.lastname: Heijdra
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D005080:Exercise Test; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007320:Inspiratory Capacity; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010507:Periodicity; D011237:Predictive Value of Tests; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000503:physiopathology; D012372:ROC Curve; D015203:Reproducibility of Results; D015656:Respiratory Mechanics; D012680:Sensitivity and Specificity; D013147:Spirometry; D059246:Tachypnea / Q000503:physiopathology*; D013997:Time Factors; D014797:Vital Capacity