title: Respiratory resistance of patients during cardiac stress testing with adenosine: is dyspnea a sign of bronchospasm?
abstract: BACKGROUND
  Adenosine is widely used for stress-testing in myocardial perfusion imaging. During adenosine infusion, dyspnea is one of the main complaints of patients. The aim of this study was to determine whether dyspnea during adenosine infusion is caused by bronchospasm.
  
  
  METHODS
  Fifty-four patients were enrolled in the study. Seven of these 54 suffered from mild chronic obstructive pulmonary disease (COPD). We continuously measured respiratory resistance (Rrs), using impulse oscillometry. Respiratory resistance was measured before, during, and after a continuous infusion of 140 microg/kg/min adenosine.
  
  
  RESULTS
  Sixty-seven percent of patients suffered from dyspnea during adenosine infusion. In patients with mild COPD, Rrs was higher compared with other patients (0.48 vs 0.27 kPa/L/s, P < .05). Neither patients with COPD nor those without COPD exhibited a significant increase in Rrs during adenosine infusion. The Rrs of patients with dyspnea was insignificantly lower compared with patients without dyspnea (P = .469).
  
  
  CONCLUSIONS
  Dyspnea as a side effect of adenosine infusion is not correlated with impaired respiratory resistance in nonasthmatic patients and in patients with mild COPD. Thus bronchospasm is ruled out as cause of this clinical symptom. Despite the small number of COPD patients enrolled in the study, adenosine infusion might be possible in patients with mild COPD.
authors.affiliation: Institute of Radiology, Nuclear Medicine, and Molecular Imaging, Heart and Diabetes Center North Rhine-Westphalia, Bad Oeynhausen, Germany. efricke@hdz-nrw.de
authors.forename: Eva
authors.initials: E
authors.lastname: Fricke
authors.forename: Elke
authors.initials: E
authors.lastname: Esdorn
authors.forename: Annett
authors.initials: A
authors.lastname: Kammeier
authors.forename: Harald
authors.initials: H
authors.lastname: Fricke
authors.forename: Rainer
authors.initials: R
authors.lastname: Preuss
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Burchert
authors.forename: Oliver
authors.initials: O
authors.lastname: Lindner
mesh_terms: D000241:Adenosine / Q000009:adverse effects*; D000368:Aged; D000403:Airway Resistance / Q000187:drug effects*; D001250:Asthma, Exercise-Induced / Q000000981:diagnostic imaging* / Q000209:etiology*; D004417:Dyspnea / Q000000981:diagnostic imaging* / Q000209:etiology*; D005080:Exercise Test / Q000009:adverse effects / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D018570:Risk Assessment / Q000379:methods; D014665:Vasodilator Agents; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*
chemical_list: D014665:Vasodilator Agents; D000241:Adenosine