title: Volumetric capnography in the exclusion of pulmonary embolism at the emergency department: a pilot study.
abstract: The analysis of the [Formula: see text] in expired air as a function of the exhaled volume (volumetric capnography) might result in a more specific exclusion tool for pulmonary embolism (PE) in addition to the Wells-score and D-dimer. A novel combination of volumetric capnography parameters ([Formula: see text]) should be decreased in PE and could possibly be used to decrease the number of requested computed tomography pulmonary angiograms (CTPA). Volumetric capnography measurements were performed on consecutive patients seen in the emergency department for which, due to suspected PE (due to increased D-dimer level or Wells-score), a CTPA was ordered. A total of 30 subjects were included, of which in 13 PE was seen on CTPA. Median [Formula: see text] was 4.36 kPa (IQR 3.92-4.88) in the no PE group versus 4.07 kPa (IQR 3.37-4.39) in the PE group (p  =  0.086). Median of the novel parameter [Formula: see text] was 1.85 min.kPa dl-1(IQR 1.21-3.00) in the no PE group versus 1.18 min.kPa dl-1(IQR 0.61-1.38) in the PE group (p  =  0.006). Using a threshold for the new parameter of 1.90 min.kPa dl-1or higher to exclude PE resulted in a negative predictive value of 100% (95% CI: 77%-100%) and would have potentially excluded PE in 47% (95% CI: 26%-69%) of the no PE group without the need for CTPA. This pilot study introduces a novel parameter [Formula: see text] which is significantly decreased in PE subjects. Future studies regarding validation and addressing aspects such as reproducibility and normalization after treatment are needed to confirm its usability in excluding PE in the emergency department.
authors.affiliation: Department of Pulmonology, Medisch Spectrum Twente, Enschede, the Netherlands. Author to whom any correspondence should be addressed.
authors.forename: Timon M
authors.initials: TM
authors.lastname: Fabius
authors.forename: Michiel M
authors.initials: MM
authors.lastname: Eijsvogel
authors.forename: Ivo
authors.initials: I
authors.lastname: van der Lee
authors.forename: Marjolein G J
authors.initials: MG
authors.lastname: Brusse-Keizer
authors.forename: Frans H
authors.initials: FH
authors.lastname: de Jongh
mesh_terms: D000368:Aged; D019540:Area Under Curve; D019296:Capnography / Q000379:methods*; D002245:Carbon Dioxide / Q000378:metabolism; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010313:Partial Pressure; D010865:Pilot Projects; D011655:Pulmonary Embolism / Q000175:diagnosis*; D012372:ROC Curve
chemical_list: D002245:Carbon Dioxide