HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:
Guest Access | Sign In via User Name/Password

This Article Full Text Free Full Text (PDF) Free Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My Personal Article Archive Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (18) Citing Articles via Google Scholar Google Scholar Articles by Rodger, M. A. Articles by Wells, P. S. Search for Related Content PubMed PubMed Citation Articles by Rodger, M. A. Articles by Wells, P. S.

Steady-State End-Tidal Alveolar Dead Space Fraction and D-Dimer^*

Bedside Tests To Exclude Pulmonary Embolism

^* From the Departments of Medicine (Drs. Rodger, Jones, Raymond, and Bredeson) and Radiology (Dr. Rasuli), University of Ottawa, Ottawa; the Department of Respiratory Therapy (Ms. Djunaedi), Ottawa Hospital - General Campus, Ottawa; and Clinical Epidemiology Unit (Dr. Wells), Ottawa Hospital Loeb Research Institute, Ottawa, Ontario, Canada.

Correspondence to: Marc A. Rodger, MD, Suite 7205, Ottawa Hospital - General Campus, 501 Smyth Rd, Ottawa, Ontario, K1H 8L6, Canada; e-mail: mrodger{at}ottawahospital.on.ca

Study objective: Less than 35% of patients suspected of having pulmonary embolism (PE) actually have PE. Safe bedside methods to exclude PE could save health-care resources and improve access to diagnostic testing for suspected PE. In patients with suspected PE, we sought to determine the sensitivity, specificity, and negative predictive value of (1) a steady-state end-tidal alveolar dead space fraction (AVDSf) of < 0.15, (2) a negative D-dimer result, and (3) the combination of a steady-state end-tidal AVDSf of < 0.15 and a negative D-dimer result.

Study design: Prospective cohort study.

Setting: Tertiary-care center in Ottawa, Ontario, Canada.

Patients: Consecutive inpatients, outpatients, and emergency department patients with suspected PE referred to the Departments of Nuclear Medicine or Radiology for investigation of suspected PE.

Interventions and measurements: All study patients had D-Dimer and alveolar dead space measurements prior to determining outcome (PE or no PE) with ventilation/perfusion scans and/or noninvasive leg vein imaging and/or pulmonary angiography.

Results: Two hundred forty-six eligible and consenting patients underwent diagnostic imaging that excluded PE in 163 patients, diagnosed PE in 49 patients, and was indeterminant in 34 patients. A negative D-dimer result excluded PE with a sensitivity of 83.0% (95% confidence interval [CI], 69.2 to 92.4%), a negative predictive value of 91.2% (95% CI, 83.4 to 96.1%), and a specificity of 57.6%. A steady-state end-tidal AVDSf of < 0.15 excluded PE with a sensitivity of 79.5% (95% CI, 63.5 to 90.7%), a negative predictive value of 90.7% (95% CI, 82.5 to 95.9%), and a specificity of 70.3%. The combination of a negative D-dimer result and a steady-state end-tidal AVDSf of < 0.15 excluded PE with a sensitivity of 97.8% (95% CI, 88.5 to 99.9%), a negative predictive value of 98.0% (95% CI, 89.4 to 99.9%), and a specificity of 38.0%.

Conclusion: This simple combination of bedside tests may safely rule out PE without further diagnostic testing in large numbers of patients with suspected PE.

Key Words: alveolar dead space • D-dimer • diagnosis • pulmonary embolism • reproducibility

This article has been cited by other articles:

				I. Tillie-Leblond, C.-H. Marquette, T. Perez, A. Scherpereel, C. Zanetti, A.-B. Tonnel, and M. Remy-Jardin Pulmonary embolism in patients with unexplained exacerbation of chronic obstructive pulmonary disease: prevalence and risk factors. Ann Intern Med, March 21, 2006; 144(6): 390 - 396. [Abstract] [Full Text] [PDF]

				M. A. Rodger, C. N. Bredeson, G. Jones, P. Rasuli, F. Raymond, A. M. Clement, A. Karovitch, H. Brunette, D. Makropoulos, M. Reardon, et al. The Bedside Investigation of Pulmonary Embolism Diagnosis Study: A Double-blind Randomized Controlled Trial Comparing Combinations of 3 Bedside Tests vs Ventilation-Perfusion Scan for the Initial Investigation of Suspected Pulmonary Embolism Arch Intern Med, January 23, 2006; 166(2): 181 - 187. [Abstract] [Full Text] [PDF]

				K. Hogg, D. Dawson, T. Tabor, B. Tabor, and K. Mackway-Jones Respiratory Dead Space Measurement in the Investigation of Pulmonary Embolism in Outpatients With Pleuritic Chest Pain Chest, October 1, 2005; 128(4): 2195 - 2202. [Abstract] [Full Text] [PDF]

				P Leman, D Guthrie, R Simpson, and F Little Improving access to diagnostics: an evaluation of a satellite laboratory service in the emergency department Emerg. Med. J., July 1, 2004; 21(4): 452 - 456. [Abstract] [Full Text] [PDF]

				F. Verschuren, G. Liistro, R. Coffeng, F. Thys, J. Roeseler, F. Zech, and M. Reynaert Volumetric Capnography as a Screening Test for Pulmonary Embolism in the Emergency Department Chest, March 1, 2004; 125(3): 841 - 850. [Abstract] [Full Text] [PDF]

				M. J.H.A. Kruip, M. G.L. Leclercq, C. v. d. Heul, M. H. Prins, and H. R. Buller Diagnostic Strategies for Excluding Pulmonary Embolism in Clinical Outcome Studies: A Systematic Review Ann Intern Med, June 17, 2003; 138(12): 941 - 951. [Abstract] [Full Text] [PDF]

				C. Kearon Diagnosis of pulmonary embolism Can. Med. Assoc. J., January 21, 2003; 168(2): 183 - 194. [Abstract] [Full Text] [PDF]

				F. Verschuren, F. Thys, and M. Rodger Steady-State End-Tidal Alveolar Dead Space Measure and D-dimer Chest, April 1, 2002; 121(4): 1373 - 1373. [Full Text] [PDF]