D-dimer and exhaled CO2/O2 to detect segmental pulmonary embolism in moderate-risk patients

Jeffrey Kline, Melanie M. Hogg, D. Mark Courtney, Chadwick D. Miller, Alan E. Jones, Howard A. Smithline, Nicole Klekowski, Randy Lanier

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Rationale: Pulmonary embolism (PE) decreases the exhaled end-tidal ratio of carbon dioxide to oxygen (etCO2/O2). Objectives: To test if the etCO2/O2 can produce clinically important changes in the probability of segmental or larger PE on computerized tomography multidetector-row pulmonary angiography (MDCTPA) in a moderate-risk population with a positive D-dimer. Methods: Emergency department and hospitalized patients with one or more predefined symptoms or signs, one or more risk factors for PE, and 64-slice MDCTPA enrolled from four hospitals. D-dimer greater than 499 ng/ml was test(+), and D-dimer less than 500 ng/ml was test(-). The median etCO2/O2 less than 0.28 from seven or more breaths was test(+) and etCO2/O2 greater than 0.45 was test(-). MDCTPA images were read by two independent radiologists and the criterion standard was the interpretation of acute PE by either reader. PE size was then graded. Measurements and Main Results: We enrolled 495 patients, including 60 (12%) with segmental or larger, and 29 (6%) with subsegmental PE. A total of 367 (74%) patients were D-dimer(+), including all 60 with segmental or larger PE (posterior probability 16%). The combination of D-dimer(+) and etCO 2/O2(+) increased the posterior probability of segmental or larger PE to 28% (95% confidence interval [CI] for difference of 12%, 3.0-22%). The combination of D-dimer(+) and etCO2/O2(-) was observed in 40 patients (8%; 95% CI, 6-11%), and none (0/40; 95% CI, 0-9%) had segmental or larger PE on MDCTPA. No strategy changed the prevalence of subsegmental PE. Conclusions: In moderate-risk patients with a positive D-dimer, the et etCO2/O2 less than 0.28 significantly increases the probability of segmental or larger PE and the etCO2/O2 greater than 0.45 predicts the absence of segmental or larger PE on MDCTPA. Clinical trial registered with www.clinicaltrials.gov (NCT 00368836).

Original languageEnglish (US)
Pages (from-to)669-675
Number of pages7
JournalAmerican Journal of Respiratory and Critical Care Medicine
Volume182
Issue number5
DOIs
StatePublished - Sep 1 2010
Externally publishedYes

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Pulmonary Embolism
Angiography
Lung
Confidence Intervals
fibrin fragment D
Breath Tests
Carbon Dioxide
Signs and Symptoms
Hospital Emergency Service
Tomography
Clinical Trials
Oxygen

Keywords

  • Capnography
  • Fibrin fragment D
  • Medical decision making
  • Tomography, spiral computed
  • Venous thromboembolism

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine

Cite this

D-dimer and exhaled CO2/O2 to detect segmental pulmonary embolism in moderate-risk patients. / Kline, Jeffrey; Hogg, Melanie M.; Courtney, D. Mark; Miller, Chadwick D.; Jones, Alan E.; Smithline, Howard A.; Klekowski, Nicole; Lanier, Randy.

In: American Journal of Respiratory and Critical Care Medicine, Vol. 182, No. 5, 01.09.2010, p. 669-675.

Research output: Contribution to journalArticle

Kline, Jeffrey ; Hogg, Melanie M. ; Courtney, D. Mark ; Miller, Chadwick D. ; Jones, Alan E. ; Smithline, Howard A. ; Klekowski, Nicole ; Lanier, Randy. / D-dimer and exhaled CO2/O2 to detect segmental pulmonary embolism in moderate-risk patients. In: American Journal of Respiratory and Critical Care Medicine. 2010 ; Vol. 182, No. 5. pp. 669-675.
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abstract = "Rationale: Pulmonary embolism (PE) decreases the exhaled end-tidal ratio of carbon dioxide to oxygen (etCO2/O2). Objectives: To test if the etCO2/O2 can produce clinically important changes in the probability of segmental or larger PE on computerized tomography multidetector-row pulmonary angiography (MDCTPA) in a moderate-risk population with a positive D-dimer. Methods: Emergency department and hospitalized patients with one or more predefined symptoms or signs, one or more risk factors for PE, and 64-slice MDCTPA enrolled from four hospitals. D-dimer greater than 499 ng/ml was test(+), and D-dimer less than 500 ng/ml was test(-). The median etCO2/O2 less than 0.28 from seven or more breaths was test(+) and etCO2/O2 greater than 0.45 was test(-). MDCTPA images were read by two independent radiologists and the criterion standard was the interpretation of acute PE by either reader. PE size was then graded. Measurements and Main Results: We enrolled 495 patients, including 60 (12{\%}) with segmental or larger, and 29 (6{\%}) with subsegmental PE. A total of 367 (74{\%}) patients were D-dimer(+), including all 60 with segmental or larger PE (posterior probability 16{\%}). The combination of D-dimer(+) and etCO 2/O2(+) increased the posterior probability of segmental or larger PE to 28{\%} (95{\%} confidence interval [CI] for difference of 12{\%}, 3.0-22{\%}). The combination of D-dimer(+) and etCO2/O2(-) was observed in 40 patients (8{\%}; 95{\%} CI, 6-11{\%}), and none (0/40; 95{\%} CI, 0-9{\%}) had segmental or larger PE on MDCTPA. No strategy changed the prevalence of subsegmental PE. Conclusions: In moderate-risk patients with a positive D-dimer, the et etCO2/O2 less than 0.28 significantly increases the probability of segmental or larger PE and the etCO2/O2 greater than 0.45 predicts the absence of segmental or larger PE on MDCTPA. Clinical trial registered with www.clinicaltrials.gov (NCT 00368836).",
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AU - Kline, Jeffrey

AU - Hogg, Melanie M.

AU - Courtney, D. Mark

AU - Miller, Chadwick D.

AU - Jones, Alan E.

AU - Smithline, Howard A.

AU - Klekowski, Nicole

AU - Lanier, Randy

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N2 - Rationale: Pulmonary embolism (PE) decreases the exhaled end-tidal ratio of carbon dioxide to oxygen (etCO2/O2). Objectives: To test if the etCO2/O2 can produce clinically important changes in the probability of segmental or larger PE on computerized tomography multidetector-row pulmonary angiography (MDCTPA) in a moderate-risk population with a positive D-dimer. Methods: Emergency department and hospitalized patients with one or more predefined symptoms or signs, one or more risk factors for PE, and 64-slice MDCTPA enrolled from four hospitals. D-dimer greater than 499 ng/ml was test(+), and D-dimer less than 500 ng/ml was test(-). The median etCO2/O2 less than 0.28 from seven or more breaths was test(+) and etCO2/O2 greater than 0.45 was test(-). MDCTPA images were read by two independent radiologists and the criterion standard was the interpretation of acute PE by either reader. PE size was then graded. Measurements and Main Results: We enrolled 495 patients, including 60 (12%) with segmental or larger, and 29 (6%) with subsegmental PE. A total of 367 (74%) patients were D-dimer(+), including all 60 with segmental or larger PE (posterior probability 16%). The combination of D-dimer(+) and etCO 2/O2(+) increased the posterior probability of segmental or larger PE to 28% (95% confidence interval [CI] for difference of 12%, 3.0-22%). The combination of D-dimer(+) and etCO2/O2(-) was observed in 40 patients (8%; 95% CI, 6-11%), and none (0/40; 95% CI, 0-9%) had segmental or larger PE on MDCTPA. No strategy changed the prevalence of subsegmental PE. Conclusions: In moderate-risk patients with a positive D-dimer, the et etCO2/O2 less than 0.28 significantly increases the probability of segmental or larger PE and the etCO2/O2 greater than 0.45 predicts the absence of segmental or larger PE on MDCTPA. Clinical trial registered with www.clinicaltrials.gov (NCT 00368836).

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KW - Capnography

KW - Fibrin fragment D

KW - Medical decision making

KW - Tomography, spiral computed

KW - Venous thromboembolism

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