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Wallis MC, Wilson MD, Mete M, Koroshetz L, Soares R, Goyal M. Bedside End-tidal Carbon Dioxide in Evaluation for Pulmonary Embolism. Acad Emerg Med 2019; 26:263-266. [PMID: 30084149 DOI: 10.1111/acem.13546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Marianne C. Wallis
- Emergency Department Medstar Washington Hospital Center Georgetown University School of Medicine Washington DC
| | - Matthew D. Wilson
- Emergency Department Medstar Washington Hospital Center Georgetown University School of Medicine Washington DC
| | - Mihriye Mete
- Epidemiology and Biostatistics Medstar Research Institute Hyattsville MD
| | | | - Rui Soares
- Georgetown University School of Medicine Washington DC
| | - Munish Goyal
- Emergency Department Medstar Washington Hospital Center Georgetown University School of Medicine Washington DC
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Jarenbäck L, Tufvesson E, Ankerst J, Bjermer L, Jonson B. The Efficiency Index (EFFi), based on volumetric capnography, may allow for simple diagnosis and grading of COPD. Int J Chron Obstruct Pulmon Dis 2018; 13:2033-2039. [PMID: 29988757 PMCID: PMC6029593 DOI: 10.2147/copd.s161345] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background Spirometry, the main tool for diagnosis and follow-up of COPD, incompletely describes the disease. Based on volumetric capnography (VCap), an index was developed for the diagnosis and grading of COPD, aimed as a complement or alternative to spirometry. Methods Nine non-smokers, 10 smokers/former smokers without COPD and 54 smokers/former smokers with COPD were included in the study. Multiple breath washout of N2 and VCap were studied with Exhalyzer D during tidal breathing. VCap was based on signals for flow rate and CO2 and was recorded during one breath preceding N2 washout. Efficiency Index (EFFi) is the quotient between exhaled CO2 volume and the hypothetical CO2 volume exhaled from a completely homogeneous lung over a volume interval equal to 15% of predicted total lung capacity. Results EFFi increased with increased Global initiative for chronic Obstructive Lung Disease (GOLD) stage and the majority of subjects in GOLD 2 and all subjects in GOLD 3 and 4 could be diagnosed as having COPD using the lower 95% confidence interval of the healthy group. EFFi also correlated with N2 washout (r=−0.73; p<0.001), forced expiratory volume in 1 second (r=0.70; p<0.001) and diffusion capacity for carbon oxide (r=0.69; p<0.001). Conclusion EFFi measures efficiency of tidal CO2 elimination that is limited by inhomogeneity of peripheral lung function. EFFi allows diagnosis and grading of COPD and, together with FEV1, may explain limitation of physical performance. EFFi offers a simple, effortless and cost-effective complement to spirometry and might serve as an alternative in certain situations.
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Affiliation(s)
- Linnea Jarenbäck
- Respiratory Medicine and Allergology, Department of Clinical Sciences, Skåne University Hospital, Lund University, Lund, Sweden,
| | - Ellen Tufvesson
- Respiratory Medicine and Allergology, Department of Clinical Sciences, Skåne University Hospital, Lund University, Lund, Sweden,
| | - Jaro Ankerst
- Respiratory Medicine and Allergology, Department of Clinical Sciences, Skåne University Hospital, Lund University, Lund, Sweden,
| | - Leif Bjermer
- Respiratory Medicine and Allergology, Department of Clinical Sciences, Skåne University Hospital, Lund University, Lund, Sweden,
| | - Björn Jonson
- Clinical Physiology, Department of Clinical Sciences, Skåne University Hospital, Lund University, Lund, Sweden
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Nassar BS, Schmidt GA. Capnography During Critical Illness. Chest 2016; 149:576-585. [DOI: 10.1378/chest.15-1369] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 09/15/2015] [Accepted: 09/16/2015] [Indexed: 11/01/2022] Open
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Mosing M, Iff I, Hirt R, Moens Y, Tusman G. Evaluation of variables to describe the shape of volumetric capnography curves during bronchoconstriction in dogs. Res Vet Sci 2012; 93:386-92. [DOI: 10.1016/j.rvsc.2011.05.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 03/29/2011] [Accepted: 05/17/2011] [Indexed: 10/18/2022]
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Verschuren F, Sanchez O, Righini M, Heinonen E, Le Gal G, Meyer G, Perrier A, Thys F. Volumetric or time-based capnography for excluding pulmonary embolism in outpatients? J Thromb Haemost 2010; 8:60-7. [PMID: 19874457 DOI: 10.1111/j.1538-7836.2009.03667.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Volumetric capnography is technically more demanding but theoretically better than the time-based alveolar deadspace fraction (P(a)CO(2) - EtCO(2))/P(a)CO(2) as a bedside diagnostic tool for excluding pulmonary embolism (PE) in outpatients. OBJECTIVE We compared both diagnostic accuracy in patients with a suspected PE and positive D-dimer enzyme-linked immunosorbent assay results. PATIENTS AND METHODS In this clinical multicenter trial with prospective inclusion and 3-month follow-up, alveolar deadspace fraction was compared by receiver operating characteristic (ROC) analysis with other parameters derived from volumetric capnography. RESULTS Capnography was performed in 239 patients, and 205 tests (86%) were conclusive. The incidence of PE was 33%. The alveolar deadspace fraction accuracy expressed with ROC curve analysis was 0.73 +/- 0.04. The diagnostic performances of parameters from volumetric capnography were not significantly better. Sixteen per cent [95% confidence interval (CI) 12-21%] of patients presented a (P(a)CO(2) - EtCO(2))/P(a)CO(2) ratio under the cut-off value of 0.15, with a low clinical probability. This combination excluded PE, with a sensitivity of 96% (95% CI 89-99%) and a negative likelihood ratio of 0.17 (95% CI 0.09-0.33%). CONCLUSION Volumetric capnography failed to show superiority to alveolar deadspace fraction measurements [(P(a)CO(2) - EtCO(2))/P(a)CO(2)] for exclusion of PE in outpatients with positive D-dimer test results. Future studies should clarify the safety of excluding PE in patients combining low clinical probability with positive D-dimer results and (P(a)CO(2) - EtCO(2))/P(a)CO(2) ratios below the cut-off value of 0.15.
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Affiliation(s)
- F Verschuren
- Université catholique de Louvain, Cliniques universitaires Saint-Luc, Acute Medicine Department, Accidents and Emergency Unit, Brussels, Belgium.
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Tang Y, Turner MJ, Baker AB. Effects of alveolar dead-space, shunt andV˙/Q˙distribution on respiratory dead-space measurements. Br J Anaesth 2005; 95:538-48. [PMID: 16126784 DOI: 10.1093/bja/aei212] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Respiratory dead-space is often increased in lung disease. This study evaluates the effects of increased alveolar dead-space (Vd(alv)), pulmonary shunt, and abnormal ventilation perfusion ratio (/) distributions on dead-space and alveolar partial pressure of carbon dioxide (Pa(co(2))) calculated by various methods, assesses a recently published non-invasive method (Koulouris method) for the measurement of Bohr dead-space, and evaluates an equation for calculating physiological dead-space (Vd(phys)) in the presence of pulmonary shunt. METHODS Pulmonary shunt, / distribution and Vd(alv) were varied in a tidally breathing cardiorespiratory model. Respiratory data generated by the model were analysed to calculate dead-spaces by the Fowler, Bohr, Bohr-Enghoff and Koulouris methods. Pa(co(2)) was calculated by the method of Koulouris. RESULTS When Vd(alv) is increased, Vd(phys) can be recovered by the Bohr and Bohr-Enghoff equations, but not by the Koulouris method. Shunt increases the calculated Bohr-Enghoff dead-space, but does not affect Fowler, Bohr or Koulouris dead-spaces, or Vd(phys) estimated by the shunt-corrected equation if pulmonary artery catheterization is available. Bohr-Enghoff but not Koulouris or Fowler dead-space increases with increasing severity of / maldistribution. When alveolar Pco(2) is increased by any mechanism, Pa(co(2)) calculated by Koulouris' method does not agree well with average alveolar Pco(2). CONCLUSIONS Our studies show that increased pulmonary shunt causes an apparent increase in Vd(phys), and that abnormal / distributions affect the calculated Vd(phys) and Vd(alv), but not Fowler dead-space. Dead-space and Pa(co(2)) calculated by the Koulouris method do not represent true Bohr dead-space and Pa(co(2)) respectively, but the shunt-corrected equation performs well.
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Affiliation(s)
- Y Tang
- Department of Anaesthetics, University of Sydney, Royal Prince Alfred Hospital, NSW, Australia
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Verschuren F, Heinonen E, Clause D, Roeseler J, Thys F, Meert P, Marion E, El Gariani A, Col J, Reynaert M, Liistro G. Volumetric capnography as a bedside monitoring of thrombolysis in major pulmonary embolism. Intensive Care Med 2004; 30:2129-32. [PMID: 15378240 DOI: 10.1007/s00134-004-2444-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2004] [Accepted: 08/24/2004] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To describe the use of volumetric capnography, a plot of expired CO(2) concentration against expired volume, in monitoring fibrinolytic treatment of major pulmonary embolism. DESIGN AND SETTING Two case reports in the emergency department of a teaching hospital. PATIENTS Two conscious and spontaneously breathing patients (69- and 31-year-old women) with major pulmonary embolism requiring thrombolysis. Decision for thrombolysis was based on the association of right ventricular afterload on echocardiography, with respiratory failure and hypotension in the first patient, and dyspnea and hemodynamically stable parameters in the second one. INTERVENTIONS Successive capnographic measurements were performed before, during, and after thrombolysis. Curves of volumetric capnography were obtained from a sidestream gas monitor with flow sensor and an arterial blood gas analysis for CO(2) partial pressure. MEASUREMENTS AND RESULTS We calculated late deadspace fraction, previously suggested as the most effective capnographic parameter in the diagnosis of pulmonary embolism. Late deadspace fraction decreased in the two patients, respectively, from 64.4% to 1.1% and from 25.6% to 5.7% after thrombolysis, with a concomitant disappearance of right heart dysfunction signs on echocardiography. CONCLUSIONS Volumetric capnography can monitor thrombolysis in major pulmonary embolism. Differences between volumetric capnography technology and the more traditional arterial to end-tidal CO(2) gradient are important to take into account for clinical application.
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Affiliation(s)
- Franck Verschuren
- Emergency and Intensive Care Department, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Avenue Hippocrate 10, 1200 Brussels, Belgium.
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Verschuren F, Liistro G, Coffeng R, Thys F, Roeseler J, Zech F, Reynaert M. Volumetric Capnography as a Screening Test for Pulmonary Embolism in the Emergency Department. Chest 2004; 125:841-50. [PMID: 15006940 DOI: 10.1378/chest.125.3.841] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
STUDY OBJECTIVE To compare the diagnostic performance of volumetric capnography (VCap), which is the plot of the expired CO(2) partial pressure against the expired volume during a single breath, with the PaCO(2) to end-tidal CO(2) (EtCO(2)) gradient, in the case of suspected pulmonary embolism (PE). DESIGN Single-center, prospective study. SETTING Emergency department of a teaching hospital. PATIENTS A total of 45 outpatients with positive enzyme-linked immunosorbent assay d-dimer levels of > 500 ng/mL. The diagnosis of PE was confirmed in 18 outpatients according to a validated procedure based on the ventilation-perfusion lung scan and/or spiral CT scanning. INTERVENTIONS Curves of VCap were obtained from a compact monitor connected to a computer. A sequence of four to six stable breaths allowed the calculation of the following several variables: alveolar dead space fraction; the ratio of alveolar dead space (VDalv) to airway dead space (VDaw); the VDalv to physiologic dead space (VDphys) fraction; the slope of phase 3; and the late dead space fraction (Fdlate) corresponding to the extrapolation of the capnographic curve to a volume of 15% of the predicted total lung capacity. RESULTS The mean (+/- SD) PaCO(2)-EtCO(2) gradient was 5.3 +/- 0.7 mm Hg in the PE-positive group and 2.8 +/- 0.7 mm Hg in the PE-negative group (p = 0.019). Four variables of the VCap exhibited a statistical difference between both groups, as follows: the VDalv/VDaw fraction(;) the slope of phase 3; the VDalv/VDphys fraction; and the Fdlate, which was 8.2 +/- 3.3% vs -7.7 +/- 2.8%, respectively (p = 0.000011). The diagnostic performance expressed as the mean area under a receiver operating characteristic curve comparison was 75.9 +/- 7.4% for the PaCO(2)-EtCO(2) gradient and 87.6 +/- 4.9% for the Fdlate (p = 0.02). CONCLUSION Fdlate, a variable of VCap, had a statistically better diagnostic performance in suspected PE than the PaCO(2)-EtCO(2) gradient. VCap is a promising computer-assisted bedside application of pulmonary pathophysiology. Future research should define the place of this technique in the diagnostic workup of PE, especially in the presence of positive d-dimers.
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Affiliation(s)
- Franck Verschuren
- Department of Emergency and Intensive Care, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Bruxelles, Belgium.
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Volumetric Capnography in the Non-intubated Critically Ill Patient. Intensive Care Med 2002. [DOI: 10.1007/978-1-4757-5551-0_51] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Kline JA, Kubin AK, Patel MM, Easton EJ, Seupal RA. Alveolar dead space as a predictor of severity of pulmonary embolism. Acad Emerg Med 2000; 7:611-7. [PMID: 10905639 DOI: 10.1111/j.1553-2712.2000.tb02033.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To determine whether the alveolar dead space volume (V(D)alv), expressed as a percentage of the alveolar tidal volume (V(D)alv/V(T)alv), can predict the degree of vascular occlusion caused by pulmonary embolism (PE). METHODS Fifty-three subjects with suspected PE were prospectively studied. Pulmonary embolism was diagnosed in 33 by high-probability ventilation/perfusion (V/Q) scan (n = 19) or by pulmonary arteriography (PAG, n = 14). Pulmonary embolism was excluded by PAG in 20 subjects. The V(D)alv/V(T)alv was determined from volumetric capnography and arterial blood gas analysis, which permits measurement of the physiologic dead space, V(D)phys (mL) = [(PaCO2 - PeCO2)/PaCO2]. tidal volume. Airway dead space (V(D)aw) was subtracted to yield the alveolar dead space [(V(D)phys - V(D)aw) = V(D)alv (mL)]; the percentage of alveolar volume occupied by alveolar dead space per breath = V(D)alv/V(T)alv x 100%. Percentage perfusion defect was determined from V/Q scans by a radiologist blinded to other data. Regression analysis was performed to show correlation between V(D)alv/V(T)alv and defect on V/Q scan or systolic pulmonary arterial pressure (SPAP). RESULTS For subjects with PE, the mean perfusion defect on lung scan was 38 +/- 22%; the mean V(D)alv = 208 +/- 115 mL, V(T)alv = 452 +/- 251 mL, and V(D)alv/V(T)alv = 43 +/- 18%. Regression of V(D)alv/V(T)alv vs perfusion defect yielded r2 = 0.41. Regression of V(D)alv/V(T)alv vs pulmonary artery pressures yielded r2 = 0.59. For subjects without PE, V(D)alv/V(T)alv = 27 +/- 14% and V(D)alv = 89 +/- 66 mL. CONCLUSIONS The V(D)alv/V(T)alv correlates with the lung perfusion defect and the pulmonary artery pressures in subjects with PE. These findings show the potential for V(D)alv/V(T)alv to quantify the embolic burden of PE.
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Affiliation(s)
- J A Kline
- Department of Emergency Medicine, Carolinas Medical Center, Charlotte, NC 28203, USA.
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Abstract
In 1990, the multicenter Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED), sponsored by the National Institutes of Health, compared the diagnostic value of the radioisotopic ventilation-perfusion lung scan (V/Q scan) with that of pulmonary angiography for the diagnosis of pulmonary embolism (PE). Despite the endurance of the radioisotopic V/Q scan as the most widely used test for evaluation of pulmonary embolism (PE), a better screening tool is clearly needed for use in the emergency department. During the past decade, several new modalities have emerged for evaluation of patients with suspected PE. We evaluate the diagnostic utility of the D-dimer test and the alveolar dead space determination as potential screening tests and of spiral computed tomography, magnetic resonance imaging, transthoracic echocardiography, and transesophageal echocardiography as potential confirmatory tests for PE. For comparison, recent data on the diagnostic utility of the alveolar-arterial oxygen gradient and the V/Q scan are included. The potential application of these new tests to a hypothetical ED population is described.
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Affiliation(s)
- J A Kline
- Department of Emergency Medicine, Carolinas Medical Center, Charlotte, NC 28232-2861, USA.
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Patel MM, Rayburn DB, Browning JA, Kline JA. Neural network analysis of the volumetric capnogram to detect pulmonary embolism. Chest 1999; 116:1325-32. [PMID: 10559095 DOI: 10.1378/chest.116.5.1325] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Pulmonary embolism (PE) produces ventilation/perfusion mismatch that may be manifested in various variables of the volume-based capnogram (VBC). We hypothesized that a neural network (NN) system could detect changes in VBC variables that reflect the presence of a PE. METHODS A commercial VBC system was used to record multiple respiratory variables from consecutive expiratory breaths. Data from 12 subjects (n = 6 PE+ and n = 6 PE-) were used as input to a fully connected back-propagating NN for model development. The derived model was tested in a prospective, observational study at an urban teaching hospital. Volumetric capnograms were then collected on 53 test subjects: 30 subjects with PE confirmed by pulmonary angiography or diagnostic scintillation lung scan, and 23 subjects without PE based on pulmonary angiography. The derived NN model was applied to VBC data from the test population. RESULTS Seventeen VBC variables were used by the derived NN model to generate a numeric probability of PE. When the derived NN model was applied to VBC data from the 53 test subjects, PE was detected with a sensitivity of 100% (95% CI = 89% to 100%) and a specificity of 48% (95% CI = 27% to 69%). The likelihood ratio positive [LR(+)] for the VBC-NN test was 1.82 and the LR (-) was 0.1. CONCLUSION This study demonstrates the feasibility of developing a rapid, noninvasive breath test for diagnosing PE using volumetric capnography and NN analysis.
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Affiliation(s)
- M M Patel
- Department of Emergency Medicine, Carolinas Medical Center, Charlotte, NC 28232, USA
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