Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access
Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc
Journal website http://www.jocmr.org

Original Article

Volume 11, Number 10, October 2019, pages 696-702


Is Bedside End-Tidal CO2 Measurement a Screening Tool to Exclude Pulmonary Embolism in Emergency Department?

Figures

Figure 1.
Figure 1. Comparison of ETCO2, D-dimer and Wells scores of the PE and non-PE groups. ETCO2: end-tidal carbon dioxide; PE: pulmonary embolism.
Figure 2.
Figure 2. ROC analyses for ETCO2, Wells score, and D-dimer level for diagnosing PE. PE: pulmonary embolism; ETCO2: end-tidal carbon dioxide; ROC: receiver operating characteristic.

Tables

Table 1. Clinical and Demographical Characteristics of Patients
 
PE, mean ± SD/n (%)Non-PE, mean ± SD/n (%)P
PE: pulmonary embolism; HT: hypertension; DM: diabetes mellitus; CAD: coronary artery disease; CHF: chronic heart failure; DVT: deep vein thrombosis; CVA: cerebrovascular accident.
Age66.3 ± 18.666 ± 14.90.920
Female32 (64)22 (44)0.045
Male18 (36)28 (56)
Comorbidity
  HT29 (58)23 (460)0.230
  DM16 (32)13 (26)0.509
  CAD10 (20)13 (26)0.476
  CHF10 (20)8 (16)0.603
  DVT11 (22)6 (12)0.183
  Malignancy7 (14)9 (18)0.585
  CVA6 (12)2 (4)0.269
Admission symptom
  Dyspnea25 (50)28 (56)0.224
  Chest pain22 (44)18 (36)
  Hemoptysis2 (4)0
  Palpitation1 (2)4 (8)
Intubation status
  Yes02 (4)0.153
  No50 (100)48 (96)
Blood pressure
  Hypertensive8 (16)4 (8)0.062
  Normotensive38 (76)34 (68)
  Hypotensive4 (8)12 (24)
Pulse rate
  > 1208 (16)14 (28)0.350
  100 - 12029 (58)25 (50)
  < 10013 (26)11 (22)
Respiratory rate
  > 2022 (44)29 (58)0.359
  12 - 2026 (52)19 (38)
  < 122 (4)2 (4)
Body temperature
  Hyperthermia10 (20)4 (8)0.084
  Normothermia40 (80)46 (92)
Blood gas analysis
  pH7.41 ± 0.087.42 ± 0.070.448
  pO262.15 ± 10.4967.85 ± 10.200.007
  pCO233.46 ± 6.2232.70 ± 6.850.559
  HCO320.65 ± 3.6521.43 ± 3.880.308
Outcome
  Admitted20 (40)50 (100)< 0.001
  Discharged30 (60)0

 

Table 2. Assessment of the Wells Score
 
Wells risk scoreCT angiographyP
PE, n (%)Non-PE, n (%)
PE: pulmonary embolism; CT: computed tomography.
< 2 (low risk)9 (18)23 (46)> 0.001
2 - 6 (moderate risk)31 (62)27 (54)> 0.001
≥ 7 (high risk)10 (20)0< 0.001

 

Table 3. ETCO2 and D-Dimer Levels
 
PE, median (IQR)Non-PE, median (IQR)P
ETCO2: end-tidal carbon dioxide; PE: pulmonary embolism; IQR: interquartile range.
ETCO221 (4)28.5 (6)< 0.001
D-dimer2,091 (2,332)850.5 (1,152)< 0.001

 

Table 4. Comparison of the Sensitivities, Specificities, PPVs, and NPVs of ETCO2, Wells Score, and D-Dimer Level for Diagnosing PE
 
AreaCut-offSensitivitySpecificityPPVNPV
PE: pulmonary embolism; ETCO2: end-tidal carbon dioxide; PPV: positive predictive value; NPV: negative predictive value.
ETCO20.90134 mm Hg100%8%52.1%100%
D-dimer0.730500 ng/mL100%18%54.9%100%
Wells score0.777480%46%59.7%69.7%

 

Table 5. Logistic Regression Analysis for PE
 
BSEPOdds ratio95% CI for odds ratio
LowerUpper
PE: pulmonary embolism; ETCO2: end-tidal carbon dioxide; SE: standard error; CI: confidence interval.
Age-0.0180.0240.4580.9820.9371.030
Sex0.4870.7100.4931.6270.4056.545
pH4.3237.2490.55175.4330.000111,697,648.876
pO2-0.0860.0420.0370.9170.8450.995
pCO20.0360.0910.6921.0370.8681.238
HCO3-0.0480.1330.7170.9530.7351.236
D-dimer0.0000.0000.0921.0001.0001.001
Wells2.0270.7200.0057.5891.85031.135
ETCO2-0.5190.1130.0000.5950.4770.743
Constat-17.01754.4480.7550.000