Concordance between capnography and capnia in adults admitted for acute dyspnea in an ED.
BACKGROUND
End-tidal carbon dioxide pressure (etCO(2)) is widely used in anaesthesia and critical care in intubated patients. The aim of our preliminary study was to evaluate the feasibility of a simple device to predict capnia in spontaneously breathing patients in an emergency department (ED).


METHODS
This study was a prospective, nonblind study performed in our teaching hospital ED. We included nonintubated patients with dyspnea (> or =18 years) requiring measurement of arterial blood gases, as ordered by the emergency physician in charge. There were no exclusion criteria. End-tidal CO(2) was measured by an easy-to-use device connected to a microstream capnometer, which gave a continuous measurement and graphical display of the etCO(2) level of a patient's exhaled breath.


RESULTS
A total of 43 patients (48 measurements) were included, and the majority had pneumonia (n = 12), acute cardiac failure (n = 8), asthma (n = 7), or chronic obstructive pulmonary disease exacerbation (n = 6). Using simple linear regression, the correlation between etCO(2) and Paco(2) was good (R = 0.82). However, 18 measurements (38%) had a difference between etCO(2) and Paco(2) of 10 mm Hg or more. The mean difference between the Paco(2) and etCO(2) levels was 8 mm Hg. Using the Bland and Altman matrix, the limits of agreement were -10 to +26 mm Hg.


CONCLUSIONS
In our preliminary study, etCO(2) using a microstream method does not seem to accurately predict Paco(2) in patients presenting to an ED for acute dyspnea.
Delerme
Samuel
S
Department of Emergency Medicine and Surgery, Centre Hospitalo-Universitaire Pitié-Salpêtrière, Assistance-Publique Hôpitaux de Paris, 75013 Paris, UPMC- Univ Paris 6, France.
Freund
Yonathan
Y
Renault
Robin
R
Devilliers
Catherine
C
Castro
Samuel
S
Chopin
Sebastien
S
Juillien
Gaelle
G
Riou
Bruno
B
Ray
Patrick
P
D000328:Adult; D000368:Aged; D001784:Blood Gas Analysis; D019296:Capnography / Q000295:instrumentation*; D004417:Dyspnea / Q000097:blood* / Q000209:etiology; D004636:Emergency Service, Hospital; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D006935:Hypercapnia / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D008173:Lung Diseases, Obstructive / Q000097:blood* / Q000150:complications* / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013990:Tidal Volume