Concordance between transcutaneous and arterial measurements of carbon dioxide in an ED.
BACKGROUND
Transcutaneous carbon dioxide pressure (PtcCO(2)) has been suggested as a noninvasive surrogate of arterial carbon dioxide pressure (PaCO(2)). Our study evaluates the reliability of this method in spontaneously breathing patients in an emergency department.


METHODS
A prospective, observational study was performed in nonintubated dyspneic patients who required measurement of arterial blood gases. Simultaneously and blindly to the physicians in charge, PtcCO(2) was measured using a TOSCA 500 monitor (Radiometer, Villeurbanne, France). Agreement between PaCO(2) and PtcCO(2) was assessed using the Bland-Altman method.


RESULTS
Forty-eight patients (mean age, 65 years) were included, and 50 measurements were done. Eleven (23%) had acute heart failure; 10 (21%), pneumonia; 7 (15%), acute asthma; and 7 (15%), exacerbation of chronic obstructive pulmonary disease. Median PaCO(2) was 42 mm Hg (range, 17-109). Mean difference between PaCO(2) and PtcCO(2) was 1 mm Hg with 95% limits of agreement of -3.4 to +5.6 mm Hg. All measurement differences were within 5 mm Hg, and 32 (64%) were within 2 mm Hg.


CONCLUSIONS
Transcutaneous carbon dioxide pressure accurately predicts PaCO(2) in spontaneously breathing patients.
Department of Emergency Medicine and Surgery, Centre Hospitalo-Universitaire Pitié-Salpêtrière, Assistance-Publique Hôpitaux de Paris, 47-83 boulevard de l'hôpital, 75013 Paris, France. samuel.delerme@psl.aphp.fr
Samuel
S
Delerme
Viviane
V
Montout
Hélène
H
Goulet
Amandine
A
Arhan
Frederic
F
Le Saché
Catherine
C
Devilliers
Bruno
B
Riou
Patrick
P
Ray
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001158:Arteries; D001785:Blood Gas Monitoring, Transcutaneous; D002245:Carbon Dioxide / Q000097:blood*; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010313:Partial Pressure; D011446:Prospective Studies; D055815:Young Adult
D002245:Carbon Dioxide