Lung cancer pulse oximetry and capnography in lung function laboratories.
OBJECTIVE
To compare values reflecting oxyhemoglobin saturation obtained by pulse oximetry (SpO2) and values for end-tidal carbon dioxide pressure (PETCO2) obtained by capnography with direct measures of gas saturation values and pressures (PaO2 and PaCO2) in arterial blood gas samples.


METHODS
We studied 57 consecutive patients ranging in age from 34 to 83 years--16 of whom were smokers--who presented for lung function testing.


RESULTS
The mean (SD) SpO2 was 95% (2.4%), and oxygen saturation measured directly in arterial blood samples was 95.1% (2.3%) (P=NS). The mean PETCO2 was 37.9 (5.3) mm Hg and PaCO2 by arterial blood gas analysis was 40.6 (5.4) mm Hg (P<.0001). The correlation between the 2 measurements of oxygen saturation (SpO2 and direct assessment) was 0.806 (P<.0001), and the correlation between PETCO2 and PaCO2 was 0.845 (P<.0001). The mean difference between the 2 expressions of oxygen saturation was 0.08% (1.46%) and between PETCO2 and PaCO2 was 2.7 (2.9) mm Hg.


CONCLUSIONS
Both measurement devices (pulse oximeter and capnograph) are appropriate for use in a lung function laboratory. The difference between PETCO2 and the PaCO2 should be kept in mind.
Giner
J
J
Unitat de Funció Pulmonar, Departament de Pneumologia, Hospital de la Santa Creu i de Sant Pau, Facultat de Medicina, Universitat Autònoma de Barcelona, Avda. Antoni M. Claret 167, 08025 Barcelona, Spain. jginer@hsp.santpau.es
Casan
P
P
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019296:Capnography; D006801:Humans; D007753:Laboratories; D008175:Lung Neoplasms / Q000097:blood / Q000378:metabolism* / Q000503:physiopathology*; D008875:Middle Aged; D010092:Oximetry; D010108:Oxyhemoglobins / Q000032:analysis
D010108:Oxyhemoglobins