Utility of capnography in predicting venous carbon dioxide partial pressure in sedated patients during outpatient oral surgery.

Twelve ASA class I patients scheduled for removal of third molars under intravenous sedation were included in the study. Samples for venous blood gas analysis were drawn every 5 minutes and the venous partial pressure of carbon dioxide was compared to the end-tidal CO2 recorded from a modified nasal cannula at the same time the samples were drawn. Correlation analysis was performed using the Pearson correlation coefficient. The overall correlation between end-tidal CO2 and PVCO2 was .54 (P = .0001). The results of the investigation indicate that through simple modifications of the end-tidal CO2 monitoring device, the correlation between end-tidal CO2 and serum PCO2 in a nonintubated patient can be improved.