Setting: The study was conducted in a tertiary-care hospital with 36,000 annual ED visits.
Type of participants: Twenty-seven patients requiring sedation with benzediazepines and/or narcotics for painful procedures.
Interventions: The ventilatory status of each patient was monitored with a capnemeter by nasal cannula as well as a pulse oximeter before, during, and after administration of the sedative agents.
Measurements: Vital signs, nasal end-tidal CO 2 (PETC02) measurements, and oxygen saturation were measured at baseline, during the procedure, and for a two-hour observation period after the procedure.
Main results: The average PETC02 increased from 35.9 to 42.1 mm Hg during the procedure while the oxygen saturation dropped from an average of 98% to 94.3%. One patient developed clinically significant apnea after the procedure that was picked up by the apnea alarm, and eight additional patients developed clinically silent hypoxemia and increased PETC02 during the procedure.
Conclusion:
The use of pulse oximetry is recommended for the detection of unrecognized hypoxemia during conscious sedation. Capnography by nasal cannula appears to be a useful modality in monitoring during conscious sedation, but further research and clinical experience are required before routine use can be recommended.
[Wright SW: Conscious sedation in the emergency department: The value of capnography and pulse oximetry.