Analgesic and physiological effects in conscious sedation with different nitrous oxide concentrations

OBJECTIVES to study the physiological changes, as well as the psychosedative and analgesic effects of nitrous oxide, in experimental conditions. STUDY DESIGN 101 dental students volunteers participated in a single nitrous oxide sedation session without dental treatment. Signs and symptoms were registered during and after the procedure. Pulse rate and hemoglobin oxygen saturation were monitored at: 100 per cent O2, 30 per cent N2O, 50 per cent N2O and 5 minutes after 100 per cent O2. A Likert scale was used to evaluate pain perception. The analgesic effects of nitrous oxide were evaluated at: 30 per cent N2O, 50 per cent N2O, and five minutes postoperatively. RESULTS Pulse rate and hemoglobin oxygen saturation decreased significantly through all the procedure and after recovery. However, oxygen saturation recovered after the final oxygenation. Only 8.2% of subjects reported the pain stimulus as being quite annoying when they inhaled 30 per cent N2O, while this percentage was of 15.8 % when inhaling 50 per cent N2O, and of 32.7 % during the recovery period. The most common effects of nitrous oxide sedation were bright eyes (99%), voice change (98%) and smiling (91%). Most of the subjects reported tingling (98%) and relax (91.1%) CONCLUSIONS nitrous oxide causes a significant decrease in heart rate and oxygen saturation, but always within safety limits. Maintaining an appropriate level of consciousness was confirmed as a feature in 50 per cent dose in this study. The analgesic effect of nitrous oxide was confirmed but a dose dependency could not be established. Key words:Nitrous oxide, conscious sedation, anxiolysis, safety, physiogical parameters, signs, symptoms, analgesia.