An interesting article titled “A Prospective, Randomized Controlled Trial of Conscious Sedation Using Propofol Combined With Inhaled Nitrous Oxide for Dental Treatment” written by Chizuko Yokoe and et al. appears in the 2015 Journal of Oral and Maxilofacial Surgery (issue 73, pp. 402-409). The article discusses how propofol is one of the most common sedative agents used during dental procedures. However, when used by itself it can lead to adverse complications in patients. The authors set to explore if you can safely combine nitrous oxide with propofol for dental procedures and also improve the quality of the sedation.
A total of 90 patients in Osaka, Japan were used in this study. All patients were between 20 and 70 years of age and were not able to undergo their procedure without the use of sedation. After the patients were seated in a dental chair, the electrocardiogram, blood pressure, heart rate, and SpO2 were monitored. A nasal cannulas were used to deliver nitrous oxide. A peripheral 22-gauge catheter was inserted into a dorsal hand vein to allow for propofol to be infused. Patients were blinded and grouped into a group receiving sedation with nitrous oxide inhalation and propofol or a group receiving sedation with propofol alone.
The dental procedure was started once the patient had a lethargic response to hearing their name. During the procedure propofols target concentration was adjusted as needed to maintain this level. Only two patients had complications. The total amount and mean concentration of propofol was significantly less in the group that received the combined nitrous oxide and propofol than in the group with just propofol. The pain associated with the propofol injection and memory of the dental procedure were less in the group that received the combined nitrous oxide and propofol. Even so, no differences were observed between the 2 groups in the proportion of patients who had postoperative nausea, drowsiness, or dizziness.
The authors state
“we found that administration of nitrous oxide combined with propofol sedation attenuated the hypotensive effect of propofol and the frequency of pain associated with the propofol injection. In addition, the combination potentiated the amnesic effect during the dental treatments.”
There are 2 possible reasons for the attenuation of the hypotensive response by nitrous oxide. First, nitrous oxide may have reduced the amount of propofol necessary to achieve equivalent sedation levels. Second, nitrous oxide has a sympathomimetic effect, which may be effective in reducing hypotension. The authors feel that using nitrous oxide with propofol is useful and may contributed to sedation quality.