We read the article by Nooh et al. entitled “Intranasal atomized dexmedetomidine for sedation during third molar extraction” with great interest. We performed a similar experiment with intranasal dexmedetomidine administration, but came across the above published paper only at the time of submitting our results. We think the study was very well designed. However, we would like to elaborate on some areas.
The authors described that the sedation status was assessed by a blinded observer using a modified Observer’s Assessment of Alertness/Sedation (OAA/S) scale and the bispectral index (BIS) every 10 min throughout the study. Fig. 2 in the results section of the paper shows that the sedation values (BIS) decreased continuously from 20 min, returning to placebo levels at 70 min after intranasal dexmedetomidine administration. However, that figure could cause considerable confusion to the reader. The BIS reflects both the EEG (electroencephalography) and EMG (electromyography) response from external stimuli and is therefore very effective in evaluating the patient’s degree of sedation and pain. It can be affected by self-directed wide opening of the mouth or movement of the face (especially the facial muscles). This being the case, we have concerns regarding the stationary BIS during strong stimuli that require the patient’s cooperation such as occur in third molar extraction and injection for local anaesthetic infiltration. In our experiment, the BIS was recorded continuously every 1 min; the BIS increased abruptly and transiently twice: immediately after local anaesthetic infiltration and during third molar extraction ( Fig. 1 ). Dexmedetomidine provided sedation that could be reversed easily with verbal or physical stimuli, as shown in Fig. 1 . Except for these two moments, the overall sedation level with dexmedetomidine was stable.