Optimum level of propofol sedation indicators for behavior management in uncooperative patients with disabilities: Eye closure, loss of eyelash reflex, and smooth insertion of bite block

We studied the usefulness of "eye closure", "loss of eyelash reflex", and "smooth insertion of bite block" to be considered as the optimum level of propofol sedation indicators for behavior management in uncooperative patients with disabilities. The subjects were 16 patients with Down's syndrome, autism or mental retardation who needed intravenous sedation because of their uncooperativeness in dental treatment. Pure oxygen was given for one minute, and nitrous oxide (N₂O) concentration was increased every other minute in a stepwise fashion by 10% increments. At the 30% concentration level, anesthesia was maintained for seven minutes, and then a tourniquet was applied and venipuncture was performed. After obtaining venous access, infusion of normal saline was started and an infusion of propofol was initiated using a TCI (Target Controlled Infusion) pump at a predicted brain concentration of 3.0 μg/ ml. N₂O was turned off immediately after securing venous access and ventilation was continued with pure oxygen. During the propofol infusion, examination was performed. The estimated brain concentrations of propofol at the time when the three indicators ("eye closure", "loss of eyelash reflex" and "smooth insertion of bite block") appeared were recorded, and the estimated brain concentrations at the time when the three indicators could be confirmed was maintained, while respiratory depression, body motion, etc. of the patients under dental treatment were observed. 1. The lowest concentration was for "eye closure", followed by "loss of eyelash reflex, and the highest concentration required was for "smooth insertion of bite block". 2. By maintaining the estimated brain concentration for "smooth insertion of bite block", dental treatment was completed without any problem in 80% of the cases. This study suggests that "smooth insertion of bite block" can be considered as an effective optimum level indicator of propofol sedation for uncooperative dental patients with disabilities. The depth of sedation level was indicated by "eye closure", "loss of eyelash reflex", and then "smooth bite block insertion (in order of increasing depth)". By inserting the bite block after loss of eyelash reflex, body motions did not occur in 62.5% of the patients. This allows undesirable stimuli to be avoided, and enables dental treatment levels of sedation to be reached smoothly.