Effects site concentrations of propofol using target-controlled infusion in dental treatment under deep sedation among different intellectual disability types

BACKGROUND: We aimed to assess the dose needed to achieve the propofol effect-site concentration using target-controlled infusion in intellectually disabled patients and to detail the most effective method for achieving a safe level of consciousness without hemodynamic changes as well as detail any resulting adverse effects. METHODS: We performed a retrospective review of sedation service records of 138 intellectually disabled patients (51, mental retardation; 36, autism; 30, brain lesion, 12 genetic diseases, 9 dementia) aged over 15 years and weighing over 30 kg. These patients had received propofol via target-controlled infusion in the special care dental clinic of Seoul National University Dental Hospital from May 2008 to September 2018 for restorative treatment (112), minor surgery (13), prosthodontics (7), periodontics treatment (5), and implant (1). RESULTS: For all groups, the duration of dental treatments was 43 ± 18 minutes, total sedation time was 73 ± 23 minutes, and total BIS values was 57 ± 12. The propofol maintenance dosage values for each group were: mental retardation, 3 ± 0.5 (2–4) µg/ml; autism, 3.1 ± 0.7 (2–5) µg/ml; brain lesion, 2.8 ± 0.7 (1.5–5) µg/ml; genetic disease, 2.9 ± 0.9 (1–4) µg/ml; and dementia 2.3 ± 0.7 (1–3.4) µg/ml. CONCLUSIONS: The dementia group needed a lower dosage to reach a safe, effective propofol effect-site concentration than the other groups. Since there were no complications, deep sedation is a great alternative to general anesthesia for dental treatment of intellectually disabled patients.

Adaptive smith predictor controller for total intravenous anesthesia automation

Anesthetic agent propofol needs to be administered at an appropriate rate to prevent hypotension and postoperative adverse reactions. To comprehend more suitable anesthetic drug rate during surgery is a crucial aspect. The main objective of this proposal is to design robust automated control system that work effi ciently in most of the patients with smooth BIS and minimum variations of propofol during surgery to avoid adverse post reactions and instability of anesthetic parameters. And also, to design advanced computer control system that improves the health of patient with short recovery time and less clinical expenditures. Unlike existing research work, this system administrates propofol as a hypnotic drug to regulate BIS, with fast bolus infusion in induction phase and slow continuous infusion in maintenance phase of anesthesia. The novelty of the paper lies in possibility to simplify the drug sensitivity-based adaption with infusion delay approach to achieve closedloop control of hypnosis during surgery. Proposed work uses a brain concentration as a feedback signal in place of the BIS signal. Regression model based estimated sensitivity parameters are used for adaption to avoid BIS signal based frequent adaption procedure and large off set error. Adaptive smith predictor with lead–lag fi lter approach is applied on 22 diff erent patients' model identifi ed by actual clinical data. The actual BIS and propofol infusion signals recorded during clinical trials were used to estimate patient's sensitivity parameters EC50 and λ. Simulation results indicate that patient's drug sensitivity parameters based adaptive strategy facilitates optimal controller performance in most of the patients. Results are obtained with proposed scheme having less settling time, BIS oscillations and small off set error leads to adequate depth of anesthesia. A comparison with manual control mode and previously reported system shows that proposed system achieves reduction in the total variations of the propofol dose. Proposed adaptive scheme provides better performance with less oscillation in spite of computation delay, surgical stimulations and patient variability. Proposed scheme also provides improvement in robustness and may be suitable for clinical practices.

Effect of target-control infusion of remifentanil on concentration for 50% of maximal effect of propofol required for loss of consciousness and onset of EEG burst suppression / 临床麻醉学杂志

Objective To investigate the effect-site concentration for 50% of maximal effect (EC50 )of propofol required for loss of consciousness and onset of burst suppression and to assess the effect of target-control infusion(TCI)of remifentanil on these EC50 of propofol.Methods Sixty patients undergoning general anesthesia for scheduled surgery were randomly divided into 2 groups (n=30):group R received TCI of remifentanil with a target concentraton of 4 ng/ml 10 minutes before TCI of propofol,which started at a target plasma concentration of 1μg/ml and then increased by 1μg/ml step every 1 minute until the burst suppression ratio reach to 15%.Group N received a mock TCI of saline instead of remifentanil and the other procedures were as same as group R.During this,all patients were assessed by modified Observ-er’s Assessment of Alertness/Sedation (OAA/S)scale,the loss of consciousness was definited by modified OAA/S values less than 2,the onset of burst suppression was definited by 15% of burst suppression ratio. Results The EC50 of effect-site concentration of propofol required for loss of consciousness and onset of burst suppression were 2.35 (95%CI 2.29-2.41)and 6.31 (95%CI 6.13-6.47)μg/ml respectively.The EC50 of propofol required for loss of consciousness was decreased to 1.73μg/ml by TCI of remifentanil,but the EC50 of propofol required for onset of burst suppression did not changed by TCI of remifentanil. Conclusion TCI of remifentanil could decrease the EC50 of propofol effect-site concentration required for loss of consciousness but has no effect on the EC50 of propofol required for onset of burst suppression.

Effect of propofol and midazolam on memory during target control infusion for sedation / 基础医学与临床

Objective To study the effect of propofol and midazolam on memory during target control infusion for sedation.Methods Forty healthy male volunteers were randomly devided into 4 groups,all subjects received target controlled infusion with propofol or midazolam for sedation.Group 1 and group 3 were sedated to OAA/S 1 or OAA/S 3 respectively by propofol;group 2 and group 4 was sedated to OAA/S 1 or OAA/S 3 by midazolam.All subjects learned a list of words before sedation and at the different sedation depths predicted.After recovery the explicit and implicit memory were tested using word stem completion method and process dissociation procedure.Results Compared with 0,there was no significant difference in explicit memory among all the 4 groups.While there was significant difference in implicit memory for group 3 and 4,and there was no significant difference in implicit memory for group1 and group2.Conclusion Sedative-hypnotic drugs not only deepen sedation,but also impair memory as serum concentration increases during target infusion.Drug-induced amnesia is independent of sedation.Propofol and midazolam have the same efficacy on memory at the same sedation scale.