Comparison of C50 for Propofol-remifentanil Target-controlled Infusion and Bispectral Index at Loss of Consciousness and Response to Painful Stimulus in Elderly and Young Patients

• Published in: Chinese medical journal 2015-08, Vol.128 (15), p.1994-1999
• Main Authors: Yang, Ning, Zuo, Ming-Zhang, Yue, Yun, Wang, Yun, Shi, Yu, Zhang, Xue-Na
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Age; Age Factors; Aged; Anesthesia; Anesthesiology; Anesthetics, Intravenous - administration & dosage; Anesthetics, Intravenous - therapeutic use; Bispectral Index; Painful Stimulus; Propofol-remifentanil; Target-controlled Infusion; C50; Consciousness; Female; Humans; Intensive care; Male; Middle Aged; Narcotics; Nitrous oxide; Older people; Original; Piperidines - administration & dosage; Piperidines - therapeutic use; Probability; Propofol - administration & dosage; Propofol - therapeutic use; Prospective Studies; Software; Unconsciousness - chemically induced; Young Adult; 双频; 异丙酚; 患者; 疼痛; 老年人; 脑电; 芬太尼
• ISSN: 0366-6999; 2542-5641
• DOI: 10.4103/0366-6999.161338

Background：In this prospective randomized study,we compared the predicted blood and effect-site C50 for propofol and remifentanil target-controlled infusion （TCI） and the bispectral index （BIS） values at loss of consciousness （LOC） and response to a standard noxious painful stimulus （LOS） in elderly and young patients,respectively.We hypothesized that the elderly patients will require lower target concentration of both propofol and remifentanil at above two clinical end-points.Methods：There were 80 American Society of Anesthesiologists （ASA） physical status Ⅰ Ⅱ unpremedicated patients enrolled in this study,they were divided into elderly group （age ≥65 years,n =40） and young group （aged 18-54 years,n =40）.Propofol was initially given to a predicted blood concentration of 1.2 μg/ml and thereafter increased by 0.3 μg/ml every 30 s until Observer＇s Assessment of Alertness and Sedation score was 1.The propofol level was kept constant,and remifentanil was given to provide a predict blood concentration of 2.0 ng/ml,and then increased by 0.3 ng/ml every 30 s until loss of response to a tetanic stimulus.BIS （version 3.22,BIS Quattro sensor） was also recorded.Results：In elderly group,the propofol effect-site C50 at LOC of was 1.5 （1.4-1.6） μg/ml,was significantly lower than that of young group,which was 2.2 （2.1-2.3） μg/ml,the remifentanil effect-site C50 at LOS was 3.5 （3.3-3.7） ng/ml in elderly patients,was similar with 3.7 （3.6-3.8） ng/ml in young patients.Fifty percent of patients lost consciousness at a BIS value of 57.3 （56.4-58.1）,was similar with that of young group,which was 55.2 （54.0-56.3）.Conclusion：In elderly patients,the predicted blood and effect-site concentrations of propofol at LOC were lower than that of young patients.At same sedation status,predicted blood and effect-site concentrations of remifentanil required at LOS were similar in elderly and young patients.BIS were not affected by age.Low-propofol/high-opioid may be optional TCI strategy for elderly patients.