Correlations between the Modified Observer's Assessment of Alertness/Sedation Scale, Bispectral Index and Propofol Effect Site Concentrations in Sedated Elderly Patients under Regional Anesthesia.

Kim,  Kwang Su; Bae,  Hong Beom; Choi,  Jong Cheol; Kim,  Seok Jai; Chung,  Sung Su; Yoo,  Kyung Yeon; Jeong,  Chang Young; Jeong,  Seong Wook

doi:2005.49.3.349

Clinical Research Article

Korean Journal of Anesthesiology 2005;49(3):349-354.
DOI: https://doi.org/10.4097/kjae.2005.49.3.349

Correlations between the Modified Observer's Assessment of Alertness/Sedation Scale, Bispectral Index and Propofol Effect Site Concentrations in Sedated Elderly Patients under Regional Anesthesia.

Kwang Su Kim, Hong Beom Bae, Jong Cheol Choi, Seok Jai Kim, Sung Su Chung, Kyung Yeon Yoo, Chang Young Jeong, Seong Wook Jeong

¹Department of Anesthesiology and Pain Medicine, Medical School, Chonnam National University, Gwangju, Korea. anesman@jnu.ac.kr
²School of Density, Chonnam National University, Gwangju, Korea.

Abstract

BACKGROUND
To maintain an adequate sedation level in elderly patients (over 65 years) under regional anesthesia, we evaluated the correlations between the modified observer's assessment of alertness/sedation (OAA/S) scale, bispectral index (BIS), propofol effect site concentrations.
METHODS
In elderly patients (over 65 years) scheduled for transurethral resection of a bladder tumor or prostate, we measured BISs and started propofol infusion using the target controlled infusion (TCI) method to sedate patients after regional anesthesia. OAA/S composite scores, measured BISs propofol effect site concentrations and vital signs were determined.
RESULTS
When the OAA/S composite score was 5, mean BIS was 97.2 +/- 1.1; when the OAA/S was 4, mean BIS was 84.3 +/- 4.6 and mean propofol effect site concentration was 0.8 +/- 0.3microgram/ml; when the OAA/S was 3, mean BIS was 78.4 +/- 4.3 and mean propofol effect site concentration was 1.2 +/- 0.3microgram/ml; and when the OAA/S was 2, mean BIS was 73.2 +/- 5.9 and mean propofol effect site concentration was 1.5 +/- 0.4microgram/ml. The OAA/S scale was found to be well correlated with BIS (Pearson's r = 0.973) and the propofol effect site concentration (Pearsons's r = -0.968). BIS was also well correlated with propofol effect site concentration (Pearson's r = -1.0).
CONCLUSIONS
BIS was found to be a good tool for monitoring sedation level in elderly patients under regional anesthesia with propofol sedation.

Key Words: BIS; effect site concentration of propofol; OAA/S scale