Age-dependent relationship between bispectral index and sedation level.
OBJECTIVE
To determine the relationship between bispectral index (BIS) and sedation.


METHODS
Prospective, observational clinical study.


METHODS
Intensive care unit of a public hospital in Japan.


METHODS
22 ASA physical status I, II, and III middle-aged (18-65 yrs) and elderly (>65 yrs) patients receiving postoperative sedation with midazolam.


METHODS
Patients were allocated to two groups: Group M was composed of middle-aged patients (<65 yrs) and Group H elderly patients (>65 yrs). Midazolam was administered at a bolus dose of 0.1 mg/kg, followed by a continuous dose of 0.04 mg/kg per hour, which was adjusted every two hours to achieve a target level of sedation at 3-6 on the Ramsay Sedation Scale (RSS); buprenorphine was administered at a constant rate (0.625 microg kg(-1) hr(-1)).


METHODS
BIS value, RSS, midazolam dose, body temperature (BT), heart rate, dopamine dose, and mean arterial pressure were recorded every two hours by an independent nurse. Data were analyzed using Spearman rank correlation and the Mann-Whitney U test.


RESULTS
BIS values decreased depending on depth of sedation; a significant correlation was noted between groups in RSS and BIS. The BIS values at levels of RSS 5 and 6 were significantly lower in Group H than Group M.


CONCLUSIONS
BIS correlated with sedation depth, with BIS scores in group H than group M at a deep sedation depth.
Yamashita
Kazunori
K
Department of Anesthesia, Nagasaki Rosai Hospital, Sasebo, Japan. kazy@plum.ocn.ne.jp
Terao
Yoshiaki
Y
Inadomi
Chiaki
C
Takada
Masafumi
M
Fukusaki
Makoto
M
Sumikawa
Koji
K
D000328:Adult; D000367:Age Factors; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D016292:Procedural Sedation / Q000295:instrumentation / Q000379:methods; D004569:Electroencephalography / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006993:Hypnotics and Sedatives; D008297:Male; D008874:Midazolam; D008875:Middle Aged; D011446:Prospective Studies; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
D006993:Hypnotics and Sedatives; D008874:Midazolam