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[The changes of bispectral index induced by administration of midazolam during propofol anesthesia]
Maiko Satomoto1, Hiroshi Aoki, Shigeyuki Yamada
1Medical Corps, 1st Air Wing, Japan Air Self Defense Force, Hamamatsu 432-8551.
Abstract:
The effect of the additional administration of midazolam or flumazenil on bispectral index (BIS) during propofol anesthesia was investigated in 22 scheduled surgical patients. Midazolam 10 or 30 micrograms.kg-1, or flumazenil 6 or 12 micrograms.kg-1 was injected to the patients to evaluate their effect on BIS after achieving steady state of hypnosis more than 1 hr of propofol anesthesia with 5 mg.kg-1.hr-1. The only midazolam 30 micrograms.kg-1 significantly reduced BIS value from 47.8 +/- 8.6 to 36.8 +/- 6.5. The synergistic interaction between midazolam and propofol assessed by BIS might be less clear than that assessed by hypnotic dose of propofol using psychopharmacological investigation.
Insights
Midazolam at 30 micrograms/kg significantly lowered the Bispectral Index (BIS) during propofol anesthesia. This suggests a potential interaction between midazolam and propofol affecting hypnotic depth monitoring.
Area of Science:
- Anesthesiology
- Pharmacology
- Neuroscience
Context:
- Propofol is a common anesthetic agent used for maintaining hypnosis during surgery.
- Monitoring hypnotic depth, often using the Bispectral Index (BIS), is crucial for patient safety.
- Understanding drug interactions is vital for optimizing anesthetic management.
Purpose:
- To investigate the impact of additional midazolam or flumazenil on the Bispectral Index (BIS) during propofol-induced anesthesia.
- To assess the synergistic effects between midazolam and propofol on hypnotic depth as measured by BIS.
Summary:
- Twenty-two surgical patients receiving steady-state propofol anesthesia were administered midazolam (10 or 30 µg/kg) or flumazenil (6 or 12 µg/kg).
- Only the higher dose of midazolam (30 µg/kg) significantly reduced the BIS values (from 47.8 ± 8.6 to 36.8 ± 6.5).
- Flumazenil did not significantly alter BIS values.
Impact:
- The findings suggest that while midazolam can enhance propofol's hypnotic effect as indicated by BIS, this interaction may be less pronounced than previously suggested by psychopharmacological studies.
- This research contributes to a better understanding of drug interactions in anesthesia and their impact on electrophysiological monitoring.
- Results may inform clinical practice regarding the combined use of midazolam and propofol for anesthesia depth management.