Bispectral index to guide induction of anesthesia: a randomized controlled study

Area of Science:

• Anesthesiology
• Neuroscience
• Pharmacology

Background:

• Hypotension is common after propofol induction for general anesthesia.
• The extent to which propofol overdose contributes to this hypotension is unclear.
• Electroencephalon-based cerebral monitoring can detect and quantify hypnotic drug overdose.

Purpose of the Study:

• To determine if electroencephalon-based cerebral monitoring (BIS) reduces hypotension during propofol induction.
• To compare the incidence and degree of hypotension between BIS-guided and weight-based propofol administration.

Main Methods:

• 235 non-geriatric patients undergoing surgery were randomized to BIS-guided (target 40-60) or weight-related propofol induction.
• The primary endpoint was the incidence of hypotension post-propofol administration.
• Secondary endpoints included hypotension severity and BIS-MAP correlation.

Main Results:

• Hypotension incidence was similar (44% vs. 45%, p=0.87) between BIS-guided and weight-based groups.
• Maximal mean arterial pressure (MAP) drop and hypotensive event proportions were comparable.
• No consistent linear correlation was found between BIS values and MAP drop.

Conclusions:

• BIS-guided propofol induction does not significantly lower the incidence or degree of arterial hypotension compared to weight-adjusted manual administration.
• Cerebral monitoring may not prevent propofol-induced hypotension in this patient population.