[Analgo-sedation in intensive care: a quantitative, EEG-based trial with propofol 1% and 2%]

Area of Science:

• Anesthesiology
• Intensive Care Medicine
• Neurophysiology

Background:

• Critically ill patients often require prolonged sedation.
• Propofol is a common anesthetic agent, but its long-term use requires careful monitoring.
• Closed-loop systems offer potential for automated and precise drug delivery.

Purpose of the Study:

• To evaluate the efficacy of an EEG median frequency-controlled closed-loop system for long-term propofol sedation in critically ill patients.
• To investigate the pharmacokinetics and pharmacodynamics of propofol (1% and 2%) during prolonged sedation.
• To compare the quality of sedation and lipid load between propofol 1% and 2%.

Main Methods:

• 16 critically ill patients requiring sedation for >= 72 hours were enrolled.
• Sedation was maintained with computer-controlled propofol (1% or 2%) using EEG median frequency.
• Alfentanil was co-administered for analgesia, with plasma concentrations and pharmacokinetics analyzed.

Main Results:

• Successful long-term sedation (77 +/- 9 hours) was achieved using the closed-loop system.
• Stable EEG median frequencies (1.5 +/- 0.2 Hz) indicated adequate sedation depth.
• Propofol plasma concentrations increased over time, suggesting potential tolerance. Propofol 2% showed a larger volume of distribution and lower triglyceride levels compared to propofol 1%.

Conclusions:

• EEG median frequency control is a viable method for long-term propofol sedation in intensive care.
• Propofol 2% is advantageous due to its lower lipid load and associated triglyceride levels.
• The study suggests a potential for developing tolerance to propofol during prolonged infusions.