Induction of anaesthesia with propofol using a target-controlled infusion system

Area of Science:

• Anesthesiology
• Pharmacology

Background:

• Propofol is a widely used intravenous anesthetic agent.
• Optimizing propofol dosing is crucial for safe and effective anesthesia induction.
• Temazepam is a common premedication agent used to reduce anxiety and facilitate anesthesia induction.

Purpose of the Study:

• To evaluate the efficacy and safety of different target blood concentrations of propofol for anesthesia induction in patients premedicated with temazepam.
• To determine the optimal target concentration of propofol for rapid anesthesia induction.

Main Methods:

• Sixty patients premedicated with temazepam were randomly assigned to receive propofol infusions targeting blood concentrations of 3, 4, or 5 µg/mL.
• Anesthesia induction time was measured from the start of infusion to loss of verbal contact.
• Success rate of induction within 3 minutes of achieving target concentration was assessed.
• Hemodynamic parameters (arterial pressure) and respiratory events (apnea) were monitored.

Main Results:

• The success rate of inducing anesthesia within 3 minutes was 40% at 3 µg/mL, 75% at 4 µg/mL, and 90% at 5 µg/mL.
• No significant differences in induction time were observed between groups for successfully induced patients.
• Arterial pressure decreased significantly within groups post-infusion, but not between groups.
• Apnea and injection pain occurred infrequently across all groups.

Conclusions:

• A target propofol concentration of 5 µg/mL, with temazepam premedication, achieves a high success rate for anesthesia induction.
• This concentration is associated with minimal major hemodynamic or respiratory side effects.
• Target-controlled infusion of propofol at 5 µg/mL is a safe and effective option for anesthesia induction in this patient population.