[S-(+)-ketamine versus ketamine racemic mixture: hemodynamic studies]

Area of Science:

• Anesthesiology
• Cardiovascular Surgery
• Pharmacology

Background:

• Ketamine is used for anesthesia induction and maintenance.
• S-(+)-ketamine is an isomer of racemic ketamine.
• Hemodynamic effects of S-(+)-ketamine versus racemic ketamine require detailed evaluation, especially during cardiac surgery.

Purpose of the Study:

• To compare the hemodynamic effects of S-(+)-ketamine and ketamine-racemic mixture.
• To evaluate these effects during anesthesia induction, steady-state, and aortic cross-clamping.
• To assess potential advantages of S-(+)-ketamine in patients undergoing coronary revascularization.

Main Methods:

• A double-blind, randomized study involving 80 patients scheduled for coronary revascularization.
• Invasive hemodynamic monitoring was employed, including ventricular volumes and pressures.
• Three study phases: anesthesia induction, steady-state anesthesia, and aortic cross-clamping during extracorporeal circulation.

Main Results:

• No significant hemodynamic changes were observed between S-(+)-ketamine and the racemic mixture during steady-state anesthesia.
• S-(+)-ketamine led to a decrease in stroke volume index and cardiac index compared to the racemic mixture.
• Significant arterial vasodilation was noted with the racemic mixture during aortic cross-clamping.

Conclusions:

• S-(+)-ketamine does not provide significant hemodynamic advantages over the racemic mixture.
• Both ketamine preparations should be used cautiously in patients with compromised coronary reserve.
• Further research may be needed to define specific clinical scenarios for their use.