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

Evaluation of hemodynamic effects of S-(+)-ketamine versus ketamine-racemic mixture during induction of anesthesia, during steady-state of a fentanyl-midazolam-anesthesia and in the period of aortic cross-clamping during extracorporeal circulation.

80 patients scheduled for coronary revascularization.

double-blind, randomized.

Induction of anesthesia with ketamine-racemic mixture (3 mg/kg) or S-(+)-ketamine (1.5 mg/kg) plus midazolam 0.15 mg/kg.

invasive hemodynamic monitoring including right ventricular volumes and pressure. STUDY 2: Bolus of ketamine-racemic mixture (3 mg/kg), S-(+)-ketamine (1.5 mg/kg) or placebo during steady-state anesthesia with fentanyl and midazolam.

see study 1, additionally left ventricular systolic and end-diastolic pressure and maximum speed of left ventricular pressure increase (dp/dt). STUDY 3: Bolus of ketamine-racemic mixture (3 mg/kg), S-(+)-ketamine (1.5 mg/kg) or placebo in the period of aortic cross clamping during ECC.

mean systemic pressure, central venous pressure, reservoir volume.

Heart rate and systemic blond pressure remained unchanged until intubation, which caused significant increases of these parameters. Stroke volume Index and cardiac index decreased in the S-(+)-group compared with racemic mixture, right- and left ventricular filling parameters remained unchanged throughout the study. STUDY 2: There were no significant hemodynamic changes with time or between the groups. STUDY 3: Significant arterial vasodilation was observed in the racemic mixture group, venous parameters remained unchanged.

There were no major differences in the hemodynamic profiles of S-(+)-ketamine and the racemic mixture. S(+)-ketamine did not provide hemodynamic advantages. The use of both preparations should be limited to selected clinical situations in patients with reduced coronary reserve.