ABSTRACT
OBJECTIVE: 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. PATIENTS: 80 patients scheduled for coronary revascularization. STUDY DESIGN: double-blind, randomized. STUDY 1: Induction of anesthesia with ketamine-racemic mixture (3 mg/kg) or S-(+)-ketamine (1.5 mg/kg) plus midazolam 0.15 mg/kg. PARAMETERS: 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. PARAMETERS: 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. PARAMETERS: mean systemic pressure, central venous pressure, reservoir volume. STUDY 1: 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. CONCLUSION: 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.
