Midazolam-sufentanil vs sufentanil-enflurane for induction of anaesthesia for CABG surgery.

Purpose: To compare the effects of midazolam-sufentanil (Group I) and sufentanil-enflurane (Group II) anaesthesia on myocardial oxygenation and metabolism in patients with preserved ventricular function undergoing CABG surgery.

Methods: Patients randomized to Group I (n = 16) received midazolam 0.3 mg.kg-1 at induction of anaesthesia, 0.15 mg.kg-1 after tracheal intubation, followed by an infusion of 2.5-10.0 micrograms.kg-1.min-1. Supplemental sufentanil (cumulative maximum of 5 micrograms.kg-1) was given for adverse haemodynamic responses. Group II (n = 16) received 5 micrograms.kg-1 sufentanil at induction. Additional sufentanil (maximum 5 micrograms.kg-1), and enflurane (0-3% inspired concentration) were administered for adverse haemodynamic responses. Haemodynamics, myocardial oxygen consumption (MVO2), and lactate extraction were determined at the following times: I) awake (AWA), 2) after induction (IND), and 3) after tracheal intubation (ETT).

Results: Systemic haemodynamics and myocardial metabolism were similar at AWA. Heart rate response was attenuated and MVO2 reduced in Group I at IND (P < 0.05). Following AWA, myocardial lactate production (MLP) occurred more frequently in Group II vs Group I patients (9/16 vs 2/16) and at more individual measurement points (Group II: 10/64 vs Group I: 3/64). Myocardial lactate flux demonstrated a deleterious trend in Group II at ETT.

Conclusions: Compared with sufentanil-enflurane, midazolam-sufentanil anaesthesia resulted in comparable and acceptable haemodynamics and myocardial oxygenation in CABG patients.