Impact of effect-site concentration of propofol on cardiac systolic function assessed by tissue Doppler imaging

OBJECTIVE: To evaluate the relationship between effect-site concentration (C(E)) of propofol during total intravenous anaesthesia (TIVA) and cardiac systolic function using tissue Doppler imaging (TDI) in patients undergoing cardiovascular procedures. METHODS: Stepwise increments of C(E) of propofol of 1.0, 2.0, 3.0 and 4.0 µg/ml (modified Marsh model) were achieved using a target-controlled infusion device. Transthoracic echocardiographic assessments using TDI were performed for each C(E) of propofol and corresponding systolic myocardial velocity (s′), mean arterial blood pressure (MAP), heart rate (HR) and bispectral index (BIS) were evaluated. RESULTS: Data from 31 patients were analysed in this prospective study. The s′ velocity decreased with increasing propofol C(E) and values recorded at propofol C(E) 3.0 and 4.0 µg/ml were near or below 8 cm/s indicating abnormal cardiac systolic function. MAP, HR and BIS also decreased with each propofol C(E) increment. CONCLUSION: Although the recommended dosage for propofol is up to 4.0 µg/ml, caution should be taken when using propofol concentrations above 2.0 µg/ml during TIVA in patients with underlying cardiovascular diseases.