Echocardiographic assessment of the haemodynamic effects of propofol: a comparison with etomidate and thiopentone.
The haemodynamic effects of propofol (2 mg/kg), etomidate (0.2 mg/kg) and thiopentone (4 mg/kg) were studied in 30 ASA 1 and 2 patients in whom anaesthesia had been induced with midazolam 0.1 mg/kg, fentanyl 5 micrograms/kg, vecuronium 0.1 mg/kg and atropine 10 micrograms/kg, and maintained with nitrous oxide in oxygen. Arterial pressure was measured directly and left ventricular diameters were determined by transoesophageal echocardiography. Systolic blood pressure after propofol and thiopentone and the end-systolic quotient (systolic pressure/end-systolic diameter), a measure of inotropy, decreased. Fractional shortening (end-diastolic-end-systolic diameter/end-diastolic diameter) decreased only in the thiopentone group. Diastolic blood pressure and end-diastolic diameter (a measure of preload) did not change in any of the groups, and the etomidate group showed no changes in the haemodynamic variables measured. Propofol shows simultaneous negative inotropy and afterload reduction, while thiopentone is exclusively negatively inotropic.