Evaluation of induction doses of propofol: comparison between endstage renal disease and normal renal function...

Anaemia, hypoproteinaemia and acidic pH in renal failure patients can alter the pharmacokinetics and pharmacodynamics of anaesthetic agents, resulting in altered dose requirements. We evaluated the induction dose of propofol in adult patients with end-stage renal disease by titrating the hypnotic effect by means of a clinical parameter as well as using a more objective assessment of hypnosis, the Bispectral Index (BIS) monitor. The dose was compared with that for patients with normal renal function. Propofol doses that provided the clinical end-point of hypnosis (syringe drop method), as well as the end-point of a mean (SD) BIS value of 50 (5), were evaluated in 27 end-stage renal disease and 27 normal renal function patients. Propofol was administered at 0.2 mg/kg every 15 seconds until these end-points were achieved. End-stage renal disease patients required significantly higher propofol doses to achieve the clinical end-point of hypnosis (1.42 (0.24) mg/kg versus 0.89 (0.2) mg/kg in normal renalfunction patients, P<0.05 unpaired "t" test). Propofol dose required to achieve a BIS of 50 (5) was also higher in end-stage renal disease patients (2.03 (0.4) mg/kg versus 1.39 (0.43) mg/kg in normal renal function patients, P<0.05). There was a significant negative correlation of propofol dose with preoperative haemoglobin concentration. A hyperdynamic circulation in renal failure patients with anaemia may be responsible for the higher propofol dose requirement in this group.