Abstract
Anaemia, hypoproteinaemia and acidic pH in renal failure patients can alter the pharmacokinetics and pharmaco-dynamics 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 0.2mg/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 renal function 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.