Effects of fentanyl, alfentanil, remifentanil and sufentanil on loss of consciousness and bispectral index during propofol induction of anaesthesia

Abstract

The bispectral index (BIS) and a sedation score were used to determine and compare the effect of propofol in the presence of fentanyl, alfentanil, remifentanil and sufentanil. Seventy-five non-premedicated patients were assigned randomly into five groups (15 in each) to receive fentanyl, alfentanil, remifentanil, sufentanil or placebo. Opioids were administered using a target-con-trolled infusion device, to obtain the following predicted effect-site concentrations: fentanyl, 1.5 ng ml(-1); alfentanil, 100 ng ml(-1); remifentanil, 6 ng ml(-1); and sufentanil, 0.2 ng ml(-1). After this, a target-controlled infusion of propofol (Diprifusor) was started to increase concentration gradually, to achieve predicted effect-site concentrations of 1, 2, and 4 microg ml(-1). At baseline and at each successive target effect-site concentration of propofol, the BIS, sedation score and haemodynamic variables were recorded. At the moment of loss of consciousness (LOC), the BIS and the effect-site concentration of propofol were noted. The relationship between propofol effect-site concentration and BIS was preserved with or without opioids. In the presence of an opioid, LOC occurred at a lower effect-site concentration of propofol and at a higher BIS50 (i.e. the BIS value associated with 50% probability of LOC), compared with placebo. Although clinically the hypnotic effect of propofol is enhanced by analgesic concentrations of mu-agonist opioids, the BIS does not show this increased hypnotic effect.

A low-dose remifentanil infusion is well tolerated for sedation in mechanically ventilated, critically-ill patients

“…19 In another study, BIS was not modified by adding a remifentanil to a propofol infusion in absence of painful stimuli. 20 It seems reasonable that also in critically-ill patients remifentanil could decrease BIS values only by removing pain. Patients with surgical or traumatic wounds were excluded from this study, hence the significant decrease of BIS observed suggests that the pain caused by monitoring and therapeutic procedures was not negligible.…”

Effects of Fentanyl And Butorphanol on Induction Dose of Propofol in Adults

“…5 Arora V et al 15 demonstrated that the mean propofol consumption in fentanyl group (2μg/kg) was slightly higher (406.7±96.36mg) as compared to butorphanol 40μg/kg group (380.5±92.4mg). Lysakowski C et al 6 showed in their study that in the presence of analgesic concentration of fentanyl, loss of consciousness occurred at a lower effect-site concentration of propofol. Pretreatment with fentanyl also potentiated the effect of propofol and hypnotic end points are achieved at lower propofol doses and concentrations.…”

The effects of a propofol/alfentanil admixture on total intravenous anaesthesia in dogs undergoing splenectomy

“…It is expected that the administration of opioids to the anaesthetic protocol does not change the values of BIS, because these drugs have no direct hypnotic action. Lysakowski et al (2001) studied the effects of fentanyl, alfentanil, remifentanil and sufentanil on the bispectral index during anaesthesia with propofol in humans; no significant differences were observed between the fentanyl group and the placebo group. Hatschbach et al (2008) found that the addition of remifentanil did not change the bispectral index in dogs undergoing propofol-mediated anaesthesiology.…”

“…Alfentanil can reduce the hypnotic and anaesthetic dose of propofol required in humans (Short et al 1992;Vuyk et al 1996;Glass et al 1997). The same dosage of propofol was used in each group, but a combination of propofol with a high dose of alfentanil resulted in lower BIS values (Group 2), while the administration of alfentanil alone does not change BIS values (Lysakowski et al 2001). In other words, the combination of alfentanil with propofol could reduce both the hypnotic and anaesthetic doses of propofol.…”