De-mystifying the 'Mixifusor'.

De-mystifying the 'Mixifusor'.
Paediatr Anaesth. 2020 Oct 13;:
Authors: Absalom AR, Rigby-Jones AE, Rushton AR, Sneyd JR
Abstract
Total intravenous anesthesia (TIVA) using a mixture of propofol and remifentanil in the same syringe has become an accepted technique in Pediatric Anesthesia. A survey by a group of respected UK anesthetists demonstrated a low incidence of serious complications, related to the pharmacology and dose of the drugs. However, a current guideline for the safe use of TIVA recommends against this practice. Pharmaceutical concerns include the physical stability of the emulsion when remifentanil is mixed with propofol; changes in drug concentration over time; non-uniform mixing of propofol and remifentanil; the risk of bacterial contamination; and the potential for drug administration errors. Propofol and remifentanil have markedly different pharmacokinetic profiles. When remifentanil is mixed with propofol and delivered as a target-controlled infusion (TCI) of propofol, remifentanil delivery is not target-controlled but passively follows the variable infusion rates calculated by the syringe driver to deliver predicted plasma or effect-site concentrations of propofol. The pharmacokinetic consequences can be illustrated using pharmacokinetic modelling similar to that used in TCI pumps. The clinical consequences reflect the dose-dependent pharmacodynamics of remifentanil. Increasing the target propofol concentration p...

Source: Paediatric Anaesthesia - October 13, 2020 Category: Anesthesiology Authors: Absalom AR, Rigby-Jones AE, Rushton AR, Sneyd JR Tags: Paediatr Anaesth Source Type: research