Laboratory evaluation of a novel anaesthesia delivery device

Abstract

SummaryHere, we describe proof of concept of a novel method for delivering volatile anaesthetics, where the liquid anaesthetic (sevoflurane or isoflurane) is formulated into an emulsion that is contained in a compact, lightweight device through which carrier gas flows. Release of anaesthetic is achieved by stirring of the formulation, allowing controlled and responsive release of anaesthetic at a variety of fixed flow rates between 0.5 l.min À1 and 5 l.min À1, with ventilated, non-ventilated and draw-over breathing systems. Anaesthetic release was evaluated using target anaesthetic concentrations ranging from 0.5% v/v to 8% v/v to mimic those typically required for induction and maintenance of anaesthesia, and lower concentrations suitable for sedation. Under all conditions, output could be maintained within 0.1% v/v of the intended setting, and the device could deliver a controlled level of anaesthetic for at least 60 min, with compensation for different ambient temperatures (10-30°C) and carrier gas flow rates. This device offers a simple, inexpensive method of delivering safe concentrations of volatile anaesthetics for a wide range of applications.

Volatile fluorinated nanoemulsions: A chemical route to controlled delivery of inhalation Anesthesia

“…Experimental studies [this paper, 19,21] indicate a strong link between formulation microstructure and anesthetic release under flow and shear. Existing theoretical frameworks for evaporation from emulsions [10,12,17,20] provide a reasonable account of the observed behavior, but this system highlights the challenge of fully understanding evaporation of volatile components under air flow and stirred conditions [17].…”