The Diamedica Draw‐Over Vaporizer: a comparison of a new vaporizer with the Oxford Miniature Vaporizer

Abstract

SummaryThe Diamedica Draw-Over Vaporizer (DDV) has been developed as an alternative to the Oxford Miniature Vaporizer (OMV). Both can function as draw-over or plenum vaporizers. The performances of these two vaporizers were compared under conditions simulating intermittent positive pressure ventilation (IPPV) and continuous flow (CF). Series 1 experiments were conducted with the vaporizers in water baths at 20, 25 and 30°C. Vaporizers were tested at dial settings of 1-4% over a range of minute volumes (1.75-6 l.min )1 ) and flow rates (3-8 l.min). Series 2 experiments compared output of the vaporizers over time at ambient temperatures of 20, 25 and 30°C. A minute volume of 6 l.min )1 (IPPV) and a gas flow of 8 l.min )1 (CF) were used with a vaporizer setting of 2%. Vapour concentrations were recorded at 5-min intervals. In series 1 IPPV experiments, the DDV vaporizer was more accurate, producing significantly fewer vapour concentrations 0.5% more than or less than setting (p = 0.013). The OMV tended to produce more favourable results under continuous flow (p = 0.42). In series 2 experiments, the accuracy of both vaporizers was similar but consistency of output over time was better for the DDV and consistency of output according to differences in ambient temperature was better for the DDV. The OMV produced more vapour concentrations that were markedly higher than dial setting, particularly at high ambient temperatures. The DDV is a suitable alternative to the OMV with some distinct advantages. These include a larger reservoir, tendency towards greater accuracy during IPPV and improved consistency of output.

Laboratory evaluation of a novel anaesthesia delivery device

“…This portability suggests potential for delivery of anaesthesia in the field, pre-hospital care or the developing world, where access to complex equipment such as anaesthetic machines may be limited and portability is a major advantage. Frequently, draw-over vaporisers such as the Oxford Miniature Vaporizer and the Diamedica Draw-Over Vaporizer [10] are used in these situations. However, the flow through this type of vaporiser, and hence the concentration of the anaesthetic delivered, varies widely throughout the respiratory cycle, and limits precision of the vaporiser.…”

“…The fluorinated surfactant Zonyl FSN-100 (technical grade, ABCR, Karlsruhe, Germany) was used as received. Zonyl FSN-100 is a commercial non-ionic surfactant of the perfluoroalkylpolyoxyethylene type with an average chemical structure of F(CF 2 CF 2 ) 3- 10-15 H [6,7]. Two anaesthetic agents, sevoflurane (99.98% purity; Abbott, Maidenhead, UK) and isoflurane (99.9% purity; Nicholas Piramal, London, UK) were used as received.…”

The Environmental Impact of the Glostavent® Anesthetic Machine

“…The Diamedica drawover vaporizer (DDV1), a low-resistance vaporizer designed for use with halothane or isoflurane, is more accurate than the Oxford Miniature Vaporizer (OMV), which was used in drawover anesthesia for many years. 11 In response to requests from armed forces and various aid agencies, a separate vaporizer (DDV2) is also available for use with sevoflurane, and this too has been shown to be accurate over the wide range of conditions likely to be encountered. 12 Trilene is still requested by anesthetists in parts of Africa, where it is popular because of its analgesic properties and low cost.…”

The Triservice Anaesthetic Apparatus: A Review

“…Examples include the Epstein-Macintosh-Oxford (EMO), the Ohmeda Portable Anaesthesia Complete (PAC) and the Oxford Miniature Vaporiser (OMV, Penlon, Oxford, UK). Despite the overwhelming numerical superiority of plenum vaporisers worldwide, developments in drawover vaporiser design continue [2]. The TSAA is designed around a modified OMV50.…”

“…Results are conflicting but the original TSAA does not appear to lend itself to this technique [10]. Sevoflurane has been used in the Universal PAC [11] and more recently Diamedica (Diamedica (UK) Ltd, Bratton Fleming, Devon, England) has developed a sevoflurane vaporiser which for the first time appears to produce a sufficient output for inhalational induction using a single vaporiser in a drawover system [2] …”