APP A RA T US The Oxyvent An anaesthetic machine designed to be used in developing countries and difficult situations

Summary The Oxyvent is an anaesthetic machine designed specifically for use in the developing world anddifficult situations. It is made up of four components, each of which has, in its own right, alreadyproved to be of great value in difficult situations. These are the drawover system, the PenlonManley Multivent Ventilator, the DeVilbiss Oxygen Concentrator and the air compressor. Thefour components are mounted on a simple trolley carrying two oxygen cylinders. The Oxyventcan be used to provide anaesthesia in the absence of electricity or oxygen or both. It is simple,robust and easily serviceable. It is versatile and can be used both as an anaesthetic machine in theoperating theatre and as a ventilator in an intensive care unit. Keywords Equipment ; anaesthesia machine, drawover system, compressor, oxygen concentrator,ventilator. Correspondence to: Dr R. J. EltringhamAccepted: 6 February 1997 In many regions of the world anaesthetics are administeredbyhealth workerswithlimitedtraining, unreliable suppliesand inadequate and poorly serviced equipment. Thedesign of an anaesthetic machine suitable for use inthese circumstances is therefore very different from oneintended for use in the UK, for example, where adequatefacilities are taken for granted. Such a machine must berobust, easy to understand and operate, require minimalmaintenance and be readily serviceable using local skills. Itshould also be versatile so that it can be used whateveranaesthetic agents and equipment are available at the timeand should be capableof functioning if either the supplyofcompressed gases or electricity are interrupted [1].It can readily be appreciated that the modern, sophis-ticated machines currently used in most hospitals in thiscountry are totally unsuitable and why attempts to intro-duce them into developing countries have usually beenexpensive failures. When the first fault arises they aregenerally discarded and consigned to the graveyard ofanaesthetic apparatus gathering dust in store roomsaround the world [1].This article describes the Oxyvent, an anaestheticmachine which has been designed specifically for use indifficult situations. It fulfils all the above requirements andcan make a considerable contribution towards safer anaes-thesia in difficult environments. The Oxyvent is made upof four components each of which has, in its own right,already proved to be of great value in difficult situations.Theseare,theDrawoverSystem[1–4],thePenlonManleyMultivent Ventilator [5–8], the DeVilbiss Oxygen Con-centrator [9, 10] and the air compressor [1, 2].In the Oxyvent, the DeVilbiss Oxygen Concentratorhas been modified so that it can also function as acompressor and has been mounted together with theother two components on a simple metal trolley whichhas two shelves, an electrical socket and cradles for two600-l oxygen cylinders at the rear (Figs 1 and 2).