An anaesthetic vaporizer must deliver a safe, reliable concentration of volatile agent to the patient. Anaesthetists should understand the basic principles of. Vaporizers are an integral part of modern-day anaesthesia, allowing the delivery of safe concentrations of volatile anaesthetic agent. Over time, vaporizer design. Anaesthesia vaporizers for inhalational anaesthetic agents. Principal, classification, types, hazards.

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For safest use, the concentration of anaesthetic vapour in the breathing attachment should be continuously monitored. The part of the fresh gas which enters the vapourising chamber flows over the wicks and vaporizerz to maximise the surface area of vapourisation. Plenum vapourisers with electronic control: Simultaneous administration of more than one vapour: This vapouriser is used in anaesthesia delivery unit and Aisys anaesthesia workstations of GE health-care.

A volume of ml is required to fully charge a vapouriser with dry wicks of which ahaesthesia ml is retained by the wick system.

Vaporizer outlet has check valve. The cassettes for halothane, enflurane and isoflurane have keyed fillers or the Easy-fil system.

Understanding vaporizers | BJA Education | Oxford Academic

Each cassette is a liquid sump without control mechanisms and can be tipped and is maintenance free. The flows are interfaced pneumatically and electronically through differential pressure transducers, control electronics and a pressure regulating valve so that anasethesia working pressure of the vapouriser is proportional to the fresh gas flow [ Figure 5 ].


A conventional vaporizer would require high fresh gas flows to dilute it to within clinically useful concentrations, making it uneconomical. Understanding Anesthesia Equipment; Vapourizers; pp. Davey AJ, Diba A.

The working principle of all these vapourisers is similar. Modern vapourisers have overcome this with smaller vapourising chambers and long inlet and outlet lines. Missing O-rings vaporizrs volatile agents. The drawover vaporizer may be mounted either way round, and may be used in circuits where re-breathing takes place, or inside the circle breathing anaesthesiia.

Variable bypass, incomplete vapourisation, bubble through or flow-over without wicks, low resistance in-circuit, non-agent-specific but intended for Halothane or Etherno temperature compensation, no interlocks. ASA physical status classification system Baricity Bispectral index Entropy monitoring Fick principle Vaproizers index Guedel’s classification Mallampati score Neuromuscular monitoring Thyromental distance.

A potential cause and cure of a major gas leak. A warm-up period is required after switching on. If the O-ring vpaorizers, or the vapouriser fails to sit properly on it, there will be a backbar leak.

Kam’s notes on volatile uptake Goldman Variable bypass, incomplete vapourisation, flow-over without wicks, low resistance in-circuit, non-agent-specific but intended for Halothaneno temperature compensation, no interlocks. This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3. Malfunction of Ohio modulus anesthesia machine.

Anaesthetic vaporizer

Saturated Vapour Pressure SVP – partial pressure of the vapour phase of a substance when at equilibrium with its liquid phase e. The amount of such a leak depends on the ambient temperature as well as the size and configuration of the internal ports. With Desflurane, the pressure inside the canister may exceed the inflow line pressure, at which point the inflow control valve and one-way must close firmly, and the unit functions as a pressurised injector.


This article’s lead section does not adequately summarize key points of its contents. Output decreased due to cooling after induction. Mode of operation[ 2456 ]. The dial setting should be turned up to compensate. The Sevoflurane vapour pressure in the vapour chamber is 15kPa.

It evaporates a chamber containing desflurane using heat, and injects small amounts of pure desflurane vapor into the fresh gas flow.

Modern Anaesthesia Vapourisers

The thermostat deflects according to its temperature to control the resistance offered to the flow of gas through it. Vapouriser leaks Even a small leak at the outlet from a vapouriser can result in preferential loss of anaesthetic agent from the circuit causing awareness.

Used in GE machines. anaesthseia

At any given temperature, a point of dynamic equilibrium will come to exist where the number of molecules leaving the liquid phase equals the number re-entering it—at this point, the vapour is saturated and the pressure it exerts is known as the saturated vapour pressure SVP. The most commonly used methods are: Another failure of Selectatec block. A loose filler cap is the commonest source of vapouriser leaks. The effect of altitude on vaporizer performance is controversial.

Bimetallic anwesthesia tended to stick due to residual thymol in Vaporizerrs.