Anesthesia machines receive pressurized medical gases and control the flow of each gas individually. The machine creates a gas mixture with the desired composition and flow rate. Then, a known concentration of inhalational agent vapor is added. 

Anesthesia Key

Here are some other details about how anesthesia machines work: 

A pressure-reducing valve reduces the high-pressure gas to a stable gas.

The flow meter adjusts to produce a certain amount of gas for the anesthesia machine.

The anesthetic is volatilized.

The selected fresh gas flow mixture passes through a vaporizer.

A safety interlock exists that should only allow one volatile agent to be dispensed into the fresh gas flow at a given time.

The O2 flush valve allows for the immediate delivery of a large volume of oxygen into the circuit.

Individual gases move through the anesthesia machine via a system called the back bar.

The gases are mixed and delivered to the patient via the common gas outlet (CGO).

Accurate measurement of individual gas flows is essential to deliver a safe anesthetic.          

The modern anesthesia workstation is an integrated unit consisting of the following components: Basic components of anesthesia machine unit (including gas delivery, electronic flowmeters, vapourizers, breathing circuit, scavenging system) Advanced Ventilation. Anesthesia and patient monitoring system

Anesthesia machines have four basic subsystems: 

Gas supply and control circuit

Breathing and ventilation circuit

Scavenging system

System function and breathing circuit monitors

Anesthesia machines also include the following components: 

Connections to piped oxygen, medical air, and nitrous oxide

Flowmeters

Vaporizers

Oxygen pressure-failure device (fail-safe) and alarm

Here are some details about these components: 

Flowmeters

These devices control and deliver gases to the common gas outlet. They can be either electronic or constant-pressure variable-orifice types. Traditional flowmeters have a needle valve for mechanical control and a glass tube with bobbin for display.

Vaporizers

These devices take liquid anesthetics and turn them into vapors so patients can inhale them. Vaporizers have a concentration control dial, bypass chamber, vaporizing chamber, filler port, and filler cap.

Anesthesia machines can be divided into three basic areas: a high-pressure system, an intermediate pressure system, and a low-pr

essure system.