Changes

==Gas supply==

==Gas supply==

A supply of gas to an anaesthetic machine can be either from cylinders or a piped source. Gases that commonly used are oxygen, medical air and nitrous oxide.

A supply of gas to an anaesthetic machine can be either from cylinders or a piped source. Gases that are commonly used are oxygen, medical air and nitrous oxide.

===Cylinders===

===Cylinders===

[[Image:pressure gauge.jpg|right|thumb|125px|<small><center>Pressure Gauge</center></small>]]

[[Image:pressure gauge.jpg|right|thumb|125px|<small><center>Pressure Gauge</center></small>]]

==Pressure Gauge==

==Pressure Gauge==

Pressure gauges indicate the pressure of gas in the pipeline of cylinders. Depending on the age of the machine they may be found above the cylinder yoke, or on the front panel of the machine. They are colour-coded and calibrated for each gas/vapour. While this oxygen gauge measures the pressure within the cylinder, which is directly related to the contents of the cylinder, the nitrous oxide gauge measures the saturated vapour pressure of the gaseous nitrous oxide and so does not indicate the fullness of the cylinder, and will only start to show a drop in pressure as the liquid nitrous is running low.

Pressure gauges indicate the pressure of gas in the pipeline of cylinders. Depending on the age of the machine they may be found above the cylinder yoke, or on the front panel of the machine. They are colour-coded and calibrated for each gas/vapour. While this oxygen gauge measures the pressure within the cylinder, which is directly related to the contents of the cylinder, the nitrous oxide gauge measures the saturated vapour pressure of the gaseous nitrous oxide and so does not indicate the fullness of the cylinder, and will only start to show a drop in pressure as the liquid nitrous is running low.