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| Typical Number in Hospital: 50 | Cost Bands: 3 | References: 2 |
For analgesia during labour, emergency surgery and dental surgery it is common to use a demand flow, or intermittent flow machine. A bag or reservoir is filled with the required gases (usually nitrous oxide and oxygen) at slightly above atmospheric pressure, and the patient inhales this gas via a low-pressure valve on demand. Some machines such as the Entonox apparatus use a premixed gas from a cylinder, while others such as the Walton 5, Mckesson, Lucy Baldwyn, AE, and Quantiflex RA actually mix the gases to a formula determined by control settings.
Demand flow systems may also include a low-resistance vaporizer in a draw-over circuit.
Content and Design Copyright 2000 Dr. Malcolm C Brown. See Title Page for more details