Anesthesia Machine: Pressure Regulation

Basic, Basic Sciences

Anesthesia machines have high, intermediate, and low pressure circuits. These are regulated by safety devices built within the machine to ensure optimal delivery to the patient.

  1. High-pressure circuit: E-cylinders attached to back of machine, Oxygen 2200psi, Nitrous Oxide 745psi. Gas travels from cylinder to first pressure regulator in anesthesia machine. Pressure regulator reduces it to a more constant pressure, 45psi. Machine is also set to only use pipeline gas (set at 50psi) so as not to waste gas cylinder content.

  2. Intermediate pressure circuit: at approximately 45 psi. Receives gas from first pressure regulator or wall pipeline, extends to second-stage reducing device. Flush valve delivers gas to common gas outlet (and subsequently to the patient) directly from intermediate circuit.

  3. Low-pressure circuit: at second stage reducing device, gas is reduced to 26psi N2O and 14psi for O2. Extends from flow control valves to common gas outlet.

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2017

Year asked

Author
Kamilla Esfahani, MD