(e) A line of independent oxygen flows to the "O2 for vaporizer" flow
control valve, flow meter, and the oxygen flush valve. Pure oxygen is necessary to
operate the vaporizer. When the flow control valve is open, it admits oxygen to a
series-connected high-flow and low-flow flow meters. This oxygen does not flow
through the common mixing passage. When the vaporizer control knob is ON, the
oxygen flows through the vaporizing chamber. Oxygen serves as a "vehicle" to carry
the vapor out of the vaporizing chamber. This vapor-saturated oxygen mixes with the
oxygen-nitrous oxide mixture flowing from the common mixing passage. If the vaporizer
control knob is OFF, all vehicle oxygen bypasses the vaporizing chamber flowing
directly to the vaporizer outlet nipple.
(f) The oxygen-nitrous oxide mixture dilutes the vapor saturated
oxygen flow. This results in an amount of anesthetic suitable to the patient. The new
mixture flows into the inhalation breathing tube.
b. The Breathing Circuits: Adult Re-breathing Circuit. Refer to figure 1-1.
(1) Adult re-breathing circuit components. The adult re-breathing circuit
consists of the following items and components:
(a) The breathing circuit pressure gauge.
(b) The nonadjustable pressure relief valve.
(d) The inhalation and exhalation check valves.
(e) The gas evacuation/relief valve.
The large breathing bag.
(g) The breathing tubes and patient connections (Y-connector, elbow,
Adult re-breathing circuit flow.
(a) The patient's breathing and the inhalation and exhalation check
valves control the direction of flow within the breathing circuit. The adjusted total flow of
gases from the delivery circuit flows to the patient via the breathing tube. The breathing
tube leads from the vaporizer to the patient Y-connector.