(c) Some of the gas which enters the small breathing bag flows
through the scavenging valve into the gas evacuation system. The anesthetist may
administer gas in the breathing bag to the patient by squeezing the breathing bag. The
anesthetist determines the amount of gas allowed to escape through the scavenging
valve. He also determines the amount of gas delivered to the patient from the breathing
bag. This provides the anesthetist the flexibility needed to anesthetize small infants as
well as larger children.
(d) The anesthetist always keeps the gas evacuator/relief valve
completely closed when using the pediatric partial re-breathing circuit. To relieve
excess pressure as shown on the breathing circuit pressure gauge, the apparatus uses
the nonadjustable pressure relief valve.
PREOPERATIVE TESTS AND PROCEDURES
To ensure the operational efficiency of the Ohmeda Anesthesia Unit before any
operation, you must perform a series of preoperative tests and procedures. While not a
true PMCS of the anesthesia apparatus, these tests and procedures ensure that the unit
is serviceable and can be safely operated.
a. Operational Checkout. The operational checkout tests the overall
functioning of the apparatus.
Connect the oxygen and nitrous lines to the gas cylinders.
Connect the test lung to the patient connection.
(3) Slowly turn on all three flow meters to ensure they work. Turn on one
flow control valve at a time; then shut it off. Leave the N2O flow control valve on.
(4) To check the pressure sensor valve, unplug the oxygen line from the
cylinder. The nitrous ball in the flow meter must drop to zero flow.
Attach the oxygen line to the gas cylinder.
Turn the N2O flow control valve off.
(7) Press the oxygen flush and observe the pressure gauge. The gauge
should rise slowly as you pressurize the system.
(8) Pressurize the system until the gauge shows a pressure of
approximately 25 centimeters of water (cm H2O).
(9) Release the oxygen flush. The system should hold pressure with the
vaporizer ON and OFF.