OF ANESTHESIA APPARATUS
In this lesson, you will learn how to calibrate the field anesthesia apparatus.
When you calibrate the field anesthesia apparatus, you verify that its output is accurate
to within the manufacturer's specifications. You verify the calibration of the field
anesthesia apparatus by comparing the output shown on the anesthesia gauges against
a known standard. The known standard is the RT200 Calibration Analyzer. The
measurements you make indicate whether the anesthesia apparatus under inspection is
worthy of being in service. You perform calibration/verification when you initially place
the unit in service and anytime you repair or replace any component. You also perform
calibration/verification periodically in accordance with local guidelines. If the unit fails
calibration, you must repair the unit before you return it to service. A properly calibrated
apparatus is essential to ensuring that the anesthetist can safely administer anesthetics.
Calibration/verification of the anesthesia unit ensures that it is safe to use during
PERFORMING CALIBRATION/ VERIFICATION
Perform calibration/verification on the flow tubes by reading the flow meter
gauges. Perform calibration/verification on the re-breathing circuit by reading the re-
breathing circuit pressure gauge. Before you start calibrating, attach the O2 and N2O
cylinders to the Ohmeda 885A. Close the system by connecting the RT200 to the
anesthesia apparatus. These functional tests allow you to ensure outputs are accurate.
Refer to the RT200 manual for hook-up instructions.
a. Checking the Flow Tubes. The function test chart (figure 2-1) shows the
tests you use to calibrate/verify the anesthesia apparatus. You must check both the
N2O and the O2 flow tubes at 1 lpm (liter per minute), at 4 lpm, and at 7 lpm. You check
the vaporizer flow tubes at 0.2 lpm, at 0.5 lpm, and at 1 lpm. For example, to
calibrate/verify the N2O flow tube, you supply N2O to the apparatus. Then conduct
function test 33 at 1 lpm and at 4 lpm; then conduct function test 37 at 7 lpm. When the
flow shown on the flow tube reaches the level in lpm as indicated on the chart, record
the readings on the RT200. You then determine if the difference between the readings
on the RT200 and the flow tube is within the limits of the manufacturer's literature. If the
readings are within the limits, you should proceed to calibrate the O2 and vaporizer flow
tubes. If the readings are not within the limits, the flow tube must be repaired or
replaced. To calibrate the O2 flow tube and the vaporizer flow tubes, repeat the
procedure above with O2 supplied to the anesthesia apparatus (with no N2O supplied).
Each flow tube must successfully complete calibration/verification before you return the
anesthesia apparatus to service.