GE Analytical Instruments ©2006 7-6 DML 14291 Rev. A
F
i
ure 7-5: Possible NO
Plateaus.
filter. NO levels start high, drop during inhalation, then increase to reach a
plateau after ~ 10 seconds.
To measure exhaled NO:
• Have the subject comfortably seated with a clear view of the computer
monitor or the NOA’s front panel display. For children < 12, ATS
recommendations suggest the subject breath room air for 5 minutes prior to
the test.
• Install a new bacterial and viral filter and a sterile blue mouthpiece on the
breath kit.
• Instruct the subject on how to perform the maneuver, in particular, it is
important to have the subject inhaled through the breath kit and they must
inhale through the breath kit if the inspiratory gas filter or Tedlar bag is being
used.
• Have the subject inhale to TLC and immediately exhale while maintaining the
pressure at 16 cm H
2
O (should be between 13 – 19 cm H
2
O), adjusting the force
of exhalation as required to maintain the desired pressure/flow.
• After the NO levels have reached a stable plateau for the required duration,
have the subject stop the exhalation and rest for at least 30 seconds between
measurements.
• After 3 replicate measurements that agree within 10% are obtained, remove
and discard the bacterial and viral filter and sterilize the blue mouthpiece
before the next subject.
Selection of NO Plateau
The ATS
recommendations define
the plateau as the first 3
second interval (2
seconds for children <
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