GE MOA 280i, Operation And Maintenance Manual

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GE Analytical Instruments ©2006
7-8
DML 14291 Rev. A
beginning [NO] and the beginning [NO] is selected as the exhaled NO value.
Flow/Pressure Characteristics of Accurate NO Restrictors
The flow rates (mL/s BTPS at 760 torr) obtained during exhalation as a function of
mouth pressure from 5 to 25 cm H
2
O for the restrictors in the Accurate NO Breath
kit are shown in Figure 7-6. The data can be fit to a logarithmic curve and the
equations for each restrictor shown in the figure. The REB program uses these
curves to calculate the flow for a given mouth pressure. Table II lists the mouth
pressure required to obtain the target flow for each restrictor.
Table II. Pressures Required to achieve Target Flows for Restrictors
Restrictor #/Target Flow Required Pressure (760 torr Atmospheric Pressure)
cm H
2
O torr mbar
#1 (30 mL/s) 8-9 6 8-9
#2 (50 mL/s) 16 12 16-17
#3 (100 mL/s) 11-12 8-9 11-12
#4 (150 mL/s) 12-13 9-10 13
#5 (200 mL/s) 12 8-9 12-13
#6 (250 mL/s) 13-14 9-10 13-14
Models of Nitric Oxide Production in the Airways
Several groups have published mathematical models of NO production in the
airways. By measuring the concentration of exhaled NO at different expiratory
flow rates, these models permit calculation of additional parameters such as
diffusing capacity, wall concentration and alveoli NO concentration. The
restrictors included with the Accurate NO breath kit permit measurement at
different flow rates from 30 to 250 mL/s BTPS for use with the following models.
The published models include:
Tsoukias, N.M., George, S.C. “A two-compartment model of pulmonary
nitric oxide exchange dynamics”. J Appl Physiol 1998; 85(2): 653-666.