EasyOne Pro™ / EasyOne Pro™ LAB
165
Appendix
One convenient approach is
The Moment ratios MR1 = M
1
/M
0
and MR2 = M
2
/M
0
can then be calculated
easily.
The parameters can be described as follows [17]: M0 can be considered as
the area under the washout curve, while Moments of higher order are the
sum of weighted area segments. The tail of the curve is given more weight
for successively higher Moments.
LCI and Moment ratios are both related to the number of volume turnovers.
LCI is a static value of the number of volume turnovers needed to reduce
end-tidal nitrogen concentration to 2%, while the latter is a dynamic
measure of MBNW.
Moment analysis has been described by several authors (see
on page 165 [17] to [21]). Clinical use of Moment Analysis is still limited
since reference values from larger groups are not yet available.
12.11
Literature
[1]
American Thoracic Society. Standardization of Spirometry: 1994
Update, Nov. 11,1994. Am J Resp Crit Care Med 1995; 152:1107-
1136.
[2]
Occupational Health and Safety Administration (OSHA), Pulmonary
Function Standards for Cotton Dust, 29 CFR: 1910.1043 Appendix D.
[3]
Social Security Administration Disability (SSD) Guidelines, CFR404:
Appendix 1 to Subpart P.
[4]
Ferguson GT, Enright PL, Buist AS, et al. Office spirometry for lung
health assessment in adults: A consensus statement from the
National Lung Health Education Program. Chest 2000; 117:1146-
1161.
[5]
ATS Pulmonary Function Laboratory Management and Procedure
Manual, American Thoracic Society, New York, NY 10019.
[6]
Enright PL, Hyatt RE. Office Spirometry. Lea & Febiger, Philadelphia,
1987.
[7]
Hyatt, RE, Scanlon PD, Nakamura M. Interpretation of Pulmonary
Function Tests - A Practical Guide. Lippincott - Raven, Philadelphia,
1997.
Mr
k
r
A
k
k
k
1
–
–
k
0
=
x
=