EasyOne Pro™ / EasyOne Pro™ LAB 181
Appendix
Calculation of the Moments requires the integral to be expressed in dis-
cretized form.
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 mea-
sure of MBNW.
Moment analysis has been described by several authors (see "Literature"
on page 182 [17] to [21]). Clinical use of Moment Analysis is still limited
since reference values from larger groups are not yet available.
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