Welch Allyn CP 150 spirometry option - User Manual - Manual (Page 56)

About composite Norm values
When the primary (selected) norm does not support a given parameter — and when
composite norm values are enabled in the operation settings — the missing value is
filled in from one of the alternative (composite) norm sources, listed here. For example,
since the Crapo norm does not support FEV6, this value is filled in from NHANES III.
Composite Norm Source Parameters Filled In When Not Supported in Primary Norm
NHANES III FVC, FEV1, FEV1%, FEV6, FEV1/FEV6, PEF, FEF25-75
Crapo 1981 FEV0.5, FEV3, FEV3/FVC
Morris 1971 FEF0.2-1.2
ECCS/Quanjer 1993 FEF25, FEF50, FEF75
The primary norm takes precedence over the composite source. For example, since the
Crapo norm supports the FVC parameter, this value always comes from Crapo, not from
the composite source.
Composite values are used when the patient does not fit the demographics of either
primary norm (adult or pediatric). For example, if the primary norms are Kory and Morris,
a 14-year-old patient fits neither norm due to age restrictions. The software would use
values from the appropriate composite norms, for example, NHANES III or ECCS/
Quanjer 1993. It would not use values from Kory or Morris.
On the screen and in reports, an abbreviation identifies the norm source for each
composite value used. For example, the abbreviation for Roca is “ro.”
To enable or disable composite norm values, see Viewing or changing the spirometry
settings.
About lung age
Lung age is a calculated value based on a patient’s demographics and spirometric
performance that gives a relative indication of the health of the subject's lungs. This
value is used primarily to encourage smoking cessation.
The CP 150 spirometer calculates lung age values according to the document Short
Report Spirometric "Lung Age" Estimation for Motivating Smoking Cessation. (Morris
1995). For single-effort tests, lung age is based on the current effort. Otherwise, it is
based on the patient’s “best” effort, as defined in the settings.
Lung age results less than 20 years are reported as “<20,” and results greater than 84
are reported as “>84.” This limitation is derived from the subject population on which
Morris based his research.
Lung age, which is expressed in years, is the average of the four formulas in the Morris
article (FVC, FEV1, FEF25-75%, and FEF0.2-1.2). Specifically, lung age is calculated as
follows:
Gender Lung Age Formula
Men [5.920 (height) – 40.000 (FVC) – 169.640 +
52 Predictive Norms, etc. CP 150 spirometry option