If you haven't already read through the proposed changes for this data type, please take a look at:
http://blogs.msdn.com/healthvaultdatatypes/archive/2008/09/17/for-review-updates-to-spirometer-measurement.aspx
Here is a draft version of the updated data type:
Peak Flow Measurement type
Element
Type
Occurrence
Description
when
approx-date-time
1..1
The date and time of the measurement.
pef
flow-value
0..1
The peak expiratory flow, measured in liters/second.
pef-best
The highest PEF measurement, measured in liters/second.
fev1
volume-value
The forced expiratory volume in one second, measured in liters.
fev6
The forced expiratory volume in six seconds, measured in liters.
measurement-flags
codable-value
Additional information about the measurement.
Examples: Incomplete measurement.
Note: fev1 has been updated from type flow-value to type volume-value to accurately describe this data element.
Volume-Value type
liters
positiveDouble
The volume measurement in liters (L).
display
display-value
The display value for the volume measurement.
The display value contains the volume measurement value stored in the user's preference of units.