# Logical Record Architecture for Health and Social Care
## Discharge Summary Release 0.02

Contents
The content of this release is not comprehensive and is not fully validated and must not be used in live system implementations.
# Reference Model Class: PQ.Time
This is unchanged in the LRA. It should only be used to represent a duration of time, which has neither end fixed, or for which the duration is totally independent of the timing of the event itself. Where one or other end of the duration can be sensibly placed at a point in time (even with great inaccuracy) an IVL data type should be used instead. PQ.Time should be used where length of time is being used as a measure of a class of event or a theoretical event. Examples could include the specification of duration of uterine contractions during labour, or an expected waiting time, or the result of a timed experiment. This is implemented as described in ISO 21090. ## Specializes ## PQ ## Attributes
Name | Data type | Occurs | Description
--- | --- | --- | ---
translation | PQR | 1..1 | in ISO 21090 the translation attribute specifies a set of equivalent measurements in to non UCUM units (but not between UCUM units). This "translation" is in fact a prospective transformation. It is possible, as with the generalisation PQV to maintain a longitudinal record of performed transformations using the source attribute. A prospective translation in PQ has a single known use case, which is the dual expression of a drug dose in UCUM and DM&D units, which is described in the MiM HL7 data types implementation. For that purpose it is retained. It should not be used for any other purpose unless a clear implementation guide can be produced. This is implemented as described in ISO 21090.
unit | UcumUnitOfMeasure | 0..1 | Attribute constrained for use within the LRA to UcumUnitOfMeasure.
## Constraints
Type | Name | Specification
--- | --- | ---
must be a unit of time | Invariant | inv: canonical.unit = "s"
## Reference Model Type ##