Events and observations

The observation class has a HISTORY class that allows timing events to be added at design time or when the clinician is collecting data.

Every observation class will have at least one timing event and if there are no constraints added then it will be left as 'Any Event'. This is an abstract idea of an event and when data is collected can be set to be a Point in time event (with a single time) or an Interval when a start and end time are added. Interval events have a maths aggregate function that allows for:

• Total: the sum of the element values over a period of time e.g. blood loss

• Average: the average of the element values over a period of time e.g. pain visual analogue

• Variation: the variation in the element value over a period of time e.g. blood pressure paradox

• Decrease: the reduction in the element value over time e.g. weight loss

• as well as increase, change, mode, actual, median, maximum, and minimum.

In some archetypes it is appropriate to add some specific events as they are common statements made in health care and the labelling can be agreed. Examples include weight loss and weight gain in the weight archetype and paradox measurement of blood pressure.

Some archetypes will have a predefined series of fixed events, and the generic 'Any event' will be removed, as in the Apgar score, where it is inappropriate to record the score at non-standard intervals. This is unusual and should only be done when it is clear that standardisation of timing is part of the benefit of the observation.