Opal Episodes
In Opal a Patient may have one or many Episodes. An Episode contains some metadata such as a start and end date, and the type of episode. This may be an inpatient stay, an outpatient treatment, a telephone consultation - or any other arbitrarily defined period of care.
Episode Categories
An episode must have a related category. An Opal EpisodeCategory
is a discoverable
subclass of opal.core.episodes.EpisodeCategory
- such as InpatientEpisode
,
OutpatientEpisode
or LiaisonEpisode
.
You can access the current category of an episode via the category
property, while
it is represented in the database in the field category_name
which will contain
the display_name
attribute of the relevant category.
episode = patient.episode_set.first()
print episode.category
# <{{ your app name }}.InpatientEpisode object>
print episode.category.display_name
# "Inpatient"
print episode.category_name
# "Inpatient"
Detail templates
The category of an episode determines which template will be used to display it
on the detail page for the patient. This template is determined by looking up
the detail_template
attribute of the EpisodeCategory
.
The Episode Category template does not comprise the entire Patient detail view. This is made of multiple episodes and by default will display some basic demographic details as well as other episodes. More detail on customising the rest of the detail tempalte is found in the detail view Template selection docs.
Default Category
The default category of episodes in an Opal application is set by the OpalApplication object's default_episode_category property.
class Application(application.OpalApplication):
default_episode_category = MyCategory.display_name
Defining your own EpisodeCategory
As EpisodeCategory is a discoverable we can define our own to meet custom requirements.
Episode categories should be defined in a file named episode_categories
of
your application or plugin.
# yourapp/episode_categories.py
from opal.core import episodes
class DropInClinicEpisode(episodes.EpisodeCategory):
display_name = "Drop-in clinic"
detail_template = "detail/drop_in.html"
Episode.active
The field .active
is used to distinguish Episodes which are ongoing. This field
is set implicitly by the Episode.save()
method, and there will generally be no
need to set this field directly as part of application code.
Whether an Episode is considered active is determined by the .is_active()
method
of the relevant EpisodeCategory.
The default implementation considers any Episode without an .end
date to be active
and any Episode with one to be inactive.
Applications may customise this behaviour by overriding the .is_active()
method.
For instance, to create a category which considered any Episode older than 2 weeks to be inactive, one might override the method as follows:
# yourapp/episode_categories.py
import datetime
from opal.core import episodes
class TwoWeeksAndStopCaringEpisode(episodes.EpisodeCategory):
def is_active(self):
delta = datetime.date.today() - self.episode.start
return bool(delta >= datetime.timedelta(days=14))
(Note that this would not alter the value in the database immediately after those 2
weeks, but would alter the value the next time the Episode.save()
method was called.)
Episode stages
An Episode will frequently consist of a number of possible stages. For instance, for an inpatient episode, a patient will first be an inpatient, and then an be discharged, with an optional interim follow up stage for inpatients who have been discharged but requrie further follow up.
Opal stores the stage of an episode as a string in the stage
property of an
Episode
. The valid possible stages for a category are accessed from the
get_stages
method of the category.
episode.category.get_stages()
# ['Inpatient', 'Followup', 'Discharged']
episode.category.has_stage('Followup')
# True