Medication management as instructions, actions and lists

Medication management is one of the most complex issues in health care computing, particularly in the distributed computing environment that openEHR aims to support. Illustrations of this complexity include:

Coding of medications may or may not include form and strength;
Ongoing and short term prescribing have different status within the EHR, number of repeats applies to both;
Ongoing medication lists need to be maintained based on communication from patient and other providers;
Current medication is a view of medication orders in the health record and may comprise ongoing and short term medication;
The state (completed, active, suspended etc) of a compound medication order will depend on the state of each order within it;
Timing of medication administration may include frequency, start and stop conditions and other variables; and
Continuous and intermittent infusions can piggyback a number of medication which may have different rates (e.g Chemotherapy, bolus medication in emergency etc).

Data groups related to a medication order or administration

Key groups include: (Note * indicates features that may differ from the instruction at the time of administration.)

Medication identification

Identifying the medication is a key requirement. This may include:

Generic name
Trade name*
Form*
Strength*
Pack (size, applicator etc)
Appropriate administration route(s)

Dosage and frequency

Dose unit (tab, puff, capsule, mls etc)*
Number of dose units (1, 2, 1-2, half, 1 and half)*
Frequency
Association with events (with meals, before travelling, before going to bed)*
Conditions (with pain, on an empty stomach)*
Duration of dose (over 20 mins, over 24 hours)*
Only when required

Administration information

Route*
Site*
Device*

Organisational information

Number of repeats/refills
Review interval

The approach has to deal with dispensing records (as these may use a different trade name and add instructions to the patient) as well as have non-clinical aspects such as deferred supply.

Prescribing and Dispensing

Information about an order may be specific to one prescription rather than to the order itself. Such information may include endorsements by the prescriber for a financial subsidy, altered supply conditions or may require authorisation of some kind to be recorded. Connecting the order with the dispensing process clearly reduces transcription errors but adds complexity as different brands and even substances may be dispensed at time. Dispensing may also be delayed or reversed.

The use of Instruction and Action Classes

It has taken many years of experiments and discussion to come up with the Instruction and Action classes to support workflow. These classes allow statements, using the action class, to be made when acting on an instruction that refer to the instruction but do not alter it. The state of the activity in the instruction is actually derived from the sum of action statements made with reference to that activity. The result is that a medication administration may leave the state of a medication order as 'active' or 'completed'. A decision not to administer a medication may leave the state of the medication order as 'cancelled' (if not started), 'suspended' or 'aborted' if not started. An action such as withheld may even leave the instruction as active.

The proposed actions that might be recorded against a medication order are:

Plan Careflow step	The medication is planned but no execution has taken place.	Current state: initial
Plan suspended Careflow step	The plan to order medication has been suspended.	Current state: postponed
Cancelled order Careflow step	The planned administration has been cancelled prior to any administration.	Current state: cancelled
Start time set Careflow step	The time to start this medication has been set.	Current state: scheduled
Issue item prescription Careflow step	The order has been transfered to the dispensary.	Current state: active, initial
Dispense medication item Careflow step	The medication has been dispensed.	Current state: active, initial
Commence medication item administration Careflow step	The medication has been taken by the patient for the first time.	Current state: active
Review medication item Careflow step	The medication has been reviewed.	Current state: active
Administer medication item Careflow step	A single administration of the medication has taken place.	Current state: active
Re-issue item prescription Careflow step	The medication has been re-prescribed for an existing order.	Current state: active
Medication item withheld Careflow step	The administration of a medication has been withheld and not given.	Current state: active
Medication item refused Careflow step	An administration of the medication was refused by the patient.	Current state: active
Reverse item dispense Careflow step	A dispensed medication is returned or not collected without use.	Current state: active, initial
Delayed supply Careflow step	The medication has not been dispensed as supply is not yet available.	Current state: suspended
Suspended administration Careflow step	The administration of the medication has been suspended.	Current state: suspended
Suspended re-order Careflow step	Reordering of this medication is not available.	Current state: suspended
Administration ceased Careflow step	The administration of this medication has been ceased before anticipated completion.	Current state: aborted
Reverse prescription Careflow step	The prescription has been cancelled but administration or dispensing may have occurred.	Current state: aborted
Completed Careflow step	The medication has been completed as prescribed.	Current state: completed

If we think about medication (and there is some detail of this in the openEHR specifications) there are a number of lists of medication a clinician would like to access. Such lists might include:

All medications ever given
All current medications
All long term medications
All short term medications
Medications stopped in hospital
Medications with altered doses..