Warfarin Dosing Tool

From the Warfarin dose screen clinicians can easily monitor and calculate INR and Warfarin dosing respectively. It can only be accessed when a New Diagnosis Indication has been entered through the Warfarin screen, see Warfarin/INR Diagnosis . The dosing tool looks at the previous INR and dose history and calculates the new weekly dose.

Note - The following error message displays if the patient's current daily dose does not equal their total weekly dose. Usually this is because the patient's weekly dose has been deleted or updated in their record and the journal entry does not match the Warfarin dosing tool. If you want to check if a patient's record has been updated you can do an audit trail, see Audit Trail.

Reminder - INR and Warfarin dose historical data must be available in Anticoagulation Manager in order for the correct dosing calculations and recalls to be performed. A minimum of one INR result and dose history is required, however, in order for the correct recall interval to be performed it is recommended that you record between three and five INR's and dosing histories. Where the patient has more than five INR's recorded, only the last five are considered.

The screen is split into four tabs. The main INR and Dose tab is the one from where the calculation is performed. The topics below explain the different sections and tabs within the Warfarin Dosing Tool screen.

Viewing Current INR Dose

This area of the Warfarin Dose screen gives details of the current diagnosis indication, previous INR value and previous weekly dosing regime, along with relevant dates. The information in this section is for reference purposes only and cannot be changed. Any data that is recorded into the patient's record automatically populates on this screen.

  • Start Date - This section shows the patient's Diagnosis Indication date and their INR target.
  • INR Date - The patient's last INR result displays alongside the date.
  • Dose Date - This shows the patient's current daily dose over a week.
  • Recall Date - This is the date when the patient should next be seen. The recall interval is based on the patient's INR doses. The more INR results recorded when starting to use Anticoagulation Manager the more accurate the recall date will be.

Adding a New INR and Dose

The information in this section is for the new INR details and dose. To record a New INR value and allow Warfarin Management to recommend a dosing regime do the following:

  1. Type directly into the INR box the new INR value, or if you receive lab results directly into Vision, the results are automatically populated and show the latest entry in the Current INR section.
  2. The Advised Warfarin Adjustment is shown. If correct, click on the Use button to allow the regime to be calculated. Select either Round Up or Round Down if displayed. (If the dose cannot be achieved with the tablet strengths available then the option to round the weekly dose Up or Down will become available and must be selected before clicking on Use).
  3. To prescribe the same Warfarin dose for each of the days make sure a tick is placed in the Same Daily Dose box. Clearing this will allow Vision+ to calculate a Warfarin dose that may be different from day to day in order to allow the exact weekly Warfarin dose to be prescribed. This check box will affect the Round Up and/or Round Down warfarin dose values.
  4. The weekly dosing regime will then be shown, and can be printed out and given/posted to the patient by clicking on Print A4 Report.
  5. The recommended Recall date is shown or can be recorded by choosing a date from the calendar. The recall intervals are taken from the patient's INR history as below:
    • One latest INR within range the recall interval is set to One week
    • Two latest INR's within range the recall interval is set to Two weeks
    • Three latest INR's within range the recall interval is set to Four weeks
    • Four latest INR's within range the recall interval is set to Six weeks
    • Five latest INR's within range the recall interval is set to Eight weeks
    • Six latest INR results within range equals a Ten week recall
    • Seven INR results within range equals a Twelve week recall
  6. Optionally, the INR and Warfarin Dose data can be viewed on the History and Trends Tab.
  7. Select OK to save the changes to the Warfarin Dosing Tool screen.

    Important - The patient's weekly dosing requirements are recorded in their journal.

Algorithm Initiation Period

You are warned if the Warfarin Dose tool is not suitable for use in the first two weeks of initiation of Warfarin and advised that the patient's recall is limited to the Maintenance period of one week. You are allowed to proceed but all recall calculations are made according to this Maintenance period.

Note - The patient's initial period is based on the start date of the Diagnosis Indication.

New Weekly Dose

When calculating a patient's weekly dose, it is sometimes necessary to stop the warfarin dose for a day, then advise the patient to start a new weekly dose in a couple of day's time. The Warfarin Dosing tool makes the next weekly dose information visible in the dosing tool.

You see the following message on the Warfarin Dose screen, advising that the patient must miss 1 day and displays their new weekly dose.

The patient's record is also updated with a clinical term for Warfarin Weekly Dose with a comment of zero (0) to indicate that the patient must not take Warfarin along with the new recommended weekly dose.

INR Manual Dose Warning Message

The following warning displays if a patient's INR result peaks above 8 within the Warfarin Dose tool and a manual dose is not entered.

High INR Adjustment

If a patient has a high INR, then the INR returns to below 5 and the patient has a therapeutic range lower than 3.5 the following warning message is shown advising that the tool cannot calculate a dose and a manual dose should be entered: