Abstract

Background: There are potential risks associated with the use of warfarin in children, particularly as the dosing requirements may decrease as patients get older.

Context: Our facility is a 715-bed freestanding pediatric tertiary care center with a large cardiac surgery center. A significant number of patients receive warfarin for treatment or prophylaxis of thromboembolic events while in hospital.

Key measures for improvement: Initial dose of warfarin and time taken to achieve goal therapeutic international normalized ratio (INR).

Strategies for change: The intervention included: (1) revision of hospital drug formulary so that warfarin dosing was in accordance with the most recent guidelines; (2) warfarin administration restricted to one time of the day (12.00 noon); (3) target therapeutic INR level documented with each warfarin order; and (4) pharmacy computer system mandated that the pharmacist confirmed the target INR, documented the most current INR, and compared the dose with the formulary guidelines. If the warfarin dose was not in accordance with the formulary guidelines, the pharmacist contacted the physician and made dosing recommendations according to the guidelines.

Effects of change: The number of patients with supratherapeutic INR values during the hospital admission was decreased by more than 50% and goal INR values were documented more frequently in the medical record. There was also an increase in subtherapeutic INR values. The intervention had no effect on the time taken to achieve the goal therapeutic INR.

Lessons learned: Instituting changes in a number of aspects of anticoagulation management and incorporating an intensive educational effort across a breadth of healthcare providers can improve anticoagulation management with warfarin in challenging patient populations such as children. Similar methods could possibly improve anticoagulation with other agents such as unfractionated heparin or low molecular weight heparin.