Many patients admitted to the emergency department (ED) use anticoagulants, mostly vitamin K antagonists (VKA). Newman et al.  showed that the majority of patients in the ED using VKA had a sub- or supra-therapeutic international normalized ratio (INR). Chronic anticoagulation is associated with an increased risk of bleeding, which is related to the degree of anticoagulation, e.g., the height of the INR . Patients using VKA presenting to the ED with hemorrhage have increased morbidity and mortality compared with patients not using VKA.
In addition to resuscitation measures, standard treatment of VKA-associated bleeding includes improvement of coagulation status. Vitamin K, fresh frozen plasma, or prothrombin complex concentrate (PCC, Co-fact©) are the most used treatment options in the Netherlands.
Sanquin, the Federation of Dutch Thrombosis Services and manufacturer/supplier of Co-fact©, provides a dosing regimen (Additional file 1) in which the proposed amount of PCC to be administered is related to the INR at presentation, the weight of the patient, and the desired target INR. This desired target INR depends on the indication: a target INR ≤ 2.1 is the aim in case of a minor (urgent) surgery or serious overdosing of anticoagulant with bleeding complications, while a target INR ≤ 1.5 is the aim for severe bleeding complications with hemodynamic instability or cerebral bleeding, or if acute surgical intervention is needed [3, 4].
Through regular use in our ED, we observed that treatment with Co-fact© is not optimal in every case. Desired INR target values are not always reached, with patients being over-treated with PCC and thus reaching lower INR values than necessary. There are also patients in whom the INR stays above the desired value. Both these outcomes may be unfavorable for the patient. The risk of an INR value above the desired target in an actively bleeding patient is evident. On the other hand, reversing VKA anticoagulation therapy to unnecessarily low INR values may come with thrombotic risks. These risks may vary with each individual patient, depending on their indication for VKA therapy and risk stratum [5, 6]. Apart from this risk, the patient is additionally administered an excess amount of drug that was not needed. This results in unnecessary costs and may present problems with restoring anti-coagulated state later on.
The aim of this study was to evaluate whether adequate INR values were reached when administering Co-fact© to ED patients using the Sanquin treatment protocol. We evaluated the results of this protocol in two different INR target groups (group 1, target INR ≤ 1.5; group 2, target INR 1.6–2.1).