Purpose Patients treated with warfarin for therapeutic anticoagulation present a challenge for the perioperative management of urgent and emergent surgery. Anticoagulation must be reversed prior to most surgical procedures to prevent intraoperative bleeding. The purpose of this module is to review the options for urgent reversal of warfarin anticoagulation and the indications for each reversal agent. Selection of the appropriate agent is important to reduce unnecessary complications of treatment and to achieve optimal reversal of anticoagulation. Principal findings When urgent surgery is required for patients taking warfarin, intravenous vitamin K 1 should be used for procedures that can be delayed for six to 12 hr. Vitamin K 1 results in the activation of existing clotting factors rather than requiring the synthesis of new proteins, which allows for its relatively rapid onset of action. Intravenous vitamin K 1 acts more quickly than oral administration, with reversal of anticoagulation occurring within six to 12 hr vs 18-24 hr, respectively. If surgery cannot be delayed, prothrombin complex concentrates (PCCs) should be given, and intravenous vitamin K 1 should be infused concurrently to ensure sustained reversal of anticoagulation. The duration of action of both PCCs and plasma is six hours due to the short half-life of factor VII. Prothrombin complex concentrates contain small amounts of heparin and are contraindicated in patients with heparin-induced thrombocytopenia. Plasma should be used only if PCCs are unavailable or are contraindicated. Conclusion Reversal of warfarin anticoagulation can be achieved in a safe and timely manner when the appropriate agent is selected and administered correctly.
Objectives of this Continuing Professional Development (CPD) module:After reading this module, the reader should be able to: 1. Identify the options for emergency reversal of warfarin anticoagulation; 2. Describe the dose, onset, and duration of action of agents that reverse warfarin anticoagulation; 3. List potential complications and contraindications of agents that reverse warfarin anticoagulation; 4. Choose the optimal agent for emergency reversal of warfarin anticoagulation, considering the timing of the operation and the risks and benefits of each agent.Despite increasing use of novel agents, warfarin remains the most widely prescribed oral anticoagulant in clinical use. A recent analysis of prescribing trends following regulatory approval for the newer agents showed that warfarin still accounted for over 75% of all the oral anticoagulants used. 1 Warfarin is indicated to reduce the risk of thromboembolic events in patients with atrial fibrillation, mechanical heart valves, and deep venous thrombosis, among other indications. Therefore, as the population ages, the use of anticoagulants, including warfarin, is projected to increase substantially.Patients treated with warfarin for therapeutic anticoagulation present a challenge for the perioperative management of urgent and emergent surgery. In order to...
Either AST or ALT can be used for early risk stratification tools when only one is known. Any criterion for N-AC discontinuation should be based on the decline of AST rather than ALT, with a potential benefit measured in days.
Introduction A low-vision assessment (LVA) is central to developing a vision rehabilitation plan. However, access to LVAs is often limited by the quantity and geographic distribution of low-vision providers, as well as patient-centred transportation challenges. A tablet-based LVA tool kit, delivered virtually, has the potential to overcome many of these barriers. The purpose of this research was to validate a key component of the tablet-based tool kit – a commercially available iPad visual acuity (VA) test (Eye Chart Pro) iPad app – in a low-vision population. Methods Participants with low vision ( n = 26) and those who were normally sighted ( n = 25) underwent VA testing with both the iPad VA test application and the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. The VA data were compared using a t-test, linear regression and Bland–Altman analysis. Results There was no significant difference in the mean absolute difference in VA (log of minimum angle of resolution (logMAR)=0.11; p = 0.82). Eye Chart Pro and Standard ETDRS Chart measures were also not significantly different ( p = 0.98). However, there were significant differences between test methods in the low-vision group and the normally sighted group ( p > 0.0001 and p = 0.007, respectively). The Bland–Altman analysis showed a mean bias (difference) of –0.0005 logMAR between methods, and 95% limits of agreement of 0.298 and –0.299 logMAR. Discussion The ETDRS chart function on the Eye Chart Pro application can reliably measure VA across a range, from normally sighted patients to those with low vision.
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