Department of Anesthesiology, Warren Alpert Medical School of Brown University, Providence, RI.
Division of Hematology and Oncology, Department of Medicine, Northwestern University Feinberg School of Medicine.
Reg Anesth Pain Med. 2018 Aug;43(6):616-620. doi: 10.1097/AAP.0000000000000782.
The American Society of Regional Anesthesia and Pain Medicine guidelines recommend discontinuation of warfarin and an international normalized ratio (INR) of 1.2 or less before a neuraxial injection. The European and Scandinavian guidelines accept an INR of 1.4 or less. We evaluated INR and levels of clotting factors (CFs) II, VII, IX, and X 5 days after discontinuation of warfarin.
Patients who discontinued warfarin for 5 days and had an INR of 1.4 or less had activities of factors II, VII, IX, and X measured. The primary outcome was the frequency of subjects with CF activities of less than 40%.
Twenty-three patients were studied; 21 (91%) had an INR of 1.2 or less. In these 21 patients, the median (interquartile range) activities of factors II, VII, IX, and X were 66% (52%-80%), 114% (95%-132%), 101% (84%-121%), and 55% (46%-63%), respectively. Ninety-five percent (99% confidence interval, 69%-99%) had CF activities of greater than 40%. The patient who did not CF activities greater than 40% had end-stage renal disease. Two subjects had an INR of greater than 1.2; the activities of factor II, VII, IX, and X were 37% and 46%, 89% and 105%, 66% and 78%, and 20% and 36%, respectively. Neither patient had CF activities of greater than 40%.
Based on 40% activity of CFs, patients with INRs of 1.2 or less can be considered to have adequate CFs to undergo neuraxial injections. The number of patients with an INR of 1.3 and 1.4 is too small to make conclusions.
美国区域麻醉与疼痛医学学会指南建议在进行脊神经根注射前停止使用华法林和 INR 达到 1.2 或更低。欧洲和斯堪的纳维亚指南接受 INR 达到 1.4 或更低。我们评估了停止使用华法林 5 天后 INR 和凝血因子（CFs）II、VII、IX 和 X 的水平。
INR 为 1.4 或更低且停止使用华法林 5 天的患者测量了因子 II、VII、IX 和 X 的活性。主要结果是 CF 活性小于 40%的患者的频率。
23 名患者进行了研究；21 名（91%）INR 达到 1.2 或更低。在这 21 名患者中，因子 II、VII、IX 和 X 的中位数（四分位间距）活性分别为 66%（52%-80%）、114%（95%-132%）、101%（84%-121%）和 55%（46%-63%）。95%（99%置信区间，69%-99%）的 CF 活性大于 40%。CF 活性大于 40%的患者有终末期肾病。2 名患者的 INR 大于 1.2；因子 II、VII、IX 和 X 的活性分别为 37%和 46%、89%和 105%、66%和 78%以及 20%和 36%。这两名患者的 CF 活性均未大于 40%。
根据 CFs 的 40%活性，INR 达到 1.2 或更低的患者可被认为具有足够的 CFs 进行脊神经根注射。INR 为 1.3 和 1.4 的患者数量太少，无法得出结论。
