Malinoski Darren, Jafari Fariba, Ewing Tyler, Ardary Chris, Conniff Heather, Baje Mark, Kong Allen, Lekawa Michael E, Dolich Matthew O, Cinat Marianne E, Barrios Cristobal, Hoyt David B
Department of Surgery, University of California, Irvine Medical Center, Orange, California 92868, USA.
J Trauma. 2010 Apr;68(4):874-80. doi: 10.1097/TA.0b013e3181d32271.
Deep venous thromboses (DVT) continue to cause significant morbidity in critically ill patients. Standard prophylaxis for high risk patients includes twice-daily dosing with 30 mg enoxaparin. Despite prophylaxis, DVT rates still exceed 10% to 15%. Anti-Xa levels are used to measure the activity of enoxaparin and 12-hour trough levels <or=0.1 IU/mL have been associated with higher rates of DVT in orthopedic patients. We hypothesized that low Anti-Xa levels would be found in critically ill trauma and surgical patients and that low levels would be associated with higher rates of DVT.
All patients on the surgical intensive care unit (ICU) service were prospectively followed. In the absence of contraindications, patients were given prophylactic enoxaparin and anti-Xa levels were drawn after the third dose. Trough levels <or=0.1 IU/mL were considered low. Screening duplex exams were obtained within 48 hours of admission and then weekly. Patients were excluded if they did not receive a duplex, if they had a prior DVT, or if they lacked correctly timed anti-Xa levels. DVT rates and demographic data were compared between patients with low and normal anti-Xa levels.
Data were complete for 54 patients. Eighty-five percent suffered trauma (Injury Severity Score of 25 +/- 12) and 74% were male. Overall, 27 patients (50%) had low anti-Xa levels. Patients with low anti-Xa levels had significantly more DVTs than those with normal levels (37% vs. 11%, p = 0.026), despite similar age, body mass index, Injury Severity Score, creatinine clearance, high risk injuries, and ICU/ventilator days.
Standard dosing of enoxaparin leads to low anti-Xa levels in half of surgical ICU patients. Low levels are associated with a significant increase in the risk of DVT. These data support future studies using adjusted-dose enoxaparin.
深静脉血栓形成（DVT）持续导致重症患者出现严重的发病情况。高危患者的标准预防措施包括每日两次给予30毫克依诺肝素。尽管采取了预防措施，DVT发生率仍超过10%至15%。抗Xa水平用于测量依诺肝素的活性，在骨科患者中，12小时谷浓度≤0.1 IU/mL与较高的DVT发生率相关。我们推测重症创伤和外科手术患者中会发现低抗Xa水平，且低水平与较高的DVT发生率相关。
对所有在外科重症监护病房（ICU）接受治疗的患者进行前瞻性随访。在没有禁忌证的情况下，患者接受预防性依诺肝素治疗，并在第三次给药后检测抗Xa水平。谷浓度≤0.1 IU/mL被视为低水平。在入院后48小时内及之后每周进行一次双功超声筛查。如果患者未接受双功超声检查、有既往DVT或缺乏正确时间点的抗Xa水平，则将其排除。比较抗Xa水平低和正常的患者之间的DVT发生率及人口统计学数据。
54例患者的数据完整。85%的患者为创伤患者（损伤严重度评分25±12），74%为男性。总体而言，27例患者（50%）抗Xa水平低。抗Xa水平低的患者发生DVT的情况显著多于抗Xa水平正常的患者（37%对11%，p = 0.026），尽管两组患者在年龄、体重指数、损伤严重度评分、肌酐清除率、高危损伤以及ICU住院/机械通气天数方面相似。
依诺肝素的标准剂量导致一半的外科ICU患者抗Xa水平低。低水平与DVT风险显著增加相关。这些数据支持未来使用调整剂量依诺肝素的研究。
