Howell Matthew D, Powers Robert D
Division of Emergency Medicine, University of Connecticut School of Medicine, Farmington, CT 06030, USA.
Am J Emerg Med. 2006 May;24(3):268-70. doi: 10.1016/j.ajem.2005.10.013.
Up to 5% of patients who receive heparin develop heparin allergy (HA), manifested by the presence of heparin antibodies (HAb) and/or the clinical syndrome of heparin-induced thrombocytopenia. As many as 10% of patients with HA develop serious thrombotic complications when reexposed to heparin. Heparin is often given empirically to emergency department (ED) patients, some of whom have been recently hospitalized and are at risk for HA/heparin-induced thrombocytopenia. Emergency department physicians should have a rapid means of determining which patients are at risk for heparin sensitivity. The prevalence of HA among ED patients is unknown; most are asymptomatic and unaware, and there is no bedside test available.
This study was designed to assess the prevalence of HA or thrombocytopenia in ED patients and to determine whether thrombocytopenia could serve as a useful marker for HA.
This was a prospective, observational study, done during the spring of 2004 in an 80000 adult visit inner-city ED. A convenience sample of 115 adult patients undergoing venipuncture had a blood specimen analyzed for platelet count using standard laboratory methods. The same blood sample was tested for the presence of antiheparin antibodies using an enzyme-linked immunosorbent assay test.
Of 115 patients, 12 (10.4%; 95% CI, 6.1%-17.4%) had thrombocytopenia (platelets <150000). Six (5.2%; 95% CI, 2.5%-10.9%) had antiheparin antibodies. There was no overlap between the 2 groups of patients.
(1) Thrombocytopenia occurs in 10% of a sample of 115 adult ED patients undergoing venipuncture in an inner-city ED. (2) Heparin allergy was present in 5% of patients in the same cohort. (3) Thrombocytopenia is neither sensitive nor specific as a marker for HA in ED patients. Heparin-allergic patients are at risk if given heparin; a method of rapid detection of patients with HA should be identified.
接受肝素治疗的患者中，高达5%会发生肝素过敏（HA），表现为存在肝素抗体（HAb）和/或肝素诱导的血小板减少临床综合征。HA患者中多达10%在再次接触肝素时会发生严重的血栓并发症。肝素常经验性地给予急诊科（ED）患者，其中一些患者近期住院，有发生HA/肝素诱导的血小板减少的风险。急诊科医生应有一种快速方法来确定哪些患者有肝素敏感性风险。ED患者中HA的患病率尚不清楚；大多数患者无症状且未意识到，并且没有床边检测方法。
本研究旨在评估ED患者中HA或血小板减少的患病率，并确定血小板减少是否可作为HA的有用标志物。
这是一项前瞻性观察性研究，于2004年春季在一家有80000例成人就诊的市中心ED进行。115例接受静脉穿刺的成年患者的便利样本，采用标准实验室方法对血标本进行血小板计数分析。使用酶联免疫吸附试验检测同一血样中抗肝素抗体的存在。
115例患者中，12例（10.4%；95%CI，6.1%-17.4%）有血小板减少（血小板<150000）。6例（5.2%；95%CI，2.5%-10.9%）有抗肝素抗体。两组患者之间无重叠。
（1）在市中心ED接受静脉穿刺的115例成年ED患者样本中，10%发生血小板减少。（2）同一队列中5%的患者存在肝素过敏。（3）血小板减少作为ED患者HA的标志物既不敏感也不特异。肝素过敏患者使用肝素会有风险；应确定一种快速检测HA患者的方法。
