Koopman Erin, Nix David E, Erstad Brian L, Demeure Michael J, Hayes Melinda M, Ruth John T, Matthias Kathryn R
Saint Mary's Hospital, Mayo Clinic, Rochester, MN, USA.
Am J Health Syst Pharm. 2007 Sep 15;64(18):1927-34. doi: 10.2146/ajhp070047.
The adequacy of end-of-procedure free cefazolin concentrations after administration for the prevention of surgical-site infection (SSI) and compliance with national guidelines for antimicrobial prophylaxis for SSI were assessed.
Patients undergoing elective surgery and receiving cefazolin for perioperative antimicrobial prophylaxis were prospectively enrolled. Antibiotic administration was controlled by the surgeon and usage was recorded. For each patient, a single blood sample for cefazolin serum free and total concentrations was obtained within 15 minutes of wound closure. A free serum concentration threshold of 4 microg/mL was arbitrarily chosen based on the minimum inhibitory concentration required to inhibit 90% of strains of methicillin-susceptible Staphylococcus aureus and Escherichia coli.
Fifty-seven subjects were enrolled, and noncompliance with published guidelines was observed for 26% of patients. Forty-six subjects had serum samples available for assay, 21.7% of whom had end-of-procedure free cefazolin concentrations of <4 microg/mL. Results of multivariate regression and population pharmacokinetic analysis revealed the importance of age and lean body weight in cefazolin clearance. Younger and taller patients had a greater risk of achieving below-threshold end-of-procedure concentrations. Of the patients for whom published guidelines were not followed, 67% had end-of-procedure free cefazolin concentrations below the threshold concentration (4 microg/mL). In contrast, less than 15% of cases where SSI prophylaxis complied with the published guidelines had below-threshold concentrations at the end of surgery.
Noncompliance with antimicrobial prophylaxis guidelines was associated with low end-of-procedure antibiotic levels. Compliance with guidelines did not guarantee adequate levels.
评估手术结束时给予头孢唑林预防手术部位感染（SSI）的游离浓度是否充足以及是否符合国家SSI抗菌预防指南。
前瞻性纳入接受择期手术并接受头孢唑林进行围手术期抗菌预防的患者。抗生素给药由外科医生控制并记录使用情况。对于每位患者，在伤口闭合后15分钟内采集一份用于检测头孢唑林血清游离和总浓度的血样。基于抑制90%的甲氧西林敏感金黄色葡萄球菌和大肠杆菌菌株所需的最低抑菌浓度，任意选择4μg/mL的游离血清浓度阈值。
纳入57名受试者，观察到26%的患者未遵守已发表的指南。46名受试者有可用的血清样本进行检测，其中21.7%的患者手术结束时头孢唑林游离浓度<4μg/mL。多变量回归和群体药代动力学分析结果显示年龄和瘦体重在头孢唑林清除中的重要性。年轻和较高的患者达到低于阈值的手术结束时浓度的风险更大。在未遵循已发表指南的患者中，67%的患者手术结束时头孢唑林游离浓度低于阈值浓度（4μg/mL）。相比之下，在符合已发表指南进行SSI预防的病例中，不到15%的患者在手术结束时浓度低于阈值。
不遵守抗菌预防指南与手术结束时抗生素水平低有关。遵守指南并不能保证达到足够的水平。
