Friedman R J, Friedrich L V, White R L, Kays M B, Brundage D M, Graham J
Department of Orthopaedic Surgery, Medical University of South Carolina, Charleston 29425.
Clin Orthop Relat Res. 1990 Nov(260):17-23.
Twenty-four patients receiving total knee arthroplasty (TKA) were randomized into one of three groups based on tourniquet inflation one, two, or five minutes after administration 1 g cefazolin. Simultaneous serum, soft-tissue, and bone samples were obtained at regular intervals during surgery. All soft-tissue and bone samples were corrected for cefazolin content. The percentage of cefazolin penetration into soft tissue and bone was calculated using the area under the concentration time curve. Adequate cefazolin concentrations for soft tissue and bone were defined as greater than or equal to 4 x minimum inhibitory concentration90 (MIC90 = 1 microgram/ml) of cefazolin to Staphylococcus aureus and coagulase-negative staphylococci. Patients were similar in age, actual body weight, creatinine clearance, and length of tourniquet inflation. The median percentage of cefazolin penetration into soft tissue and bone for the five-, two-, and one-minute groups was 14.5% and 4.6%, 6.7% and 3.0%, and 5.9% and 4.6%, respectively; the percentage of penetration into soft tissue between the five- and one-minute groups was statistically significant. A higher percentage of patients achieved the desired cefazolin concentration (greater than or equal to 4 micrograms/g) if a five-minute interval was selected. The five-minute group achieved the highest mean ratios of concentration to MIC compared with the two- and one-minute groups, although the differences were not statistically significant. The standard 1 g of cefazolin with a five-minute interval between administration and tourniquet inflation resulted in adequate mean soft-tissue and bone concentrations for prophylaxis during TKA with a tourniquet time less than two hours. Additional doses are not warranted after tourniquet release.
24例行全膝关节置换术（TKA）的患者在静脉注射1g头孢唑林后，根据止血带充气时间分为三组，分别为充气时间在给药后1分钟、2分钟或5分钟。手术过程中定期采集血清、软组织和骨组织样本。所有软组织和骨组织样本均校正头孢唑林含量。采用浓度-时间曲线下面积计算头孢唑林在软组织和骨组织中的穿透率。软组织和骨组织中头孢唑林的有效浓度定义为大于或等于4倍头孢唑林对金黄色葡萄球菌和凝固酶阴性葡萄球菌的最低抑菌浓度90（MIC90 = 1μg/ml）。患者在年龄、实际体重、肌酐清除率和止血带充气时间方面相似。5分钟组、2分钟组和1分钟组头孢唑林在软组织和骨组织中的穿透率中位数分别为14.5%和4.6%、6.7%和3.0%、5.9%和4.6%；5分钟组和1分钟组在软组织中的穿透率差异有统计学意义。如果选择5分钟的间隔时间，达到所需头孢唑林浓度（大于或等于4μg/g）的患者比例更高。与2分钟组和1分钟组相比，5分钟组的浓度与MIC的平均比值最高，尽管差异无统计学意义。在给药和止血带充气间隔5分钟给予标准剂量1g头孢唑林，对于止血带使用时间少于2小时的TKA手术，可在软组织和骨组织中产生足够的平均预防浓度。止血带松开后无需追加剂量。
