Bevacqua B K, Slucky A V, Cleary W F
Anesthesia Service, VA Medical Center, Cleveland, Ohio 44106.
Anesthesiology. 1994 Jun;80(6):1234-40. doi: 10.1097/00000542-199406000-00010.
Continuation of intrathecal anesthesia into the postoperative period has been limited by important safety concerns. Principal among these has been the assumption that extended intrathecal therapy leads to spinal (epidural and intrathecal) space infections. To address the role of extended intrathecal catheter therapy as a cause of infections, we cultured all intrathecal catheters used to provide postoperative analgesia.
All intrathecal catheters were inserted in the operating room using sterile technique. The catheters were used either for the duration of the patients stay in the intensive care unit or until they were no longer judged to provide a therapeutic advantage. They were removed without skin preparation. The distal 2-3 cm of the catheters was cultured using semiquantitative culture methods. Results were divided into four groups: group 1, negative culture results; group 2, ten or fewer colonies of growth; group 3, more than 10 colonies on initial plates and/or growth from broth cultures; and group 4, any bacterial growth, along with evidence of local or central nervous system infections.
Cultures were obtained from 139 patients with a mean indwelling catheter time of 66.1 h. Group 1 (102 patients) had a mean indwelling duration of 55 h. Group 2 (26 patients) and group 3 (11 patients) had significantly longer indwelling duration (83.2 h P = .0023, 129.6 h P = < .0001, respectively) than group 1. Cultures of cerebrospinal fluid obtained simultaneously with catheter cultures in 9 cases (5 in group 2 and 4 in group 3) showed no growth. No patient had evidence of local or central nervous system infection. Difficulty of catheter placement (number of attempts made and the number of levels explored), antibiotic administration, the composition of the postoperative infusions and the number of catheter breaks in the postoperative period were similar in each group. With the exception of two catheters in group 3, (cultured at 49 and 54 h), significant bacterial growth (more than ten colonies) was observed only after more than 96 h of indwelling duration.
Application of semiquantitative culture methods assisted in explaining the results seen in group 2 as secondary to contamination of the catheter that occurred on removal. Higher numbers of bacteria (group 3) may define a population at increased risk for infectious complications. The results of this study do not absolutely resolve the issue of infectious risk associated with postoperative intrathecal catheter use, nor do they define a safe period beyond which the risk of continued catheter use would be unacceptable. However, it appears that limited periods of use (96 h or less) is not associated with either frequent local or spinal infections. Semiquantitative culture methods may help identify individuals (with catheter cultures yielding more than ten colonies) at increased risk for infectious complications and in need of closer observation.
鞘内麻醉持续至术后阶段受到重要安全问题的限制。其中主要的担忧是认为延长鞘内治疗会导致脊柱（硬膜外和鞘内）间隙感染。为了探讨延长鞘内导管治疗作为感染原因的作用，我们对所有用于提供术后镇痛的鞘内导管进行了培养。
所有鞘内导管均在手术室采用无菌技术插入。导管在患者入住重症监护病房期间使用，或直至不再被认为具有治疗优势。导管拔除时未进行皮肤准备。采用半定量培养方法对导管远端2 - 3厘米进行培养。结果分为四组：第1组，培养结果为阴性；第2组，生长菌落数为10个或更少；第3组，初始平板上有超过10个菌落和/或肉汤培养有生长；第4组，有任何细菌生长，同时伴有局部或中枢神经系统感染的证据。
从139例患者获取了培养样本，平均留置导管时间为66.1小时。第1组（102例患者）平均留置时间为55小时。第2组（26例患者）和第3组（11例患者）的留置时间明显长于第1组（分别为83.2小时，P = 0.0023；129.6小时，P = < 0.0001）。9例（第2组5例，第3组4例）与导管培养同时获取的脑脊液培养无生长。没有患者有局部或中枢神经系统感染的证据。每组中导管置入的难度（尝试次数和探查节段数）、抗生素使用、术后输注的成分以及术后导管破损的数量相似。除第3组的两根导管（分别在49小时和54小时培养）外，仅在留置时间超过96小时后才观察到显著的细菌生长（超过10个菌落）。
半定量培养方法有助于解释第2组的结果是由于拔除导管时发生的污染所致。细菌数量较多（第3组）可能确定了感染并发症风险增加的人群。本研究结果并未绝对解决与术后鞘内导管使用相关的感染风险问题，也未确定一个安全期限，超过该期限继续使用导管的风险将不可接受。然而，似乎有限的使用期限（96小时或更短）与频繁的局部或脊柱感染均无关联。半定量培养方法可能有助于识别感染并发症风险增加且需要密切观察的个体（导管培养菌落数超过10个）。
