Intraoperative wound irrigation to prevent surgical site infection after laparotomy: IOWISI

术后手术部位感染（SSI）是第三大最常见的医院感染，是术后发病率和死亡率的主要原因。此外，SSI增加了治疗费用和住院时间。腹部内脏手术后，SSI发生率特别高（14-25%）。在皮肤闭合前用生理盐水或消毒溶液对皮下组织进行预防性术中伤口冲洗（IOWI），假设是降低SSI发生率的一种简单而经济的选择，并且已经在临床实践中频繁使用。然而，目前尚无关于其使用的官方建议，临床实践差异很大。由于潜在的负面影响，如组织毒性或增加微生物耐药性的风险，以前常见的基于碘或含有抗生素的灌溉溶液不再被批准用于这一适应症。新的抗菌聚己烷基溶液被批准用于手术软组织伤口冲洗，并被证明是组织耐受和促进伤口愈合。然而，它们尚未在内脏手术的随机临床试验中得到评价。因此，我们于2017年3月启动了一项多中心、随机、观察者盲的IOWISI试验，研究剖腹术后闭合皮肤前用聚己胺溶液或生理盐水进行IOWI的疗效。基于对41项临床试验的荟萃分析结果，计算了540例患者的样本量，采用三臂研究设计（聚己胺组、生理盐水组和不进行伤口冲洗的对照组）。该试验目前在德国外科试验网络CHIRNET的13个中心进行。所有通过剖腹手术进行选择性或紧急内脏手术的患者都被筛选参加试验。试验的主要终点是术后30天的ssi率。根据以往试验的经验，招募期最初设定为24个月。然而，经过18个月的招募，很明显，这不足以达到540个可分析终点的目标。一方面，这是由于一些研究中心由于监管障碍而推迟启动。另一方面，患者群体中急诊翻修手术的数量远高于预期。因此，样本量必须增加到700例患者，以获得540个可分析终点，并保证试验结果的统计效力。此外，还招募了更多的学习中心，成功解决了当地的招生问题。因此，征聘期间必须再延长21个月。该试验的结果将为使用IOWI的明确临床建议提供证据，并影响当前的指南。此外，它们将为所有参与的患者提供改善治疗的机会。

Postoperative surgical site infection (SSI) represents the third most common hospital infection and contributes substantially to postoperative morbidity and mortality. In addition, SSI increase treatment costs and length of hospital stay. Following visceral abdominal surgery, SSI rates are especially high (14-25%). Prophylactic intraoperative wound irrigation (IOWI) of the subcutaneous tissue before skin closure with saline or antiseptic solutions, hypothetically represents an easy and economical option to reduce SSI rates and is already frequently used in clinical practice. However, there are currently no official recommendations on its use and clinical practice varies largely. Formerly common irrigation solutions based on iodine or containing antibiotics are no longer approved for this indication, due to potentially negative effects like tissue toxicity or the risk of increasing microbial resistances. New antiseptic polyhexanide-based solutions are approved for soft-tissue wound irrigation in surgery, and were shown to be tissue tolerable and promote wound healing. However, they have not been evaluated in randomized clinical trials in visceral surgery. Therefore, in March 2017 the multicenter, randomized, observer-blinded IOWISI trial was initiated to investigate the efficacy of IOWI with polyhexanide solution or saline before skin closure after laparotomy. Based on the results of a meta-analysis on 41 clinical trials a sample-size of 540 patients was calculated for a 3-armed study design (polyhexanide- vs. saline irrigation vs. control group without wound irrigation). The trial is currently conducted in 13 centers within the German surgical trial network CHIRNET. All patients undergoing elective or emergency visceral surgery by laparotomy are screened for the trial. The primary endpoint of the trial is the SSI-rate 30 days postoperatively. Based on the experience from previous trials, the recruitment period was initially set to 24 months. However, after 18 months of recruitment it became clear that this would not be sufficient to reach the goal of 540 analyzable endpoints. On the one hand, this was due to a delay of the initiation of some study centers because of regulatory hurdles. On the other hand, the number of emergency revision surgeries in the patient population was much higher than expected. Therefore, the sample size has to be increased to 700 patients to obtain 540 analyzable endpoints and ensure the statistical power of the trial results. In addition, more study centers have been recruited and local recruitment problems have been successfully resolved. Hence, the recruitment period has to be extended for another 21 months. The results of this trial will provide evidence for definite clinical recommendations regarding the use of IOWI and influence current guidelines. Moreover, they will provide all participating patients the opportunity of an improved treatment.