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

术后手术部位感染(SSI)是第三大常见的医院感染，对术后发病率和死亡率有很大影响。此外，SSI增加了治疗费用和住院时间。内脏腹部手术后，SSI的发生率特别高(14-25%)。术中预防性伤口冲洗(IOWI)在用生理盐水或消毒液闭合皮肤之前对皮下组织进行预防性伤口冲洗，被认为是一种简单而经济的降低SSI发生率的选择，并已经常用于临床实践。然而，目前还没有关于其使用的官方建议，临床实践也存在很大差异。以前常见的基于碘或含有抗生素的冲洗溶液不再被批准用于这一适应症，因为潜在的负面影响，如组织毒性或增加微生物耐药性的风险。新型防腐聚己烷基溶液被批准用于手术中软组织伤口冲洗，并被证明是组织耐受性和促进伤口愈合。然而，它们还没有在内脏外科的随机临床试验中进行评估。因此，2017年3月，启动了多中心、随机、观察者盲的IOWISI试验，以观察在开腹手术后闭合皮肤之前使用聚己内酰胺溶液或生理盐水进行IOWI的疗效。根据对41项临床试验的荟萃分析结果，计算了540名患者的样本大小，用于三臂研究设计(聚己内酯、生理盐水冲洗与不伤口冲洗的对照组)。该试验目前在德国外科试验网络CHIRNET内的13个中心进行。所有通过剖腹手术接受择期或紧急内脏手术的患者都被筛选为试验对象。试验的主要终点是术后30天的SSI比率。根据以往审判的经验，招聘期最初定为24个月。然而，经过18个月的征聘后发现，这显然不足以达到540个可分析终点的目标。一方面，这是由于一些学习中心因监管障碍而推迟启动。另一方面，患者群体中紧急翻修手术的数量远远高于预期。因此，样本量必须增加到700名患者，以获得540个可分析的终点，并确保试验结果的统计能力。此外，还招聘了更多的学习中心，并成功解决了当地的招聘问题。因此，招聘期必须再延长21个月。这项试验的结果将为有关IOWI使用的明确临床建议提供证据，并影响当前的指南。此外，他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.