Here is the design of a clinical trial:

Official Title: Vacuum Assisted Closure Versus On-demand Relaparotomy in Patients With Fecal or Diffuse Peritonitis: A Multicenter Randomized Controlled Trial

Included conditions:
- Fecal Peritonitis
- Secondary Peritonitis
- Diffuse; Peritonitis

Study Armgroups:
- {'label': 'Vacuum assisted closure', 'type': 'ACTIVE_COMPARATOR', 'description': 'The VAC® Abdominal Dressing System (KCI Vacuum Assisted Closure, San Antonio, TX, USA) will be used. Intestines, including lateral aspects, are covered by the visceral protective layer. The first layer of foam is placed in the laparostoma on the visceral protective layer and must extend below the fascia at a distance of 5 cm from the facial opening. Above this, a minimum of one piece of foam is folded and placed in the laparostoma. Finally, the laparostoma will be covered by the occlusive drape. A circular opening of approximately 5 cm in diameter will be created in the drape where the connection tubes to the vacuum pump will be placed. Simultaneously while applying the negative pressure of 125 mmHg, the wound edges are approximated manually towards the midline. Each dressing change must be performed in the operation theatre with the patient in general anesthesia and muscle relaxation.', 'interventionNames': ['Procedure: Vacuum assisted closure']}
- {'label': 'Relaparotomy "on-demand"', 'type': 'ACTIVE_COMPARATOR', 'description': "The Isreaelsson principle includes a running suture of the fascia with a distance of 5 mm between the stitches of 5 mm and the distance to the facial edge of 5-10 mm. Monofilament PDS 2-0 or equivalent is used. The suturing is started cranially and caudally, and the sutures are tied with self-locking knots. Four times as much suture material as the length of the wound must be used. The peritoneal fluid must be cultured at closure.\n\nThe treating surgeon decides to perform a ROD and should be guided by the patient's general condition, gastrointestinal function, renal function, and inflammatory parameters at daily rounds.", 'interventionNames': ['Procedure: Relaparotomy "on demand"']}

Interventions:
- {'type': 'PROCEDURE', 'name': 'Vacuum assisted closure', 'description': 'The Vacuum assisted closure system consists of an abdominal dressing covering the intra abdominal viscera over the dressing there will be placed a blue sponge which will be covered by drape and connected to a vacuum pump.', 'armGroupLabels': ['Vacuum assisted closure'], 'otherNames': ['VAC® Abdominal Dressing System, KCI, (San Antonio, TX)']}
- {'type': 'PROCEDURE', 'name': 'Relaparotomy "on demand"', 'description': 'Abdomen is closed at the index operation after source of peritonitis is treated. Every 48-hours the patients are evaluated for the need of relaparotomy based on clinical and paraclinical parameters.', 'armGroupLabels': ['Relaparotomy "on-demand"']}

Primary Outcomes:
- {'measure': 'Primary endpoint is to compare peritonitis related complications and Comprehensive Complication Index (CCI) between NPWT treatment (VAC) and conventional treatment (ROD) at 30, 90 days and 1 year.', 'description': 'Disease-Related Major Morbidity Needing Readmission and Conservative Treatment but Not Surgery\n\n* Fistula\n* Wound dehiscence/incisional hernia with obstruction\n* Abscess needing percutaneous drainage\n* Renal failure\n* Myocardial infarction\n* Gastric or duodenal bleeding\n* Respiratory failure\n* Urosepsis\n\nDisease-Related Major Morbidity Needing Surgical Intervention During First Admission or Readmission\n\n* Incisional hernia\n* Bowel obstruction or herniation due to intra-abdominal adhesions\n* Burst abdomen\n* Abdominal compartment syndrome\n* Fistula\n* Intra-abdominal bleeding\n* Intra-abdominal hematoma needing surgical evacuation\n* Perforation of visceral organ confirmed at surgery\n* Anastomotic leakage\n* Ischemia or necrosis of a visceral organ\n* Enterostomy dysfunction due to prolapse, stenosis, or retraction\n* Gastric or duodenal ulcer bleeding needing intervention of any type', 'timeFrame': '1 year'}

Please estimate the sample size based on the assumption: 
Desired power of 80%, significance level of 0.05, and an expected drop-out rate of 5%.
Sample size and power
          With an expected peritonitis-related complications rate of 40% in the ROD group [20] and 25% in the VAC group [42, 44], the desired power of 80%, a significance level of 0.05, and an expected drop-out of 5%, a total of 340 patients should be included.
          As the CCI distribution in this group of patients is unknown, we could not perform an explicit sample size calculation for this secondary outcome. A 0.32 standard deviation difference in mean CCI between the two groups could be detected with 80% power with this sample size.
          To ensure sufficient recruitment, the study will be multicentre and European. Eight active centres have been included, and two are in process. Randomisation tools along with eligibility criteria are accessible through our website. The workflow and relevant contact details appear on posters at the participating departments. Study progress will be available on the website.