Prospective Studies in Progress Irrigation Versus No Irrigation at Operation for Children with Perforated Appendicitis

This is a prospective, randomized clinical trial involving patients who present to the hospital with perforated appendicitis. The aim of this study is to determine if irrigation of the abdominal area containing purulent material is beneficial at the time of laparoscopic appendectomy.

The power calculation was based on the postoperative abscess rate in our previous prospective study looking at antibiotic usage for perforated appendicitis (J Pediatr Surg 43:981-985, 2008). An unacceptable abscess rate needed to be chosen. Our current rate is 20%, or one-fifth of the patients presenting with perforation. If this were to increase by 15%, it would place just over one-third of the patients at risk which would be unacceptable. This is comparable to the 36% rejection level we used for our previous IRB approved trial (#07 02-031). Using a delta of 0.15 with an alpha of 0.05 and power of 0.8, the appropriate sample size becomes 109 patients in each arm. Therefore, we will anticipate enrolling 220 patients.

Subjects will be those children who are found to have severe inflammatory changes on imaging or a high clinical suspicion of perforation. Permission will be obtained from their parents or guardians prior to the operation. All of these children will be under stress prior to the operation and randomization. Therefore, we have requested waiving assent as we have done with our previous perforated appendicitis studies. 

The final decision to include a child in the study will made after appendiceal perforation has been visually confirmed during surgery. Perforation will be defined as an identifiable hole in the appendix or stool (fecalith) in the abdomen. The randomization assignment will be made known at the initiation of the operation and, at confirmation of perforation, the patient will utilize the next randomization slot.

The irrigation group will have a suction irrigator device set up with a one liter bag of normal saline. The surgeon must use at least 500 ml of this bag but may use as much as he chooses. The no irrigation group will have the suction irrigator set up without connection to saline. This will leave the surgeon with the capacity for suction only. After the operation, both groups will be managed according to the same protocol.

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