Irrigation Versus No Irrigation for Perforated Appendicitis

This will be a prospective, randomized clinical trial involving patients who present to the hospital with perforated appendicitis. This will be a definitive study.

Power calculation was based on abscess rate in the previous prospective study. An unacceptable abscess rate needed to be chosen. Our current rate is 20%, or one-fifth of the patients. 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 the previous IRB approved trial (#07 02-031). Using a delta of 0.15 with alpha of 0.05 and power of 0.8, the sample size is 109 patients in each arm. Therefore we will anticipate enrolling 220.

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 parents prior to the operation. All of these children will be under duress prior to randomization, therefore we request waiving assent as we have done with the previous perforated appendicitis studies.

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

The irrigation group will have suction irrigator set up with a 1 liter bag of normal saline. The surgeon must use at least 500 ml of this bag but may use as much as they choose.