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.