Terry Puet
Pulsed Irrigation Enhanced Evacuation: New Method for Treating Fecal Impaction

Published in Arch Phys Med Rehabil, Vol. 72, October 1991 Terry A. Puet, MD, Lovsho Phen, MD, Dorothy L. Hurst, RN Hillside Rehabilitation Hospital, 8747 Squires Lane, NE, Warren, Ohio 44484, USA.


Fecal impaction is a common problem in patients with neurologic impairment. The pulsed irrigation enhanced evacuation (PIE*) procedure is a new method of clearing fecal impactions using pulses of small amounts of warm water to rehydrate stool and improve peristalsis. Thirty-seven PIE* procedures were performed on 28 patients with a variety of neurologic problems. The PIE* procedure was observed to be effective and safe. It should be a useful adjunct to a proper bowel management program.

Keywords: Defecation; Enema; Feces, Impacted

Stool impaction is common in patients with neurologic problems including stroke1, spinal cord injury2, multiple sclerosis1, and other causes of neurogenic bowel. It is also common in patients immobilized after orthopedic procedures and in patients in nursing homes.3

Traditional programs for preventing and treating impactions include enemas, laxatives and stool softeners.1-3 Sometimes, however, these are not effective. We decided to test a new procedure, pulsed irrigation enhanced evacuation (PIE*), using the Avatar machine, for its safety and efficacy in treating this difficult problem.

Our institution is a free-standing rehabilitation hospital that serves many patients with neurologic problems in the early stages when their mobility and bowel function are most impaired. The bowel program for these patients is managed by a bowel and bladder department within the nursing department, and is supervised by a physician. Despite this arrangement, there are frequently patients who cannot develop successful bowel evacuation programs using multiple oral agents, suppositories, Therevac Plus mini enemas,4 Fleet, and soapsuds enemas. When stool becomes impacted and the bowel distended, these treatments do not work effectively.5 In an attempt to find another alternative for these patients, we evaluated the PIE* procedure.

The PIE* procedure is based on the principle that pulses of small amounts of warm water will rehydrate the stool and serve to loosen and disperse an impaction. The Avatar machine consists of a reservoir filled with warm tap water, with the temperature controlled at 33.8C to 39.4C; a pump which is programmed by a control board; and a removable reservoir for the fecal material which is drained. Attached to this unit is disposable tubing that ends in a speculum with a cuff similar to a rectal tube. To perform the procedure, the speculum is inserted and the cuff inflated to prevent leakage of water and stool. A low volume of water approximately 25cc per second is introduced into the rectum. A typical pulse cycle lasts one to four seconds, and is followed by a drainage cycle. The maximum pressure does not exceed 2 pounds per square inch. The typical procedure lasts 15 to 20 minutes. It is continued until the return discharge fluid is clear of fecal material. The tubing is replaced for each procedure, preventing cross-contamination between patients. In addition to impaction, this procedure can be done as a bowel preparation for barium enemas, intravenous pyelograms (IVP's), colonoscopy, and surgery, or as part of a chronic bowel program.

Thirty-seven procedures were performed on 28 individuals. Thirty-six of these procedures were done to treat stool impaction and one was done in preparation for IVP. The study population included 14 patients recovering from cerebrovascular accidents, eight patients with spinal cord injuries, two patients with Parkinson disease, two patients with closed head injuries, one with idiopathic megacolon, and one patient on peritoneal dialysis. Because of impaired bowel function, most of these individuals were being treated with oral bowel medications, suppositories, and enemas, and many were on multiple agents. Despite this aggressive treatment, impaction developed in these patients.

The procedure was performed by the bowel and bladder nurse following a physician's order and informed consent by the patient. After each procedure a questionnaire was filled out by the nurse to rate its effectiveness. The success of a procedure was based on the amount of stool obtained, a decrease in abdominal distension, and an improvement in symptoms. Partial success was defined as an abdominal flat plate still showing significant stool despite the procedure being done until the discharge fluid was clear. Twenty-four procedures were successful on the first attempt to clear the fecal impaction. Four were partially successful, with complete success on a repeat attempt the next day. One individual had two partially successful procedures, with complete clearing on the third. (This patient was successful on one attempt on two subsequent occasions.) Two procedures were unsuccessful, both on the same patient, due to leaking around the rectal tube.

Patients reported feeling better after all 24 successful procedures and after clearing on those requiring multiple attempts. Patients also reported significant relief after all partially successful procedures, but most still felt distended or constipated until complete clearing was achieved. In general, the procedure was tolerated well. Twenty-four of the patients reported no pain. One patient with a history of angina pectoris had chest pain after the procedure, relieved by nitroglycerin. One patient had slight discomfort during the procedure, but continued. Two patients became cold and clammy during the procedure; two had that reaction several hours later. These four patients had diabetes mellitus, but glucometers did not show hypoglycemia. The symptoms lasted less than five minutes, resolved spontaneously, and did not require discontinuation of the procedure. There were no episodes of autonomic dysreflexia in those patients with spinal cord injuries. In 23 patients, oral agents, suppositories, and Therevac Plus mini enemas were effective after disimpaction with PIE*; the remaining five continued to require frequent enemas.

The PIE* procedure has been evaluated for long-term safety and use in spinal cord injured patients (unpublished data). It was found to be safe, effective and well-tolerated. We felt that, in addition, it could be a useful adjunctive treatment for those people who develop fecal impaction despite routine bowel management programs. In our study group, the PIE* procedure proved to be very effective in disimpacting patients with a variety of neurologic problems. It was tolerated quite well, and it was not uncommon for patients to fall asleep during the procedure. The most serious complication encountered was chest pain, but the alternative of using enemas can also result in irritation to the bowel wall, rectal bleeding, angina, hypertension or arrhytmias.1,3,6

All the study patients had conditions known to increase the risk of fecal impaction. The general treatment for these conditions has been covered extensively elsewhere.1,3,7 Two of the patients are particularly interesting. One patient with idiopathic megacolon had numerous disimpactions, including disimpaction using irrigation and colonoscopy. Even this latter treatment was not effective before the PIE*. Surgery is recommended for patients at that point1,7,8 and was being considered for this patient. The PIE* procedure has been able to delay the need for surgery in the six months of follow-up. Another patient in this study was receiving peritoneal dialysis. Immobilization following amputation led to impaction, which in turn led to decreased effectiveness of the peritoneal dialysis. After disimpaction, dialysis was again effective. Patients with renal failure can also have particular problems with impactions due to antacids.9

We believe that the PIE* procedure may prove useful in treating fecal impactions due to a variety of problems, as well as in cleaning the colon for procedures including IVP, colonoscopy or barium enema. We have not evaluated the use of this procedure in the treatment of patients with complete obstruction of ileus, or in patients with previous abdominal surgery, and do not recommend it for these patients at this time. Most of all, this procedure has assisted us in maintaining an effective bowel program by providing a means of rapidly and completely clearing impactions when standard treatments failed.

List of all published studies.


1. Alessi CA, Henderson CT: Constipation and fecal impaction in the long-term care patient. Clinics in Ger Med 1988;4:3, 571-588.

2. Gore, RM, Mintzer RA, Calenoff L: Gastrointestinal complications of spinal cord injury. Spine 1981;6:6, 538-544.

3. Kallman H, Constipation in the elderly. AFP 1983; 27:1,179-184.

4. Brier L J, Benedict A: Eliminating suppositories in bowel training. Amer J of Nurs 1986;522-524.

5. Klein H: Constipation and fecal impaction. Med Clinics of NA 1982;66:5, 1135-1141.

6. Cefalu CA, McKnight GT, Pike JI: Treating impaction: a practical approac to an unpleasant problem. Geriatrics 1981;36:5,143-146.

7. Portenoy RK: Constipation in the cancer patient: causes and management. Med Clinicis of NA 1987;71:2,303-311.

8. Wrenn K: Fecal impaction. New Eng J Med 1989;321:10,658-662.

9. Welch JP, Schweizer RT, Bartus SA: Management of antacid impactions in hemodialysis and renal transplant patients. Amer J of Surg 1980;139:561-568