Split-dose bowel prep better for hospitalized patients, too

In October 2014, the U.S. Multi-Society Task Force on Colorectal Cancer published new consensus guidelines aimed at enhancing the effectiveness of bowel preparation for colonoscopy. The main recommendation was the use of split-dose preparations (SDPs), where half the laxative is administered the night before and half the morning of the procedure. An alternative is a same-day, split-dose regimen.

Writing in Gastroenterology, the task force noted that "efficacy and tolerability of bowel preparations are important and related goals, but efficacy is of primary importance because of the substantial consequences of inadequate cleansing." Many studies, as well as anecdotal evidence have found, however, that SDPs are not only more effective but also more tolerable for many patients.

In a study published in the September 2012 issue of Gastrointestinal Endoscopy, researchers at Mayo Clinic's campus in Phoenix compared adenoma detection rates, polyp detection rates and colonoscopy completion rates before and after an institution-wide switch to SDPs. Not only did all outcomes improve in the split-dose cohort, but patients also found the smaller volume easier to take.

Study author Francisco C. Ramirez, M.D., notes, "Patients are happier when the dose is split. They're willing to wake up at 4:00 a.m. to drink the second part, not only because they do better with less volume, but also because they know it will lead to a better exam and a greater chance of finding more polyps."

The Mayo Clinic experience has been replicated worldwide, says Victoria Gomez, M.D., a gastroenterologist at Mayo campuses in Jacksonville, Florida, and Rochester, Minnesota. "Studies all over the world advocate split-dose preparation. One to 2 liters in the morning, four to six hours before the procedure, makes the biggest improvement in the quality of colonoscopy," she says. "Overnight, the quality of cleansing begins to decline because of the influx of small bowel residue into the right side of the colon."

Research has shown that same-day dosing is even more effective. In a study published in the November 2010 issue of The American Journal of Gastroenterology, the Phoenix group found that the quality of the prep for afternoon exams was seven times better with a same-day compared with a prior-day regimen.

Most of the focus of bowel prep studies has been on the outpatient setting, but it's just as important to consider hospitalized patients, Dr. Gomez points out.

"These patients are sicker, bedridden, on multiple medications, so colon cleansing is more challenging, affecting the staff and increasing health care costs due to repeat procedures. At Mayo's campus in Florida, we started using split-dose regimens for outpatients, but that hadn't translated to the hospital. Then we worked with the nurse educators to change to split dosing for hospitalized patients. Implementation of this quality improvement initiative was feasible and successful and did not add any additional costs," she explains.

Comparing preparations

The U.S. Multi-Society Task Force recommends using 4 liters of a standard polyethylene glycol (PEG)-electrolyte lavage solution in split doses, in large part because PEG solutions cause very few shifts in fluids and electrolytes.

"They remain one of the safest cleansing agents for people with heart and kidney disease, hospitalized patients, and older adults," Dr. Gomez says. "The newer oral sulfate solutions require half the volume of PEG solutions and have demonstrated positive results with regard to adequate colon cleansing. But the big caveat may be that many of the studies of alternative bowel preparation regimens excluded patients who are bedridden, prone to chronic constipation or have slowed bowel transit due to pain medications. It's the role of the physician to take into account patient factors that might affect the quality of the preparation."

Communication is key

Split-dose regimens, appropriate cleansing agents and liberalized pre-colonoscopy diets have all been shown to enhance bowel preparation quality. But according to Dr. Gomez, the most important factor is good communication between the practitioner and patient. "It takes more than just handing a patient a prescription for the procedure; you have to explain what it entails. Providing education and communication beforehand so patients know what to expect is the best way to lessen dissatisfaction and improve outcomes," she says.

For more information

Johnson DA, et al. Optimizing adequacy of bowel cleansing for colonoscopy: Recommendations from the U.S. Multi-Society Task Force on Colorectal Cancer. Gastroenterology. 2014;147:903.

Gurudu SR, et al. Increased adenoma detection rate with system-wide implementation of a split-dose preparation for colonoscopy. Gastrointestinal Endoscopy. 2012;76:603.

Gurudu SR, et al. Quality of bowel cleansing for afternoon colonoscopy is influenced by time of administration. The American Journal of Gastroenterology. 2010;105:2318.