HEALTH-SYSTEM EDITION
CLINICAL PRACTICE

Experts call for perspective when TPN guidelines collide

Among patients who for one reason or another can't take food by mouth or feeding tube, which patients should receive total parenteral nutrition (TPN) through an intravenous drip? When? Why?

In a lively debate, two physicians active in drafting their organizations' competing guidelines on TPN use addressed those questions at this year's Nutrition Week symposium sponsored by the American Society for Parenteral & Enteral Nutrition (ASPEN), held in late January in San Antonio.

Focusing mainly on a cost-benefit approach was Ronald L. Koretz, M.D., chief of gastroenterology at Olive View-UCLA Medical Center, who helped draft the position statement of the American Gastroenterological Association (AGA) regarding TPN. "We are spending 15% of our gross domestic product on health care—two to three times what other countries are spending—but we're not getting two to three times the benefit," he pointed out.

That 15% could grow to 25% by 2030, and if health professionals don't begin to better help contain costs through more actively basing clinical practices on cost-benefit analyses, then bureaucrats and politicians will cut the costs, with less desirable results, he warned. "TPN has defined complications and defined costs, so the important question is whether it has defined benefits," he said.

Using randomized clinical trials of TPN and meta-analyses of such trials, AGA grades TPN's value in specific sets of patient circumstances on a scale of A through E, said Koretz. A grade of A indicates patient situations in which data show TPN definitely of value, B indicates likely efficacy and cost-effectiveness, C indicates insufficient data, D suggests no benefit, and E indicates harm, he explained. Grades A and B are rare in the AGA system, with Cs and Ds applying in most situations, and use of TPN with cancer chemotherapy drawing an E, he noted.

"In general, there is demonstrated value only in some circumstances where patients have no functioning gut for 14 days or longer," Koretz asserted.

Disagreeing strongly with the AGA position was ASPEN guidelines coauthor Daniel Teitelbaum, M.D., associate professor of surgery at the University of Michigan Hospitals in Ann Arbor. He focused on the importance of adequate nutrition, especially for critically ill patients. "AGA's recommendations about groups of patients are very firm, quite radical, and based on very poorly selected studies, and that's a shame, because they can mislead people about what's appropriate," he contended.

Both AGA and ASPEN agreed that in most cases, there aren't sufficient data to make recommendations, but Teitelbaum, unlike Koretz, believes that shouldn't call for discouraging use of TPN, especially in critically ill patients.

"What you have to rely on in those situations is that we know once you start starving patients for two weeks or more, particularly those patients with high metabolic needs, you get into a very dangerous situation," Teitelbaum said.

The physicians looked at four hypothetical cases to illustrate their guideline differences. They agreed TPN could provide little benefit for a 48-year-old man with alcoholic hepatitis, jaundice, esophageal and gastrointestinal bleeding, antibiotic-induced diarrhea, and a range of related complications who refused enteral feeding.

But in two older surgery patients, one pre-op and one post-op, ASPEN guidelines suggested TPN if the patient became malnourished or could not absorb food taken by mouth or tube after seven to 10 days, while AGA recommended against it.

The greatest contrast came in the case of a hypothetical 42-year-old fireman admitted to intensive care with acute respiratory distress and on a mechanical ventilator for two days. He was expected to remain on the ventilator another week, with an ileus and a failed attempt at placing an enteric tube. "We felt that in five to 10 days, that fireman should be receiving nutrition support, enteral if possible, or parenteral otherwise. But AGA felt it should be 14 days at least before you consider giving that type of nutrition, and the studies on which they base their recommendations for many critically ill patients—such as this one—are just inappropriate," Teitelbaum maintained.

So, what do clinicians do when guidelines collide? Both Teitelbaum and Koretz suggested clinicians take a step back, look at all the evidence, and consider how it best applies to the situation at hand.

Kathleen Gura, Pharm.D., BCNSP, agreed. She is a nutrition support team leader at Children's Hospital in Boston, where physicians, pharmacists, dietitians, and nurses work together as teams, providing nutrition support to patients. "Guidelines are only guidelines, not absolutes, and it's important to do what's best for each patient," she concluded.

Dale Chenoweth

Dale Chenoweth. Experts call for perspective when TPN guidelines collide.

Drug Topics

2003;6:HSE24.