Letters to the Editor )rimarily during the first few days of feeding or whether t was consistent throughout each 2-week trial. Constipation is very difficult to define. What is conitipation to one group may not be to another. Regardless, To the Editor: i n the study by Shankardass et all constipation is defined I have read the article by Shankardass et all withis >72 hours without stool. Because the reader is not interest. These authors conclude that the addition of ]provided with data as to the amount of formula actually dietary fiber to enteral formulas improves gastrointes- jreceived, I wonder if the formula may have been held
Fiber
or
No Fiber in Tube-Fed Patients
tinal tolerance and function. It is difficult for me to reach the same conclusion based only on the subjective evidence presented. There were no significant differences in either stool frequency or wet weight of stool between groups receiving Ensure or Enrich. In fact, the data indicate a trend toward lower stool output in the Ensure group. A greater stool weight would be expected in the Enrich group because of the greater fiber content. Neither group had &dquo;diarrhea&dquo; based on the accepted definitions of three or more liquid stools daily or a wet stool weight > 200 g.2 There seems to be a major discrepancy between the objective data and the investigator’s subjective comments at least in terms of diarrhea. I am unaware of constipation being described as a side effect of tube feeding. In addition, the subjective assessment was undertaken by four different investigators and four different institutions without mention of any method of quality control or variability control either within or between the various observers. I would also question the definition of abdominal distention that could occur in a patient with altered gastrointestinal motility whether it be primary or secondary to a postoperative ileus, CNS effects, etc. Perhaps if the same investigator had evaluated all the patients, the data would be more consistent. The patients in this study’ were fed based on their &dquo;total daily energy requirements.&dquo; No information is provided on how this was measured or estimated. I find it difficult to assume that the total daily energy was similar in both groups because the patients’ weights were quite significantly different. In addition, it is unclear to me how much formula patients actually received; we are given only an idea of what the goal was. Did one group receive a higher percentage of their estimated or measured needs? If so, was this because of gastrointestinal complications, or was it caused by patients removing their tubes or going for procedures? In the latter scenario, better gastrointestinal tolerance would obviously be due to the need to tolerate less formula. In addition, it is mentioned that some patients were bolus fed. How many in each group were fed this way? It is unfortunate that in a study where the aim is to evaluate tolerance to two different feeds that bolus feeding either wasn’t excluded or made a separate arm in the study. The data do indicate that significantly fewer laxatives were used by the Enrich group.’ My question here is whether this effect was
any of these periods? What constituted stool? Did &dquo;stool&dquo; include mucus and &dquo;starvation stools&dquo;? Was the &dquo;constipation&dquo; primarily a factor before full rate and strength were reached with the formula? The baseline gastrointestinal function in these patients is undefined. Although the study is a crossover design, did those with head trauma receive one formula first for instance? There were a number of patients with CNS insults in this study. CNS trauma may be associated with either constipation or stool incontinence.~ Unfortunately, no data table described the constituents of each study group and the time during which they received the feeds. I do not know whether waiting 4 weeks after the insult to begin feedings was long enough to assume the baseline to be stable. Finally, I wonder what the nutritional status and serum albumin levels were in the patients ? Were they similar between groups and were the patients themselves nutritionally stable over the length of the study? Hypoalbuminemia may be associated with malabsorption.3 If that condition is corrected the improvement in gastrointestinal tolerance could have been dependent on being fed, but independent of the type of formula. If a decrease in laxative use alone is evidence enough that using a fiber-containing formula improves gastrointestinal tolerance in a relatively long-term tube-fed patient then the conclusions of Shankardass et all are supported. However, the information presented in their study leaves more questions in my mind than it answers, and I am afraid I cannot come to the same conclusion as the authors.
surfing
c ,
ALAN L. BUCHMAN, M.D. Division of Pediatric Gastroenterology and Nutrition UCLA Medical Center-Los Angeles, CA REFERENCES 1. Shankardass K, Chuchmach S, Chelswick K. et al: Bowel function of long-term tube-fed patients consuming formulae with and without dietary fiber. JPEN 14:508-512, 1990 2. Krejs GJ. Fordtran JS: Diarrhea in Gastrointestinal Disease: Pathology,Diagnosis, Management, Philadelphia, WB Saunders, Sleisinger MH, Fortran JS (eds). 3rd ed. 1983, p 257 3. Brinson RR, Kohs BE: Hypoalbuminemia is an indicator of diarrheal incidence in critically ill patients. Crit Care Med 15:506-509. 1987
91 Downloaded from pen.sagepub.com at NANYANG TECH UNIV LIBRARY on May 24, 2015
Fiber
or
No Fiber in Tube-Fed Patients
tinal tolerance and function. It is difficult for me to reach the same conclusion based only on the subjective evidence presented. There were no significant differences in either stool frequency or wet weight of stool between groups receiving Ensure or Enrich. In fact, the data indicate a trend toward lower stool output in the Ensure group. A greater stool weight would be expected in the Enrich group because of the greater fiber content. Neither group had &dquo;diarrhea&dquo; based on the accepted definitions of three or more liquid stools daily or a wet stool weight > 200 g.2 There seems to be a major discrepancy between the objective data and the investigator’s subjective comments at least in terms of diarrhea. I am unaware of constipation being described as a side effect of tube feeding. In addition, the subjective assessment was undertaken by four different investigators and four different institutions without mention of any method of quality control or variability control either within or between the various observers. I would also question the definition of abdominal distention that could occur in a patient with altered gastrointestinal motility whether it be primary or secondary to a postoperative ileus, CNS effects, etc. Perhaps if the same investigator had evaluated all the patients, the data would be more consistent. The patients in this study’ were fed based on their &dquo;total daily energy requirements.&dquo; No information is provided on how this was measured or estimated. I find it difficult to assume that the total daily energy was similar in both groups because the patients’ weights were quite significantly different. In addition, it is unclear to me how much formula patients actually received; we are given only an idea of what the goal was. Did one group receive a higher percentage of their estimated or measured needs? If so, was this because of gastrointestinal complications, or was it caused by patients removing their tubes or going for procedures? In the latter scenario, better gastrointestinal tolerance would obviously be due to the need to tolerate less formula. In addition, it is mentioned that some patients were bolus fed. How many in each group were fed this way? It is unfortunate that in a study where the aim is to evaluate tolerance to two different feeds that bolus feeding either wasn’t excluded or made a separate arm in the study. The data do indicate that significantly fewer laxatives were used by the Enrich group.’ My question here is whether this effect was
any of these periods? What constituted stool? Did &dquo;stool&dquo; include mucus and &dquo;starvation stools&dquo;? Was the &dquo;constipation&dquo; primarily a factor before full rate and strength were reached with the formula? The baseline gastrointestinal function in these patients is undefined. Although the study is a crossover design, did those with head trauma receive one formula first for instance? There were a number of patients with CNS insults in this study. CNS trauma may be associated with either constipation or stool incontinence.~ Unfortunately, no data table described the constituents of each study group and the time during which they received the feeds. I do not know whether waiting 4 weeks after the insult to begin feedings was long enough to assume the baseline to be stable. Finally, I wonder what the nutritional status and serum albumin levels were in the patients ? Were they similar between groups and were the patients themselves nutritionally stable over the length of the study? Hypoalbuminemia may be associated with malabsorption.3 If that condition is corrected the improvement in gastrointestinal tolerance could have been dependent on being fed, but independent of the type of formula. If a decrease in laxative use alone is evidence enough that using a fiber-containing formula improves gastrointestinal tolerance in a relatively long-term tube-fed patient then the conclusions of Shankardass et all are supported. However, the information presented in their study leaves more questions in my mind than it answers, and I am afraid I cannot come to the same conclusion as the authors.
surfing
c ,
ALAN L. BUCHMAN, M.D. Division of Pediatric Gastroenterology and Nutrition UCLA Medical Center-Los Angeles, CA REFERENCES 1. Shankardass K, Chuchmach S, Chelswick K. et al: Bowel function of long-term tube-fed patients consuming formulae with and without dietary fiber. JPEN 14:508-512, 1990 2. Krejs GJ. Fordtran JS: Diarrhea in Gastrointestinal Disease: Pathology,Diagnosis, Management, Philadelphia, WB Saunders, Sleisinger MH, Fortran JS (eds). 3rd ed. 1983, p 257 3. Brinson RR, Kohs BE: Hypoalbuminemia is an indicator of diarrheal incidence in critically ill patients. Crit Care Med 15:506-509. 1987
91 Downloaded from pen.sagepub.com at NANYANG TECH UNIV LIBRARY on May 24, 2015
