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CorreS ondence The Editors will be pleased to receive and consider for publication correspondence containing information of interest to physicians or commenting on issues of the day. Letters ordinarily should not exceed 600 words and must be typewritten, double-spaced, and submitted in duplicate (the original typescript and one copy). Authors will be given the opportunity to review the editing of their correspondence before publication.

Total Parenteral Nutrition TO THE EDrrOR: We have read with interest the survey by Katz and Oyel from our institution. We agree that total parenteral nutrition (TPN) may at times be overused at our and other institutions. The conclusions made by the authors on the patients surveyed are not necessarily valid, however. First of all, the authors failed to evaluate the clinical outcome in the patients they studied. They assumed their heterogeneous sample to reflect that of previous studies, some of which showed a lack of efficacy involving specific patient groups. In essence, a historical control was used, which may not have been applicable to the group surveyed by Katz and Oye. In addition, the authors failed to separate perioperative TPN into preoperative and postoperative. Mullen and colleagues have shown that preoperative TPN of as little as seven days' duration is effective in reducing morbidity and mortality in a heterogeneous group of surgical patients.2 In addition, Williams and co-workers found significantly fewer wound infections in patients who had received TPN for as little as seven days as compared with controls.3 Starker and colleagues found a clear reduction in postoperative morbidity in malnourished patients receiving even seven days of nutritional support.4 They note that the length of time required for preoperative complications varies among patients and must be individualized. We agree. Therefore, a blanket claim by Katz and Oye that all patients who received only seven days of TPN received it inappropriately is misleading and incorrect. Unfortunately, these authors provide no information on the outcomes of the inpatients. Askanazi and co-workers have evaluated the results of using seven days of postoperative TPN on the length of hospital stay.5 These authors found a significant decrease (from a mean of 24 days to 17 days) in the time spent in hospital for patients undergoing radical cystectomy who were supported with TPN. Again, no information on hospital duration is provided by Katz and Oye. In addition, Katz and Oye selected seven days as the minimal need for duration of TPN administration without regard to their patients studied and without consulting more recent literature. Young and colleagues clearly showed that preoperative TPN significantly increased the capacity for hepatic protein synthesis measures by '4C-leucine incorporation in the liver after only three days of support. Plasma amino acid, fibronectin, and immunoglobulin A levels were also noted to increase following three days of TPN administration.6 Katz and Oye also incorrectly assume that intravenous TPN is often inappropriate because it supplies fewer calories. In smaller patients, peripheral TPN is often more than adequate to supply caloric and protein requirements. We usually supply patients with up to 1,520 kcal and 100 grams of protein daily with a regimen of peripheral TPN, which, incidentally, is associated with fewer complications than TPN by central catheter. Finally, these authors assume that because patients had oral intake after seven days, this was

adequate to meet their needs, yet they list no data on caloric counts or ability to tolerate enteral feeding. Katz and Oye present interesting data. One cannot conclude, however, that patients who received TPN intravenously or centrally for seven days or less received it inappropriately. More information is needed on the economics of hospital stay duration, complications, and ability to tolerate enteral feeding in this patient group before such a conclusion can be justified. Total parenteral nutrition administered for less than seven days may not be clinically beneficial; however, it is unclear from the present study whether its use is truly inappropriate. ALAN L. BUCHMAN, MD Fellow, Division of Pediatric Gastroenterology and Nutrition MARVIN E. AMENT, MD Professor of Pediatrics Chief, Division of Pediatric Gastroenterology and Nutrition UCLA School of Medicine Los Angeles, CA 90024 REFERENCES

1. Katz SJ, Oye RK: Parenteral nutrition use at a university hospital-Factors associated with inappropriate use. West J Med 1990; 152:683-686 2. Mullen JL, Buzby GP, Matthews DC, Smale BF, Rosato EF: Reduction of operative morbidity and mortality by combined preoperative and postoperative nutritional support. Ann Surg 1980; 192:604-613 3. Williams RH, Heatley RV, Lewis MH: Proceedings: A randomized controlled trial of preoperative intravenous nutrition in patients with stomach cancer. Br J Surg 1976; 63:667-671 4. Starker PM, LaSala PA, Askanazi J, Todd G, Hensle TW, Kinney JM: The influence of preoperative total parenteral nutrition upon morbidity and mortality. Surg Gynecol Obstet 1986; 162:569-574 5. Askanazi J, Hensle TW, Starker PM, et al: Effect of immediate postoperative nutritional support on length of hospitalization. Ann Surg 1986; 203:236239 6. Young GA, Zeiderman MR, Thompson M, McMahon MJ: Influence of preoperative intravenous nutrition upon hepatic protein synthesis and plasma proteins and amino acids. JPEN J Parenter Enteral Nutr 1989; 13:596-602 *

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Drs Katz and Oye Respond We agree with Buchman and Ament that the effectiveness of parenteral nutrition should be based on outcome. Our retrospective review of parenteral nutrition use was designed to determine what proportion of use in a university hospital followed the guidelines that have been recommended by the American Society of Parenteral and Enteral Nutrition and the American College of Physicians. We used a conservative criterion of seven days because both organizations cite a range of seven to ten days needed for appropriate support. Our study was not intended to evaluate outcomes, nor would such information be meaningful given the study design. The literature on preoperative parenteral nutrition cited by Buchman and Ament is selective and not particularly relevant to our patient population. Of 72 surgical patients included in our review, only three received parenteral nutrition before surgical procedures were done, and only one received it for more than two days. This suggests that in the era of prospective payment, preoperative use represents a minute proportion of use of this therapy.

Total parenteral nutrition.

662 CorreS ondence The Editors will be pleased to receive and consider for publication correspondence containing information of interest to physician...
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