Parenteral nutrition and oral intake: effect of branched-chain amino acids

The effect of peripheral parenteral nutrition (PPN) on voluntary food intake was examined in healthy male subjects. Each study (lasting 17 to 19 days) was divided into three phases: Ringer's lactate (RL); PPN administered as a combination of glucose, fat, and amino acids; and finally RL. During the middle phase, some of the subjects received a parenteral formula in which half of the amino acids had been replaced with the branched-chain amino acids (BCPPN). When PPN was infused, subjects reduced their food intake within 48 hours by approximately 80% of the infused calories (p less than 0.001) within 48 hours, whereas intake was reduced by less than 40% of the infused calories when BCPPN was infused. Use of branched-chain amino acid-enriched parenteral nutrition may minimize the reduction in food intake seen during intravenous nutrition, possibly hastening a return to normal eating.     

Parenteral nutrition in septic patients: effect of increasing nitrogen intake

Metabolic effects of increasing nitrogen intake during total parenteral nutrition (TPN) were studied in nine septic patients. The patients were given 5% dextrose (D5W) for 1 d. For the next 6 d they received total parenteral nutrition (TPN), at 1.35 times resting energy expenditure (REE), containing either 191 or 366 mg N/(kg.d) Non-protein calories were divided equally between glucose and lipid emulsion. Three patients were studied on both diets (n = 6 for each diet). On the high- but not the low-N diet were significant increases in protein oxidation, blood urea N, O2 consumption, and CO2 production. TPN normalized most plasma amino acid levels but intramuscular amino acids remained unchanged. Transient positive N balance occurred during days 1-3 on the high- but not the low-N intake; on days 5-6 N balance did not differ significantly from zero on either diet and the improvement (165 mg N/[kg.d]) was the same for both diets.     

Towards improved fat intake and nutrition for Malaysians

An examination of the fat composition of the diet of a Malaysian urban hostel population obtained by chemical analysis of representative meals prepared by a 7-day rotation menu, revealed both nutritional attributes and limitations when compared against the dietary messages contained in the American Heart Association (AHA) and World Health Organisation (WHO) models. The Malaysian diet supplies 26% kcal i.e. 66 g total fat (51 g vegetable fats, 15 g animal fats) and contains <300 mg cholesterol, which are below the upper limits for these dietary constituents in the AHA and WHO models and conflicts with the perception that Malaysians in general, may be consuming too much fat and cholesterol. The supply of essential fatty acids (EFA), however, appears sub-optimal at 3.2% kcal mainly due to the comparatively low content of both the omega-6 (linoleic acid) and omega-3 [alpha-linolenic, eicosapentaenoate (EPA) and docosahexaenoate (DHA)] fatty acids in the Malaysian diet. The estimated omega-6/omega-3 fatty acid ratio of 10 further reflects an imbalance of these two families of polyunsaturated fatty acids (PUFA), which can be corrected to a ratio of 5 to 7 by moderate increases in the consumption of fish, soyabean-based foods, and pulses and nuts. Considering the current status of knowledge on the health effects of the different families of fatty acids, the ratio of 2:3:1 for the saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and PUFA in the diet is judged to improve fat intake and nutrition in Malaysians. Such a dietary fatty acids ratio can be satisfied by the use of a cooking oil containing 28% SFA, 53% MUFA, and 19% PUFA, which may obtained by the judicious blending of palm olein with MUFA-rich and PUFA-rich vegetable oils. Alternatively, moderate increases in the consumption of marine fish, pulses, nuts, soybean-based foods and their products would also serve the same end.     

Parenteral nutrition: multidisciplinary management

Parenteral nutrition may be needed to give nutritional support to patients with severe acute (temporary or reversible) or chronic intestinal failure. Parenteral nutrition needs to be given only by health workers trained in its use otherwise life-threatening complications (especially sepsis) may occur.     

Parenteral nutrition: Hospital to home

Parental nutrition support is the provision of essential nutrients intravenously, bypassing the intestinal tract. It is used in a variety of clinical settings and medical conditions. Parenteral nutrition is a complex technology that requires the input of many professionals, including dietitians. The role of the dietitian in parenteral nutrition support involves direct patient care, consultative services, education, program development, and research. Even though this field of practice is still developing, some common practices can be described. Nutrition assessment determination of macronutrient and micronutrient requirements, and monitoring are vital aspects of the provision of parenteral nutrition support that benefit from the knowledge and experience of a dietitian. The future of parental nutrition includes identification of preferred fuels for specific disease states, development of new lipid emulsions, and identification of conditionally essential nutrients.     

胃肠外营养与肿瘤生长

由于临床上癌症病人存在不同程度的营养不良，使病人难以耐受手术，化疗及放疗，给临床治疗带来很多困难，有人从动物实验到临床应用中证实了胃肠外营养的有效性，因此，本文综述了癌症病人的营养状况，代谢变化，包括能量，蛋白质，碳水化合物，脂肪代谢，以及癌症病人ＴＰＮ的应用。     

Parenteral nutrition: first decade, trends.

Parenteral feeding has saved lives and enhanced therapy of patients who cannot eat. Future trends of this technique for patients, physicians, hospitals are discussed.     

Experimentally induced glucose intolerance increases oral ethanol intake in rats

A number of studies have shown a relationship between glucose tolerance and ethanol intake. The present study uses a relatively simple procedure to induce glucose intolerance to test whether this condition is sufficient to produce an increase in chronic ethanol intake in male rats. Subjects were divided equally into four groups where they were given access to one of four solutions: peppermint-flavored sucrose (40%), peppermint-flavored saccharin (0.1%), peppermint in water (0.1%), or water alone presented three times a week, for a period of 11 weeks. After 12 weeks all animals were subjected to an oral glucose tolerance test which revealed that the chronically prepared sucrose animals had become glucose intolerant. At the start of week 13 all animals were given access to a 6% ethanol solution flavored with peppermint in place of the previous solutions for a period of 11 weeks. Sucrose animals displayed an immediate preference for ethanol and consumed approximately three times more ethanol than the remaining groups. The results of this study indicate that rats that are made glucose intolerant by long term access to a high concentration of sucrose, when given the opportunity, will subsequently choose to drink more ethanol than control animals.     

Parenteral nutrition safe practices: results of the 2003American Society for Parenteral and Enteral Nutrition survey

BACKGROUND: The American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.) recently published a revision of its "Safe Practices for Parenteral Nutrition" guidelines. Because there is a paucity of published scientific evidence to support good practices related to ordering, compounding, and administering parenteral nutrition (PN), a survey was performed in the process of the revision to gain insight into the discrepancies between reported practices and previous guidelines. METHODS: A web-based survey consisting of 45 questions was conducted (n = 651) June 1-30, 2003. Respondents were queried about primary practice setting, professional background, processes for writing PN orders, computer order entry of PN orders, problems with PN orders, and adverse events related to PN. RESULTS: There were 651 survey responses, 90% of which were from hospital-based practitioners. Almost 75% of responders processed between 0 and 20 PN orders per day. Overall, physicians (78%) were responsible for writing PN orders, but dietitians and pharmacists had significant involvement. PN base components were most often ordered as percentage final concentration after admixture (eg, 20% dextrose), which is inconsistent with safe practice guidelines of ordering by total amount per day (eg, 200 g/day). There was no consistent method for ordering PN electrolytes. Approximately 45% of responders reported adverse events directly related to PN that required intervention. Of these events, 25% caused temporary or permanent harm, and 4.8% resulted in a near-death event or death. CONCLUSIONS: Although the survey found consistency in PN practices for many areas queried, significant variation exists in the manner by which PN is ordered and labeled.     

全胃切除术后肠内营养和肠外营养的Meta分析

目的:以肠内营养(EN)和肠外营养(PN)治疗为对比,评价全胃切除术后采用不同营养支持方式的有效性、经济性和安全性. 方法:检索国外文献Pubmed数据库,同时检索国内文献CNKI、维普和万方数据库,鉴定为随机对照试验,采用RevMan 5.1软件进行Meta分析. 结果:共纳入23个随机对照试验(RCT),Meta分析结果显示,与PN组比,EN组可提高胃癌全胃切除术的血红蛋白[WMD=3.66,95％ CI(1.21,6.11)]和转铁蛋白含量[WMD =0.22,95％ CI(0.13,0.31)],缩短术后住院时间[WMD=4.95,95％ CI(-6.54,-3.37)],减少术后并发症的发生率[OR=0.38,95％ CI(-6.54,-3.37)]. 结论:采用EN对全胃切除术后进行营养支持,能有效地改善病人的营养状况,缩短病人的住院时间,降低并发症的发生率.     

肠外营养和腹腔镜下手术治疗乳糜性腹水

目的:观察PN支持和腹腔镜治疗乳糜性腹水的作用. 方法:对l例乳糜性腹水的病人,先后应用单纯PN支持4周和PN支持+腹腔镜治疗1周,通过腹腔引流观察腹水引流量的变化,同时观察病人体质量和一般营养状况的变化. 结果:在单纯PN支持的过程中,腹水的流出量逐天减少.恢复饮食后.腹水量又逐渐增多,体质量有所增加,血清ALB水平无明显变化.经PN支持+腹腔镜治疗1周后,腹水量明显减少.恢复饮食后,腹水量亦无明显增多,体质量有明显增加;血清ALB水平有明显升高. 结论:应用PN支持和腹腔镜治疗乳糜性腹水,不仅能明显减少腹水量,而且还能较好地维持机体的营养状态.     

Parenteral nutrition, biochemistry and respiratory gas exchange

Lipid-based total parenteral nutrition (TPN) may have an advantage over glucose-based TPN in certain patients because less carbon dioxide is produced. This conclusion, however, does not properly derive from respiratory quotient (RQ) data. Stoichiometric analysis of glucose and lipid metabolism leads to conclusions similar clinically but at variance conceptually with those based on RQ. Thus, changing from glucose to lipid oxidation is associated with an 11% increase in oxygen consumption, a 23% decrease in carbon dioxide production, and a fall in RQ. In contrast, the diversion of glucose metabolism to synthesis of palmitylstearyloleyl triglyceride results in an 8-fold increase in RQ, but contrary to widely published concepts, the rate of carbon dioxide production falls by 68%. However, even this reduced carbon dioxide production associated with lipogenesis is undesirable because it is not associated with significant ATP production.