Trace metal and essential fatty acid deficiency during total parenteral nutrition.

While deficiences of trace metals and essential fatty acids are rare in humans fed orally, the widespread use of total parenteral nutrition (TPN) has increased the likelihood of encountering these deficiences. A 14-year-old boy, with total villous atrophy of the small intestine, suffered from severe malnutrition and was placed on a conventional TPN regimen. Although not immediately recognized, he rapidly developed deficiencies of zinc, copper and essential fatty acids. Careful monitoring of the course of the illness and the responses to sequential treatments with zinc, lipid, and copper given intravenously allowed examination of the effects of the deficiencies on skin, intestine, liver, and hemopoietic systems and helped to establish normal requirements for the metals. The progress of the illness suggested that patients with intestinal malabsorption may be especially at risk of developing some of these lesser known complications of TPN.     

Essential and non-essential amino acid requirement in injured patients receiving total parenteral nutrition

The metabolic derangements of injury are known to influence nitrogen (N) requirements whilst less is known about individual amino acid (AA) requirements. This study was designed to investigate prospectively N vs AA requirement in 36 injured patients treated with total parenteral nutrition (TPN). The non-protein caloric input was 30 kcal kg^-1 day^-1 and three AA solutions were assessed containing the same AAs but in different proportion. Overall N intake was set at 0.35 g N kg^-1 day^-1 for solution A and B and 0.24 g N kg^-1 day^-1 for solution C. Solution B was similar to A, both being enriched in branched chain AAs (BCAA: 0.69 g kg^-1 day^-1 in B compared with 0.55 g kg^-1 day^-1 in A) while decreased in aromatic and sulphurated forms (1.75 times the normal need). Solution C was designed to maintain a daily input of BCAA similar to A (0.52 g kg^-1 day^-1) but with the supply of aromatic and sulphurated AA between solutions A and B, the supply of other AAs (lysine, theonine, histidine, arginine, glycine) being dependent on the selected N intake. For all the essential AAs the supply was always greater than normal allowances. Increasing BCAA over 0.55 g kg^-1 day^-1 did not improve N balance when N intake was 0.35 g kg^-1 day^-1, whilst nutrition with solution C was unable to maintain N balance. Moreover we found indirect evidence that this N intake, 0.52g kg^-1 day^-1 was more sparing than 0.37 g kg^-1 day^-1 of BCAA. N balance of the three groups suggests that injured patients need more than 0.24 g N kg^-1 day^-1 probably for non-essential AA synthesis. The study of plasma AA values support the increased non-essential N need in group C and allows us to suggest the proper AA composition of the overall optimal daily N intake (0.28–0.30 g N kg^-1 day^-1) in catabolic patients: BCAA about 0.5 g kg^-1 day^-1, phenylalanine, methionine, tryptophane, threonine and lysine from 2–3 to 5–10 times the normal allowance, the remainding N supply (about 0.14 g kg^-1 day^-1) should be made up from histidine, arginine, tyrosine, serine, proline, glycine, glutamic and aspartic acid. Presented in abstract form at the 3rd European Congress on Intensive Care Medicine, Hamburg, June 11–14, 1986     

The effects of n-3 polyunsaturated fatty acid-rich total parenteral nutrition on neutrophil apoptosis in a rat endotoxemia

Although recruited neutrophils function as first-line defense to remove bacteria, delayed apoptosis is implicated in persistent inflammation leading to organ injury. Leukotrien B₄, n-6 polyunsaturated fatty acids (PUFAs) product, is one of the mediators that delay neutrophil apoptosis. The mechanism of the beneficial effects of supplementation of fish oil-based long-chain n-3 PUFAs in parenteral nutrition for critically ill patients has not been fully understood. One possible mechanism is the less inflammatory n-3 PUFAs products can compete with proinflammatory n-6 PUFAs products for access to the enzymes. The aim of this study was to determine whether n-3 PUFA rich parenteral nutrition may alter the composition of fatty acids in the neutrophil membrane and restore delay of neutrophil apoptosis during endotoxin-induced systemic inflammation in rats. The animals in group 1 were treated with 20% Hicaliq NC-N in Neoparen-2 for three days. The animals in group 2 (referred to as n-6 PUFA-rich parenteral nutrition) were given parenteral nutrition solutions containing 20% soybean oil in Neoparen-2 (n-6/n-3 = 10). The animals in group 3 (referred to as n-3 PUFA-rich parenteral nutrition) were administered parenteral nutrition consisting of 10% soybean oil and 10% fish oil emulsion (n-6/n-3 = 1.3). The n-3/n-6 ratio of the neutrophil membrane was significantly increased in group 3 and was associated with restored lipopolysaccharide-delayed-apoptosis of neutrophils in bone marrow cells and increased production of leukotriene B₅ from peritoneal neutrophils stimulated by lipopolysaccharide. Our preliminary results showed that n-3 PUFA-rich parenteral nutrition regulated neutrophil apoptosis and prevented synthesis of pro-inflammatory eicosanoids, explaining the protective effects seen in the clinical setting.     

完全胃肠外营养的护理

完全胃肠外营养（TPN）是指通过中心静脉或周围静脉插管输入营养液，如葡萄糖、氨基酸、脂肪乳、电解质、微量元素、水溶性及脂溶性微生素等，患者在不能或不能完全充分由胃肠道摄取营养的情况下，使蛋白质、热量、电解质、微生素的补充仍能达到较满意的程度，对促进患者康复效果显著。现总结如下。     

Zinc and total parenteral nutrition.

Present knowledge of trace element nutritional requirements and the effects of TPN solutions unsupplemented with zinc indicate that zinc supplementation must be considered for any patient receiving prolonged TPN. Zinc sulfate appears to be the supplement of choice, and infusions of freeze-dried plasma appear to be an unsatisfactory method for supplying zinc, even during short-term therapy. As long as accepted dosage regimens are followed, there appears to be little risk of toxicity when TPN solutions are supplemented with zinc.     

Combined enteral-parenteral nutrition versus total parenteral nutrition in brain-injured patients

A comparative nutritional study in brain-injured patients (BIP) was performed to assess the influence of a combined enteral-parenteral nutrition (CN) and a total parenteral nutrition (TPN) on protein catabolism in the early posttraumatic period. 20 male BIP (Glasgow coma scale 5–7) were randomized to one of the two feeding regimes. Nutritional support was based on 150–175% basic energy expenditure. Amino acid intake was 1.4 g/kg/day in the TPN and 2.4 g/kg/day in the CN group. Negative nitrogen balance (NNB) averaged x (SEM=3.06 g/m²/day) in the TPN group and x (SEM=2.33 g/m²/day) in the CN group. Between both feeding regimes not statistically significant differences could be observed concerning mortality, N-balance, creatinine and 3-methylhistidine excretions. Protein concentration of the regurgitated gastric fluid was significantly higher in the CN than in the TPN study group. Data imply that both alimentary regimes are of similar value, but BIP with imparired gastric function, such as high tube reflux, are better treated by TPN.     

Practical aspects and complications of total parenteral nutrition

The objective of this article has been to review the practical aspects of parenteral feeding in the critical care setting. The general principles outlined in this chapter have evolved as a result of a 10-year experience with a busy nutrition support service in a tertiary teaching institution. We are hopeful that these practical guidelines, in part empirical and based on the major research advances in the field, will be of assistance to those involved in the nutritional care of critically ill patients.     

Dietary omega-3 fatty acid deficiency and visual loss in infant rhesus monkeys

Linolenic acid (18:3 omega 3) is a dietary precursor of docosahexaenoic acid (22:6 omega 3), the major fatty acid in the photoreceptor membranes of the retina. We hypothesized that rhesus monkeys deprived of dietary omega-3 fatty acids during prenatal and postnatal development would show plasma depletion of these fatty acids and visual impairment. Semipurified diets low in omega-3 fatty acids were fed to one group of adult female rhesus monkeys throughout pregnancy and to their infants from birth. A control group of mothers and infants received similar diets but supplying ample linolenic acid. In the plasma phospholipids of deficient infants, linolenic acid was generally undetectable and 22:6 omega 3 levels became progressively depleted, falling from 42% of control values at birth to 21% at 4 wk, 9% at 8 wk, and 6% at 12 wk of age. In the other plasma lipid classes, 22:6 omega 3 was undetectable by 12 wk. The visual acuity of the deprived infants, as measured by the preferential looking method, was reduced by one-fourth at 4 wk (P less than 0.05) and by one-half at 8 and 12 wk (P less than 0.0005) compared with control infants. These results suggest that omega-3 fatty acids may be an essential nutrient, and that 22:6 omega 3 may have a specific function in the photoreceptor membranes of the retina.     

Renal function in rats with essential fatty acid deficiency

1. Renal function was studied in 50-, 70-, 90- and 200-day-old rats with essential fatty acid deficiency. The pharmacokinetics of tobramycin was investigated in 90-day-old essential fatty acid-deficient rats. 2. A higher glomerular filtration rate and a higher serum concentration of urea were seen in 50-day-old essential fatty acid-deficient rats compared with age-matched controls. Later, the glomerular filtration rate progressively deteriorated in parallel with a decline in effective renal plasma flow and with a concomittant rise in serum levels of urea and creatinine. The serum concentration of protein was lower in the rats with essential fatty acid deficiency and that of sodium was higher than in the control rats. The non-renal clearance of tobramycin was increased in the rats with essential fatty acid deficiency. 3. The early hyperfiltration in essential fatty acid-deficient rats with the subsequent fall in glomerular filtration rate, which was paralleled by a rise in serum levels of urea and creatinine, as well as the increased non-renal clearance of tobramycin, are in accordance with the clinical manifestations of cystic fibrosis. Rats with essential fatty acid deficiency might be a useful model with which to study the pathophysiological renal changes in cystic fibrosis related to the progressive essential fatty acid deficiency in this disease.     

Fructose,xylitol and glucose in total parenteral nutrition

A comparison was made between isocaloric amounts of 24% glucose and 24% Triofusin^® (composed of 120 g fructose, 60 g glucose and 60 g xylitol per liter) during the course of a 6-day, 3-phase crossover study of 15 patients undergoing total parenteral nutrition. The patients received a total of 0.5 g carbohydrate per kilogram body weight per hour and 6 g carbohydrate per kg per day. Plasma glucose was significantly higher during glucose infusion (7–22 mmol/l, median: 9 mmol/l) than during Triofusin^® infusion (5–16 mmol/l, median: 6 mmol/l). A moderate to severe glucosuria was detected in three patients during infusion of 24% glucose, and this declined considerably during the Triofusin^® period. The total renal carbohydrate loss during the glucose period was 0–143 g, median: 6 g per day, and during the Triofusin^® period was 6–68 g, median: 10 g per day. The nitrogen balance and carbamide production rate were the same in the two infusion regimes. Changes in biochemical liver parameters were observed in most of the patients, but these could not be attributed to parenteral nutrition. None of the patients developed symptoms of metabolic acidosis. There was a slightly but significantly higher urinary excretion of oxalate in the Triofusin^® period (0.1–1.1 mmol per day, median: 0.5 mmol per day) than in the glucose period (0.1–1.0 mmol per day, median: 0.4 mmol per day). Most of the patients exhibited a slightly increased urinary excretion of urate, irrespective of the infusion regimen. Serum urate remained normal. It was concluded that Triofusin^® infused in the described dosage is a suitable calorie source for parenteral nutrition, but that it does not present a distinct advantage over the use of pure glucose solution. In patients suffering from reduced glucose tolerance, however, Triofusin^® represents a more easily manageable calorie source.This work was supported by grants from the Danish Medical Research Council (J.No. 512-15484), King Christian X's Foundation, P. Carl Petersen's Foundation and the Foundation for Advancement of Medical Science     

全肠外营养对早产儿营养、免疫功能及行为发育的影响

目的 探讨全肠外营养对早产儿营养、免疫功能及行为发育的影响.方法 选取100例早产儿作为研究对象,将其随机分为观察组和对照组,每组50例,对照组患儿给予常规对症治疗,观察组患儿在对照组疗法的基础上加用完全肠外营养支持治疗.对2组患儿的日平均体质量增长量,治疗前后的血清球蛋白、白蛋白、前白蛋白水平,血液IgG、IgA、IgM及C反应蛋白水平及行为发育情况进行比较.结果 观察组患儿的日平均体质量增长和治疗后的血清白蛋白、球蛋白、前白蛋白水平均显著高于对照组(P＜0 05);观察组患儿治疗后的血液IgG、IgM、IgA水平显著高于对照组(P＜0.05),而血液C反应蛋白水平显著低于对照组(P＜0.05);观察组患儿的各项行为发育评分均显著高于对照组(P＜0.05).结论 对早产儿应用完全肠外营养支持治疗可显著改善患儿的营养状况,提高其免疫功能并促进其行为功能的发育.