Effects of different lipid emulsions on lymphocyte function during total parenteral nutrition.

A prospective randomized study of the immunological effects of three total parenteral nutrition (TPN) regimens in patients undergoing preoperative parenteral nutrition was conducted. In one regimen the calories were derived solely from glucose. The others were identical except that 50 per cent of the calories were provided as lipid emulsion, in one as long-chain triglycerides (LCT) only while the other contained half the fat as medium-chain triglycerides (MCT) and half as LCT (MCT/LCT). Natural killer (NK) activity and lymphokine-activated killer (LAK) activity were significantly higher after TPN with the MCT/LCT solution. A significant fall in LAK activity occurred after TPN with the LCT solution. The interleukin 2 content in supernatants from activated T lymphocytes was significantly higher after TPN with the LCT-containing solution. Solutions containing LCT and those containing MCT perturb cytokine interactions, but this is less with MCT-containing solutions, which may augment certain responses. These observations may have implications for the design of TPN regimens.     

Medium-chain triglycerides metabolism and its application in total parenteral nutrition

Twenty patients undergoing uneventful gastrectomy were randomly assigned to receive TPN containing either 10% Intralipid or 10% Lipofundin (MCT/LCT) beginning postoperative day (POD) 1 through POD 6. Patients were given non-protein energy 27 kcal/kg/d and nitrogen 0.14 g/kg/d through peripheral vein along with fat emulsion. Body weight, hemoglobin, blood lymphocyte count, SGPT, serum bilirubin, AKP, BUN, Cr, serum albumin, transferrin, prealbumin, fibronectin, creatine phosphokinase, serum and plasma cholesterol, triglycerides, plasma free fatty acids, blood sugar, serum insulin, urinary creatinine and nitrogen balance were monitored. It was found that MCT-based fat emulsion was tolerated without any side effects. Kinetics study showed that levels of medium chain free fatty acids increased during MCT-based fat emulsion infusion, but returned to normal within 2 hours on cessation of infusion, indicating good clearance of MCT. Plasma concentration of triglycerides in the LCT group was higher than that in the MCT group at 2 hours after infusion. On POD 6, better nitrogen balance was observed in the MCT group, 0.44 +/- 0.21 g/d (-1.4 +/- 0.51 g/d in the LCT group). Urinary excretion of creatinine in the MCT group was also less than in the LCT group (0.76 +/- 0.03 g/d vs. 1.034 +/- 0.11 g/d). LCT was also observed to induce an elevation of serum bilirubin (1.12 +/- 0.11 mg/dl). These results indicate that MCT-based fat emulsion appears to be a safe energy source.     

Hepatic reticuloendothelial function during parenteral nutrition including an MCT/LCT or LCT emulsion after liver transplantation – a double-blind study

It has been demonstrated that total parenteral nutrition (TPN) modulates the function of the hepatic reticuloendothelial system (RES). The objective of this study was to evaluate the impact of two different TPN lipid emulsions on the recovery of allograft RES function after orthotopic liver transplantation (OLTx). In a prospective, double-blind study, OLTx patients were randomly assigned to two treatment groups. Group I ( n=13) received a TPN regimen that included long-chain triglycerides (LCT). Group II ( n=9) received a TPN regimen that included a fat emulsion consisting of both medium-chain triglycerides (MCT) and LCT. At baseline, i.e., on days 2 or 3 after OLTx ( t1), before lipids for TPN were started, hepatic RES function was determined using the human serum albumin millimicrosphere technique (K-value, 1/min). A second measurement ( t2) was obtained after 7 days of TPN, including one of the study's two fat emulsions. The mean (+/- SD) K-value (1/min) was 0.48+/-0.16 in the LCT group and 0.55+/-0.28 in the MCT/LCT group at t1, and it improved to 0.62+/-0.21 in the LCT group and to 0.86+/-0.32 in the MCT/LCT group at t2. RES function recovery was significantly better in the MCT/LCT group ( P< or = 0.05). MCT/LCT emulsion appears to be the TPN fat emulsion of choice after OLTx as it seems to have less impact on hepatic RES recovery.     

Parenteral nutrition in ventilated patients with chronic obstructive pulmonary disease: long chain vs medium chain triglycerides

AIM: The aim of this study was to assess the usefulness of a lipid formulation containing a physical mixture of medium (MCT) and long chain triglycerides (LCT) compared with a long chain triglycerides emulsion in patients affected by chronic obstructive pulmonary disease with acute respiratory failure. METHODS: Twenty-four patients requiring mechanical ventilation were randomly selected in 2 groups and received total parenteral nutrition. Twelve patients received a MCT/LCT emulsion (50:50), the others used a 100% LCT emulsion. Nutritional status, metabolic rate, time of ventilatory support and weaning were evaluated. RESULTS: Both groups showed an improvement of all nutritional parameters evaluated; oxygen uptake, carbon dioxide output and respiratory gas exchange ratio were similar in both groups. The duration of mechanical ventilation was not significantly different; however, the time of weaning in the MCT/LCT group was significantly shorter. The longer weaning time in the LCT group patients could be related to vasoactive intermediates deriving from long chain fatty acids. The T-cell subsets, which were evaluated for both groups, showed a significant decrease of T helper-T suppressor ratio in the LCT group. CONCLUSION: MCT/LCT emulsion is an effective lipid supplementation and should be considered the therapy of choice in COPD patients; however, the relationship between lipid emulsions administered and length of weaning requires further investigations.     

The metabolic consequences of infusing emulsions containing medium chain triglycerides for parenteral nutrition: a comparative study with conventional lipid.

In order to test the hypothesis that medium chain triglycerides (MCT's) are a safe and potentially superior energy source during parenteral nutrition 13 patients were entered into a randomised cross over trial. They received either a long chain triglyceride emulsion (LCT) or a 50% medium chain (MCT)/50% LCT mixture as part of their energy supply. Nitrogen balance was significantly better when MCT/LCT was infused and the greater levels of plasma ketones and lower plasma triglyceride levels suggested that MCT was more readily metabolised in these patients. Routine haematology, biochemistry and liver function tests gave no indication of harmful side effects from MCT.     

肝移植术后早期脂肪乳剂支持治疗对移植肝功能影响的临床研究

目的　研究含脂肪乳剂的肠外营养 (TPN)对肝移植受体肝脏功能的影响。方法　选择2 0 0 1年 9月～ 2 0 0 4年 6月期间在我所肝移植中心住院行肝移植手术治疗的患者 ,取符合标准的 30例作为研究对象 ,随机分组 ,进行前瞻性的临床研究。肝移植术后 6h开始给予单糖或脂肪乳剂和单糖联合功能的TPN(分别为Glu对照组和MCT/LCT组 ) ,TPN期为 7d ,期间严格禁食。于TPN后第 1、4、7、10、30、90及 180天收集标本 ,检测血ALT、AST、GGT、TBil及DBil。结果　TPN支持后MCT/LCT和Glu组ALT、AST、GGT、TBil及DBil水平均呈现下降趋势 ,与单糖组相比 ,脂肪乳组降低迅速。结论　含脂肪乳的TPN较单糖TPN更有利于促进移植肝早期功能恢复     

中-长链脂肪乳剂与长链脂肪乳剂在静脉营养中的疗效比较

１９９３年１０月至１９９４年２月对中－长链脂肪乳剂（实验组，ｎ＝４０）和长链脂肪乳剂（对照组，ｎ＝３０）在静脉营养中的疗效进行了对比观察。从术后第１天起，除从周围静脉输注必需液体外，每日静滴中－长链或长链脂肪乳剂５００～１０００ｍｌ，连续３～５天。监测项目包括血压、脉搏、呼吸、体温、血红蛋白、白细胞、肝肾功能、血甘油三酯及血胆固醇。结果显示：两组均无全身反应；在输脂肪乳剂后６小时，两组血甘油三酯含量均明显升高，并于１２小时时达峰值，１６小时时已明显下降，但对照组明显高于实验组（Ｐ＜０．０５），２４小时时仍维持较高水平。由此表明，中－长链脂肪乳剂较易从血清中清除；中链甘油三酯能快速进入线粒体被氧化供能，不依赖内毒碱的转运，能经肝脏生成更多的酮体，极少再脂化为脂肪贮存起来。     

中链甘油三酯对手术后接受肠外营养患者代谢的影响

目的比较长链甘油三酯(LCT)和中链甘油三酯(MCT)2种脂肪乳的代谢效应差异.方法24例胃、结肠手术患者和6例志愿者参加本研究,均有知情同意.患者随机分为2组,分别接受含50%MCT或单纯LCT的肠外营养.测定前臂动静脉血中甘油三酯的浓度差及氮平衡.结果MCT组肌肉利用脂肪乳的能力明显提高,氮平衡也有所改善,且术后体重减轻较少.在脂肪乳廓清试验中发现,血清酮体浓度MCT组[(0.063±0.004)mmol/L]明显高于LCT组[(0.039±0.002)mmol/L].氮储存的增加与酮体和胰岛素水平的增加相关.结论含50%MCT的脂肪乳用于肠外营养是安全的,可作为又一种能改善机体蛋白代谢的能量物质.     

中、长链脂肪乳剂对肝硬变家兔胆红素代谢及肝功能的影响

研究长链脂肪乳剂和中/长链混合脂肪乳剂二种不同肠外营养液支持下,观察血中游离脂肪酸浓度变化对胆红素和肝功能的影响。方法:21只新西兰大白兔经结扎胆总管制成胆源性肝硬化动物模型,随机分为三组:正常对照组(n=6);肝硬化肠外营养PN-LCT组(n=10);肝硬化肠外营养PN-MCT/LCT组(n=11)。两组的PN液所含热量及氮量均相等。在PN的第1、7天,用高效液相色谱(HPLC)测定PN后4h血中游离脂肪酸(FFA)浓度,并常规测定胆红素及白蛋白和肝脏酶学的变化。结果:肝硬变形成后,总胆红素及直接胆红素、丙氨酸转氨酶(ALT)、天门东氨酸转氨酶、碱性磷酸酶、γ-谷酰转肽酶均明显升高,而白蛋白明显下降,P<0.01。PN期间,FFA及FFA/白蛋白比值也明显升高,P<0.01。PN第7天时,LCT组直接胆红素及ALT和FFA/白蛋白比值均明显高于MCT/LCT组,P<0.01。结论:MCT/LCT乳剂可能是应用于肝硬变兔更为理想的能量来源。     

Carnitine supplementation vs. medium-chain triglycerides in postburn nutritional support

The effect of dietary supplementation of carnitine on protein metabolism was studied in a burned guinea-pig model. Animals bearing a 30 per cent total body surface area burn were enterally infused with three isocaloric and isonitrogenous diets via gastrostomy feeding tubes for 14 days. Two diets contained safflower oil (long-chain triglycerides, LCT) and another diet contained medium-chain triglycerides (MCT) as their lipid sources (30 per cent of total calories as lipid). L-Carnitine was added to one of the two diets containing safflower oil. There were no significant differences in nitrogen balance, urinary excretion, serum albumin or transferrin among the three groups. However, the use of MCT in place of LCT appeared to increase liver weight and liver nitrogen. In this model, carnitine supplementation did not enhance the nitrogensparing effect of fat following burn injury.     

含不同脂肪乳剂的肠外营养对肝移植大鼠肝脏功能的影响

目的　研究含不同脂肪乳剂的肠外营养 (TPN)对肝移植大鼠肝脏功能的影响。方法　建立肝移植大鼠模型 ,按照提供的能源不同分为单糖 (GLU )、脂肪乳剂MCT/LCT、LCT、STG 4个组 ,实验期为 7d ,记录实验期内动物死亡情况 ,于TPN后第 1、4、7d收集标本 ,检测AKBR(动脉血酮体比值 )、血ALT、AST、血TBIL。以正常和肝移植大鼠作为对照。结果　单糖组 7d动物死亡率显著高于脂肪乳剂组 (5 0 %vs0 % )。与脂肪乳组相比 ,单糖组动物 7d内血清ALT和AST水平降低缓慢、TBIL水平持续显著升高 ,AKBR水平在TPN后 1d恢复并稳定于较高水平 ,但于 7d时显著降低。在 1、4d时STG组动物血清ALT降低较MCT/LCTTPN组及LCTTPN组更为显著 ,MCT/LCTTPN组血清ALT水平低于LCTTPN组。结论　单糖TPN加重移植肝脏功能损害 ,动物死亡率增高 ,含脂肪乳的TPN能促进移植肝功能恢复。在减轻移植肝功能损害方面的优越性 ,依次为STG、MCT/LCT和LCT。     

不同碳链脂肪乳剂对肝脏外科患者脂肪及肝脏能量代谢的影响

目的 观察两种不同碳链脂肪乳剂对肝脏外科患者术后脂肪及肝脏能量代谢的影响。方法 选择肝脏外科患者25例,随机分为2组;给予肠外营养,长链脂肪乳剂组（LCT组）12例,中／长链脂肪乳剂组（MCT组）13例。LCT组脂肪乳剂为20％英脱利匹特（Intralipid),MCT组为２０％为保肪宁（Lipofundin),连续观察１周。在术前,术后１d、7d作脂肪廓清实验（IVFTT）,并测定血及尿液中肉毒碱（CNT）以及动脉血酮体浓度及比率（AKBR）的变化。结果 MCT组清除率为LCT组的1倍,半衰期为LCT组的1／2;术后血CNT明显升高,尿排出减少,术后7d时,LCT组血CNT高于NCT组,尿CNT低于MCT组,P＜0．05;血AKBR术后1d明显下降,随后MCT组逐渐回升,在术后7d时,MCT组明显高于LCT组,P＜0．01。结论 MCT组体内清除迅速,对CNT依赖较小,并对肝脏能量代谢有保护作用。提示MCT乳剂可能是肝脏外科患者更为理想的脂肪能源。     

A comparison of medium-chain and long-chain triglycerides in surgical patients.

Available lipid emulsions made from soybean or safflower oil are classified as long-chain triglycerides (LCT). In contrast, medium-chain triglyceride (MCT) emulsions have different physical properties and are metabolized by other biochemical pathways. To compare the differences between these two fat emulsions, the authors studied 12 surgical patients and 6 volunteers. These subjects were randomly assigned to receive parenteral nutrition with MCT or LCT emulsion. Measurement of arterial and venous concentration differences across the forearm demonstrated that muscle utilization was significantly improved with MCT administration. There was also a trend toward improved nitrogen balance in the MCT group, and less weight loss in the postoperative period also was observed in this group. During the fat clearance test, the serum ketone concentrations were significantly higher in the MCT than the LCT group. The improvement in nitrogen retention may be associated with increasing ketone and insulin levels. Fat emulsions containing 50% MCT are safe for use in parenteral nutrition and may provide an alternate fuel that improves protein metabolism.     

Influences of endotoxin on oxidation of fatty acid in rabbits: a comparison between medium chain- and long chain-fatty acids

Medium chain triglyceride emulsion (MCT) which is composed of 10% emulsion of tricaprylin (C8) or long chain triglyceride emulsion (LCT, 10% Intralipos) was infused intravenously to 20 rabbits for a period of 180 min (n = 10; MCT, n = 10; LCT). Five rabbits of each group were also given lipopolysaccharide (LPS B, E. Coli 055: B5, Difco Laboratories, Detroit Michigan, U.S.A.) at a rate of 0.3mg/kg/hr to a total dose of 0.9 mg/kg. The production of ketone-bodies (acetoacetate and beta-hydroxybutyrate) was quantified. MCT was more easily oxidized than LCT, regardless of the administration of LPS. Oxidation of LCT was suppressed by the administration of LPS, while that of MCT was not suppressed. In the presence of LPS, MCT caused a more pronounced decrease in the arterial ketone body ratio (acetoacetate/beta-hydroxybutyrate) than LCT. These results indicate that MCT seems to be a better energy source than LCT under the condition where the transport of fatty acid across the mitochondrial membrane was impaired by the administration of LPS.     

Comparison of the fat elimination between long-chain triglycerides and medium-chain triglycerides in rats with ischemic acute renal failure

To guide the administration of fat emulsion in the nutritional support of acute renal failure (ARF), pharmacokinetic analysis with an one-compartment open model after bolus intravenous injection was performed to compare the elimination kinetics of long-chain triglycerides (LCT) and medium-chain triglycerides (MCT) in ischemic acute renal failure rats. Sprague-Dawley rats were randomized into four groups, namely LCT normal group, LCT ARF group, MCT normal group and MCT ARF group. The model of ischemic acute renal failure was induced by clamping the left renal artery for 60 min and contralateral nephrectomy. All the rats were fasted with water ad libitum for 10 h before 0.3 g/kg body weight of 10% Intralipid (LCT) or 10% Lipofundin (MCT: LCT = 50:50) was injected as a bolus to them via the tail vein. The serum triglyceride concentration was determined at 2, 10, 40, 70, 100, 130 and 160 min after intravenous injection for kinetic analysis. The results showed that the elimination rate constant (ke) of LCT ARF group was significantly decreased, while the half life period (t1/2) of it was significantly longer than those of LCT normal group. The ke and t1/2 of MCT showed no statistical difference between normal and ARF groups. In the normal group the ke of LCT was significantly decreased compared with MCT whereas the t1/2 was significantly prolonged. In the ARF group the ke of LCT was much less than that of MCT while the t1/2 was much longer. The serum insulin levels of both MCT groups were significantly higher than those of LCT groups. These results indicate that MCT will be eliminated more rapidly than LCT in ARF rats. MCT may also increase the secretion of insulin. In conclusion, MCT may be more favorable than LCT in the nutritional management of ARF.     

Does the newer preparation of propofol,an emulsion of medium/long chain triglycerides cause less injection pain in children when premixed with lignocaine?

Background: Injection pain during propofol administration can be particularly distressing in children. The newly available emulsion of propofol in medium and long chain triglycerides (LCT) is reported to cause less injection pain because of lower concentrations of free propofol. This study compared the incidence of injection pain during administration of propofol emulsion of LCT and propofol emulsion of medium and long chain triglycerides (MCT/LCT) both premixed with lignocaine in children. Methods: This prospective, randomized, double blind study was conducted after obtaining institutional ethics committee approval, parental consent and included 84 children aged 5–15 years. Preoperatively, an intravenous cannula was inserted in all children. four children were excluded. Those included, depending on the randomization, received 3 mg·kg^?1 of either propofol LCT or propofol MCT/LCT both premixed with lignocaine (0.1%). The incidence and intensity of injection pain was assessed. Results: Pain on injection of propofol LCT with lignocaine was observed in 16/40 children (40%), five of these children complained of severe pain. In comparison, 14/40 (35%) children complained of pain following propofol MCT/LCT premixed with lignocaine (P = 0.644), the intensity being severe in two children (P = 0.698). Conclusions: Propofol MCT/LCT and propofol LCT premixed with lignocaine are both associated with pain on injection in children; the incidence and intensity of the injection pain are similar.     

Propofol-induced injection pain: comparison of a modified propofol emulsion to standard propofol with premixed lidocaine

Propofol is well known for its association with pain on injection. The most frequently used method to reduce this pain is premixture with lidocaine. Recently, a modified lipid emulsion of propofol containing medium-chain triglycerides (MCT) with long-chain triglycerides (LCT), in contrast to the usual LCT formulation, has been advocated to alleviate pain. In a randomized, prospective, controlled, double-blind study on 222 surgical patients, we compared the effect of the two solutions on the incidence and intensity of injection pain. Patients were randomly allocated to receive either propofol MCT/LCT (group M; n = 109) or standard propofol LCT with the addition of 20 mg of lidocaine (2 mL of lidocaine 1%) to 200 mg of propofol (group L; n = 113). Pain scores were assessed using a verbal analog scale (VAS) ranging from 0-10. Group L was found to have significantly less pain on the injection of propofol (mean VAS, 2.5 +/- 2.9) (mean +/- sd) than group M (mean VAS, 3.8 +/- 3.2; P = 0.002). Regarding postoperative recall of pain on injection, patients in group L indicated significantly less pain (mean VAS, 2.2 +/- 2.4) than patients in group M (mean VAS, 3.0 +/- 2.7; P = 0.02). Premixing of 20 mg of lidocaine (2 mL of lidocaine 1%) to 200 mg of standard propofol LCT causes less pain on injection than propofol MCT/LCT and thus increases patient comfort.     

Propofol in a medium- and long-chain triglyceride emulsion: pharmacological characteristics and potential beneficial effects

Hypertriglyceridemia is a possible unwanted effect during long-term propofol sedation while using a formulation containing long-chain triglycerides (LCT) from soybean oil. The use of propofol formulated in a solvent consisting of medium-chain triglycerides (MCT) and LCT might reduce the risk. Because a new solvent may affect the pharmacological profile of propofol, in this prospective, randomized, controlled, and double-blinded study we compared the pharmacodynamic and kinetic characteristics of propofol diluted in MCT/LCT fat solution with those of propofol formulated in LCT fat emulsion. In addition, serum triglyceride levels were measured during and after the administration of both drugs. Thirty patients likely to require mechanical ventilation over at least 48 h were randomized to receive either propofol 2% MCT/LCT (Group 1) or propofol 2% LCT (Group 2). Infusion rates of propofol (2.34 +/- 0.83 mg. kg(-1). h(-1) in Group 1 versus 2.31 +/- 0.6 mg. kg(-1). h(-1) in Group 2), the plasma propofol concentrations during infusion (0.95 +/- 0.53 versus 0.98 +/- 0.32 micro g/mL), and the concentrations and arousal behavior after discontinuation of the drug did not show significant differences. Plasma triglyceride concentrations during sedation did not differ between the groups, whereas there was a tendency toward a more rapid triglyceride elimination in Group 1 after termination of the propofol administration. IMPLICATIONS: Propofol diluted in an emulsion of medium- and long chain-triglycerides shows equivalent pharmacological properties during long-term sedation compared with its hitherto well known formulation containing long-chain triglycerides only. In addition, potential favorable effects on the plasma triglyceride profile could be found.     

The injection pain of propofol with different emulsion

BACKGROUND: Incidence and intensity of pain on intravenous injection of propofol were assessed with emulsion of long-chain/medium-chain triglycerides (LCT/MCT, 50: 50) and only long-chain triglycerides (LCT, 100) in patients undergoing different elective surgical interventions in this prospective, randomized, cross over and double-blinded study. METHODS: 1) Forty six patients were assigned to two groups. One group received 0.2 mg x kg(-1) LCT/ MCT propofol prior to LCT propofol administration. The other group received 0.2 mg x kg(-1) LCT propofol prior to LCT/MCT propofol administration. Pain elicited upon questioning was assessed with each injection in the two groups. Patients were asked to grade the pain as VAS of 0 to 100 mm. 2) Fifty one patients were randomly assigned to two groups. One group received 0.4 mg x kg(-1) LCT propofol. The other group received 0.4 mg x kg(-1) LCT/MCT propofol. Patients were asked to grade the pain as VAS of 0 to 100 mm. RESULTS: Pain of LCT propofol injection was stronger than LCT/MCT propofol. As incidence of 0.4 mg x kg(-1) propofol injection, VAS on LCT/MCT propofol and LCT propofol gave score as 0 and 23.5 (P=0.0019). CONCLUSIONS: Propofol with emulsion of long- and medium-chain triglycerides appears to reduce the injection pain than with emulsion of only long-chain triglycerides.     

Comparative study between propofol in a long-chain triglyceride and propofol in a medium/long-chain triglyceride during sedation with target-controlled infusion

This study was performed to compare the pharmacological characteristics of propofol in an emulsion of both medium- and long-chain triglycerides (MCT/LCT) with those of propofol in an LCT emulsion, by measuring the sedative level and the plasma concentration of propofol during sedation using a target-controlled infusion (TCI) technique. Forty ASA 1 or 2 adult patients who required spinal anaesthesia for surgery were enrolled in this study. The patients were divided into two groups: a propofol LCT group (n = 20) and a propofol MCT/LCT group (n = 20). Propofol was injected intravenously at target blood concentrations of 2.0, 3.0 and 4.0 microg x ml(-1). The bispectral (BIS) index was recorded, and arterial blood was drawn to measure the actual plasma concentrations of propofol at each predicted concentration. Propofol was assayed by high-performance liquid chromatography. Propofol MCT/LCT was associated with significantly less pain than propofol LCT (P < 0.05). There were no significant differences between the two groups in BIS index or in plasma concentration of propofol at each predicted concentration. Computer-generated TCI of propofol MCT/LCT during sedation is comparable with that of propofol LCT with respect to pharmacokinetics and pharmacodynamics. The formulation of MCT/LCT has a beneficial effect with respect to less pain on injection.