The main determinants of nitrogen balance during total parenteral nutrition in critically ill injured patients

Factors influencing nitrogen balance during total parenteral nutrition have been investigated in 34 critically ill injured patients studied during the first 6 days after trauma. Basal nitrogen balance was severely negative (-0.26±0.12 (SD) g·kg^-1), but improved consistently during treatment. Nitrogen intake proved to be the major determinant of a positive, or less negative, nitrogen balance, only secondarily followed by total energy intake corrected to predicted basal energy expenditure, according to multiple regression analysis. The amount of non-protein calories and the non-protein calorie to nitrogen ratio appeared to have little significance on nitrogen balance, when corrected for the two former variables.     

肠内和肠外营养支持对重型颅脑损伤预后的疗效观察

目的 观察早期肠内营养对重型颅脑损伤患者营养支持效果及预后.方法 将40例重型颅脑损伤患者随机分成肠内营养(EN组)和肠外营养(PN组),比较两组使用营养液前、使用后7 d、14 d上臂围(MAC)、上臂肌围(MAMC)、三头肌皮脂厚度(TSF)、血清白蛋白(ALB)、血红蛋白(Hb)代谢和预后情况.结果 EN组使用后7 d、14 d上臂围(MAC)、上臂肌围(MAMC)、血清白蛋白(ALB)、血红蛋白(Hb)检验指标高于PN组,EN组好转率80%、感染性并发症40%,PN组好转率70%、感染性并发症80%.结论 重型颅脑损伤患者早期肠内营养,有保护肠粘膜屏障、减少并发症,改善患者预后的作用.     

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     

机械通气患者肠内营养与肠外营养支持对撤机时间的影响

目的 :观察肠内营养与肠外营养支持对机械通气患者撤机时间的影响。方法 :将 6 0例机械通气患者随机分为肠内营养支持组 ( 30例 )和肠外营养支持组 ( 30例 ) ,观察撤机的时间 ,同时在营养支持前 1天及营养支持第 8天观察血清白蛋白和血红蛋白的变化。结果 :肠内营养支持组撤机时间明显早于肠外营养支持组 (P <0 .0 5 ) ,2周内的撤机成功率明显高于肠外营养支持组 (P <0 .0 1) ;患者的血清白蛋白在营养支持后较前升高明显 (P <0 .0 5 )。结论 :机械通气患者给予肠内营养支持符合生理状态 ,较肠外营养有更好的营养效果 ,能显著缩短机械通气时间 ,增加撤机成功率。     

肠内肠外营养对急性重症胰腺炎患者术后的影响

目的探讨肠内营养与肠外营养对急性重症胰腺炎患者术后的影响。方法对ICU收治的52例急性重症胰腺炎术后患者,根据治疗方法分为肠内营养组+肠外营养组(EN+PN组,n=26)与全肠外营养组(TPN组,n=26)。观察两组患者治疗前后、营养代谢指标(前白蛋白、转铁蛋白)及免疫功能(IgA、IgG、IgM水平;CD4+、CD8+、T细胞比值)的变化情况。结果与TPN组比较,EN+PN组治疗营养代谢指标前白蛋白下降,差异有统计学意义(t=8.26,P<0.05);而免疫功能IgA、IgG、IgM、CD4+、CD8+、CD4+/CD8水平改变差异亦有统计学意义(t分别=9.57、5.30、11.09、3.94、3.61、2.19,P均<0.05)。结论早期肠内营养在促进蛋白质合成代谢、促进免疫功能恢复方面优于肠外营养。     

Influence of parenteral nutrition on rates of net substrate oxidation in severe trauma patients

Optimal nutritional support should use a patient's energy expenditure as a guide for administering sufficient but not excessive caloric intake. Eight patients requiring parenteral nutrition were evaluated, using indirect calorimetry measurements, to determine the nutritional influence on the rates of substrate utilization in the critical period of catabolic illness due to accidental trauma. Five days of total parenteral nutrition, providing calories to match the measured basal resting energy expenditure and N to replace the initial urinary losses a) shifted the RQ from 0.74 +/- 0.03 to 0.81 +/- 0.03, b) improved but could not reverse negative N balance, c) decreased net fat oxidation, d) increased carbohydrate and protein oxidation, e) elevated daily norepinephrine and epinephrine excretion rates, and f) attained positive energy balance. The results suggest that positive energy balance could be achieved in trauma patients by providing total energy intake matching their basal measured energy expenditure plus 7% to 10% for activity energy expenditure. To prevent further loss of lean body mass, an N intake of 350 mg/kg.day was needed in these catabolic ICU patients.     

Effect of L-lysine-induced amino acid imbalance on nitrogen balance in patients treated by total parenteral nutrition

Cumulative nitrogen balances of 109 patients in 3 groups under total parenteral nutrition were studied with regard to their daily intake of l-lysin. Patients in group 1 who received a mean daily amount of 4.5 g l-lysin exclusively from the amino-acid solution showed a cumulative nitrogen balance of -51.9 g N 10 days into the study. Patients in groups 2 and 3 received, additionally, l-lysin HCl for prophylaxis or therapy of metabolic alkalosis. Thus patients in group 2 received 5.3 g l-lysin (nitrogen balance -101.4 g N/10 days) and in group 3, 8.5 g l-lysin (nitrogen balance -97.6 g N/10 days). The markedly higher negative nitrogen balance in these groups is interpreted as the effect of an amino acid imbalance due to inadequate l-lysin intake; therefore, l-lysin should no longer be used for treatment of metabolic alkalosis in patients under total parenteral nutrition.     

Validity of urinary urea nitrogen as a measure of total urinary nitrogen in adult patients requiring parenteral nutrition

The validity of the urinary urea nitrogen (UUN) estimate of total urinary nitrogen (TUN) was tested in patients who required iv nutrition. UUN and TUN were determined in 120 urine collections from ten preoperative, 13 postoperative, and 11 stressed patients. The relationship between TUN and UUN was examined by linear regression, and analysis of covariance was used on log-transformed data to assess differences between the patient groups. Although there was a close relationship between UUN and TUN for the preoperative patients (r2 = .94, total range of differences = 3.85 g N), this was not as accurate in postoperative and stressed patients (r2 = .69 and .76, respectively, total range of differences = 16.8 and 10.7 g N, respectively). There was no significant difference between the slopes of the regression lines for the relationship between UUN and TUN for three groups (f = 1.1, df = 2114, p less than .3), but the intercepts of the regression lines differed between the preoperative and stressed patient groups (t = 3.47, v = 114, p less than .001). The relationship between TUN and UUN for the whole group was improved by the inclusion of the independent variables of both the patient's clinical state and the urinary creatinine excretion. Arm muscle circumference, which is an estimate of muscle mass, may replace creatinine excretion with little loss in prediction accuracy.     

Comparison of modified amino acids and standard amino acids in parenteral nutrition support of thermally injured patients

Twenty thermally injured patients who could not tolerate enteral nutrition support were randomized to receive parenteral nutrition (PN) with either modified amino acids (MAA) or standard amino acids (SAA). There was no significant difference between groups for age, sex, weight, percent BSA area burn, percent third-degree burn, or operative procedures. N balance (NB) was measured and serum was harvested for circulating fibronectin (Fn), somatomedin-C/insulin-like growth Factor I (Sm-C), prealbumin (PA), and retinol-binding protein (RBP) analysis on days 1, 4, 7, 14, 21, and 28 of PN. The patient groups received similar doses of PN for a similar number of days. Fn did not change significantly from baseline in either group and there was no significant difference between groups. Sm-C increased significantly from baseline at day 7 in the SAA group and in both groups on day 14, but there was no significant difference between groups. PA and RBP increased significantly from baseline on day 7 in the MAA group and in both groups on days 14, 21, and 28. RBP was significantly higher in the MAA group only on day 21, and there was no significant difference between groups for PA. NB increased significantly from baseline for all study days; however, there was no significant difference between groups. PN in thermally injured patients significantly improves NB and increases visceral protein concentrations. However, there appears to be no difference between PN with MAA or SAA.     

透析中肠外营养对血液透析患者营养状况的影响

目的评估透析中肠外营养作为营养不良血液透析患者的营养干预措施的有效性和安全性。方法本试验采用前瞻性、随机、对照试验方法,选择暨南大学第四附属医院肾内科36例患者随机分为三组①对照组,②50%葡萄糖干预组,③8.5%氨基酸干预组,试验前后测量营养状况指标及其他生化指标。结果①干预前后比较,葡萄糖和氨基酸干预组的营养指标升高,尤以血清前白蛋白（PA）、血清转铁蛋白（TRF）、蛋白分解率（PCR）升高明显,具有统计学意义（P〈0.05）;②50%葡萄糖干预组干预后谷氨酸、色氨酸和亮氨酸水平明显提高,具有统计学意义（P〈0.05）,8.5%氨基酸干预组干预后谷氨酰胺、苏氨酸、酪氨酸、缬氨酸、苯丙氨酸、亮氨酸、必需氨基酸以及总氨基酸的水平均明显提高,具有统计学意义（P〈0.05）;③三组患者干预前后的三酰甘油、胆固醇、低密度脂蛋白以及C反应蛋白均没有统计学意义（P〉0.05）。结论透析中肠外营养干预可以提高血液透析患者营养状况,也可以改善患者的血清氨基酸状态,但不会影响患者炎症状况和引起血脂的升高。     

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.     

Hormonal changes in catabolic patients during parenteral nutrition

This study assesses the hormonal changes in 23 catabolic surgical patients during the three different regimens of parenteral nutrition: one with glucose, another with glucose and fat as energy sources, and a third one rich in amino acids. Before treatment, plasma insulin and cortisol concentrations, as well as daily urinary excretion of 17-oxogenic steroids and catecholamines, were normal. Plasma growth hormone concentration was close to normal. Plasma testosterone and daily urinary excretion of 17-oxosteroids were decreased. The response of plasma cortisol concentration to glucagon was impaired but the responses of insulin and growth hormone were close to normal. During the glucose regimen plasma insulin increased by 270% and plasma testosterone by 60%. There was a 55% decrease in plasma growth hormone concentration and a 31% rise in plasma cortisol concentration. The lipid regimen enhanced plasma insulin by 120%. During the amino acid regimen plasma insulin concentration was 150% higher, but plasma growth hormone concentration 45% lower than initially. The glucose and amino acid regimens augmented the response of insulin to glucagon by 180 and 50%, respectively, but decreased that of growth hormone by 59 and 80%, respectively. The lipid programme caused no significant change in the hormonal response to glucagon.     

Peripheral,visceral and body nitrogen balance of catabolic patients,without and with parenteral nutrition

The effect of major trauma and sepsis on skeletal muscle, central tissue and whole body nitrogen (N) metabolism was investigated in 5 patients before and during TPN (30 kcal, 0.30 g N kg^-1 day^-1). Fasting 3-methylhistidine (MEH) urinary excretion was elevated (407.9±67.6 mol m^-2 day^-1), muscle and body N balances (NB) were markedly negative (-28.2±4.6 g m^-2 day^-1 and-15.7±3.1 g m^-2 day^-1), while central tissue NB was positive (13.0±2.4 g m^-2 day^-1). TPN effected a reduction in MEH excretion (261.8±27.5 mmol m^-2 day^-1-p<0.05) and decreased the release of almost all amino acids from muscle tissue, some of them acting as catabolic markers. Muscle (-7.2±1.2 g m^-2 day^-1-p<0.01) as well as body NB (-4.8±1.4 g m^-2 day^-1-p<0.01) improved, whilst central tissue NB worsened, even though still positive (3.1±1.6 g m^-2 day^-1-p<0.05). Gathering fasting and TPN data MEH excretion was significantly related to both body (r=0.89) and muscle (r=0.73) NB, that were highly related to each other (r=0.93), being muscle always worse than body NB. In conclusion, the anticatabolic activity of TPN is confirmed, although our setting did not achieve muscle NB, it was consistently improved and seems to be the major determinant of body NB, in contrast central NB and central N utilization (46.4%±5.4 vs 15.8%±8.4-p<0.05) worsened.     

Failings in the care of patients receiving parenteral nutrition

John Tingle discusses an NCEPOD report which reveals serious failings in the care of hospital patients receiving parenteral nutrition.     

早期添加肠外营养对创伤患者营养摄入和预后的影响

目的 观察创伤患者早期添加肠外营养(PN)后蛋白质和能量摄入的变化,及对预后的影响.方法 采用回顾性对照研究方法,将195例创伤患者按伤后7d内是否添加PN分为对照组(105例)和混合营养组(90例).比较两组的营养支持时间、14d内蛋白质和能量的摄入及临床结局的差异.结果 两组患者伤情程度一致,急性生理学与慢性健康状况评分系统Ⅱ(APACHEⅡ)评分、损伤严重度评分(ISS)和格拉斯哥昏迷评分(GCS)无明显差异.与对照组相比,混合营养组开始营养支持的时间(h)较早(40.0±21.0比55.1±23.5,P＜0.01),肠内营养(EN)开始时间(h)延迟(75.2±54.5比55.1±23.5,P＜0.01),48 h内EN比例低[14.4％(13/90)比43.8％(46/105),P＜0.01],恢复口服饮食的时间(d)无统计学差异(10.8±3.7比11.4±3.6,P＞0.05).混合营养组在治疗3、7、t4d摄人的能量(kJ)均优于对照组(3d:3981.6±2209.3比2683.2±1414.9,7 d:5477.5±2008.4比3619.1 ± 1429.9,14 d:6250.2±2533.2比5199.9±1972.7,P＜0.05或P＜0.01);两组蛋白质的摄入量(g)均较低,混合营养组治疗3d明显低于对照组(20.6±18.4比26.5± 13.8 P＜0.05).与对照组比较,混合营养组住院时间(d)明显延长(73.9±62.5比50.9±33.3,P＜0.01),而病死率[4.4％(4/90)比3.8％(4/t05)]、感染和急性呼吸窘迫综合征(ARDS)的发生率[8.9％(8/90)比3.8％(4/105),5.6％(5/90)比7.6％(8/105)]、机械通气时间(d:8.3±4.6比7.3±4.7)、ICU停留时间(d:17.6±13.2比14.2±11.3)均无统计学差异(均P＞0.05).结论 虽然创伤患者早期加用PN能增加能量摄入,但不规范的PN不能改变创伤患者的预后,并可增加住院天数.     

肠外营养对胃癌术后患者营养和免疫功能的影响

目的探讨化疗期间肠外营养对胃癌术后患者营养及免疫功能的影响。方法 80例胃癌术后需行化疗的患者,随机分为对照组和观察组,每组40例。对照组给予单纯化疗(FAM方案),观察组在化疗同时接受肠外营养。观察2组化疗后的临床疗效、外周血血清白蛋白(ALB)、转铁蛋白(TRF)、前白蛋白(PAB)水平、T淋巴细胞亚群数量。结果与化疗前比较,2组化疗后血清ALB、PAB、TRF水平明显降低(P<0.01);观察组化疗后血清ALB、PAB、TRF水平明显高于对照组(P<0.05,P<0.01)。与化疗前比较,观察组化疗后CD3+、CD4+淋巴细胞亚群数量及CD4+/CD8+比值明显增加(P<0.01)。观察组化疗后CD3+、CD4+淋巴细胞亚群数量及CD4+/CD8+比值明显高于对照组(P<0.01)。结论胃癌患者化疗期间给予肠外营养可改善患者营养状态和免疫功能。     

肠内营养和肠外营养用于食管癌术后早期患者的效果观察

目的 比较肠内营养和肠外营养用于食管癌术后早期患者的效果.方法 78例食管癌术后早期患者,按入院日期单双号分为肠内营养组和肠外营养组,通过检测两组营养指标、免疫指标的变化,以及消化道症状的表现、并发症、住院费用等,对两种营养方式进行比较.结果 早期肠内营养组营养指标优于肠外营养组;胃肠功能恢复时间、住院费用显著减少.结论 食管癌术后营养支持可用肠内营养.     

肠内、肠外营养在胃癌术后早期的临床应用的比较

目的通过对肠内营养和肠外营养在胃癌术后早期应用的比较,探讨肠内营养应用的疗效。方法60例胃癌术后患者分为肠内营养(EN)组和肠外营养(PN)组,各30例,两组营养支持均等热量、等氮量,检测其手术前1天、术后第7天的体重、血浆白蛋白、前白蛋白及术后肛门排气时间、平均住院日等结果进行比较。结果两组患者体重均下降,但EN组下降少于PN组,差异无统计学意义(P>0.05),而EN组血浆白蛋白、前白蛋白下降的数值明显小于PN组(P<0.05),术后肛门排气时间及平均住院日数也早于PN组(P<0.05)。结论胃癌术后早期临床采用肠内营养支持方法是有效可行的。     

Hyperammonemia during parenteral nutrition of intensive-care patients]

Metabolic features of parenteral feeding with conventional amino acid solutions were examined in 47 patients over a long period. 30 patients were kept alive by artificial respiration. The metabolic parameters ammonium, blood urea nitrogen, GOT, alkaline phosphatase were carried out, in 6 patients the pattern of amino acids was analysed. All patients showed a significant increase of ammonium during the course of parenteral feeding. The amino acids demonstrated pattern of imbalance. The other other parameters were not changed significantly. Traumatic, hypoxic or toxic liver damage might influence the reduction of liver function.     

低氮低热量肠外营养支持治疗在重度腹部创伤中的应用探讨

目的 探讨低氮、低热量肠外营养支持对重度腹部创伤中的早期应用.方法 选择80例重度腹部创伤患者,随机分为低氮、低热量组(研究组,n=40)和对照组(n=40),分别接受低氮、低热量和传统肠外营养治疗,观察两组的血糖水平、氮平衡、血浆蛋白水平、免疫指标和并发症的变化情况.结果 与对照组相比,低氮、低热量组氮平衡改善,研究组血糖改善明显优于对照组(P＜0.05),术后并发症的发生率明显降低(P＜0.05),而血浆蛋白水平改变和免疫指标下降(P＞0.05).结论 重度腹部创伤早期低氮、低热量肠外营养支持是一种安全、有效的治疗方法.