The effect on energy and nitrogen metabolism by continuous, bolus, or sequential infusion of a defined total parenteral nutrition formulation in patients after major surgical procedures

Preoperative overnight parenteral nutrition (TPN) improves skeletal muscle protein metabolism indicated by microarray algorithm analyses in a randomized trial

Loss of muscle mass is associated with increased risk of morbidity and mortality in hospitalized patients. Uncertainties of treatment efficiency by short‐term artificial nutrition remain, specifically improvement of protein balance in skeletal muscles. In this study, algorithmic microarray analysis was applied to map cellular changes related to muscle protein metabolism in human skeletal muscle tissue during provision of overnight preoperative total parenteral nutrition (TPN). Twenty‐two patients (11/group) scheduled for upper GI surgery due to malignant or benign disease received a continuous peripheral all‐in‐one TPN infusion (30 kcal/kg/day, 0.16 gN/kg/day) or saline infusion for 12 h prior operation. Biopsies from the rectus abdominis muscle were taken at the start of operation for isolation of muscle RNA. RNA expression microarray analyses were performed with Agilent Sureprint G3, 8 × 60K arrays using one‐color labeling. 447 mRNAs were differently expressed between study and control patients (P < 0.1). mRNAs related to ribosomal biogenesis, mRNA processing, and translation were upregulated during overnight nutrition; particularly anabolic signaling S6K1 (P < 0.01–0.1). Transcripts of genes associated with lysosomal degradation showed consistently lower expression during TPN while mRNAs for ubiquitin‐mediated degradation of proteins as well as transcripts related to intracellular signaling pathways, PI3 kinase/MAPkinase, were either increased or decreased. In conclusion, muscle mRNA alterations during overnight standard TPN infusions at constant rate altered mRNAs associated with mTOR signaling; increased initiation of protein translation; and suppressed autophagy/lysosomal degradation of proteins. This indicates that overnight preoperative parenteral nutrition is effective to promote muscle protein metabolism.

Nutrition Monitoring in the PICU

The ideal set of variables for nutritional monitoring that may correlate with patient outcomes has not been identified. This is particularly difficult in the PICU patient because many of the standard modes of nutritional monitoring, although well described and available, are fraught with difficulties. Thus, repeated anthropometric and laboratory markers must be jointly analyzed but individually interpreted according to disease and metabolic changes, in order to modify and monitor the nutritional treatment. In addition, isotope techniques are neither clinically feasible nor compatible with the multiple measurements needed to follow progression. On the other hand, indirect alternatives exist but may have pitfalls, of which the clinician must be aware. Risks exist for both overfeeding and underfeeding of PICU patients so that an accurate monitoring of energy expenditure, using targeted indirect calorimetry, is necessary to avoid either extreme. This is very important, since the monitoring of the nutritional status of the critically ill child serves as a guide to early and effective nutritional intervention.

Effects of growth hormone and insulin-like growth factor-1 on postoperative muscle and substrate metabolism

This study explored if a combined supplementation of GH and IGF-1 had an additive effect on whole body nitrogen economy, energy, substrate and skeletal muscle metabolism following surgical trauma. Patients were randomized to controls (C; n = 10), to GH (0.15 IU/kg/injection) (GH; n = 7) or GH combined with IGF-1 (40 μg/kg/injection) subcutaneously twice a day (GH-IGF-1; n = 9) together with standardized parenteral nutrition. Muscle amino acids, glutathione and the ribosomal pattern reflecting protein synthesis, and nitrogen balance were measured. GH- and GH-IGF-1 groups showed lower urea and higher plasma glucose concentrations. Energy expenditure increased in the GH-group. GH-IGF-1 prevented a decrease in muscle polyribosomes indicating a preserved muscle protein synthesis. In the GH group unaltered BCAA and AAA levels were seen in muscle indicating an unchanged protein breakdown, while the other groups showed increased muscle concentrations postoperatively. Without statistically difference GH marginally improved the nitrogen balance, in terms of higher values, and growth factors improved the nitrogen balance when the shift in urea was taken into account. To conclude, growth factors influences urea metabolism, protein degradation and protein synthesis. There was no clearcut additional effect when combining GH and IGF-1 but the study was probably underpowered to outrule this and effects on nitrogen balance.

Initiation factors for translation of proteins in the rectus abdominis muscle from patients on overnight standard parenteral nutrition before surgery

Previous studies have provided conflicting conclusions concerning the efficacy of improving protein balance in patients by standard intravenous nutrition [TPN (total parenteral nutrition)], which is either explained by suboptimal nutritional regimens or insensitive clinical methods. The aim of the present study was therefore to evaluate the effects on the initiation of translation of skeletal muscle proteins by standard overnight TPN. A total of 12 patients who underwent standard surgery were included. TPN was provided as an all-in-one treatment by constant infusion [0.16 gN·kg−1 of body weight·day−1 (30 kcal·kg−1 of body weight·day−1)]. Saline-infused patients served as controls. Rectus abdominis muscle biopsies were taken at the time of the operation. The phosphorylation state of the proteins for initiation of translation was quantified. Plasma glucose, and serum insulin, glycerol, triacylglycerols (triglycerides) and NEFAs (non-esterified fatty acids; ‘free fatty acids’) were not significantly altered during TPN infusion, whereas total plasma amino acids increased, as shown by increases in methionine, phenylalanine, threonine, alanine, arginine, aspartic acid, glycine and histidine (P<0.05). Overnight TPN increased the formation of active eIF4G–eIF4E (where eIF is eukaryotic-initiation factor) complexes (P<0.05), whereas the inhibitory complex 4E-BP1 (eIF4E-binding protein)–eIF4E was moderately decreased (P<0.06). TPN increased the amount of the most phosphorylated form of 4E-BP1 (P<0.05), and increased the amount (P<0.04) and phosphorylation (P<0.01) of p70S6K (70 kDa ribosomal protein S6 kinase). In conclusion, an overnight pre-operative constant infusion of standard TPN altered initiation factor complexes, indicating activation of the initiation of protein translation in rectus abdominis muscle in the presence of increased plasma amino acid levels, but without a concomitant increase in energy substrates and insulin. In contrast with our results from previous studies, the methodology used in the present study appears to be more sensitive in reflecting directional changes in human muscle protein synthesis compared with traditional methods, particularly based on measurements of amino acid flux.

Combined growth hormone/insulin-like growth factor I in addition to glutamine-supplemented TPN results in net protein anabolism in critical illness

Protein loss leading to reduced lean body mass is recognized to contribute to the high levels of morbidity and mortality seen in critical illness. This prospective, randomized, controlled study compared the effects of conventional parenteral nutrition (TPN), glutamine-supplemented (0.4 g.kg-1.day-1) TPN (TPNGLN), and TPNGLN with combined growth hormone (GH, 0.2 IU.kg-1.day-1) and IGF-I (160 microg.kg-1.day-1) on protein metabolism in critical illness. Nineteen mechanically ventilated subjects [64 +/- 3 yr, body mass index (BMI) 23.8 +/- 1.3, kg/m2] were initially studied in the fasting state (study 1) and subsequently after 3 days of nutritional with/without hormonal support (study 2). All had recently been admitted to the ICU and the majority were postemergency abdominal surgery (APACHE II 17.5 +/- 1.0). Protein metabolism was assessed using a primed constant infusion of [1-13C]leucine. Conventional TPN contained mixed amino acids, Intralipid, and 50% dextrose. TPNGLN, unlike TPN alone, resulted in an increase in plasma glutamine concentration ( approximately 50%, P < 0.05). Both TPN and TPNGLN decreased the rate of protein breakdown (TPN 15%, P < 0.002; TPNGLN 16%, P < 0.05), but during these treatments the patients remained in a net negative protein balance. Combined treatment with TPNGLN + GH/IGF-I increased plasma IGF-I levels (10.3 +/- 0.8 vs. 48.1 +/- 9.1 nmol/l, study 1 vs. study 2, P < 0.05), and in contrast to therapy with nutrition alone, resulted in net protein gain (-0.75 +/- 0.14 vs. 0.33 +/- 0.12 g protein.kg-1.day-1, study 1 vs. study 2, P < 0.05). Therapy with GH/IGF-I + TPNGLN, unlike nutrition alone, resulted in net positive protein balance in a group of critically ill patients.

Stability of total nutrient admixtures in reference to ambient temperatures

OBJECTIVE

To evaluate the stability of emulsions under different temperatures simulating clinical conditions of storage and exposure during infusion, five total nutrient admixture formulas in this institution were analyzed: adult, patients with hepatic failure, infants, stressed patients, and patients with renal failure.

METHODS

Each mixture was allocated in a sterile 100-mL glass bottle, which was prefilled and refilled with nitrogen gas. Bottles were stored at 4 degrees C for 0 d, 3 d, and 7 d and then exposed to three different temperatures: usual room temperature (18 degrees C to 25 degrees C), high (>28 degrees C) in a water bath, or storage (4 degrees C) for 24 and 48 h. The gross inspection of the emulsions and parallel measurements of pH, particle sizes, divalent ions, peroxide levels, and microbial cultures were performed.

RESULTS

Every lot was stable near 18 degrees C, but 8 of 10 lots stored for 7 d (25 degrees C and >28 degrees C) and 15 of 20 lots stored for 3 and 7 d (25 degrees C and >28 degrees C) showed coalescence. The overall coalescence incidences by storage, exposure, and heat were statistically significant (P < 0.005).

CONCLUSION

For the safety of total nutrient admixtures, special attention is required to keep the ambient temperature below 28 degrees C and completely exclude air from the container.

Economic investigation of the use of three-compartment total parenteral nutrition bag: prospective randomized unblinded controlled study

Optimal strategy for total parenteral nutrition (TPN) administration is essential both in terms of clinical effectiveness and economic efficiency. The aim of the present economic analysis was to provide a systematic and comprehensive cost comparison of the application of three currently available TPN systems: Separate Bottles (SB), Hospital-Compounded Bags (HCB) and Three-Compartment Bags (TCB). Sixty patients, admitted to the Geneva University Hospital and requiring TPN, were randomly assigned to one of the three systems. Three standard TPN formulas were prescribed to meet the patients' protein energy needs. TPN-related activities of medical, nursing and pharmacy staff were timed for the 24 hours of TPN administration. Manpower, nutrient solutions and medical supplies costs were calculated on the basis of mean Swiss salaries and hospital prices. TCB was the least expensive TPN system. SB and HCB systems' application costs were 120 and 150% of TCB cost, respectively. All intersystems cost comparisons were statistically significant (ANOVA p < or = 0.01). SB system required more items and manipulations, resulting in higher nurses manpower cost. Pharmacy overhead cost due to compounding was responsible for the higher cost of HCB system. Detailed manpower data presented in this study allow for an estimation of TPN application costs in other hospitals, using local salaries, specific product prices and compounding costs.