Intravenous Amino Acid Infusion Research Articles

Amino Acid Infusion for Perioperative Functional Renal Protection: A Meta-analysis

ObjectiveAcute kidney injury (AKI) is a common perioperative complication. To date, no single intervention has been proven effective for AKI prevention in this setting. However, intravenous amino acids (AA) administration may recruit renal functional reserve and, thereby, attenuate the perioperative loss of glomerular filtration rate. Accordingly, we performed a meta-analysis to assess the efficacy of AA infusion for perioperative renal functional protection. MethodsWe performed a meta-analysis of controlled studies in perioperative patients (P) evaluating intravenous AA infusion (I) versus any comparator (C). The primary outcome was AKI at longest follow-up (O). We performed a random effects meta-analysis on the relative risk (RR) scale to assess the effect of AA infusion. We used a Bayesian approach to estimate the probability of benefit (RR<1) for the primary outcome. Secondary outcomes included renal-replacement therapy, serum creatinine, and estimated glomerular filtration rate. Tertiary outcomes included mechanical ventilation duration, intensive care unit and hospital length of stay and mortality. (PROSPERO: CRD42024547225). ResultsWe identified 15 studies (14 RCTs and one prospective before-after study) reporting at least one outcome of interest (4,544 patients), with six studies (4,084 patients) reporting the primary outcome. AKI occurred 504/2,041 (24.7%) in AA patients vs 614/2,041 (30.1%) in controls (RR=0.66; 95% CI, 0.47 to 0.94; I2=50%; p=0.02), which corresponded to a 99.1% probability of AKI reduction with AA. Moreover, coherent with such findings, AA reduced serum creatinine, and hospital length of stay, and increased eGFR. ConclusionsThis meta-analysis suggests that AA administration likely reduces the perioperative incidence of AKI.

Preanalytical impact on the accuracy of measurements of glucagon, GLP-1 and GIP in clinical trials

Background Plasma concentrations of glucagon, GLP-1 and GIP are reported in numerous clinical trials as outcome measures but preanalytical guidelines are lacking. We addressed the impact of commonly used blood containers in metabolic research on measurements of glucagon, GLP-1 and GIP in humans. Methods Seventeen overweight individuals were subjected to an overnight fast followed by an intravenous infusion of amino acids to stimulate hormonal secretion. Blood was sampled into five containers: EDTA-coated tubes supplemented with DMSO (control), a neprilysin inhibitor, aprotinin (a kallikrein inhibitor) or a DPP-4 inhibitor, and P800 tubes. Plasma was kept on ice before and after centrifugation and stored at −80 Celsius until batch analysis using validated sandwich ELISAs or radioimmunoassays (RIA). Results Measures of fasting plasma glucagon did not depend on sampling containers, whether measured by ELISA or RIA. Amino acid-induced hyperglucagonemia was numerically higher when blood was collected into P800 tubes or tubes with aprotinin. The use of p800 tubes resulted in higher concentrations of GLP-1 by RIA compared to control tubes but not for measurements with sandwich ELISA. Plasma concentrations of GIP measured by ELISA were higher in control tubes and negatively affected by P800 and the addition of aprotinin. Conclusions The choice of blood containers impacts on measurements of plasma concentrations of glucagon, GLP-1 and GIP, and based on this study, we recommend using EDTA-coated tubes without protease inhibitors or P800 tubes for measurements of glucagon, GLP-1 and GIP in clinical trials.

Perioperative Intravenous Amino Acid Infusion in Major Urologic Surgery.

Post-operative acute kidney injury (PO-AKI) is a serious complication that may occur after major abdominal surgery. The administration of intravenous perioperative amino acids (AAs) has been proven to increase kidney function and has some beneficial effects to prevent PO-AKI. The aim of this study was to establish if the perioperative infusion of AAs may reduce the incidence of PO-AKI in patients undergoing major urological minimally invasive surgery. From a total of 331 patients, the first 169 received perioperative crystalloid fluids and the following 162 received perioperative AA infusions. PO-AKIs were much higher in the crystalloid group compared to the AA group (34 vs. 17, p = 0.022) due to a lower incidence of KDIGO I and II in the AA group (14 vs. 30 p = 0.016). The AA group patients who developed a PO-AKI presented more risk factors compared to those who did not (2 (2-4) vs. 1 (1-2), p = 0.031) with a cut-off of 3 risk factors in the ROC curve (p = 0.007, sensitivity 47%, specificity 83%). The hospital length of stay was higher in the crystalloid group (p < 0.05) with a consequent saving in hospital costs. Perioperative AA infusion may help reduce the incidence of PO-AKI after major urological minimally invasive surgery.

Effect of Amino Acid Infusion on Amniotic Fluid Index in Pregnancies Associated With Oligohydramnios and Fetal Growth Restriction.

Background Oligohydramnios and fetal growth restriction have been known for ages, with increased risk of disease and death during antenatal, neonatal, and adult life leading to operative interventions and perinatal mortality and morbidity. The amniotic fluid index varies with gestational age and is used to detect fetal well-being. Various oral and IV hydration and amino acid infusion therapies are studied to improve amniotic fluid index (AFI) and fetal weight. Objective To study the effect of intravenous amino acid infusion on AFI in pregnancies associated with oligohydramnios and fetal growth restriction (FGR). Material and methods A semi-experimental study done in Acharya Vinoba Bhave Rural Hospital (AVBRH), Sawangi Meghe, Wardha enrolled pregnant women in the in-patient department (IPD) unit of Obstetrics & Gynecology and divided them into two groups of 52 each, which met inclusion and exclusion criteria. Group A received IV amino acid infusion on an alternate day, whereas group B received IV hydration, and serial monitoring was done till delivery. Results The mean gestational age at admission was 32.73 ± 2.21 in the IV amino acid group and 32.25 ± 2.27 in the IV hydration group. In both groups, the mean AFI at admission was observed at 4.93±2.03 cm and 4.22 ± 2.00 cm, respectively. The mean AFI on the 14th day in the IV amino acid group was 7.52 ± 2.04, and in the IV hydration group, 5.89± 2.20 with a significant p-value of <0.0001.

THE EFFECTS OF DIETARY EUBIOTICS OR INTRAVENOUS AMINO ACID INFUSIONS ON NUTRIENT DIGESTIBILITY, RUMEN FERMENTATION, PERFORMANCE AND BLOOD PARAMETERS OF BUFFALO CALVES UNDER SUBTROPICAL CLIMATIC CONDITIONS

This study was conducted to compare the effects of dietary eubiotics or intravenous amino acid infusions (IVAAI) as two different growth promoters on nutrient digestibility, rumen fermentation, performance, and blood biochemical parameters of buffalo calves in subtropical climatic conditions. Thirty male buffalo calves (284.40 ± 18.45 kg) were randomly distributed into three groups and fed a basal diet (BD) of concentrate feed mixture and roughages. The first group was fed BD and considered as the control, the second group was fed the BD supplemented with eubiotics at 1.0 kg/ton of concentrate, whereas the third group was intravenously infused with amino acid (IVAAI) injection at a dose of 2.0 ml/100 kg body weight. Results showed that the total gain and the average daily gain were improved (P &lt; 0.05) with dietary eubiotics. The digestibility of some nutrients was increased (P &lt; 0.05) with dietary addition of eubiotics. In addition, eubiotics stabilize (P &lt; 0.05) the rumen pH, which reduce the risk of subacute ruminal acidosis but increased (P &lt; 0.05) ruminal NH3-N and total volatile fatty acids. The rectal temperature was decreased (P &lt; 0.05) with eubiotics supplementation. In conclusion, the use of eubiotics induced superior positive effects on the digestibility of nutrients, rumen fermentation, rumen enzymes, rumen protein concentration, growth performance, feed conversion, blood parameters and ameliorated the harmful effects of thermal stress of buffalo calves in comparison with intravenous infusion of amino acids. Key words: eubiotics; amino acids; buffalo calves; nutrient digestibility; rumen fermentation; growth performance

O25 Milk and plasma amino acid concentration response to abomasal or intra-venous amino acid infusion in dairy cows

O25 Milk and plasma amino acid concentration response to abomasal or intra-venous amino acid infusion in dairy cows

O26 Whole body leucine kinetics response to abomasal or intra-venous amino acid infusion in lactating dairy cows

O26 Whole body leucine kinetics response to abomasal or intra-venous amino acid infusion in lactating dairy cows

1385-P: Impact of Preanalytical and Analytical Factors on Glucagon and GLP-1 Levels in Humans

Glucagon and glucagon-like peptide-1 (GLP-1) have important roles in the development and treatment of diabetes. Their plasma concentrations are currently being measured in more than 500 clinical studies according to clinicaltrial.gov. As glucagon and total GLP-1 (reflecting the secretion and action of GLP-1 and is analytically independent of DPP-4 activity) circulate in the low picomolar range it has been troublesome to accurately measure their plasma concentrations. Equally important are so-called preanalytical considerations including the use of enzyme inhibitors. The latter may also depend on the analytical approach, for example single-antibody assay versus sandwich ELISA. To provide guidelines for measurement of glucagon and GLP-1 in clinical trials we obtained blood samples using four different blood-containers (with either neprilysin inhibitor: sacubitrilat 25 µg/mL; trasylol 500KIU/mL; P800 tubes; or vehicle) from healthy individuals (male/female; 7/4; mean ± SD; age: 32 ± 12 years, BMI; 26 ± 4 kg/m2) after an overnight fast and following an intravenous amino acid (AA) infusion (14 g/L; 331 mg/min/kg body weight. Plasma concentrations of glucagon increased significantly during the AA-infusion independent of blood containers and assays. The sandwich ELISA showed significant lower levels of glucagon with addition of neprilysin inhibitor whereas both trasylol and P800 tubes resulted in increased levels during the AA-infusion. Glucagon levels measured by the two radioimmunoassays (RIA) did not depend on the containers. Levels of total GLP-1 did not depend on the containers using a sandwich ELISA (Mercodia) but increased by a factor of a 2.5 when plasma from P800 containers was assayed using a C-terminal specific RIA. In summary, levels of glucagon and GLP-1 depend on both preanalytical and analytical factors that should be standardized for future clinical studies. Disclosure S. Kjeldsen: None. N.J. Jensen: None. N. Heinz: None. B. Hartmann: Board Member; Bainan Biotech. J.J. Holst: Advisory Panel; Novo Nordisk. Board Member; Antag Therapeutics, Bainan Biotech. N.J. Wewer Albrechtsen: Research Support; Mercodia AB, Novo Nordisk, Regeneron Pharmaceuticals Inc. Speaker's Bureau; Merck &amp; Co., Inc., Mercodia AB. Funding Nicolai J. Wewer Albrechtsen were financed by NNF Excellence Emerging Investigator Grant – Endocrinology and Metabolism (Application No. NNF19OC0055001) , EFSD Future Leader Award (NNF21SA0072746) and DFF Sapere Aude.

Post ERCP Cholecystitis Managed Successfully with Intravenous Amino Acid Infusion: A Case Report

Post ERCP Cholecystitis Managed Successfully with Intravenous Amino Acid Infusion: A Case Report

Effect of Amino Acids Infusion on Maternal and Perinatal Outcome in 3rd Trimester Idiopathic Oligohydramnios

Background: Unexplained 3rd trimester oligohydramnios is associated with adverse pregnancy outcomes if not treated appropriately. We conducted this study to evaluate the role of parenteral amino acids to improve amniotic fluid volume in idiopathic oligohydramnios encountered in the 3rd trimester thus improving perinatal outcomes. Methods: This study was conducted at the department of obstetrics and gynecology, Arif Memorial teaching hospital for a period of two years from January 2020 till December 2021. A total of 60 cases of confirmed idiopathic 3rd trimester oligohydramnios were included in the study. They were infused with intravenous amino acid infusion on alternate days for a week then once weekly till the patient was delivered with weekly serial ultrasound monitoring for the increase in AFI. The maternal outcome was noted in terms of mode of delivery. The fetal outcome was noted in terms of healthy newborns, LBW babies, need for NICU admission, and poor Apgar score. All this relevant information was entered in a predesigned proforma. Data were analyzed in SPSS version 22. Results: The mean age of the participants was 28.5±4.6years. The mean gestational age at presentation was 31.4±2.10weeks. There were 25 (41.6%) primi gravida, 35 (58.3%) were multi gravida. The mean value of AFI before amino acid infusion in the study population was 5.1±1.35. There were 11 cases (18%) of AFI &lt;5cm, 49(81%) cases of AFI between 5.1-8cm at the first visit. While after amino acid infusion, 6 (10%) patients were observed in severe oligohydramnios group while 33 (55%) in borderline oligohydramnios group and 21(35%) patients had AFI improved to normal range i.e. &gt;8cm at the time of delivery. The mean increase in AFI after amino acid infusion in the study population at the time of delivery was 2.30±0.65. Out of 60 patients, 42 (70%) delivered by vaginal route at term, 15 (25%) cases delivered by cesarean section, and 1 patient (2%) delivered by instrumental delivery. All these deliveries were at term. While 2 (3.3%) cases were delivered preterm due to no improvement in AFI which remained &lt;5cm even after amino acid infusion. Conclusion: Parenteral amino acid infusion in unexplained oligohydramnios in the third trimester may result in improved pregnancy outcomes. Keywords: Amino acid infusion, Maternal and perinatal outcome, Idiopathic oligohydramnios

Lipopolysaccharide challenge following intravenous amino acid infusion in postpartum dairy cows: II. Clinical and inflammatory responses

Amino acids (AA) are integral nutrients for a functioning immune system. Postpartum cows experience AA deficits early postpartum that may influence the response to immune activation. This study investigated the clinical and inflammatory responses to a systemic inflammatory stimulus after a 4-d intravenous (IV) AA infusion with a mix of essential and nonessential AA designed to ameliorate the estimated metabolizable protein deficit in early postpartum cows. Our objectives were (1) to describe the clinical and inflammatory response to an acute IV lipopolysaccharide (LPS) challenge in early postpartum cows, and (2) to compare these clinical and inflammatory responses between IV AA-treated and control cows. Cows (n = 14, 4 ± 1 d in milk) were continuously infused IV for 4 d in a matched-pair randomized controlled design and received 0.9% NaCl (CTRL) or IV AA (IVAA) to supply 1 g/kg of BW per day of combined essential and nonessential AA. After infusion ended, cows were challenged with IV LPS (0.0625 µg/kg of BW over 1 h), and serial blood samples were collected for complete blood cell counts and to quantify plasma cytokines and acute-phase proteins. Body temperature, heart rate, and respiratory rate were monitored for 24 h during challenge. During challenge, maximum body temperature was greater in IVAA (41.3 ± 0.20°C) than in CTRL (40.6 ± 0.19°C). In both groups, respiratory rate increased during the first 2 h following challenge, whereas heart rate first decreased over the first 2 h and then increased to reach a maximum at 4 h. Acute leucopenia occurred within 1 h of challenge in both groups before leukocytosis was observed at 24 h, with white blood cell counts returning to baseline values within 72 h. Plasma haptoglobin and serum amyloid A concentrations increased 3-fold and 4-fold in both groups and peaked at 48 and 24 h following challenge, respectively. Plasma concentrations of TNF-α and IL-10 increased within 1 h and peaked at 2 h following the start of challenge. Plasma IL-10 concentrations increased to a greater extent in CTRL compared with IVAA during challenge. Despite differences in IL-10 concentration, previous AA infusion did not alter the acute-phase protein response to LPS challenge. We conclude that AA infusion before systemic inflammatory challenge decreased the anti-inflammatory response but did not alter concentrations of other systemic markers of inflammation.

Lipopolysaccharide challenge following intravenous amino acid infusion in postpartum dairy cows: I. Production, metabolic, and hormonal responses

Postpartum cows experience a nadir in energy and AA deficit early postpartum. At the same time, cows are challenged with inflammatory stimuli and often show heightened immune responsiveness, further increasing their metabolic needs during this critical time. This study investigated the response to a systemic inflammatory stimulus after a 4-d intravenous (IV) AA infusion designed to ameliorate the estimated metabolizable protein (MP) deficit in postpartum cows. Our objectives were to (1) describe the production and metabolic responses to early postpartum IV AA infusion, (2) determine the metabolic and hormonal responses to an acute IV lipopolysaccharide (LPS) challenge in early postpartum cows, and (3) compare these metabolic and hormonal responses between IV AA treated and control cows. Cows (n = 14, 4 ± 1 d in milk) were continuously IV infused for 4 d in a matched-pair randomized controlled design and received IV AA (IVAA) or 0.9% NaCl (CTRL). Treatment with IV AA consisted of 1 g/kg of BW per day of combined essential AA (EAA) and nonessential AA (NEAA). After infusion ended, cows were challenged IV with LPS (0.0625 µg/kg of BW over 1 h), and serial blood samples were collected to quantify AA, metabolite, and hormone concentrations. Amino acid infusion increased plasma EAA and NEAA concentrations and ameliorated the estimated MP deficit but not the metabolizable energy deficit in IVAA cows. Patterns of dry matter intake during infusion were different between groups. Milk yield and milk protein content and yield were unaffected, but IV AA was associated with increased milk fat content and yield of both de novo and preformed fatty acids. Before LPS infusion, plasma EAA and NEAA concentrations were greater in IVAA compared with CTRL. During LPS challenge, plasma AA concentrations decreased to a greater degree in IVAA than CTRL. Glucagon concentrations were greater and glucose concentrations lower in IVAA during challenge; however, previous AA infusion did not affect the time-dependent changes in concentrations of energy metabolites or glucoregulatory hormones. Plasma urea nitrogen concentration increased in both treatments following challenge, although the temporal pattern depended on treatment. Effects of AA infusion on milk fat response were pronounced and likely due to a combination of increased lipolysis and de novo milk fat synthesis. Despite differences in circulating concentrations of nutrients and hormones before challenge, metabolic responses to systemic inflammation did not differ between the 2 treatments. We conclude that AA infusion changed metabolic status and milk fat but did not appear to alter the metabolic response to subsequent systemic inflammation.

A case of Canine Necrolytic Migratory Erythema treated with intravenous amino acid infusions

去勢雄，9歳齢のトイプードルが疼痛を伴う四肢の肉球の紅斑およびびらんを主訴に当院を受診した。臨床および病理組織学的検査により，肝臓の空胞状変性を伴う壊死性遊走性紅斑（肝皮症候群）と診断した。治療としてプレドニゾロン，亜鉛補給，肝庇護療法，卵黄の給餌およびアミノ酸輸液を行なった。症状は一時的に改善したが，貧血，糖尿病，細菌感染などを伴って第207病日に死亡した。治療期間中の血中総分岐鎖アミノ酸（BCAA）およびチロシン濃度をモニタリングし，その意義を検討した。

Comprehensive assessment of post-prandial protein handling by the application of intrinsically labelled protein in vivo in human subjects.

All human tissues are in a constant state of remodelling, regulated by the balance between tissue protein synthesis and breakdown rates. It has been well-established that protein ingestion stimulates skeletal muscle and whole-body protein synthesis. Stable isotope-labelled amino acid methodologies are commonly applied to assess the various aspects of protein metabolism in vivo in human subjects. However, to achieve a more comprehensive assessment of post-prandial protein handling in vivo in human subjects, intravenous stable isotope-labelled amino acid infusions can be combined with the ingestion of intrinsically labelled protein and the collection of blood and muscle tissue samples. The combined application of ingesting intrinsically labelled protein with continuous intravenous stable isotope-labelled amino acid infusion allows the simultaneous assessment of protein digestion and amino acid absorption kinetics (e.g. release of dietary protein-derived amino acids into the circulation), whole-body protein metabolism (whole-body protein synthesis, breakdown and oxidation rates and net protein balance) and skeletal muscle metabolism (muscle protein fractional synthesis rates and dietary protein-derived amino acid incorporation into muscle protein). The purpose of this review is to provide an overview of the various aspects of post-prandial protein handling and metabolism with a focus on insights obtained from studies that have applied intrinsically labelled protein under a variety of conditions in different populations.

The Impact of Amino Acids on Postprandial Glucose and Insulin Kinetics in Humans: A Quantitative Overview.

Different amino acids (AAs) may exert distinct effects on postprandial glucose and insulin concentrations. A quantitative comparison of the effects of AAs on glucose and insulin kinetics in humans is currently lacking. PubMed was queried to identify intervention studies reporting glucose and insulin concentrations after acute ingestion and/or intravenous infusion of AAs in healthy adults and those living with obesity and/or type 2 diabetes (T2DM). The systematic literature search identified 55 studies that examined the effects of l-leucine, l-isoleucine, l-alanine, l-glutamine, l-arginine, l-lysine, glycine, l-proline, l-phenylalanine, l-glutamate, branched-chain AAs (i.e., l-leucine, l-isoleucine, and l-valine), and multiple individual l-AAs on glucose and insulin concentrations. Oral ingestion of most individual AAs induced an insulin response, but did not alter glucose concentrations in healthy participants. Specific AAs (i.e., leucine and isoleucine) co-ingested with glucose exerted a synergistic effect on the postprandial insulin response and attenuated the glucose response compared to glucose intake alone in healthy participants. Oral AA ingestion as well as intravenous AA infusion was able to stimulate an insulin response and decrease glucose concentrations in T2DM and obese individuals. The extracted information is publicly available and can serve multiple purposes such as computational modeling.

Do Nutritional Interventions Improve the Outcomes of Patients with Cirrhosis and Ascites: A Systematic Review of Randomized Trials.

Ascites is a common, morbid complication of cirrhosis. Nutritional interventions such as sodium-restriction and high-protein diet are considered standard of care. However, their evidence base is limited. We performed a systematic review of randomized trials of nutritional interventions for ascites. Increasing consumption of calories and protein alone was ineffective. Studies reached contradictory conclusions regarding sodium restriction in patients taking combination diuretics. Intravenous amino acid infusion alone did not improve outcomes, peripheral parenteral nutrition did not improve outcomes except alone but reduced mortality in conjunction with branched-chain amino acid evening snack. Patients may benefit from sodium restriction and a protein-rich evening snack. Future trials should prioritize standardizing nutritional targets and tailoring interventions to the specific needs of patients including the socioeconomic factors impacting adherence.

Successful Long-Term Management of Canine Superficial Necrolytic Dermatitis With Amino Acid Infusions and Nutritionally Balanced Home-Made Diet Modification

A 10-year old, castrated male, Bichon Frise with a history of hyperadrenocorticism and intrahepatic portal vein hypoplasia was diagnosed with superficial necrolytic dermatitis (SND). The dog exhibited thick crusts on the chin, muzzle, prepuce, and paws. In addition, the dorsal surfaces of all paws were erythematous while the palmar/plantar surfaces were hyperkeratotic, hardened, and painful. The dog was treated with intravenous amino acid infusions (AAI), raw egg yolks, as well as zinc and omega-3 fatty acid oral supplements. The dog required AAI once every 2–3 weeks because this coincided with recrudescence of painful skin lesions. The dog was subsequently diagnosed with diabetes mellitus. A consult with the Nutrition Service was pursued 220 days after the original SND diagnosis because of concern for feeding raw eggs and for malnutrition since appetite was variable, muscle condition was reduced, and greater than 50% of ingested calories were from foods that were not nutritionally complete. There was also concern regarding the variability of the diet and the impact it would have on the management of diabetes mellitus. The diet was prepared by the dog owner according to a provided recipe and presented twice daily. The diet was rich in high quality protein and fat. All other treatments including medications, supplements, and bathing schedule remained unchanged at the time of diet modification. The dog was subclinical for SND associated clinical signs approximately 3 weeks after the diet modification, which also coincided with the last AAI. The AAI was postponed and was next administered 7 weeks later (i.e., 10 weeks from the previous infusion). The dog remained subclinical for SND related clinical signs and continued to receive AAI once every 10–12 weeks until he was euthanized 718 days later for complications related to severe multi-drug resistant, skin infections. In conclusion, this report highlights a novel role for nutritionally balanced home-made diets designed by a board-certified veterinary nutritionist could substantially increase time interval between AAI and outcome in dogs with SND.

Intravenous amino acid therapy for kidney protection in cardiac surgery patients: A pilot randomized controlled trial

ObjectiveTo determine whether a continuous intravenous infusion of standard amino acids could preserve kidney function after on-pump cardiac surgery. MethodsAdult patients scheduled to receive cardiac surgery lasting longer than 1 hour on-pump were randomized to standard care (n = 36) or an infusion of amino acids initiated immediately after induction of anesthesia (n = 33). The study's primary outcome measurements assessed renal function. These assessments included duration of renal dysfunction, duration and severity of acute kidney injury (AKI), estimated glomerular filtration rate (eGFR) over time, urine output, and use of renal-replacement therapy. Complications and other measures of morbidity were also assessed. ResultsSixty-nine patients (mean age 71.5 [standard deviation 9.2] years; 19 of 69 women) were enrolled and randomized. Patients received coronary artery bypass graft surgery (37/69), valve surgery (24/69), coronary artery bypass graft and valve surgery (6/69), or other procedures (2/69). Mean on-pump time was 268 [standard deviation 136] minutes. Duration of renal dysfunction did not differ between the groups (relative risk, 0.86; 95% confidence interval [CI], 0.19-3.79, P = .84). However, patients who received the amino acid infusion had a reduced duration of AKI (relative risk, 0.02; 95% CI, 0.005-0.11, P < .0001) and greater eGFR (+10.8%; 95% CI, 1.0%-20.8%, P = .033). Daily mean urine output was also significantly greater in patients who received the amino acid infusion (1.4 ± 0.5 vs 1.7 ± 0.9 L/d; P = .046). ConclusionsCommencing an infusion of standard amino acids immediately after the induction of anesthesia did not alter duration of renal dysfunction; however, other key measures of renal function (duration of AKI, eGFR and urine output) were significantly improved. These results warrant replication in multicenter clinical trials.

Haemodynamic or metabolic stimulation tests to reveal the renal functional response: requiem or revival?

ABSTRACTRenal stimulation tests document the dynamic response of the glomerular filtration rate (GFR) after a single or a combination of stimuli, such as an intravenous infusion of dopamine or amino acids or an oral protein meal. The increment of the GFR above the unstimulated state has formerly been called the renal functional reserve (RFR). Although the concept of a renal reserve capacity has not withstood scientific scrutiny, the literature documenting renal stimulation merits renewed interest. An absent or a blunted response of the GFR after a stimulus indicates lost or diseased nephrons. This information is valuable in preventing, diagnosing and prognosticating acute kidney injury and pregnancy-related renal events as well as chronic kidney disease. However, before renal function testing is universally practiced, some shortcomings must be addressed. First, a common nomenclature should be decided upon. The expression of RFR should be replaced by renal functional response. Second, a simple protocol must be developed and propagated. Third, we suggest designing prospective studies linking a defective stimulatory response to emergence of renal injury biomarkers, to histological or morphological renal abnormalities and to adverse renal outcomes in different renal syndromes.

A supplemental intravenous amino acid infusion sustains a positive protein balance for 24\xa0hours in critically ill patients

BackgroundProviding supplemental amino acids to ICU patients during a 3-h period results in improved whole-body net protein balance, without an increase in amino acid oxidation. The primary objective was to investigate if a 24-h intravenous amino acid infusion in critically ill patients has a sustained effect on whole-body protein balance as was seen after 3 h. Secondary objectives were monitoring of amino acid oxidation rate, urea and free amino acid plasma concentrations.MethodsAn infusion of [1-13C]-phenylalanine was added to ongoing enteral nutrition to quantify the enteral uptake of amino acids. Primed intravenous infusions of [ring-2H5]-phenylalanine and [3,3-2H2]-tyrosine were used to assess whole-body protein synthesis and breakdown, to calculate net protein balance and to assess amino acid oxidation at baseline and at 3 and 24 hours. An intravenous amino acid infusion was added to nutrition at a rate of 1 g/kg/day and continued for 24 h.ResultsEight patients were studied. The amino acid infusion resulted in improved net protein balance over time, from -1.6 ± 7.9 μmol phe/kg/h at 0 h to 6.0 ± 8.8 at 3 h and 7.5 ± 5.1 at 24 h (p = 0.0016). The sum of free amino acids in plasma increased from 3.1 ± 0.6 mmol/L at 0 h to 3.2 ± 0.3 at 3 h and 3.6 ± 0.5 at 24 h (p = 0.038). Amino acid oxidation and plasma urea were not altered significantly.ConclusionWe demonstrated that the improvement in whole-body net protein balance from a supplemental intravenous amino acid infusion seen after 3 h was sustained after 24 h in critically ill patients.Trial registrationThis trial was prospectively registered at Australian New Zealand Clinical Trials Registry. ACTRN, 12615001314516. Registered on 1 December 2015.