Search

Studies demonstrate that caloric restriction in the first seven days in the ICU is safe. The amount of protein that should be delivered, however, is still unclear with clinical trials suggesting mixed results. Despite some capacity to customize the delivery of protein using supplemental modules, protein delivered is best determined by the concentration of protein contained in enteral formula (EF) ordered. This fact provides an opportunity to explore the potential clinical effects of protein delivery and lower carbohydrate intake on clinical outcomes compared with conventional enteral formulas.Retrospective analysis of clinical outcomes according to the amount of protein delivered in critically ill patients admitted to intensive care units at Geisinger Health System.2000 encounters (1899 patients) in patients on enteral nutrition were divided into three groups receiving EF with either ≤20% protein (standard formula - SF), 21-25% protein (high protein - HP) or 25% protein (VHP). Protein intake increased up to day 7 (p 0.0001). Patients on VHP received more protein than other groups (p 0.0001). Multivariable regression analysis showed no evidence of harm. In fact, we observed increased mortality with SF and HP formulas at 30-days post-discharge when compared to patients on VHP even when the effects of other variables (including age, BMI, sex, primary diagnosis, diabetes, history of dialysis, ICU days kept NPO) were taken into consideration.Increasing protein intake while reducing carbohydrate intake appears to be safe. Further research aimed at defining a causative effect of increasing protein delivery while reducing carbohydrate load on outcomes is warranted.

Background: Enteral nutrition (EN) increases hyperglycemia due to high carbohydrate concentrations while providing insufficient protein. The study tested whether an EN formula with very high‐protein‐ and low‐carbohydrate‐facilitated glucose control delivered higher protein concentrations within a hypocaloric protocol. Methods: This was a multicenter, randomized, open‐label clinical trial with parallel design in overweight/obese mechanically ventilated critically ill patients prescribed 1.5 g protein/kg ideal body weight/day. Patients received either an experimental very high‐protein (37%) and low‐carbohydrate (29%) or control high‐protein (25%) and conventional‐carbohydrate (45%) EN formula. Results: A prespecified interim analysis was performed after enrollment of 105 patients (52 experimental, 53 control). Protein and energy delivery for controls and experimental groups on days 1–5 were 1.2 ± 0.4 and 1.1 ± 0.3 g/kg ideal body weight/day (P = .83), and 18.2 ± 6.0 and 12.5 ± 3.7 kcals/kg ideal body weight/day (P < .0001), respectively. The combined rate of glucose events outside the range of >110 and ≤150 mg/dL were not different (P = .54, primary endpoint); thereby the trial was terminated. The mean blood glucose for the control and the experimental groups were 138 (−SD 108, +SD 177) and 126 (−SD 99, +SD 160) mg/dL (P = .004), respectively. Mean rate of glucose events >150 mg/dL decreased (Δ = −13%, P = .015), whereas that of 80–110 mg/dL increased (Δ = 14%, P = .0007). Insulin administration decreased 10.9% (95% CI, −22% to 0.1%; P = .048) in the experimental group relative to the controls. Glycemic events ≤80 mg/dL and rescue dextrose use were not different (P = .23 and P = .53). Conclusions: A very high‐protein and low‐carbohydrate EN formula in a hypocaloric protocol reduces hyperglycemic events and insulin requirements while increasing glycemic events between 80–110 mg/dL.

Bas et al. report the clinical measurement, using High Performance Liquid Chromatography (HPLC), of asymmetric dimethyarginine in two groups of patients undergoing aortic coarctation repair.

Protein loss, manifested as loss of muscle mass, is observed universally in all critically ill patients. Depletion of muscle mass is associated with impaired function and poor outcomes. In extreme cases, protein malnutrition is manifested by respiratory failure, lack of wound healing, and immune dysfunction. Protecting muscle loss focused initially on meeting energy requirements. The assumption was that protein was being used (through oxidation) as an energy source. In healthy individuals, small amounts of glucose (approximately 400 calories) protect muscle loss and decrease amino acid oxidation (protein-sparing effect of glucose). Despite expectations of the benefits, the high provision of energy (above basal energy requirements) through the delivery of nonprotein calories has failed to demonstrate a clear benefit at curtailing protein loss. The protein-sparing effect of glucose is not clearly observed during illness. Increasing protein delivery beyond the normal nutrition requirements (0.8 g/k/d) has been investigated as an alternative solution. Over a dozen observational studies in critically ill patients suggest that higher protein delivery is beneficial at protecting muscle mass and associated with improved outcomes (decrease in mortality). Not surprisingly, new Society of Critical Care Medicine/American Society for Parenteral and Enteral Nutrition guidelines and expert recommendations suggest higher protein delivery (>1.2 g/kg/d) for critically ill patients. This article provides an introduction to the concepts that delineate the basic principles of modern medical nutrition therapy as it relates to the goal of achieving an optimal management of protein metabolism during critical care illness, highlighting successes achieved so far but also placing significant challenges limiting our success in perspective.

Background and objectives Standard enteral nutrition (EN) formulas can worsen hyperglycemia in diabetic patients. We hypothesized that altering the proportion of macronutrients in a formula; increasing protein while decreasing carbohydrate concentrations would improve glycemic response. The objective of this study was to demonstrate that an EN formula containing a very high concentration of protein (in the form of whey peptides) and low concentration of carbohydrate provide better control of postprandial blood glucose relative to a very high-protein/higher-carbohydrate formula. Subjects and methods This was a randomized crossover clinical trial of 12 ambulatory adult subjects with type 2 diabetes. The primary outcome was glycemic response following a bolus of isocaloric amounts of two EN formulas; the secondary outcome was insulin response. Subjects were randomized to the experimental or the control formula, on two separate days, 5–7 days apart. Results Mean blood glucose concentrations at 10–180 min post-infusion and mean area under the curve for glucose over 240 min post-infusion were significantly lower with the experimental formula than with the control formula (71.99 ± 595.18 and 452.62 ± 351.38, respectively; p = 0.025). There were no significant differences in the mean insulin concentrations over time, insulinogenic indices, and first-phase insulin measurements. Conclusions An EN formula containing high-protein and low-carbohydrate loads can significantly improve glucose control in subjects with type 2 diabetes in ambulatory settings as evidenced by observed improved glucose control without significant difference in insulin response.

Nonessential amino acids are synthesized de novo and therefore not diet dependent. In contrast, essential amino acids must be obtained through nutrition since they cannot be synthesized internally. Several nonessential amino acids may become essential under conditions of stress and catabolic states when the capacity of endogenous amino acid synthesis is exceeded. Arginine and glutamine are 2 such conditionally essential amino acids and are the focus of this review. Low arginine bioavailability plays a pivotal role in the pathogenesis of a growing number of varied diseases, including sickle cell disease, thalassemia, malaria, acute asthma, cystic fibrosis, pulmonary hypertension, cardiovascular disease, certain cancers, and trauma, among others. Catabolism of arginine by arginase enzymes is the most common cause of an acquired arginine deficiency syndrome, frequently contributing to endothelial dysfunction and/or T-cell dysfunction, depending on the clinical scenario and disease state. Glutamine, an arginine precursor, is one of the most abundant amino acids in the body and, like arginine, becomes deficient in several conditions of stress, including critical illness, trauma, infection, cancer, and gastrointestinal disorders. At-risk populations are discussed together with therapeutic options that target these specific acquired amino acid deficiencies.

The International Protein Summit in 2016 brought experts in clinical nutrition and protein metabolism together from around the globe to determine the impact of high-dose protein administration on clinical outcomes and address barriers to its delivery in the critically ill patient. It has been suggested that high doses of protein in the range of 1.2-2.5 g/kg/d may be required in the setting of the intensive care unit (ICU) to optimize nutrition therapy and reduce mortality. While incapable of blunting the catabolic response, protein doses in this range may be needed to best stimulate new protein synthesis and preserve muscle mass. Quality of protein (determined by source, content and ratio of amino acids, and digestibility) affects nutrient sensing pathways such as the mammalian target of rapamycin. Achieving protein goals the first week following admission to the ICU should take precedence over meeting energy goals. High-protein hypocaloric (providing 80%-90% of caloric requirements) feeding may evolve as the best strategy during the initial phase of critical illness to avoid overfeeding, improve insulin sensitivity, and maintain body protein homeostasis, especially in the patient at high nutrition risk. This article provides a set of recommendations based on assessment of the current literature to guide healthcare professionals in clinical practice at this time, as well as a list of potential topics to guide investigators for purposes of research in the future.

Calculation of energy and protein doses for critically ill patients is still a matter of controversy. For more than 40 years of nutrition support, the total amount of nutrients to be delivered to these patients has been calculated based on expert recommendations, and this calculation is based on the administration of nonprotein calories in one attempt to ameliorate catabolic response and avoid the weight loss. New evidence suggests protein delivery is the most important intervention to improve clinical and metabolic outcomes. This article describes the metabolic rationale and the new evidence supporting a change in the approach of metabolic support of the critically ill, proposing a physiological-based intervention supported by the recognition of ancillary characteristics of the metabolic response to trauma and injury. A moderate dose of calories around 15 kcal/kg/d with a delivery of protein of 1.5 g/kg/d appears to be the new recommendation for many hypercatabolic patients in the first week following injury.

The precise value of the normal adult protein requirement has long been debated. For many reasons-one of them being the difficulty of carrying out long-term nutrition experiments in free-living people-uncertainty is likely to persist indefinitely. By contrast, the controlled environment of the intensive care unit and relatively short trajectory of many critical illnesses make it feasible to use hard clinical outcome trials to determine protein requirements for critically ill patients in well-defined clinical situations. This article suggests how the physiological principles that underlie our understanding of normal protein requirements can be incorporated into the design of such clinical trials. The main focus is on 3 principles: (1) the rate of body nitrogen loss roughly predicts an individual's minimum protein requirement and is thus essential to measure to identify individual patients and clinical situations in which the minimum protein requirement is importantly increased, (2) existing muscle mass sets an upper limit on the rate at which amino acids can be mobilized from muscle for transfer to central proteins and sites of injury and is thus important to monitor to identify patients who are at greatest risk of protein deficiency-related adverse outcomes, and (3) negative energy balance increases the dietary protein requirement, so calorie-deprived patients-whether obese or not-should be enrolled in hard clinical outcome trials that compare the current practice of "permissive underfeeding" (underprovision of all nutrients, including protein) with hypocaloric nutrition supplemented by a suitably generous amount of protein.

Objective The aim of this study was to assess the effects of an arginine-based immunonutrition intervention for patients undergoing elective colorectal surgery on postsurgical utilization and cost outcomes. Methods This analysis was based on data from two Washington State databases: Surgical Care and Outcomes Assessment Program (SCOAP) linked to the Comprehensive Hospital Abstract Reporting System (CHARS). The sample (N=722) comprises adult patients who underwent elective colorectal surgery with anastomosis in a Washington State hospital that participated in the Strong for Surgery (S4S) initiative between January 1, 2012, and December 31, 2013. A generalized linear model was used to predict the outcomes, adjusting for demographic characteristics and patient health conditions within a multivariate regression framework. Results Findings from this study demonstrated significantly fewer readmissions and hospital days for the intervention group during the 180 d after index hospitalization. Clinical benefits included decreased risk for infections and venous thromboembolism. There was a similar pattern toward lower total costs in the immunonutrition patient group; however, these were not statistically different compared with the control group at any time point. Savings in the immunonutrition group were substantial—mean total costs per patient were less by ∼$2500 at index hospitalization, $3500 less through 30 d of follow-up, and $5300 less over 180 d compared with the control group. Conclusion These findings suggest that arginine-based immunonutrition should be thoroughly evaluated for incorporation into clinical practice for patients undergoing elective surgery. Moreover, there is a need to assess the effects of the intervention in other hospitals both within and outside Washington.

Hospital-acquired malnutrition is universally present across the globe. Little progress has been made on overcoming hospital-acquired malnutrition despite known presence for at least 40 years. Technologies and methods to deliver the recommended calories and protein are available in most healthcare settings. Despite this, inadequate nutrient delivery continues to be a problem. Correia and colleagues propose a simplified algorithm that assists clinicians in becoming aware of poor nutrient intake and suggest nutrition interventions.

Clinicians in intensive care units (ICUs) have to decide whether supplemental parenteral nutrition should be ordered for a critically ill patient who cannot be fed and is kept �nil per os (NPO),� for instance, because of gastrointestinal tract dysfunction. Without early supplemental parenteral nutrition, the patient is temporarily starved, an approach based on the assumption that physiologic compensatory processes are protective and thus there will be no untoward clinical consequences. In contrast, clinicians who order early supplemental parenteral nutrition presumably consider the accumulating caloric deficit to be deleterious for critically ill patients. Although determining the best approach might seem straightforward, a clear answer remains evasive.1- 2