Risks and benefits of nutritional support during critical illness

Nutritional supplementation in children with severe pneumonia in Uganda and Kenya (COAST-Nutrition): a phase 2 randomised controlled trial

Background

Severe pneumonia in African children results in poor long-term outcomes (deaths/readmissions) with undernutrition as a key risk factor. We hypothesised additional energy/protein-rich Ready-to-Use Therapeutic Foods (RUTF) would meet additional nutritional requirements and improve outcomes.

Methods

COAST-Nutrition was an open-label Phase 2 randomised controlled trial in children (aged 6 months-12 years) hospitalised with severe pneumonia (and hypoxaemia, SpO2 <92%) in Mbale, Soroti, Jinja, Masaka Regional Referral Hospitals, Uganda and Kilifi County Hospital, Kenya (ISRCTN10829073 (registered 6th June 2018) PACTR202106635355751 (registered 2nd June 2021)). Children were randomised (ratio 1:1) to enhanced nutritional supplementation with RUTF (plus usual diet) for 56 days vs usual diet (control). The primary outcome was change in mid-upper arm circumference (MUAC) at 90 days as a composite with mortality. Secondary outcomes include anthropometric status, mortality, and readmissions at Days 28, 90 and 180.

Findings

Between 12 August 2018 and 22 April 2022, 846 eligible children were randomised, 424 to RUTF and 422 to usual diet, and followed for 180-days [12 (1%) lost-to-follow-up]. RUTF supplement was initiated in 417/419 (>99%). By Day 90, there was no significant difference in the composite endpoint (probabilistic index 0.49, 95% CI 0.45-0.53, p = 0.74). Respective 90-day mortality (13/420 3.1% vs 14/421 3.3%) and MUAC increment (0.54 (SD 0.85) vs 0.55 (SD 0.81)) were similar between arms. There was no difference in any anthropometric secondary endpoints to Day 28, 90 or 180 except skinfold thickness at Day 28 and Day 90 was greater in the RUTF arm. Serious adverse events were higher in the RUTF arm (n = 164 vs 108), mainly due to hospital readmission for acute illness (54/387 (14%) vs 37/375 (10%).

Interpretation

Our study suggested that nutritional supplementation with RUTF did not improve outcomes to 180 days in children with severe pneumonia.

Funding

This trial is part of the EDCTP2 programme (grant number RIA-2016S-1636-COAST-Nutrition) supported by the European Union, and UK Joint Global Health Trials scheme: Medical Research Council, Department for International Development, Wellcome Trust (grant number MR/L004364/1, UK).

Children's Oxygen Administration Strategies And Nutrition Trial (COAST-Nutrition): a protocol for a phase II randomised controlled trial

Background: To prevent poor long-term outcomes (deaths and readmissions) the integrated global action plan for pneumonia and diarrhoea recommends under the 'Treat' element of Protect, Prevent and Treat interventions the importance of continued feeding but gives no specific recommendations for nutritional support. Early nutritional support has been practiced in a wide variety of critically ill patients to provide vital cell substrates, antioxidants, vitamins, and minerals essential for normal cell function and decreasing hypermetabolism. We hypothesise that the excess post-discharge mortality associated with pneumonia may relate to the catabolic response and muscle wasting induced by severe infection and inadequacy of the diet to aid recovery. We suggest that providing additional energy-rich, protein, fat and micronutrient ready-to-use therapeutic feeds (RUTF) to help meet additional nutritional requirements may improve outcome. Methods: COAST-Nutrition is an open, multicentre, Phase II randomised controlled trial in children aged 6 months to 12 years hospitalised with suspected severe pneumonia (and hypoxaemia, SpO 2 <92%) to establish whether supplementary feeds with RUTF given in addition to usual diet for 56-days (experimental) improves outcomes at 90-days compared to usual diet alone (control). Primary endpoint is change in mid-upper arm circumference (MUAC) at 90 days and/or as a composite with 90-day mortality. Secondary outcomes include anthropometric status, mortality, readmission at days 28 and 180. The trial will be conducted in four sites in two countries (Uganda and Kenya) enrolling 840 children followed up to 180 days. Ancillary studies include cost-economic analysis, molecular characterisation of bacterial and viral pathogens, evaluation of putative biomarkers of pneumonia, assessment of muscle and fat mass and host genetic studies.   Discussion: This study is the first step in providing an option for nutritional support following severe pneumonia and will help in the design of a large Phase III trial. Registration: ISRCTN10829073 (6 th June 2018) PACTR202106635355751 (2 nd June 2021).

Children's Oxygen Administration Strategies And Nutrition Trial (COAST-Nutrition): a protocol for a phase II randomised controlled trial

Background: To prevent poor long-term outcomes (deaths and readmissions) the integrated global action plan for pneumonia and diarrhoea recommends under the 'Treat' element of Protect, Prevent and Treat interventions the importance of continued feeding but gives no specific recommendations for nutritional support. Early nutritional support has been practiced in a wide variety of critically ill patients to provide vital cell substrates, antioxidants, vitamins, and minerals essential for normal cell function and decreasing hypermetabolism. We hypothesise that the excess post-discharge mortality associated with pneumonia may relate to the catabolic response and muscle wasting induced by severe infection and inadequacy of the diet to aid recovery. We suggest that providing additional energy-rich, protein, fat and micronutrient ready-to-use therapeutic feeds (RUTF) to help meet additional nutritional requirements may improve outcome. Methods: COAST-Nutrition is an open, multicentre, Phase II randomised controlled trial in children aged 6 months to 12 years hospitalised with suspected severe pneumonia (and hypoxaemia, SpO 2 <92%) to establish whether supplementary feeds with RUTF given in addition to usual diet for 56-days (experimental) improves outcomes at 90-days compared to usual diet alone (control). Primary endpoint is change in mid-upper arm circumference (MUAC) at 90 days and/or as a composite with 90-day mortality. Secondary outcomes include anthropometric status, mortality, readmission at days 28 and 180. The trial will be conducted in four sites in two countries (Uganda and Kenya) enrolling 840 children followed up to 180 days. Ancillary studies include cost-economic analysis, molecular characterisation of bacterial and viral pathogens, evaluation of putative biomarkers of pneumonia, assessment of muscle and fat mass and host genetic studies.   Discussion: This study is the first step in providing an option for nutritional support following severe pneumonia and will help in the design of a large Phase III trial. Registration: ISRCTN10829073 (6 th June 2018) PACTR202106635355751 (2 nd June 2021).

Enteral and supplemental parenteral nutrition enriched with omega-3 polyunsaturated fatty acids in intensive care patients - A randomized, controlled, double-blind clinical trial

BACKGROUND & AIMS

Enteral nutrition (EN) and parenteral nutrition (PN) enriched with omega-3 polyunsaturated fatty acids (PUFA) have beneficial effects in critical illness. This study aimed to assess the combined effect of EN and supplemental PN enriched with omega-3 PUFA on blood oxygenation in intensive care unit (ICU) patients.

METHODS

Single-center, prospective, randomized, controlled, double-blind, phase III trial conducted from 10/2013 to 11/2017. A total of 100 ICU patients (18-85 years, APACHE II score > 15) requiring mechanical ventilation were randomly assigned to received combined EN and PN either with omega-3 PUFA (omega-3 group) or without (control group) for up to 28 days. Primary endpoint: 'change of PaO₂/FiO₂ from day (D) 1 to D4'. Secondary endpoints: lung function parameters, ICU complications, length of hospital stay, days free of ICU care/ventilation/sedation/catecholamine treatment, mortality, erythrocyte fatty acid composition, inflammatory parameters. Safety parameters: standard laboratory assessment, vital signs, physical examination, SOFA score, adverse events.

RESULTS

Combined EN and PN covered energy requirements to more than 80%. Blood oxygenation (ΔPaO₂/FiO₂ from D1 to D4: -1.3 ± 83.7, n = 42, and 13.3 ± 86.1, n = 39, in omega-3 and control group, respectively, p = 0.7795) and other lung function parameters did not differ between groups but days free of catecholamine treatment were significantly higher in the omega-3 group (~4 days, p = 0.0481). On D6, significantly more patients in the omega-3 group tolerated EN alone (51.0% vs. 29.8%, p = 0.0342). Eicosapentaenoic acid (EPA) content in erythrocytes was significantly increased in the omega-3 group at last observation compared with the control group (ΔEPA: 0.928 ± 0.808% vs. -0.024 ± 0.190%, p < 0.0001). No further significant group differences were detected.

CONCLUSIONS

Enteral and supplemental PN both enriched with omega-3 PUFA did not improve lung function but allowed earlier weaning from catecholamine treatment and PN. Supplemental PN succeeded to adequately cover energy requirements in critically ill patients.

TRIAL REGISTRATION

www.clinicaltrials.gov, registration number: NCT01162928.

Medical Nutrition Terminology and Regulations in the United States and Europe-A Scoping Review: Report of the ISPOR Nutrition Economics Special Interest Group

BACKGROUND

The term medical nutrition (MN) refers to nutritional products used under medical supervision to manage disease- or condition-related dietary needs. Standardized MN definitions, aligned with regulatory definitions, are needed to facilitate outcomes research and economic evaluation of interventions with MN.

OBJECTIVES

Ascertain how MN terms are defined, relevant regulations are applied, and to what extent MN is valued.

METHODS

ISPOR's Nutrition Economics Special Interest Group conducted a scoping review of scientific literature on European and US MN terminology and regulations, published between January 2000 and August 2015, and pertinent professional and regulatory Web sites. Data were extracted, reviewed, and reconciled using two-person teams in a two-step process. The literature search was updated before manuscript completion.

RESULTS

Of the initial 1687 literature abstracts and 222 Web sites identified, 459 records were included in the analysis, of which 308 used MN terms and 100 provided definitions. More than 13 primary disease groups as per International Classification of Disease, Revision 10 categories were included. The most frequently mentioned and defined terms were enteral nutrition and malnutrition. Less than 5% of the records referenced any MN regulation. The health economic impact of MN was rarely and insufficiently (n = 19 [4.1%]) assessed, although an increase in economic analyses was observed.

CONCLUSIONS

MN terminology is not consistently defined, relevant European and US regulations are rarely cited, and economic evaluations are infrequently conducted. We recommend adopting consensus MN terms and definitions, for example, the European Society for Clinical Nutrition and Metabolism consensus guideline 2017, as a foundation for developing reliable and standardized medical nutrition economic methodologies.

Essential Amino Acid Profile in Parenteral Nutrition Mixtures: Does It Meet Needs?

BACKGROUND AND AIMS

The study compares the essential amino acid (EAA) composition of different parenteral nutrition (PN) mixtures with whey protein EAA profile and the theoretical daily EAA requirements (set by WHO/FAO/UNU or IAAO method). According to the individual EAA profile, the potential effect of several PN mixtures was evaluated on the skeletal muscle mass (SMM) of patients on home PN.

METHODS

Eight AA solutions and fifteen complete PN mixtures were considered. Twenty-nine clinically stable patients with short bowel syndrome on home total PN were retrospectively evaluated. SMM was estimated by bioelectrical impedance analysis.

RESULTS

The prescribed doses of EAA that showed a significant increase in home PN patients muscle mass were considerably greater than the theoretical ones, showing an EAA profile similar to whey protein. At the daily dose of 1 g of total AA s/kg body weight (BW), the considered PN mixtures mostly failed to improve SMM. Only prescribed doses which included more than 0.25 g/kg BW of total BCAA with at least 0.10 g/kg BW leucine, 0.08 g/kg BW isoleucine, and 0.06 g/kg BW methionine showed a significant increase in SMM.

CONCLUSIONS

The theoretical daily requirement for each EAA was met by all considered PN solutions when the prescribed daily dose of total AAs was set at 1 g/kg BW. Nevertheless, our data suggest that only an increase in total BCAA, also richer in single AA leucine, isoleucine, and methionine, is associated with the maintenance and/or increase of SMM. According to these preliminary observations, we support the prescription of an EAA composition of PN mixtures close to that of whey protein for the preservation of SMM in patients on long-term total PN.

Metal and metalloid concentrations in soil, surface water, and vegetables and the potential ecological and human health risks in the northeastern area of Hanoi, Vietnam

Heavy metal and metalloid contamination and related risks for the environment and human health are matters of increasing concern. This study assessed metal and metalloid concentrations in soil, surface water, and locally grown vegetable to assess exposure and related risks for the environment and human health in the northeastern rural area of Hanoi. Concentrations of metals and metalloids in soils exceeded regulatory thresholds in some locations (e.g., Me Linh and Gia Lam districts). The carcinogenic elements As and Cr were identified as a major concern with concentrations up to 693 μg g^-1 and 147 μg g^-1, respectively. Industrial point sources or groundwater irrigation practices in the intensive organic farming areas were identified as potential factors contributing to the accumulation of carcinogenic metals and metalloids in topsoil layers. Metal and metalloid concentrations detected in water and vegetables were below the regulatory threshold levels (WHO guideline and maximum allowable limits). While contamination was not observed at a large geographical scale, local soil contamination in specific areas of agricultural importance could pose high ecological and human health-related risks with unclear long-term impacts. The highly carcinogenic soil contamination detected in this study may be a factor adding to the increased cancer incidence rate in Hanoi area, as the total carcinogenic risk calculated for Hanoi area exceeds the cancer likelihood threshold by a factor of 25. Further research is needed to examine potential links, and the involvement of both stakeholders and policy makers is needed to adequately evaluate the risks for Hanoi area and coordinate future remediation plans if risks are justified.

Safety of parenteral nutrition in patients receiving a ventricular assist device

Patients with advanced heart failure and poor nutritional status are predisposed to higher rates of infection, bleeding, and mortality. We have increasingly used perioperative parenteral nutrition (PN) in ventricular assist device (VAD) patients and now report our initial experience. We performed a retrospective review of 43 consecutive patients who received implantable VADs from 2006 to 2009. We compared outcomes for patients receiving PN for >7 days perioperatively vs ≤7 days. In addition, we compared patients who received preoperative enteral nutrition (EN) with those who did not. Fourteen patients received perioperative PN in addition to EN for >7 days compared with 29 patients who received either PN for ≤7 days or EN alone. Univariate analysis showed no differences in infection, bleeding, thrombus, stroke, length of stay, or mortality. Multivariate stepwise regression including EN, preoperative PN, Interagency Registry for Mechanically Assisted Circulation score, age, gender, and VAD indication showed that only EN was associated with infection. Prolonged use of perioperative PN appears to be safe and well tolerated in patients undergoing VAD implantation. Preoperative EN, while increasing infection risk, seems to have no harmful effect on survival.

Energy requirements and the use of predictive equations versus indirect calorimetry in critically ill patients

Nutrition support has been shown to have a positive impact on critically ill patients who meet their defined goals of nutrition therapy. However, inappropriate energy assessment can contribute to under- or overfeeding resulting in deleterious effects. Thus, assessment of energy expenditure in critically ill patients is crucial to prevent negative impacts from inappropriate feeding. Currently, the optimal energy requirement and appropriate energy assessment in these patients is controversial. Indirect calorimetry or predictive equations have been suggested to evaluate energy expenditure in critically ill patients. Indirect calorimetry is a gold standard for evaluating energy expenditure, but it is not always available and has some limitations. Many predictive equations, therefore, have been developed to predict energy expenditure in critically ill patients. However, these equations cannot be used generally in these patients since they were developed in a unique patient population. Many studies compared measured energy expenditure with predictive energy expenditure, but the data regarding accuracy is not robust. Therefore, clinicians should consider using these equations carefully based on the current supporting data. Indirect calorimetry is recommended for use in evaluating energy expenditure in critically ill patients if it is available.

Adequacy of nutritional support and reasons for underfeeding in neurosurgical intensive care unit patients

PURPOSE

The purpose of the study was to identify the adequacy of enteral feeding, and the reason and prevalence of under-nutrition, and to determine the relationships between caloric intake and resulting nutritional parameters among neurosurgical intensive care unit (ICU) patients.

METHODS

The participants for this descriptive study were 47 neurosurgical ICU patients who had enteral feeding initiated after ICU admission. Data were collected from the initial day of enteral feeding for 7 days. Data related to enteral feeding, feeding interruptions or delay, prealbumin, and transferrin were collected.

RESULTS

The mean age of the participants was 56.62 years. Twenty-six patients did not receive their feeding formula more than once during 7 days, and 11 had interruptions more than 6 times. The mean number of feeding interruptions was 3.23 (SD = 4.47). On the average, only 76.44% of the estimated energy requirement was provided by enteral feeding to the patients. The frequency of underfeeding was 52.17% with respect to enteral feeding. The most frequent reason for the feeding interruption was observation before and after intubation and extubation, which was unavoidable. The next most common reason was gastrointestinal bleeding, mostly due to old clots or trace, followed by residual volume less than 100 mL. Changes in prealbumin and transferrin levels for 7 days between the underfed and adequately fed groups were not statistically significant.

CONCLUSION

The management of enteral feeding by nurses was overprotective because of the unpredictable nature of ICU patients in terms of their underlying disease process. The management of feeding intolerance needs to be evidence-based and nurses must consistently follow the protocol that has been supported as a useful measure.

Charisma: an integrated approach to automatic H&E-stained skeletal muscle cell segmentation using supervised learning and novel robust clump splitting

Histological image analysis plays a key role in understanding the effects of disease and treatment responses at the cellular level. However, evaluating histology images by hand is time-consuming and subjective. While semi-automatic and automatic approaches for image segmentation give acceptable results in some branches of histological image analysis, until now this has not been the case when applied to skeletal muscle histology images. We introduce Charisma, a new top-down cell segmentation framework for histology images which combines image processing techniques, a supervised trained classifier and a novel robust clump splitting algorithm. We evaluate our framework on real-world data from intensive care unit patients. Considering both segmentation and cell property distributions, the results obtained by our method correspond well to the ground truth, outperforming other examined methods.

Hepatic growth hormone resistance after acute injury

Severe injury and infection are often followed by accelerated protein catabolism and acute insulin resistance. This results in several effects that complicate and prolong recovery, including weakness, immobility, impaired wound healing, and organ dysfunction. Recent studies have demonstrated the development of GH resistance during severe inflammation, providing a potential mechanism for the protein loss that follows injury and infection. To understand this GH resistance, we recently developed a murine model of acute injury. Mice were subjected to soft-tissue injury, alone or combined with hemorrhage, and injected iv with GH 30, 60, or 90 minutes later. Hepatic GH signaling was measured via Western analysis. GH-induced signal transducer and activator of transcription 5 phosphorylation was decreased immediately after completion of the trauma procedure, and at 30 and 60 minutes, but further decreased by 90 minutes after trauma. Combined trauma and hemorrhage resulted in severely decreased GH-induced signal transducer and activator of transcription 5 phosphorylation compared with trauma alone, and this was true at all time points studied. Western analysis revealed an apparent decrease in the molecular weight of the hepatic GH receptor (GHR) after trauma and hemorrhage, but not trauma alone. Additional studies determined that the hemorrhage-induced decrease in receptor size was not due to changes in GHR N-linked glycosylation. These results suggest that GH sensitivity is rapidly impaired after acute injury and that trauma combined with hemorrhage results in a more severe form of GH resistance resulting from alteration or inactivation of hepatic GHR.

Impact of early parenteral nutrition on metabolism and kidney injury

A poor nutritional state and a caloric deficit associate with increased morbidity and mortality, but a recent multicenter, randomized controlled trial found that early parenteral nutrition to supplement insufficient enteral nutrition increases morbidity in the intensive care unit, including prolonging the duration of renal replacement therapy, compared with withholding parenteral nutrition for 1 week. Whether early versus late parenteral nutrition impacts the incidence and recovery of AKI is unknown. Here, we report a prespecified analysis from this trial, the Early Parenteral Nutrition Completing Enteral Nutrition in Adult Critically Ill Patients (EPaNIC) study. The timing of parenteral nutrition did not affect the incidence of AKI, but early initiation seemed to slow renal recovery in patients with stage 2 AKI. Early parenteral nutrition did not affect the time course of creatinine and creatinine clearance but did increase plasma urea, urea/creatinine ratio, and nitrogen excretion beginning on the first day of amino acid infusion. In the group that received late parenteral nutrition, infusing amino acids after the first week also increased ureagenesis. During the first 2 weeks, ureagenesis resulted in net waste of 63% of the extra nitrogen intake from early parenteral nutrition. In conclusion, early parenteral nutrition does not seem to impact AKI incidence, although it may delay recovery in patients with stage 2 AKI. Substantial catabolism of the extra amino acids, which leads to higher levels of plasma urea, might explain the prolonged duration of renal replacement therapy observed with early parenteral nutrition.

Association between illness severity and timing of initial enteral feeding in critically ill patients: a retrospective observational study

Background

Early enteral nutrition is recommended in cases of critical illness. It is unclear whether this recommendation is of most benefit to extremely ill patients. We aim to determine the association between illness severity and commencement of enteral feeding.

Methods

One hundred and eight critically ill patients were grouped as “less severe” and “more severe” for this cross-sectional, retrospective observational study. The cut off value was based on Acute Physiology and Chronic Health Evaluation II score 20. Patients who received enteral feeding within 48 h of medical intensive care unit (ICU) admission were considered early feeding cases otherwise they were assessed as late feeding cases. Feeding complications (gastric retention/vomiting/diarrhea/gastrointestinal bleeding), length of ICU stay, length of hospital stay, ventilator-associated pneumonia, hospital mortality, nutritional intake, serum albumin, serum prealbumin, nitrogen balance (NB), and 24-h urinary urea nitrogen data were collected over 21 days.

Results

There were no differences in measured outcomes between early and late feedings for less severely ill patients. Among more severely ill patients, however, the early feeding group showed improved serum albumin (p = 0.036) and prealbumin (p = 0.014) but worsened NB (p = 0.01), more feeding complications (p = 0.005), and prolonged ICU stays (p = 0.005) compared to their late feeding counterparts.

Conclusions

There is a significant association between severity of illness and timing of enteral feeding initiation. In more severe illness, early feeding was associated with improved nutritional outcomes, while late feeding was associated with reduced feeding complications and length of ICU stay. However, the feeding complications of more severely ill early feeders can be handled without significantly affecting nutritional intake and there is no eventual difference in length of hospital stay or mortality between groups. Consequently, early feeding shows to be a more beneficial nutritional intervention option than late feeding in patients with more severe illness.

Early parenteral nutrition evokes a phenotype of autophagy deficiency in liver and skeletal muscle of critically ill rabbits

Muscular and hepatic abnormalities observed in artificially fed critically ill patients strikingly resemble the phenotype of autophagy-deficient mice. Autophagy is the only pathway to clear damaged organelles and large ubiquitinated proteins and aggregates. Fasting is its strongest physiological trigger. Severity of autophagy deficiency in critically ill patients correlated with the amount of infused amino acids. We hypothesized that impaired autophagy in critically ill patients could partly be evoked by early provision of parenteral nutrition enriched with amino acids in clinically used amounts. In a randomized laboratory investigation, we compared the effect of isocaloric moderate-dose iv feeding with fasting during illness on the previously studied markers of autophagy deficiency in skeletal muscle and liver. Critically ill rabbits were allocated to fasting or to iv nutrition (220 kcal/d, 921 kJ/d) supplemented with 50 kcal/d (209 kJ/d) of either glucose, amino acids, or lipids, while maintaining normoglycemia, and were compared with healthy controls. Fasted critically ill rabbits revealed weight loss and activation of autophagy. Feeding abolished these responses, with most impact of amino acid-enriched nutrition. Accumulation of p62 and ubiquitinated proteins in muscle and liver, indicative of insufficient autophagy, occurred with parenteral feeding enriched with amino acids and lipids. In liver, this was accompanied by fewer autophagosomes, fewer intact mitochondria, suppressed respiratory chain activity, and an increase in markers of liver damage. In muscle, early parenteral nutrition enriched with amino acids or lipids aggravated vacuolization of myofibers. In conclusion, early parenteral nutrition during critical illness evoked a phenotype of autophagy deficiency in liver and skeletal muscle.

Clinical review: Optimizing enteral nutrition for critically ill patients--a simple data-driven formula

In modern critical care, the paradigm of 'therapeutic nutrition' is replacing traditional 'supportive nutrition'. Standard enteral formulas meet basic macro- and micronutrient needs; therapeutic enteral formulas meet these basic needs and also contain specific pharmaconutrients that may attenuate hyperinflammatory responses, enhance the immune responses to infection, or improve gastrointestinal tolerance. Choosing the right enteral feeding formula may positively affect a patient's outcome; targeted use of therapeutic formulas can reduce the incidence of infectious complications, shorten lengths of stay in the ICU and in the hospital, and lower risk for mortality. In this paper, we review principles of how to feed (enteral, parenteral, or both) and when to feed (early versus delayed start) patients who are critically ill. We discuss what to feed these patients in the context of specific pharmaconutrients in specialized feeding formulations, that is, arginine, glutamine, antioxidants, certain ω-3 and ω-6 fatty acids, hydrolyzed proteins, and medium-chain triglycerides. We summarize current expert guidelines for nutrition in patients with critical illness, and we present specific clinical evidence on the use of enteral formulas supplemented with anti-inflammatory or immune-modulating nutrients, and gastrointestinal tolerance-promoting nutritional formulas. Finally, we introduce an algorithm to help bedside clinicians make data-driven feeding decisions for patients with critical illness.

Early versus late parenteral nutrition in critically ill adults

BACKGROUND

Controversy exists about the timing of the initiation of parenteral nutrition in critically ill adults in whom caloric targets cannot be met by enteral nutrition alone.

METHODS

In this randomized, multicenter trial, we compared early initiation of parenteral nutrition (European guidelines) with late initiation (American and Canadian guidelines) in adults in the intensive care unit (ICU) to supplement insufficient enteral nutrition. In 2312 patients, parenteral nutrition was initiated within 48 hours after ICU admission (early-initiation group), whereas in 2328 patients, parenteral nutrition was not initiated before day 8 (late-initiation group). A protocol for the early initiation of enteral nutrition was applied to both groups, and insulin was infused to achieve normoglycemia.

RESULTS

Patients in the late-initiation group had a relative increase of 6.3% in the likelihood of being discharged alive earlier from the ICU (hazard ratio, 1.06; 95% confidence interval [CI], 1.00 to 1.13; P=0.04) and from the hospital (hazard ratio, 1.06; 95% CI, 1.00 to 1.13; P=0.04), without evidence of decreased functional status at hospital discharge. Rates of death in the ICU and in the hospital and rates of survival at 90 days were similar in the two groups. Patients in the late-initiation group, as compared with the early-initiation group, had fewer ICU infections (22.8% vs. 26.2%, P=0.008) and a lower incidence of cholestasis (P<0.001). The late-initiation group had a relative reduction of 9.7% in the proportion of patients requiring more than 2 days of mechanical ventilation (P=0.006), a median reduction of 3 days in the duration of renal-replacement therapy (P=0.008), and a mean reduction in health care costs of €1,110 (about $1,600) (P=0.04).

CONCLUSIONS

Late initiation of parenteral nutrition was associated with faster recovery and fewer complications, as compared with early initiation. (Funded by the Methusalem program of the Flemish government and others; EPaNIC ClinicalTrials.gov number, NCT00512122.).

Glycemic control and nutritional strategies in the cardiothoracic surgical intensive care unit--2010: state of the art

Patients in the cardiothoracic surgical intensive care unit are generally critically ill and undergoing a systemic inflammatory response to cardiopulmonary bypass, ischemia/reperfusion, and hypothermia. This presents several metabolic challenges: hyperglycemia in need of intensive insulin therapy, catabolism, and uncertain gastrointestinal tract function in need of nutritional strategies. Currently, there are controversies surrounding the standard use of intensive insulin therapy and appropriate glycemic targets as well as the use of early enteral nutrition ± parenteral nutrition. In this review, an approach for intensive metabolic support in the cardiothoracic surgical intensive care unit is presented incorporating the most recent clinical evidence. This approach advocates an IIT blood glucose target of 80-110 mg/dL if, it can be implemented safely, with early nutrition support (using parenteral nutrition as needed) to prevent a critical energy debt.

Amino acid composition in parenteral nutrition: what is the evidence?

PURPOSE OF REVIEW

Complete parenteral nutrition solutions contain mixed amino acid products providing all nine essential amino acids and a varying composition of nonessential amino acids. Relatively little rigorous comparative efficacy research on altered parenteral nutrition amino acid composition has been published in recent years.

RECENT FINDINGS

Limited data from randomized, double-blind, adequately powered clinical trials to define optimal doses of total or individual amino acids in parenteral nutrition are available. An exception is the growing number of studies on the efficacy of glutamine supplementation of parenteral nutrition or given as a single parenteral agent. Parenteral glutamine appears to confer benefit in selected patients; however, additional data to define optimal glutamine dosing and the patient subgroups who may most benefit from this amino acid are needed. Although some promising studies have been published, little data are available in the current era of nutrition support on the clinical efficacy of altered doses of arginine, branched chain amino acids, cysteine, or taurine supplementation of parenteral nutrition.

SUMMARY

Despite routine use of parenteral nutrition, surprisingly little clinical efficacy data are available to guide total or specific amino acid dosing in adult and pediatric patients requiring this therapy. This warrants increased attention by the research community and funding agencies to better define optimal amino acid administration strategies in patient subgroups requiring parenteral nutrition.

Increasing intravenous glucose load in the presence of normoglycemia: effect on outcome and metabolism in critically ill rabbits

OBJECTIVES

Endocrine disturbances and a feeding-resistant wasting syndrome, characterized by a negative protein balance, promote delayed recovery and poor outcome of critical illness. Parenteral nutrition alone cannot counteract the hypercatabolic state, possibly in part as a result of aggravation of the hyperglycemic response to illness. In critically ill rabbits, we investigated the impact of varying amounts of intravenous glucose while maintaining normoglycemia on mortality, organ damage, and markers of catabolism/anabolism.

DESIGN

Prospective, randomized laboratory investigation.

SETTING

University animal and molecular laboratory.

SUBJECTS

Three-month-old male rabbits.

INTERVENTIONS

Critically ill rabbits were randomized into a fasting group, a standard parenteral nutrition group, and two groups receiving either intermediate or high additional physiological amounts of intravenous glucose while maintained normoglycemic with insulin. These groups were compared with a hyperglycemic group and healthy rabbits. Protein and lipid load was equal for all fed groups.

MEASUREMENTS AND MAIN RESULTS

Varying intravenous glucose load did not affect mortality or organ damage provided hyperglycemia was prevented. Fasted critically ill rabbits lost weight, which was attenuated by increasing intravenous glucose load. As compared with healthy rabbits, mRNA expression and/or activity of several ubiquitin-proteasome pathway components, cathepsin-L and calpain-1, was elevated in skeletal muscle of fasted critically ill rabbits. Intravenous feeding was able to counteract this response. Excessive glucose load and/or hyperglycemia, however, reduced the protective effect of feeding. Genes investigated in the diaphragm and myocardium revealed roughly a similar response. Except in the normoglycemic group with intermediate glucose load, circulating thyroid hormone and insulin-like growth factor-1 levels decreased, most pronounced in hyperglycemic rabbits.

CONCLUSIONS

Increasing intravenous glucose infusion within the physiological range, while maintaining normoglycemia, was safe for organ function and survival of critically ill rabbits. Concomitantly, it reduced the catabolic responses as compared with fasting. Whether this has a beneficial effect on muscle function and mass remains to be investigated.

Intensive metabolic support: evolution and revolution

OBJECTIVE

To describe a new aspect of critical care termed intensive metabolic support.

METHODS

We performed a MEDLINE search of the English-language literature published between 1995 and 2008 for studies regarding the metabolic stages of critical illness, intensive insulin treatment, and intensive metabolic support in the intensive care unit, and we summarize the clinical data.

RESULTS

Intensive metabolic support is a 3-component model involving metabolic control and intensive insulin therapy, early nutrition support, and nutritional pharmacology aimed at preventing allostatic overload and the development of chronic critical illness. To improve clinical outcome and prevent mortality, intensive metabolic support should start on arrival to the intensive care unit and should end only when patients are in the recovery phase of their illness.

CONCLUSIONS

Intensive metabolic support should be an essential part of the daily treatment strategy in critical care medicine. This will involve a newfound and extensive collaboration between the endocrinologist and the intensivist. We call for well-designed future studies involving implementation of this protocol to decrease the burden of chronic critical illness.

Comparison of resting energy expenditure prediction methods with measured resting energy expenditure in obese, hospitalized adults

BACKGROUND

Several methods are available to estimate caloric needs in hospitalized, obese patients who require specialized nutrition support; however, it is unclear which of these strategies most accurately approximates the caloric needs of this patient population. The purpose of this study was to determine which strategy most accurately predicts resting energy expenditure in this subset of patients.

METHODS

Patients assessed at high nutrition risk who required specialized nutrition support and met inclusion and exclusion criteria were enrolled in this observational study. Adult patients were included if they were admitted to a medical or surgical service with a body mass index > or = 30 kg/m(2). Criteria excluding patient enrollment were pregnancy and intolerance or contraindication to indirect calorimetry procedures. Investigators calculated estimations of resting energy expenditure for each patient using variations on the following equations: Harris-Benedict, Mifflin-St. Jeor, Ireton-Jones, 21 kcal/kg body weight, and 25 kcal/kg body weight. For nonventilated patients, the MedGem handheld indirect calorimeter was used. For ventilated patients, the metabolic cart was used. The primary endpoint was to identify which estimation strategy calculated energy expenditures to within 10% of measured energy expenditures.

RESULTS

The Harris-Benedict equation, using adjusted body weight with a stress factor, most frequently estimated resting energy expenditure to within 10% measured resting energy expenditure at 50% of patients.

CONCLUSION

Measured energy expenditure with indirect calorimetry should be employed when developing nutrition support regimens in obese, hospitalized patients, as estimation strategies are inconsistent and lead to inaccurate predictions of energy expenditure in this patient population.

Enteral and parenteral nutrition distinctively modulate intestinal permeability and T cell function in vitro

BACKGROUND

Nutritional support is an established element of therapy for various indications. However, its impact on the mucosal barrier function is not well understood.

AIM OF THE STUDY

We investigated the influence of EN and PN on intestinal epithelial cells and peripheral blood (PBMC) and lamina propria mononuclear cells (LPMC), all of which are involved in the mucosal defense against bacterial translocation and systemic inflammation.

METHODS

Integrity of epithelial cells was measured as transepithelial electrical resistance (TER) of confluent Caco-2 monolayers in the presence of 1% EN, PN and a parenteral amino acid mixture (AM). To determine wound healing capacities, an established migration model with IEC-6 cells was used. Furthermore, we investigated apoptosis, cell activation, proliferation and cytokine secretion of Caco-2, HT29 and of stimulated PBMC and LPMC cultured with or without 1 and 5% EN, AM or PN.

RESULTS

We demonstrated that EN, AM and PN promoted the integrity of the epithelial monolayer and reconstituted epithelial cell continuity TGF-beta-dependently and -independently. Interestingly, only PN induced apoptosis and decreased the mitochondrial membrane potential. The activation status of PBMC was significantly reduced by EN and AM. Specifically, EN leads to an increased apoptosis rate, inhibited cell cycle progression and increased pro-inflammatory cytokine secretion. Both EN and PN reduced the activation status and the release of pro- and anti-inflammatory cytokines.

CONCLUSIONS

Our study provides evidence that by promoting wound healing and regulating T cell function, EN, AM, and PN potently interact with the intestinal barrier and immune system, thus justifying its use in diseases accompanied by impaired mucosal barrier function.

Systematic review: nutritional support in acute pancreatitis

BACKGROUND

There has been controversy concerning the merits of enteral and parenteral nutrition compared with no supplementary nutrition in the management of patients with acute pancreatitis.

AIM

To perform a systematic review of the data from randomized controlled trials (RCTs) in acute pancreatitis that compares enteral nutrition with no supplementary nutrition, parenteral nutrition with no supplementary nutrition and enteral nutrition with parenteral nutrition.

METHODS

A search was undertaken in the MEDLINIE, EMBASE and the Cochrane Central Register of Controlled Trials.

RESULTS

Fifteen RCTs were included. Enteral nutrition, when compared with no supplementary nutrition, was associated with no significant change in infectious complications: ratio of relative risks (RR) 0.56, 95% confidence interval (CI) 0.07-4.32, P = 0.58, but a significant reduction in mortality: ratio of RR 0.22, 95% CI 0.07-0.70, P = 0.01. Parenteral nutrition, when compared with no supplementary nutrition, was associated with no significant change in infectious complications: RR 1.36, 95% CI 0.18-10.40; P = 0.77, but a significant reduction in mortality: RR 0.36, 95% CI 0.13-0.97, P = 0.04. Enteral nutrition, when compared with parenteral nutrition, was associated with a significant reduction in infectious complications: RR 0.41, 95% CI 0.30-0.57, P < 0.001, but no significant change in mortality: RR 0.60, 95% CI 0.32-1.14, P = 0.12.

CONCLUSIONS

The use of either enteral or parenteral nutrition, in comparison with no supplementary nutrition, is associated with a lower risk of death in acute pancreatitis. Enteral nutrition is associated with a lower risk of infectious complications compared with parenteral nutrition.

Special commentary: a call for intensive metabolic support

PURPOSE OF REVIEW

This special commentary addresses recent clinical reviews regarding appropriate nutrition and metabolic support in the critical care setting.

RECENT FINDINGS

There are divergent approaches between North America and Europe for the use of early nutrition support and combined enteral nutrition and parenteral nutrition support possibly due to the commercial availability of specific parenteral nutrients. The advent of intensive insulin therapy has changed the landscape of metabolic support in the intensive care unit, and previous notions about infective risk of parenteral nutrition will need to be re-addressed. Patients with brain failure may benefit from an intensive insulin therapy with a blood glucose target that is higher than that used in patients without brain failure. Patients with heart failure may benefit from the addition of nutritional pharmacology that targets proximate oxidative pathophysiological pathways. Intradialytic parenteral nutrition may be viewed as another form of supplemental parenteral nutrition when enteral nutrition is insufficient in patients on hemodialysis in the intensive care unit.

SUMMARY

It is proposed that intensive metabolic support be routinely implemented in the intensive care unit based on the following steps: intensive insulin therapy with an appropriate blood glucose target, nutrition risk assessment, early and if needed combined enteral nutrition and parenteral nutrition to target 20-25 kcal/kg/day and 1.2-1.5 g protein/kg/day, and nutritional and metabolic monitoring.

Regulation of tissue iodothyronine deiodinase activity in a model of prolonged critical illness

BACKGROUND

The low plasma triiodothyronine (T3) observed during prolonged critical illness can be explained in part by suppressed hepatic deiodinase type I (D1) and increased D3 activity. Infusion of thyrotropin-releasing hormone (TRH) can restore D1 and D3 activity in critically ill rabbits, but it remains unknown whether this is a direct effect of TRH or the TRH-induced rise in circulating thyroxine (T4) and T3.

METHODS

To answer this specific question, burn-injured rabbits randomly received a 4-day treatment with saline, T4, T3, T4+T3, or TRH, started on day 4 of the illness. Plasma iodothyronine concentrations, D1 and D3 activity, and T3-responsive gene expression were quantified in liver and kidney.

RESULTS

Infusion of T4, T3, or TRH increased circulating T3 levels and hepatic D1 activity. Co-infusion of T3 with T4 enhanced T4 to T3 conversion as demonstrated by lower T4, higher T3, and lower reverse T3 (rT3) levels and tended to further increase hepatic D1 activity. Hepatic D1 activity correlated positively with circulating T3 and the T3/rT3 ratio, but not with T4, rT3, or thyroid-stimulating hormone.

CONCLUSIONS

During prolonged critical illness, D1 activity is primarily regulated via changes in circulating T3, suggesting that the low plasma T3 concentrations may be important in sustaining low D1 activity in this condition.

Early nutritional therapy: the role of enteral and parenteral routes

PURPOSE OF REVIEW

Early nutrition is defined as the initiation of nutritional therapy within 48 h of either hospital admission or surgery. However, optimal timing for initiation of nutritional therapy through either enteral or parenteral routes remains poorly defined with the existing data. We reviewed the recent literature investigating the role of early enteral and parenteral nutrition in critical illness and perioperative care.

RECENT FINDINGS

Recent studies in both trauma/surgical and nonsurgical patients support the superiority of early enteral over early parenteral nutrition. However, late commencement of enteral feeding should be avoided if the gastrointestinal tract is functional. Both prolonged hypocaloric enteral feeding and hypercaloric parenteral nutrition should be avoided, although the precise caloric target remains controversial.

SUMMARY

Early enteral nutrition remains the first option for the critically ill patient. However, there seems to be increased favor for combined enteral-parenteral therapy in cases of sustained hypocaloric enteral nutrition. The key issue is when the dual regimen should be initiated. Although more study is required to determine the optimal timing to initiate a combined enteral-parenteral approach, enteral nutrition should be initiated early and parenteral nutrition added if caloric-protein targets cannot be achieved after a few days.

Metabolic effects of enteral versus parenteral alanyl-glutamine dipeptide administration in critically ill patients receiving enteral feeding: a pilot study

BACKGROUND

Glutamine (Gln) may become conditionally indispensable during critical illness. The short-term metabolic effects of enteral versus parenteral Gln supplementation are unknown in this clinical setting.

OBJECTIVES

We studied metabolic effects of intravenous (i.v.) alanyl-Gln dipeptide (AG) supplementation and enteral (e.n.) AG supplementation on plasma Gln concentration, antioxidant status, plasma lymphocyte subset number, gut permeability and nitrogen balance in adult critically ill patients requiring tube feeding compared to a control group not receiving Gln supplementation.

METHODS

In a double-blind, pilot clinical trial, 44 medical and surgical ICU patients received identical Gln-free tube feedings 24 h/day and were randomized to either isonitrogenous control (n=15), e.n. AG (n=15) or i.v. AG (n=14) groups (AG). Twelve patients were discontinued from the study. The goal AG dose was 0.5 g/kg/day. Biochemical and metabolic endpoints were measured at baseline and on day 9 (plasma Gln, antioxidant indices, lymphocyte subsets; serum IGF-1 and IGF-binding protein-3; intestinal permeability). Nitrogen balance was determined between study days 6 and 8.

RESULTS

Illness severity indices, clinical demographics, enteral energy and nitrogen intake and major biochemical indices were similar between groups during study. Plasma Gln was higher in the i.v. AG (565+/-119 microM, mean+/-SEM) vs the e.n. AG (411+/-27 microM) group by day 9 (p=0.039); however, subjects in the i.v. AG group received a higher dose of AG (i.v. AG 0.50 versus e.n. AG 0.32+/-0.02 g/kg/day; p<0.001). E.n. AG subjects showed a significant increase in plasma alpha-tocopherol levels over time and maintained plasma gamma-tocopherol concentrations. There were no differences between groups for plasma concentrations of vitamin C, glutathione, malondialdehyde (MDA), T-lymphocyte subsets, intestinal permeability or nitrogen balance.

CONCLUSIONS

This study showed that alanyl-Gln administration by enteral or parenteral routes did not appear to affect antioxidant capacity or oxidative stress markers, T-lymphocyte subset (CD-3, CD-4, CD-8) number, gut barrier function or whole-body protein metabolism compared to unsupplemented ICU patients requiring enteral tube feeding. Enteral Gln appeared to maintain plasma tocopherol levels in this pilot metabolic study.

Early nutrition support in the intensive care unit: a US perspective

PURPOSE OF REVIEW

Early nutrition support, defined as within the first 24-48 h of ICU care, is recommended by clinical practice guidelines. The purpose of this paper is to provide an evidence-based US perspective on early nutrition support in critical illness, explain its mechanism of action, and describe its implementation using combined enteral and parenteral nutrition support.

RECENT FINDINGS

Recent American and Canadian guidelines recommend starting enteral nutrition within the first 24-48 h of ICU care. This is mainly due to accrued 'energy debt' from underfeeding in certain patients. This energy debt leads to increased risks of complications and longer lengths of stay. Strong clinical evidence, however, in the form of prospective, randomized, controlled intervention studies of early nutrition support in the setting of routine intensive insulin therapy, is lacking.

SUMMARY

Early enteral nutrition should be first-line therapy in the ICU. If a caloric goal of 20-25 kcal/kg/day is not possible, then combined enteral and parenteral nutrition should be started. In the new age of intensive insulin therapy, parenteral nutrition has not been shown to confer significant additional infective risk. There are many unanswered questions, but a proactive posture for metabolic support in the ICU is advocated.