Optimizing energy and protein balance in the ICU

Why One-Size-Fits-All Doesn't Work in Intensive Care Unit Nutrition?

Nutrition therapy is a complex intervention with several underlying considerations that may influence effectiveness. Considerations include the mechanism of action of the intervention and the patient phenotype, including sex, ethnicity, body composition, and the patients' nutritional and inflammatory status. Energy and protein targets are elements of nutrition therapy that may be particularly influenced by individual patient factors. Biomarkers may provide a useful tool to monitor and individualize nutrition therapy in the future. The considerations mentioned, with many yet to be studied, highlight the rationale for more individualized interventions moving away from a 'one-size-fits-all' approach.

Clinical Outcomes of Hypocaloric/Hyperproteic vs Normocaloric Enteral Feeding in the Acute Phase of Critical Illness among Patients Admitted in the Intensive Care Unit: A Systematic Review with Meta-analysis

Objectives

To examine the effect of hypocaloric/hyperproteic enteral feeding vs normocaloric feeding on the survival of critically ill patients in the acute phase in the intensive care unit (ICU).

Methodology

Randomized clinical trials utilizing hypocaloric, hyperproteic, and normocaloric enteral feeding in the ICU were searched using the following terms ((((critically ill) OR (intensive care) OR (mechanically ventilated)) AND ((low-calorie enteral feeding) OR (high-protein enteral feeding)))) in MEDLINE, PubMed, Scopus, and Google Scholar by two independent authors.

Results

There were no significant differences in hospital mortality [odds ratio (OR), 1.0; 95% confidence interval (CI), 0.77, 1.31; p = 0.99, I 2 = 0%], days on mechanical ventilation (MD, -0.05; 95% CI, -0.37, 0.28; p = 0.78, I 2 = 0%), the odds of acquiring infectious complications (OR, 0.90; 95% CI, 0.71, 1.14; p = 0.38, I 2 = 0%), and the length of ICU stay (MD, 0.60; 95% CI, -2.39, 3.59; p = 0.69, I 2 = 96%). The length of hospital stay was significantly lower by 4.18 days in the normocaloric group (MD, 4.18; 95% CI, 2.50, 5.85; p < 0.00001, I 2 = 0%).

Conclusion

This meta-analysis showed no significant differences in mortality, infectious complications, days of mechanical ventilation, and ICU length of stay between groups. Findings on hospital length of stay were interpreted with caution due to the low quality of evidence and clinical heterogeneity.

How to cite this article

Permejo CC, Evangelista TJP. Clinical Outcomes of Hypocaloric/Hyperproteic vs Normocaloric Enteral Feeding in the Acute Phase of Critical Illness among Patients Admitted in the Intensive Care Unit: A Systematic Review with Meta-analysis. Indian J Crit Care Med 2024;28(11):1069-1083.

Association between first-week propofol administration and long-term outcomes of critically ill mechanically ventilated patients: A retrospective cohort study

BACKGROUND & AIM

Propofol is commonly used in ICUs, but its long-term effects have not been thoroughly studied. In vitro studies suggest it may harm mitochondrial function, potentially affecting clinical outcomes. This study aimed to investigate the association between substantial propofol sedation and clinical outcomes in critically ill patients.

METHODS

We conducted a single-centre cohort study of critically ill, mechanically ventilated (≥7 days) adults to compare patients who received a substantial dose of propofol (cumulative >500 mg) during the first week of ICU admission with those who did not. The primary outcome was the association between substantial propofol administration and 6-month mortality, adjusted for relevant covariates. Subanalyses were performed for administration in the early (day 1-3) and late (day 4-7) acute phases of critical illness due to the metabolic changes in this period. Secondary outcomes included tracheostomy need and duration, length of ICU and hospital stay (LOS), discharge destinations, ICU, hospital, and 3-month mortality.

RESULTS

A total of 839 patients were enrolled, with 73.7 % receiving substantial propofol administration (substantial propofol dose group). Six-month all-cause mortality was 32.4 %. After adjusting for relevant variables, we found no statistically significant difference in 6-month mortality between both groups. There were also no significant differences in secondary outcomes.

CONCLUSION

Our study suggests that substantial propofol administration during the first week of ICU stay in the least sick critically ill, mechanically ventilated adult patients is safe, with no significant associations found with 6-month mortality, ICU or hospital LOS, differences in discharge destinations or need for tracheostomy.

Effect of protein underdosing on the prognosis of patients with severe acute heart failure in the early acute phase: A single-institutional retrospective cohort study

BACKGROUND

The appropriate protein dose during the early acute phase of severe acute heart failure (AHF) remains unknown. We hypothesized that protein underdosing during this period may lead to a poor prognosis. Thus, we investigated the relationship between protein sufficiency rate and prognosis during the early acute phase in patients with severe AHF.

METHODS

This retrospective observational study investigated patients with AHF requiring invasive mechanical ventilation who were admitted in the intensive care and cardiac care units between January 2015 and August 2021. These patients were ranked according to the tertile of protein sufficiency rate on intubation day 2. Univariate and multivariate logistic regression analyses were performed to determine whether a low protein sufficiency rate on intubation day 2 was an independent factor for in-hospital mortality. Patients were weighted using the inverse probability of treatment weighting (IPTW) method to determine the differences in baseline characteristics.

RESULTS

A total of 118 patients were included in the study and divided into low-protein (n = 40) and non-low-protein (n = 78) groups with protein sufficiency rates of ≤10% and >10%, respectively.In the multivariate analysis of in-hospital mortality, low protein sufficiency on day 2 was identified as an independent factor (odds ratio [OR] = 2.77, 95% confidence interval [CI] = 1.05-7.27, P = 0.039). After adjusting for baseline characteristics using the IPTW method, multiple logistic regression analysis of in-hospital mortality revealed low protein sufficiency on day 2 as an independent factor (OR = 3.32, 95% CI = 1.18-9.32, P = 0.023).

CONCLUSION

Protein underdosing in the early acute phase of severe AHF may be associated with increased in-hospital mortality.

Biomarkers in critical care nutrition

The goal of nutrition support is to provide the substrates required to match the bioenergetic needs of the patient and promote the net synthesis of macromolecules required for the preservation of lean mass, organ function, and immunity. Contemporary observational studies have exposed the pervasive undernutrition of critically ill patients and its association with adverse clinical outcomes. The intuitive hypothesis is that optimization of nutrition delivery should improve ICU clinical outcomes. It is therefore surprising that multiple large randomized controlled trials have failed to demonstrate the clinical benefit of restoring or maximizing nutrient intake. This may be in part due to the absence of biological markers that identify patients who are most likely to benefit from nutrition interventions and that monitor the effects of nutrition support. Here, we discuss the need for practical risk stratification tools in critical care nutrition, a proposed rationale for targeted biomarker development, and potential approaches that can be adopted for biomarker identification and validation in the field.

The clinical relevance and mechanism of skeletal muscle wasting

Skeletal muscle wasting occurs in both chronic and acute diseases. Increasing evidence has shown this debilitating process is associated with short- and long-term outcomes in critical, cancer and surgical patients. Both muscle quantity and quality, as reflected by the area and density of a given range of attenuation in CT scan, impact the patient prognosis. In addition, ultrasound and bioelectrical impedance analysis (BIA) are also widely used in the assessment of body composition due to their bedside viability and no radioactivity. Mechanism researches have revealed complicated pathways are involved in muscle wasting, which include altered IGF1-Akt-FoxO signaling, elevated levels of myostatin and activin A, activation of NF-κB pathway and glucocorticoid effects. Particularly, central nervous system (CNS) has been proven to participate in regulating muscle wasting in various conditions, such as infection and tumor. Several promising therapeutic agents have been under developing in the treatment of muscle atrophy, such as myostatin antagonist, ghrelin analog, non-steroidal selective androgen receptor modulators (SARMs). Notably, nutritional therapy is still the fundamental support in combating muscle wasting. However, the optimizing and tailored nutrition regimen relies on accurate metabolism measurement and large clinical trials in the future. Here, we will discuss the current understanding of muscle wasting and potential treatment in clinical practice.

Caloric Adequacy in the First Week of Mechanically Ventilated Patients has No Impact on Long-term Daily Life Activities

Aim and objective

The aim and objective of this study is to test the effect of an optimized caloric supply in the first week of intensive care unit (ICU) stay in mechanically ventilated patients on the ability to perform their activities of daily living (ADL) in the long-term.

Materials and methods

A prospective observational study comparing patients who achieved an adequate caloric target (≥80%) vs those whose target was inadequate (<80%). The primary outcome under study is the instrumental ADL (IADL) scale after 6 months of discharge.

Results

Ninety-two patients were evaluated in the ICU and 50 were alive at 6 months. Follow-up was lost for 3 patients and 47 patients were evaluated at ICU and after 6 months. Thirty-four patients reached the energetic target and 13 did not reach it. There was no significant variation in IADL.

Conclusion

The energy adequacy in the first week of hospitalization was achieved by most survivors; however, this conduct does not seem to have influenced the ability to perform ADL after 6 months of discharge.

How to cite this article

Dariano AP, Couto CFL, Rubin BA, Viana MV, Friedman G. Caloric Adequacy in the First Week of Mechanically Ventilated Patients has No Impact on Long-term Daily Life Activities. Indian J Crit Care Med 2020;24(12):1206–1212.

Association of PROtein and CAloric Intake and Clinical Outcomes in Adult SEPTic and Non-Septic ICU Patients on Prolonged Mechanical Ventilation: The PROCASEPT Retrospective Study

Background

The optimal nutritional support for critically ill septic patients remains unknown. This study evaluates the associations of macronutrient intake during the first week of intensive care unit (ICU) admission and long‐term clinical outcomes in septic and non‐septic patients.

Methods

Prolonged mechanically ventilated patients were retrospectively studied. The association of protein (low: <0.8 g/kg/d, medium: 0.8–1.2 g/kg/d, high >1.2 g/kg/d) and energy intake (<80%, 80%–110%, 110% of target) during days 1–3 and 4–7 after ICU admission and 6‐month mortality was analyzed for septic and non‐septic patients separately.

Results

A total of 423 patients were investigated. Of these, 297 had sepsis. In the sepsis group, medium protein intake at days 4–7 was associated with lower 6‐month mortality (hazard ratio [HR]: 0.646, 95% confidence interval [CI]: 0.418‐0.996, P=0.048) compared with high intake. In the non‐sepsis group, early high and late low protein intake were associated with higher 6‐month mortality (HR: 3.902, 95% CI: 1.505‐10.115, P=0.005; HR: 2.642, 95% CI: 1.128‐6.189, P=0.025) compared with low and high protein intake, respectively. For energy intake, late energy intake of >110% was associated with decreased mortality in septic patients (HR: 0.400, 95% CI: 0.222‐0.721, P=0.002), whereas in non‐septic patients, late medium energy intake (80%–110%) was associated with better survival (HR: 0.379, 95% CI: 0.175‐0.820, P=0.014), both compared with low energy intake.

Conclusion

Divergent associations of macronutrient intake were found; early high protein intake in non‐septic patients, but not in septic patients, was found to be associated with higher 6‐month mortality.

Impact of a computer-assisted decision support system (CDSS) on nutrition management in critically ill hematology patients: the NUTCHOCO study (nutritional care in hematology oncologic patients and critical outcome)

BACKGROUND

Mortality of critically ill hematology (HM) patients has improved over time. Thus, those patients require an extensive diagnostic workup and the optimal use of available treatments. There are no data regarding nutrition strategy for critically ill HM patients, while nutritional support is crucial for both HM and critically ill patients. We hypothesized that the implementation of a computer-assisted decision support system (CDSS), designed to supervise a nutritional intervention by a multidisciplinary team, would be able to increase guidelines adherence and outcomes.

RESULTS

In this before/after study, 275 critically ill hematology patients admitted to the ICU over 5-year period were included. Energy and protein intakes were delivered using standard protocol in the 147 patients (53%) of the 'before group' and using a CDSS in order to reach every day predefined caloric and protein targets accordingly to the catabolic or anabolic status in the 128 patients (47%) of the 'after group.' Using a Poisson regression, we showed that the use of CDSS allowed to reach a relative increase in the rate of days in compliance with caloric (1.57; 95% confidence interval (CI), [1.17-2.10], p = 0.0025) and protein targets (3.86 [2.21-6.73], p < 0.0001) in the 'after group' by more than 50% as compared with the 'before group.' Interestingly, compliance rates were low and only reached 30% after intervention. Hospital mortality, ICU-acquired infection, and hospital, and ICU length of stay were similar in the two groups of patients. Importantly, exploratory analysis showed that hospital mortality was lower in the 'after group' for neutropenic and severely ill patients.

CONCLUSION

For critically ill hematology patients, the use of a nutritional CDSS allowed to increase the days in compliance with caloric and protein targets as compared with no CDSS use. In this context, overall hospital mortality was not affected.

Safety and efficacy of volume-based feeding in critically ill, mechanically ventilated adults using the 'Protein & Energy Requirements Fed for Every Critically ill patient every Time' (PERFECT) protocol: a before-and-after study

BACKGROUND

Underfeeding in critical illness is common and associated with poor outcomes. According to large prospective hospital studies, volume-based feeding (VBF) safely and effectively improves energy and protein delivery to critically ill patients compared to traditional rate-based feeding (RBF) and might improve patient outcomes. A before-and-after study was designed to evaluate the safety, efficacy and clinical outcomes associated with VBF compared to RBF in a single intensive care unit (ICU).

METHODS

The sample included consecutively admitted critically ill adults, mechanically ventilated for at least 72 h and fed enterally for a minimum of 48 h. The first cohort (n = 46) was fed using RBF, the second (n = 46) using VBF, and observed for 7 days, or until extubation or death. Statistical comparison of percentage feed volume, energy and protein delivered, plus indices of feed intolerance, were the primary outcomes of interest. Secondary observations included ventilation period, mortality, and length of ICU stay (LOICUS).

RESULTS

Groups were comparable in baseline clinical and demographic characteristics and nutrition practices. Volume delivered to the VBF group increased significantly by 11.2% (p ≤ 0.001), energy by 13.4% (p ≤ 0.001) and protein by 8.4% (p = 0.02), compared to the RBF group. In the VBF group, patients meeting > 90% of energy requirements increased significantly from 47.8 to 84.8% (p ≤ 0.001); those meeting > 90% of protein requirements changed from 56.5 to 73.9% (p = 0.134). VBF did not increase symptoms of feed intolerance. Adjusted binomial logistic regression found each additional 1% of prescribed feed delivered decreased the odds of vomiting by 0.942 (5.8%), 95% CI [0.900-0.985], p = 0.010. No differences in mortality or LOICUS were identified. Kaplan-Meier found a significantly increased extubation rate in patients receiving > 90% of protein requirements compared to those meeting < 80%, (p = 0.006). Adjusted Cox regression found the daily probability of being extubated tripled in patients receiving > 90% of their protein needs compared to the group receiving < 80%, hazard ratio 3.473, p = 0.021, 95% CI [1.205-10.014].

CONCLUSION

VBF safely and effectively increased the delivery of energy and protein to critically ill patients. Increased protein delivery may improve extubation rate which has positive patient-centred and financial implications, warranting larger confirmatory trials. This investigation adds weight to the ICU literature supporting VBF, and the growing evidence which advocates for enhanced protein delivery to improve patient outcomes.

Adequacy of enteral nutritional support in intensive care units does not affect the short- and long-term prognosis of mechanically ventilated patients: a pilot study

OBJECTIVE

To correlate short-term (duration of mechanical ventilation and length of intensive care unit stay) and long-term (functional capacity) clinical outcomes of patients who reached nutritional adequacy ≥ 70% of predicted in the first 72 hours of hospitalization in the intensive care unit.

METHODS

This was a prospective observational pilot study conducted in an 18-bed intensive care unit. A total of 100 mechanically ventilated patients receiving exclusive enteral nutritional support and receiving intensive care for more than 72 hours were included. Patients who never received enteral nutrition, those with spinal cord trauma, pregnant women, organ donors and cases of family refusal were excluded. The variables studied were nutritional adequacy ≥ 70% of predicted in the first 72 hours of hospitalization, length of intensive care unit stay, duration of mechanical ventilation and the ability to perform activities of daily living after 12 months, assessed via telephone contact using the Lawton Activities of Daily Living Scale.

RESULTS

The mean duration of mechanical ventilation was 18 ± 9 days, and the mean intensive care unit length of stay was 19 ± 8 days. Only 45% of the patients received more than 70% of the target nutrition in 72 hours. There was no association between nutritional adequacy and short-term (duration of mechanical ventilation, length of stay in the intensive care unit and mortality) or long-term (functional capacity and mortality) clinical outcomes.

CONCLUSION

Critically ill patients receiving caloric intake ≥ 70% in the first 72 hours of hospitalization did not present better outcomes in the short term or after 1 year.

Prescribed hypocaloric nutrition support for critically-ill adults

BACKGROUND

There are controversies about the amount of calories and the type of nutritional support that should be given to critically-ill people. Several authors advocate the potential benefits of hypocaloric nutrition support, but the evidence is inconclusive.

OBJECTIVES

To assess the effects of prescribed hypocaloric nutrition support in comparison with standard nutrition support for critically-ill adults SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Cochrane Library), MEDLINE, Embase and LILACS (from inception to 20 June 2017) with a specific strategy for each database. We also assessed three websites, conference proceedings and reference lists, and contacted leaders in the field and the pharmaceutical industry for undetected/unpublished studies. There was no restriction by date, language or publication status.

SELECTION CRITERIA

We included randomized and quasi-randomized controlled trials comparing hypocaloric nutrition support to normo- or hypercaloric nutrition support or no nutrition support (e.g. fasting) in adults hospitalized in intensive care units (ICUs).

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We meta-analysed data for comparisons in which clinical heterogeneity was low. We conducted prespecified subgroup and sensitivity analyses, and post hoc analyses, including meta-regression. Our primary outcomes were: mortality (death occurred during the ICU and hospital stay, or 28- to 30-day all-cause mortality); length of stay (days stayed in the ICU and in the hospital); and Infectious complications. Secondary outcomes included: length of mechanical ventilation. We assessed the quality of evidence with GRADE.

MAIN RESULTS

We identified 15 trials, with a total of 3129 ICU participants from university-associated hospitals in the USA, Colombia, Saudi Arabia, Canada, Greece, Germany and Iran. There are two ongoing studies. Participants suffered from medical and surgical conditions, with a variety of inclusion criteria. Four studies used parenteral nutrition and nine studies used only enteral nutrition; it was unclear whether the remaining two used parenteral nutrition. Most of them could not achieve the proposed caloric targets, resulting in small differences in the administered calories between intervention and control groups. Most studies were funded by the US government or non-governmental associations, but three studies received funding from industry. Five studies did not specify their funding sources.The included studies suffered from important clinical and statistical heterogeneity. This heterogeneity did not allow us to report pooled estimates of the primary and secondary outcomes, so we have described them narratively.When comparing hypocaloric nutrition support with a control nutrition support, for hospital mortality (9 studies, 1775 participants), the risk ratios ranged from 0.23 to 5.54; for ICU mortality (4 studies, 1291 participants) the risk ratios ranged from 0.81 to 5.54, and for mortality at 30 days (7 studies, 2611 participants) the risk ratios ranged from 0.79 to 3.00. Most of these estimates included the null value. The quality of the evidence was very low due to unclear or high risk of bias, inconsistency and imprecision.Participants who received hypocaloric nutrition support compared to control nutrition support had a range of mean hospital lengths of stay of 15.70 days lower to 10.70 days higher (10 studies, 1677 participants), a range of mean ICU lengths of stay 11.00 days lower to 5.40 days higher (11 studies, 2942 participants) and a range of mean lengths of mechanical ventilation of 13.20 days lower to 8.36 days higher (12 studies, 3000 participants). The quality of the evidence for this outcome was very low due to unclear or high risk of bias in most studies, inconsistency and imprecision.The risk ratios for infectious complications (10 studies, 2804 participants) of each individual study ranged from 0.54 to 2.54. The quality of the evidence for this outcome was very low due to unclear or high risk of bias, inconsistency and imprecisionWe were not able to explain the causes of the observed heterogeneity using subgroup and sensitivity analyses or meta-regression.

AUTHORS' CONCLUSIONS

The included studies had substantial clinical heterogeneity. We found very low-quality evidence about the effects of prescribed hypocaloric nutrition support on mortality in hospital, in the ICU and at 30 days, as well as in length of hospital and ICU stay, infectious complications and the length of mechanical ventilation. For these outcomes there is uncertainty about the effects of prescribed hypocaloric nutrition, since the range of estimates includes both appreciable benefits and harms.Given these limitations, results must be interpreted with caution in the clinical field, considering the unclear balance of the risks and harms of this intervention. Future research addressing the clinical heterogeneity of participants and interventions, study limitations and sample size could clarify the effects of this intervention.

Protein delivery in critical illness

PURPOSE OF REVIEW

Protein delivery in the critically ill still is a highly debated issue. Here, we discuss only the most recent updates in the literature concerning protein nutrition of the critically ill.

RECENT FINDINGS

Up to now, there are no randomized controlled trials (RCTs) published on enteral provision of protein that were randomized for protein level of intake. In the past year, there have been two new observational studies published, one of which in critically ill children. Also, two randomized controlled trials with high parenteral amino acid provision have been published. The overall view on nutrition support has not been changed convincingly by these studies. Recent findings have confirmed that protein and amino acid provision are highly important for outcome in critically ill patients. For the first time, a randomized study confirmed this, however, only on the short term. The other RCT confirmed that an extreme dosing of amino acids is not related to improvement in outcome. One observational study showed that the effect of protein on outcome should be adjusted for energy intake and vice versa, showing that adequate protein is related to improved outcome and adequate energy provision is not. The other observational study confirmed importance of protein in paediatric ICU but also gained some insight into improvement of protein delivery by postpyloric feeding and usefulness of a dedicated dietitian in the ICU.

SUMMARY

We will continue to improve protein delivery to critically ill patients; however, the quest for evidence and feeding guidelines still remains.

High-Protein Hypocaloric Nutrition for Non-Obese Critically Ill Patients

High-protein hypocaloric nutrition, tailored to each patient's muscle mass, protein-catabolic severity, and exogenous energy tolerance, is the most plausible nutrition therapy in protein-catabolic critical illness. Sufficient protein provision could mitigate the rapid muscle atrophy characteristic of this disease while providing urgently needed amino acids to the central protein compartment and sites of tissue injury. The protein dose may range from 1.5 to 2.5 g protein (1.8-3.0 g free amino acids)/kg dry body weight per day. Nutrition should be low in energy (≈70% of energy expenditure or ≈15 kcal/kg dry body weight per day) because efforts to match energy provision to energy expenditure are physiologically irrational, risk toxic energy overfeeding, and have repeatedly failed in large clinical trials to demonstrate clinical benefit. The American Society for Parenteral and Enteral Nutrition currently suggests high-protein hypocaloric nutrition for obese critically ill patients. Short-term high-protein hypocaloric nutrition is physiologically and clinically sensible for most protein-catabolic critically ill patients, whether obese or not.

Energy Requirements in Critically Ill Patients

During the management of critical illness, optimal nutritional support is an important key for achieving positive clinical outcomes. Compared to healthy people, critically ill patients have higher energy expenditure, thereby their energy requirements and risk of malnutrition being increased. Assessing individual nutritional requirement is essential for a successful nutritional support, including the adequate energy supply. Methods to assess energy requirements include indirect calorimetry (IC) which is considered as a reference method, and the predictive equations which are commonly used due to the difficulty of using IC in certain conditions. In this study, a literature review was conducted on the energy metabolic changes in critically ill patients, and the implications for the estimation of energy requirements in this population. In addition, the issue of optimal caloric goal during nutrition support is discussed, as well as the accuracy of selected resting energy expenditure predictive equations, commonly used in critically ill patients.

Timing of PROTein INtake and clinical outcomes of adult critically ill patients on prolonged mechanical VENTilation: The PROTINVENT retrospective study

BACKGROUND & AIMS

Optimal protein intake during critical illness is unknown. Conflicting results on nutritional support during the first week of ICU stay have been published. We addressed timing of protein intake and outcomes in ICU patients requiring prolonged mechanical ventilation.

METHODS

We retrospectively collected nutritional and clinical data on the first 7 days of ICU admission of adult critically ill patients, who were mechanically ventilated in our ICU for at least 7 days and admitted between January 1st 2011 and December 31st 2015. Based on recent literature, patients were divided into 3 protein intake categories, <0.8 g/kg/day, 0.8-1.2 g/kg/day and >1.2 g/kg/day. Our primary aim was to identify the optimum protein dose and timing related to the lowest 6 month mortality. Secondary endpoints were ventilation duration, need for renal replacement therapy (RRT), ICU length of stay (LOS) and mortality and hospital LOS and mortality.

RESULTS

In total 455 patients met the inclusion criteria. We found a time-dependent association of protein intake and mortality; low protein intake (<0.8 g/kg/day) before day 3 and high protein intake (>0.8 g/kg/day) after day 3 was associated with lower 6-month mortality, adjusted HR 0.609; 95% CI 0.480-0.772, p < 0.001) compared to patients with overall high protein intake. Lowest 6-month mortality was found when increasing protein intake from <0.8 g/kg/day on day 1-2 to 0.8-1.2 g/kg/day on day 3-5 and >1.2 g/kg/day after day 5. Moreover, overall low protein intake was associated with the highest ICU, in-hospital and 6-month mortality. No differences in ICU LOS, need for RRT or ventilation duration were found.

CONCLUSIONS

Our data suggest that although overall low protein intake is associated with the highest mortality risk, high protein intake during the first 3-5 days of ICU stay is also associated with increased long-term mortality. Therefore, timing of high protein intake may be relevant for optimizing ICU, in-hospital and long-term mortality outcomes.

A prospective study of energy and protein intakes in critically ill patients

BACKGROUND & AIMS

Providing adequate and appropriate food and nutrients satisfying the patients' safe nutritional need is one of the most important care practices for critically ill patients (CIPs) in ICU settings, and is strongly related to the patients' safety.

METHODS

In this prospective cross-sectional study data were collected from a 52-bed medical intensive care unit on 777 consecutive patients in six different ICUs. The patients' weights and heights were measured based on ulna length, knee height, MAC, Calf C, and Wrist C. Also, patient weight change history was asked for. All currently in-use dietary supplements and formulas in the ICU settings were checked for their ingredients. The patients' nutritional need was calculated individually for the disease state based on dietary ESPEN guidelines.

RESULTS

Mean ICU and hospital stay duration was 14.45 ± 11.81 and 15.38 ± 11.88 days respectively. Mean energy and protein requirements in the target population were 1804.61 ± 201.76 Kcal/day and 77.94 ± 12.72 gr/day, respectively. Mean actual energy and protein intakes were 1052.75 ± 561.25 Kcal/day and 35.38 ± 23.19 gr/day, respectively. Satisfaction percents for mean energy and protein requirement in the total population were 58.34% (1052.75/1804.4) and 45.41% (35.38/77.9), respectively. In 21.4% and 4.4% of the studied group, energy and protein intakes were about 75-100% of the patients' actual need, respectively. Another data analysis for patients with over 10 days of inpatient time showed that only 14.2% of patients had energy intakes, and only 3.2% of them had protein intakes in the range of 75-100% of their requirements.

CONCLUSION

Results showed that energy and protein intakes in CIPs are low, disproportionate to their requirements. Therefore, actual dietary intake records, individual dietary requirement calculation, and individual dietary planning in relation with the patients' disease and stress should be considered. Such an accurate nutritional care process can promote patient safety.

Protein Kinetics and Metabolic Effects Related to Disease States in the Intensive Care Unit

Evaluating protein kinetics in the critically ill population remains a very difficult task. Heterogeneity in the intensive care unit (ICU) population and wide spectrum of disease processes creates complexity in assessing protein kinetics. Traditionally, protein has been delivered in the context of total energy. Focus on energy delivery has recently come into question, as the importance of supplemental protein in patient outcomes has been shown in several recent trials. The ICU patient is prone to catabolism, immobilization, and impaired immunity, which is a perfect storm for massive loss of lean body tissue with a unidirectional flow of amino acids from muscle to immune tissue for immunoglobulin production, as well as liver for gluconeogenesis and acute phase protein synthesis. The understanding of protein metabolism in the ICU has been recently expanded with the discovery of how the mammalian target of rapamycin complex 1 is regulated. The concept of "anabolic resistance" and identifying the quantity of protein required to overcome this resistance is gaining support among critical care nutrition circles. It appears that a minimum of at least 1.2 g/kg/d with levels up to 2.0 g/kg/d of protein or amino acids appears safe for delivery in the ICU setting and may yield a better clinical outcome.

Sarcopenia in critically ill patients

Sarcopenia occurring as a primary consequence of aging and secondary due to certain medical problems including chronic disease, malnutrition and inactivity is a progressive generalized loss of skeletal muscle mass, strength and function. The prevalence of sarcopenia increases with aging (approximately 5-13 % in the sixth and seventh decades). However, data showing the prevalence and clinical outcomes of sarcopenia in intensive care units (ICUs) are limited. A similar condition to sarcopenia in the ICU, called ICU-acquired weakness (ICU-AW), has been reported more frequently. Here, we aim to examine the importance of sarcopenia, especially ICU-AW, in ICU patients via related articles in Medline.

The dilemma of protein delivery in the intensive care unit

OBJECTIVE

Optimal protein delivery in the intensive care unit (ICU) may offer a significant mortality benefit, whereas energy overfeeding leads to worse outcomes. The aim of the present study was to assess actual protein versus energy delivery in a multidisciplinary adult ICU.

METHODS

We conducted a retrospective review of ICU charts to determine total protein delivery and energy delivery, inclusive of non-nutritional energy sources (NNES), from admission until a maximum of 7 d. The outcome variables were protein and energy delivery relative to targets and cumulative protein and energy balance.

RESULTS

We included 71 patients (49% male), with a mean age of 49.2 ± 17.1 y. Of the patients, 68% were medical and 32% surgical. Nutrition therapy was initiated within 14.5 ± 14.1 h. The majority (80%) received enteral nutrition (EN). Median protein delivery and energy delivery were 75 g/d (1.1 g·kg·d(-1), range 21-135 g/d) and 1642 kcal/d (26 kcal·kg·d(-1), range 740-2619 kcal/d), meeting 89% (range 24-103%) and 100% (range 39-133%) of target, respectively. NNES, mostly from carbohydrate-containing intravenous fluids, contributed 8% (range 0-29%) to total energy delivery (133 kcal/d, range 0-561). Protein and energy underfeeding occurred in 51% and 27% of cases, respectively. Only 59% of those with an adequate energy delivery (90-110% of target) achieved an adequate protein delivery. A significant negative correlation was found between cumulative protein and energy balance and time to initiation of NT (protein: R = -0.33, P = 0.006; energy: R = -0.28, P = 0.017).

CONCLUSIONS

Early initiation of EN with currently available energy-rich formulas is insufficient to achieve adequate protein delivery. NNES add to total energy delivery. Novel EN formulas with a lower nonprotein energy-to-nitrogen ratio may help to optimize protein delivery without the harmful effects of energy overfeeding.

Nutritional needs for the critically ill in relation to inflammation

PURPOSE OF REVIEW

This review focuses on nutritional needs in critically ill patients. The inflammation corresponding to acute stress is highlighted. Simultaneously, we try to avoid limiting the perspective to only the acute phase.

RECENT FINDINGS

During the last year, a number of important studies on nutritional needs in the critically ill have been published, including large randomized controlled trials. In particular studies addressing the needs for energy and proteins in the critically ill have imparted new knowledge in this field. However, there are few studies concerning the rehabilitation phase after critical illness.

SUMMARY

Although the recent findings and publications contribute to a more nuanced understanding of nutrition during critical illness, the implications for clinical practice are not in discord with the current recommendations of guidelines.

Protein-energy nutrition in the ICU is the power couple: A hypothesis forming analysis

BACKGROUND & AIMS

We hypothesize that an optimal and simultaneous provision of energy and protein is favorable to clinical outcome of the critically ill patients.

METHODS

We conducted a review of the literature, obtained via electronic databases and focused on the metabolic alterations during critical illness, the estimation of energy and protein requirements, as well as the impact of their administration.

RESULTS

Critically ill patients undergo severe metabolic stress during which time a great amount of energy and protein is utilized in a variety of reactions essential for survival. Energy provision for critically ill patients has drawn attention given its association with morbidity, survival and long-term recovery, but protein provision is not sufficiently taken into account as a critical component of nutrition support that influences clinical outcome. Measurement of energy expenditure is done by indirect calorimetry, but protein status cannot be measured with a bedside technology at present.

CONCLUSIONS

Recent studies suggest the importance of optimal and combined provision of energy and protein to optimize clinical outcome. Clinical randomized controlled studies measuring energy and protein targets should confirm this hypothesis and therefore establish energy and protein as a power couple.

Effect of Critical Illness on Triglyceride Absorption

BACKGROUND

Adequate nutrition support for critically ill patients optimizes outcome, and enteral feeding is the preferred route of nutrition. Small intestinal glucose absorption is frequently impaired in critical illness. Despite lipid being a major constituent of liquid nutrient administered, there is little information about lipid absorption during critical illness.

OBJECTIVES

To determine small intestinal lipid, as well as glucose, absorption in critical illness compared with health.

MATERIALS AND METHODS

Twenty-nine mechanically ventilated critically ill patients and 16 healthy volunteers were studied. Liquid nutrient (60 mL, 1 kcal/mL), containing 200 µL (13)C-triolein and 3 g 3-O-methyl-glucose (3-OMG), was infused directly into the duodenum at a rate of 2 kcal/min. Exhaled (13)CO2 and serum 3-OMG concentrations were measured at timed intervals over 360 minutes. Lipid absorption was measured as the cumulative percentage dose (cPDR) of (13)CO2 recovered at 360 minutes. Glucose absorption was measured as the area under the 3-OMG concentration curve. Data are median (range) and analyzed using the Mann-Whitney U and Pearson correlation tests.

RESULTS

Lipid absorption was markedly less in the critically ill (cPDR(13)CO2: patients, 22.6% [0%-100%] vs healthy participants, 40.7% [5.3%-84.7%]; P = .018). While glucose absorption was less at 60 minutes in the critically ill (3-OMG60: 13.2 [3.5-29.5] vs 21.1 [9.3-31.9] mmol/L·min; P = .003), this was not apparent at 360 minutes (3-OMG360: 92.7 [54.5-147.9] vs 107.9 [64.0-168.7] mmol/L·min; P = .126). There was no relationship between lipid and glucose absorption.

CONCLUSION

Small intestinal absorption of lipid is diminished during critical illness.

Enhanced Protein-Energy Provision via the Enteral Route in Critically Ill Patients (PEP uP Protocol): A Review of Evidence

Nutrition support is an integral part of care among critically ill patients. However, critically ill patients are commonly underfed, leading to consequences such as increased length of hospital and intensive care unit stay, time on mechanical ventilation, infectious complications, and mortality. Nevertheless, the prevalence of underfeeding has not resolved since the first description of this problem more than 15 years ago. This may be due to the traditional conservative feeding approaches. A novel feeding protocol (the Enhanced Protein-Energy Provision via the Enteral Route Feeding Protocol in Critically Ill Patients [PEP uP] protocol) was proposed and proven to improve feeding adequacy significantly. However, some of the components in the protocol are controversial and subject to debate. This article is a review of the supporting evidences and some of the controversy associated with each component of the PEP uP protocol.

[Nutrition in critical illness]

Critically ill patients are often unable to eat by themselves over a long period of time, sometimes for weeks. In the acute phase, serious protein-energy malnutrition may develop with progressive muscle weakness, which may result in assisted respiration of longer duration as well as longer stay in intensive care unit and hospital. In view of the metabolic processes, energy and protein intake targets should be defined and the performance of metabolism should be monitored. Enteral nutrition is primarily recommended. However, parenteral supplementation is often necessary because of the disrupted tolerance levels of the gastrointestinal system. Apparently, an early parenteral supplementation started within a week would be of no benefit. Some experts believe that muscle loss can be reduced by increased target levels of protein. Further studies are needed on the effect of immune system feeding, fatty acids and micronutrients.

When and how should sepsis patients be fed?

PURPOSE OF REVIEW

To provide an overview on the recent literature regarding metabolism during sepsis and outcome-related effects of nutrition therapy in septic patients. The question when and how these patients should be fed with respect to macronutrient intake is elaborated.

RECENT FINDINGS

Although the incidence of severe sepsis has steadily increased over the past years, still no strong evidence is available with respect to the role of energy and protein provision in these patients. On the basis of recent large randomized trials in mixed patient populations, the updated sepsis guidelines recommend early but limited nutrition via the enteral route rather than targeted feeding. Lately, the results of a large trial challenged the importance of the route of feeding on the clinical outcome of critically ill patients. Four post-hoc analyses of prospective randomized trials including a large number of severely septic patients yielded conflicting results. One reported significant mortality reduction with near-target calorie and protein intake by exclusive enteral nutrition, whereas the second showed an advantage of enteral compared to combined nutrition, albeit resulting in a lower calorie and protein provision. The other two analyses found no association at all of either lower or higher daily caloric or protein intake, respectively, with clinical outcomes.

SUMMARY

In the absence of strong clinical evidence, pathophysiological findings are discussed and nutritional strategies for septic patients derived. Future studies should explore the individual response to specific exogenous supply of macronutrients and micronutrients in the acute and persistent phase of severe systemic inflammation.

Effect of initiating enteral protein feeding on whole-body protein turnover in critically ill patients

BACKGROUND

Critically ill patients are susceptible to protein catabolism. Enteral feeding may ameliorate protein loss, but its effect is not well characterized in terms of protein kinetics.

OBJECTIVE

We established a method of quantifying the effect of enteral protein feeding on whole-body protein turnover and studied critically ill patients receiving early enteral nutrition.

DESIGN

In a proof-of-concept study, we established, in healthy subjects (n = 6), a method of measuring the effect of continuous enteral protein feeding on whole-body protein turnover by using ¹³C-phenylalanine (¹³C-Phe) intrinsically labeled casein by a nasogastric feeding tube and an intravenous ²H₅-Phe tracer. The protocol was applied to study critically ill patients (n = 10) during the initial hypocaloric-hyponitrogenous dose of enteral nutrition.

RESULTS

Patients were catabolic with a negative protein balance. The median splanchnic extraction fraction of hourly dietary Phe intake was 92% (range: 86-99%); that is, the availability of dietary Phe in arterial plasma was low. In patients with a stable parenteral amino acid supply (n = 7), the median net protein balance improved during enteral feeding from -8.6 to -5.8 μmol · kg body weight⁻¹ · h⁻¹ (P = 0.018).

CONCLUSIONS

Whole-body protein turnover and the contribution of dietary protein can be quantified in critically ill patients by using intravenous and enteral stable-isotope Phe tracers. The whole-body protein balance improved during early hypocaloric-hyponitrogenous enteral protein feeding in these patients.

Inflammation, negative nitrogen balance, and outcome after aneurysmal subarachnoid hemorrhage

OBJECTIVE

To analyze the impact of inflammation and negative nitrogen balance (NBAL) on nutritional status and outcomes after subarachnoid hemorrhage (SAH).

METHODS

This was a prospective observational study of SAH patients admitted between May 2008 and June 2012. Measurements of C-reactive protein (CRP), transthyretin (TTR), resting energy expenditure (REE), and NBAL (g/day) were performed over 4 preset time periods during the first 14 postbleed days (PBD) in addition to daily caloric intake. Factors associated with REE and NBAL were analyzed with multivariable linear regression. Hospital-acquired infections (HAI) were tracked daily for time-to-event analyses. Poor outcome at 3 months was defined as a modified Rankin Scale score ≥ 4 and assessed by multivariable logistic regression.

RESULTS

There were 229 patients with an average age of 55 ± 15 years. Higher REE was associated with younger age (p = 0.02), male sex (p < 0.001), higher Hunt Hess grade (p = 0.001), and higher modified Fisher score (p = 0.01). Negative NBAL was associated with lower caloric intake (p < 0.001), higher body mass index (p < 0.001), aneurysm clipping (p = 0.03), and higher CRP:TTR ratio (p = 0.03). HAIs developed in 53 (23%) patients on mean PBD 8 ± 3. Older age (p = 0.002), higher Hunt Hess (p < 0.001), lower caloric intake (p = 0.001), and negative NBAL (p = 0.04) predicted time to first HAI. Poor outcome at 3 months was associated with higher Hunt Hess grade (p < 0.001), older age (p < 0.001), negative NBAL (p = 0.01), HAI (p = 0.03), higher CRP:TTR ratio (p = 0.04), higher body mass index (p = 0.03), and delayed cerebral ischemia (p = 0.04).

CONCLUSIONS

Negative NBAL after SAH is influenced by inflammation and associated with an increased risk of HAI and poor outcome. Underfeeding and systemic inflammation are potential modifiable risk factors for negative NBAL and poor outcome after SAH.

Early high protein intake is associated with low mortality and energy overfeeding with high mortality in non-septic mechanically ventilated critically ill patients

Introduction

Early protein and energy feeding in critically ill patients is heavily debated and early protein feeding hardly studied.

Methods

A prospective database with mixed medical-surgical critically ill patients with prolonged mechanical ventilation (>72 hours) and measured energy expenditure was used in this study. Logistic regression analysis was used to analyse the relation between admission day-4 protein intake group (with cutoffs 0.8, 1.0, and 1.2 g/kg), energy overfeeding (ratio energy intake/measured energy expenditure > 1.1), and admission diagnosis of sepsis with hospital mortality after adjustment for APACHE II (Acute Physiology and Chronic Health Evaluation II) score.

Results

A total of 843 patients were included. Of these, 117 had sepsis. Of the 736 non-septic patients 307 were overfed. Mean day-4 protein intake was 1.0 g/kg pre-admission weight per day and hospital mortality was 36%. In the total cohort, day-4 protein intake group (odds ratio (OR) 0.85; 95% confidence interval (CI) 0.73 to 0.99; P = 0.047), energy overfeeding (OR 1.62; 95%CI 1.07 to 2.44; P = 0.022), and sepsis (OR 1.77; 95%CI 1.18 to 2.65; P = 0.005) were independent risk factors for mortality besides APACHE II score. In patients with sepsis or energy overfeeding, day-4 protein intake was not associated with mortality. For non-septic, non-overfed patients (n = 419), mortality decreased with higher protein intake group: 37% for <0.8 g/kg, 35% for 0.8 to 1.0 g/kg, 27% for 1.0 to 1.2 g/kg, and 19% for ≥1.2 g/kg (P = 0.033). For these, a protein intake level of ≥1.2 g/kg was significantly associated with lower mortality (OR 0.42, 95%CI 0.21 to 0.83, P = 0.013).

Conclusions

In non-septic critically ill patients, early high protein intake was associated with lower mortality and early energy overfeeding with higher mortality. In septic patients early high protein intake had no beneficial effect on mortality.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-014-0701-z) contains supplementary material, which is available to authorized users.

Proteins and amino acids are fundamental to optimal nutrition support in critically ill patients

Proteins and amino acids are widely considered to be subcomponents in nutritional support. However, proteins and amino acids are fundamental to recovery and survival, not only for their ability to preserve active tissue (protein) mass but also for a variety of other functions. Understanding the optimal amount of protein intake during nutritional support is therefore fundamental to appropriate clinical care. Although the body adapts in some ways to starvation, metabolic stress in patients causes increased protein turnover and loss of lean body mass. In this review, we present the growing scientific evidence showing the importance of protein and amino acid provision in nutritional support and their impact on preservation of muscle mass and patient outcomes. Studies identifying optimal dosing for proteins and amino acids are not currently available. We discuss the challenges physicians face in administering the optimal amount of protein and amino acids. We present protein-related nutrition concepts, including adaptation to starvation and stress, anabolic resistance, and potential adverse effects of amino acid provision. We describe the methods for assessment of protein status, and outcomes related to protein nutritional support for critically ill patients. The identification of a protein target for individual critically ill patients is crucial for outcomes, particularly for specific subpopulations, such as obese and older patients. Additional research is urgently needed to address these issues.

Daily protein intake and patient outcomes in severe acute kidney injury: findings of the randomized evaluation of normal versus augmented level of replacement therapy (RENAL) trial

BACKGROUND AND AIMS

We aimed to examine the association between daily protein intake (DPI) and outcomes in patients from the Randomized Evaluation of Normal versus Augmented Level (RENAL) trial.

METHODS

We analyzed the association between DPI and clinical outcomes using multivariable logistic regression, Cox proportional hazards models and time-adjusted analysis.

RESULTS

During ICU stay, mean DPI was 37.6 g/day among survivors and 37.7 g/day among nonsurvivors (p = 0.96; DPI of 0.5 g/kg/day). Only 159 (10.9%) of the patients received a mean DPI of >1 g/kg. Patients with a DPI above the median had a 43.1% mortality compared with 46.1% for a DPI below the median (p = 0.25). On multivariate analysis, a lower DPI was not associated with increased odds ratios for 90-day mortality or any secondary outcomes. Cox proportional hazards models and time-adjusted analysis confirmed these findings.

CONCLUSIONS

In the RENAL study, mean DPI was low. Within the confines of such low DPI, greater amounts of DPI were not independently associated with improved clinical outcomes. Video Journal Club "Cappuccino with Claudio Ronco" at www.karger.com/?doi=363175.

New ways of defining protein and energy relationships in inborn errors of metabolism

Dietary restrictions required to manage individuals with inborn errors of metabolism (IEM) are essential for metabolic control, however may result in an increased risk to both short and long-term nutritional status. Dietary factors most likely to influence nutritional status include energy intake, protein quality and quantity, micronutrient intake and the frequency and extent to which the diet must be altered during periods of increased physical or metabolic stress. Patients on the most restrictive diets, including those with intakes consisting of low levels of natural protein or those with recurrent illness or frequent metabolic decompensation carry the most nutritional risk. Due to the difficulties in determining condition specific requirements, dietary intake recommendations and nutritional monitoring tools used in patients with IEM are the same as, or extrapolated from, those used in healthy populations. As a consequence, evidence is lacking for the safest dietary prescriptions required to manage these patients long term, as tolerance to dietary therapy is generally described in terms of metabolic stability rather than long term nutritional and health outcomes. As the most frequent therapeutic dietary manipulation in IEM is alteration in dietary protein, and as protein status is critically dependent on adequate energy provision, the use of a Protein to Energy ratio (P:E ratio) as an additional tool will better define the relationship between these critical components. This could accurately define dietary quality and ensure that not only an adequate, but also a safe and balanced intake is provided.

Causes and consequences of interrupted enteral nutrition: a prospective observational study in critically ill surgical patients

BACKGROUND

Malnutrition and underfeeding are major challenges in caring for critically ill patients. Our goal was to characterize interruptions in enteral nutrition (EN) delivery and their impact on caloric debt in the surgical intensive care unit (ICU).

MATERIALS AND METHODS

We performed a prospective, observational study of adults admitted to surgical ICUs at a Boston teaching hospital (March-December 2012). We categorized EN interruptions as "unavoidable" vs "avoidable" and compared caloric deficit between patients with ≥1 EN interruption (group 1) vs those without interruptions (group 2). Multivariable logistic regression was used to investigate the association of EN interruption with the risk of underfeeding. Poisson regression was used to investigate the association of EN interruption with length of stay (LOS) and mortality.

RESULTS

Ninety-four patients comprised the analytic cohort. Twenty-six percent of interruptions were deemed "avoidable." Group 1 (n = 64) had a significantly higher mean daily and cumulative caloric deficit vs group 2 (n = 30). Patients in group 1 were at a 3-fold increased risk of being underfed (adjusted odds ratio, 2.89; 95% confidence interval [CI], 1.03-8.11), had a 30% higher risk of prolonged ICU LOS (adjusted incident risk ratio [IRR], 1.27; 95% CI, 1.14-1.42), and had a 50% higher risk of prolonged hospital LOS (adjusted IRR, 1.53; 95% CI, 1.41-1.67) vs group 2.

CONCLUSIONS

In our cohort of critically ill surgical patients, EN interruption was frequent, largely "unavoidable," and associated with undesirable outcomes. Future efforts to optimize nutrition in the surgical ICU may benefit from considering strategies that maximize nutrient delivery before and after clinically appropriate EN interruptions.

Fundamental determinants of protein requirements in the ICU

PURPOSE OF REVIEW

Currently, feeding the ICU patient is highly discussed. Energy feeding has been the topic of randomized studies, but protein feeding has not. Study results are contradictory on early feeding; however, little is known about early protein requirement. What is this protein requirement based on, therefore what are the fundamental determinants?

RECENT FINDINGS

Recent studies have addressed the importance of protein feeding and/or muscle (protein) wasting in critically ill patients. Targeted feeding has been shown to improve protein balance in one study, and infection rate in one study. Low muscle mass that is already present during ICU admission has been shown to be related to higher mortality, in two studies. Four studies have related muscle wasting to (protein) feeding strategies with very diverse results: Two small studies have reported no advantage [n = 15, computed tomography] or negative impact (n = 62, ultrasound, 50% sepsis patients) of protein on muscle wasting. Two studies, one small (n = 33, computed tomography) and one very large (n = 1372, Subjective Global Assessment), have reported a positive impact of (early) feeding on muscle wasting.

SUMMARY

Fundamental to adequate protein feeding in critically ill patients, at least 1.2 g protein/kg per day, is targeted energy feeding using indirect calorimetry. The level of protein requirement is related to fat free mass or muscle mass, which makes sex and BMI also relevant. Targeted early protein feeding is found to improve short-term outcome, reduction of muscle wasting and hospital mortality. Long-term outcome of protein feeding has not been studied. However, targeted protein feeding may be harmful in sepsis patients. Up to now, we lack biomarkers that provide caregivers with an instrument to increase protein feeding up to the individual protein requirement of the critically ill patient.

Whole body protein turnover in critically ill patients with multiple organ failure

BACKGROUND & AIMS

To evaluate the effect of nutrition therapy on protein turnover in critically ill patients isotopically labeled amino acids can be used. Here parallel measurements using (13)C-leucine and (2)H5-phenylalanine were performed to evaluate if one tracer was to be preferred.

METHODS

As a reference group, healthy volunteers (n = 8) were studied in the postabsorptive state and during parenteral nutrition delivery. ICU patients with multiple organ failure (n = 8) were studied during parenteral nutrition delivery only.

RESULTS

For the volunteers, the net protein balances changed from negative to positive during parenteral nutrition delivery (compared to the postabsorptive state) when evaluated with leucine and phenylalanine (P < 0.0001). For phenylalanine this change was attributable to an increased protein synthesis (P < 0.0001), while for leucine the change was attributable to a decreased protein degradation (P < 0.0001). For the patients, only measured during parenteral nutrition delivery, the estimates by the two amino acid tracers agreed, showing a protein balance not statistically significantly different from zero. The whole body protein turnover was higher than that of the healthy volunteers during parenteral nutrition delivery. In the patients, the net protein balance correlated positively to the amount of amino acids given.

CONCLUSIONS

Critically ill patients with multiple organ failure have an increased protein turnover. The findings in the healthy volunteers indicate that the use of the two different amino acid tracers in parallel in future studies should be considered.

Whole body protein kinetics during hypocaloric and normocaloric feeding in critically ill patients

Introduction

Optimal feeding of critically ill patients in the ICU is controversial. Existing guidelines rest on rather weak evidence. Whole body protein kinetics may be an attractive technique for assessing optimal protein intake. In this study, critically ill patients were investigated during hypocaloric and normocaloric IV nutrition.

Methods

Neurosurgical patients on mechanical ventilation (n = 16) were studied during a 48-hour period. In random order 50% and 100% of measured energy expenditure was given as IV nutrition during 24 hours, corresponding to hypocaloric and normocaloric nutrition, respectively. At the end of each period, whole body protein turnover was measured using d5-phenylalanine and 13C-leucine tracers.

Results

The phenylalanine tracer indicated that whole-body protein synthesis was lower during hypocaloric feeding, while whole-body protein degradation and amino acid oxidation were unaltered, which resulted in a more negative protein balance, namely −1.9 ± 2.1 versus −0.7 ± 1.3 mg phenylalanine/kg/h (P = 0.014). The leucine tracer indicated that whole body protein synthesis and degradation and amino acid oxidation were unaltered, but the protein balance was negative during hypocaloric feeding, namely −0.3 ± 0.5 versus 0.6 ± 0.5 mg leucine/kg/h (P < 0.001).

Conclusion

In the patient group studied, hypocaloric feeding was associated with a more negative protein balance, but the amino acid oxidation was not different. The protein kinetics measurements and the study’s investigational protocol were useful for assessing the efficacy of nutrition support on protein metabolism in critically ill patients.

[An immunohistochemical study of various breast tissues using CA15-3 (MAb 115D8 and MAb DF3)]

A CA15-3 RIA KIT, composed with two different monoclonal antibodies (115D 8 and DF 3), has been seen to react with the sera of breast cancer patients. Although the subclass of both antibodies is different, the antigen that reacted with them seems to be same, with a range from 300-450 kd. To reveal the reacting pattern of both antibodies, an immunohistochemical study was performed involving various breast tissues. In general, normal and benign breast tumors exhibited an apical stain by 115D8 and an apical and focal cytosol stain by DF 3. Breast carcinomas displayed not only an apical stain but a strong cytosol stain. However, the staining patterns showed little difference.