Best timing for energy provision during critical illness

Comparative characteristics of some methods for estimating energy expenditure in critically ill mechanically ventilated patients

AIM

To compare the energy expenditure (EE) assessed by ventilator-derived carbon dioxide production (EE-VCO2-ventilator) and the energy expenditure calculated from six predictive equations with the gold standard energy expenditure measured with indirect calorimetry (IC) in mechanically ventilated patients.

Fiberoptic endoscopic validation of a clinical screening test of swallowing function in critically ill patients performed within 24 h after extubation

BACKGROUND

A bedside screening tool of swallowing dysfunction (SD) (BSSD) after extubation would be useful to identify patients who are at risk of SD. We aimed to evaluate the accuracy of our BSSD in comparison with fiberoptic endoscopic evaluation of swallowing (FEES) in critically ill patients after extubation.

METHODS

We conducted a 1-year prospective monocentric study to evaluate the accuracy of our BSSD to diagnose SD following endotracheal intubation in comparison with FEES (gold standard). Patients intubated for longer than 48 h were included. Both tests were assessed within 24 h after extubation. Primary endpoint was the accuracy of the BSSD. Secondary endpoint was to assess risk factors of SD.

RESULTS

Seventy-nine patients were included in the study. Thirty-three patients (42%) presented with a SD. The BSSD showed a sensitivity of 88% (95% CI 0.72-0.97) and a specificity of 91% (95% CI 0.79-0.98), a positive predictive value of 88% (95% CI 0.72-0.97) and a negative predictive value of 91% (95% CI 0.79-0.97). The AUC reached 0.83 (95% CI 0.74-0.92).

CONCLUSION

Our study describes an accurate clinical screening tool to detect SD after extubation in critically ill patients. Screening-positive cases should be confirmed by instrumental tests, ideally using FEES.

Nutritional Status in Intensive Care Unit: A Meta-Analysis and Systematic Review

It is important to consider the nutritional status of patients in the intensive care unit (ICU) since it is a key element in the ability to overcome and survive critical illnesses and clinical outcomes. The aim of the present study was to provide a meta-analysis and systematic overview in determining the nutritional status of patients in ICU by examining other studies. All studies published during 2015-2019 on nutritional status in ICU were retrieved from Medline (via PubMed), Embase, Scopus, and Web of Science databases. Finally, 23 articles were included in the meta-analysis. Results obtained from these studies showed that the nutritional status of patients in ICU was inappropriate (the pooled proportion of malnutrition was 0.51 in the type of study stratified), in which many patients in this unit had different degrees of malnutrition (moderate-mild malnourished and severe malnutrition is 0.46 and 20%, respectively). According to the results of this study, the nutritional status of patients in ICU was unsatisfactory; hence, it is necessary to consider the nutritional status along with other therapeutic measures at the beginning of the patient's admission.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members.As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020)

The Japanese Clinical Practice Guidelines for Management of Sepsis and Septic Shock 2020 (J-SSCG 2020), a Japanese-specific set of clinical practice guidelines for sepsis and septic shock created as revised from J-SSCG 2016 jointly by the Japanese Society of Intensive Care Medicine and the Japanese Association for Acute Medicine, was first released in September 2020 and published in February 2021. An English-language version of these guidelines was created based on the contents of the original Japanese-language version. The purpose of this guideline is to assist medical staff in making appropriate decisions to improve the prognosis of patients undergoing treatment for sepsis and septic shock. We aimed to provide high-quality guidelines that are easy to use and understand for specialists, general clinicians, and multidisciplinary medical professionals. J-SSCG 2016 took up new subjects that were not present in SSCG 2016 (e.g., ICU-acquired weakness [ICU-AW], post-intensive care syndrome [PICS], and body temperature management). The J-SSCG 2020 covered a total of 22 areas with four additional new areas (patient- and family-centered care, sepsis treatment system, neuro-intensive treatment, and stress ulcers). A total of 118 important clinical issues (clinical questions, CQs) were extracted regardless of the presence or absence of evidence. These CQs also include those that have been given particular focus within Japan. This is a large-scale guideline covering multiple fields; thus, in addition to the 25 committee members, we had the participation and support of a total of 226 members who are professionals (physicians, nurses, physiotherapists, clinical engineers, and pharmacists) and medical workers with a history of sepsis or critical illness. The GRADE method was adopted for making recommendations, and the modified Delphi method was used to determine recommendations by voting from all committee members. As a result, 79 GRADE-based recommendations, 5 Good Practice Statements (GPS), 18 expert consensuses, 27 answers to background questions (BQs), and summaries of definitions and diagnosis of sepsis were created as responses to 118 CQs. We also incorporated visual information for each CQ according to the time course of treatment, and we will also distribute this as an app. The J-SSCG 2020 is expected to be widely used as a useful bedside guideline in the field of sepsis treatment both in Japan and overseas involving multiple disciplines.

Validity of predictive equations to estimate RMR in females with varying BMI

Estimation of RMR using prediction equations is the basis for calculating energy requirements. In the present study, RMR was predicted by Harris-Benedict, Schofield, Henry, Mifflin-St Jeor and Owen equations and measured by indirect calorimetry in 125 healthy adult women of varying BMI (17-44 kg/m2). Agreement between methods was assessed by Bland-Altman analyses and each equation was assessed for accuracy by calculating the percentage of individuals predicted within ± 10 % of measured RMR. Slopes and intercepts of bias as a function of average RMR (mean of predicted and measured RMR) were calculated by regression analyses. Predictors of equation bias were investigated using univariate and multivariate linear regression. At group level, bias (the difference between predicted and measured RMR) was not different from zero only for Mifflin-St Jeor (0 (sd 153) kcal/d (0 (sd 640) kJ/d)) and Henry (8 (sd 163) kcal/d (33 (sd 682) kJ/d)) equations. Mifflin-St Jeor and Henry equations were most accurate at the individual level and predicted RMR within 10 % of measured RMR in 71 and 66 % of participants, respectively. For all equations, limits of agreement were wide, slopes of bias were negative, and intercepts of bias were positive and significantly (P < 0⋅05) different from zero. Increasing age, height and BMI were associated with underestimation of RMR, but collectively these variables explained only 15 % of the variance in estimation bias. Overall accuracy of equations for prediction of RMR is low at the individual level, particularly in women with low and high RMR. The Mifflin-St Jeor equation was the most accurate for this dataset, but prediction errors were still observed in about one-third of participants.

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.

Resting energy expenditure in critically ill patients: Evaluation methods and clinical applications

Patients on intensive care present systemic, metabolic, and hormonal alterations that may adversely affect their nutritional condition and lead to fast and important depletion of lean mass and malnutrition. Several factors and medical conditions can influence the energy expenditure (EE) of critically ill patients, such as age, gender, surgery, serious infections, medications, ventilation modality, and organ dysfunction. Clinical conditions that can present with EE change include acute kidney injury, a complex disorder commonly seen in critically ill patients with manifestations that can range from minimum elevations in serum creatinine to renal failure requiring dialysis. The nutritional needs of this population are therefore complex, and determining the resting energy expenditure is essential to adjust the nutritional supply and to plan a proper diet, ensuring that energy requirements are met and avoiding complications associated with overfeeding and underfeeding. Several evaluation methods of EE in this population have been described, but all of them have limitations. Such methods include direct calorimetry, doubly labeled water, indirect calorimetry (IC), various predictive equations, and, more recently, the rule of thumb (kcal/kg of body weight). Currently, IC is considered the gold standard.

Plasma glutamine levels in patients after non-elective or elective ICU admission: an observational study

BACKGROUND

A low plasma glutamine level at the time of acute admission to the intensive care unit (ICU) is an independent predictor of an unfavourable outcome in critically ill patients. The primary objective of this study was to determine whether there are differences in plasma glutamine levels upon non-elective or elective ICU admission. The secondary objective was to compare glutamine levels over time, and to determine correlations between glutamine levels and the severity of illness and presence of infection in ICU patients.

METHODS

We performed a single-centre observational study in a closed-format, 22-bed, mixed ICU. Plasma glutamine levels were measured at admission and every morning at 6.00 a.m. during the ICU stay. We aimed to include at least 80 patients per group. The study was approved by the local Medical Ethics Committee.

RESULTS

In 88 patients after elective surgery, the median plasma glutamine level at admission was significantly higher compared with that in 90 non-elective patients (0.43 mmol/l [0.33-0.55 mmol/l] versus 0.25 mmol/l [0.09-0.37 mmol/l], P = 0.001). During the ICU stay, plasma glutamine levels remained significantly higher in elective patients than in non-elective patients. There was a significant correlation between the APACHE IV score and glutamine levels (R = 0.52, P < 0.001). Moreover, backward linear regression analysis showed that this correlation was independently associated with the APACHE IV score and the presence of infection, but not with the type of admission.

CONCLUSIONS

Plasma glutamine levels are significantly lower after non-elective admission compared with elective admission to the ICU. A considerable amount of elective and non-elective patients have decreased plasma glutamine levels, but this is not independently associated with the type of admission. In contrast to previous studies, we found that plasma glutamine levels were determined by the severity of illness and the presence of an infection.

TRIAL REGISTRATION

ClinicalTrials.gov, number NCT02310035.

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 management in critically ill trauma patients is challenging

Background

The physiological stress following major trauma in critical illness leads to rapid malnutrition and provision of optimal nutritional support in these circumstances can be challenging.

Case report

We present a complex trauma case where relatively aggressive nutritional support failed to minimise weight loss.

Conclusion

Nutritional support plays an integral role in the care of critically ill major trauma patients and needs to be continuously monitored in the subacute and rehabilitation phase.

Ventilator-derived carbon dioxide production to assess energy expenditure in critically ill patients: proof of concept

Introduction

Measurement of energy expenditure (EE) is recommended to guide nutrition in critically ill patients. Availability of a gold standard indirect calorimetry is limited, and continuous measurement is unfeasible. Equations used to predict EE are inaccurate. The purpose of this study was to provide proof of concept that EE can be accurately assessed on the basis of ventilator-derived carbon dioxide production (VCO₂) and to determine whether this method is more accurate than frequently used predictive equations.

Methods

In 84 mechanically ventilated critically ill patients, we performed 24-h indirect calorimetry to obtain a gold standard EE. Simultaneously, we collected 24-h ventilator-derived VCO₂, extracted the respiratory quotient of the administered nutrition, and calculated EE with a rewritten Weir formula. Bias, precision, and accuracy and inaccuracy rates were determined and compared with four predictive equations: the Harris–Benedict, Faisy, and Penn State University equations and the European Society for Clinical Nutrition and Metabolism (ESPEN) guideline equation of 25 kcal/kg/day.

Results

Mean 24-h indirect calorimetry EE was 1823 ± 408 kcal. EE from ventilator-derived VCO₂ was accurate (bias +141 ± 153 kcal/24 h; 7.7 % of gold standard) and more precise than the predictive equations (limits of agreement −166 to +447 kcal/24 h). The 10 % and 15 % accuracy rates were 61 % and 76 %, respectively, which were significantly higher than those of the Harris–Benedict, Faisy, and ESPEN guideline equations. Large errors of more than 30 % inaccuracy did not occur with EE derived from ventilator-derived VCO₂. This 30 % inaccuracy rate was significantly lower than that of the predictive equations.

Conclusions

In critically ill mechanically ventilated patients, assessment of EE based on ventilator-derived VCO₂ is accurate and more precise than frequently used predictive equations. It allows for continuous monitoring and is the best alternative to indirect calorimetry.

Malnutrition in the ICU patient population

Malnutrition has been identified as a cause for disease as well as a condition resulting from inflammation associated with acute or chronic disease. Malnutrition is common in acute-care settings, occurring in 30% to 50% of hospitalized patients. Inflammation has been associated with malnutrition and malnutrition has been associated with compromised immune status, infection, and increased intensive care unit (ICU) and hospital length of stay. The ICU nurse is in the best position to advocate for appropriate nutritional therapies and facilitate the safe delivery of nutrition.

[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.

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.

Current status of parenteral nutrition and enteral nutrition application: an assessment of nutritional prescriptions from 59 hospitals in the People's Republic of China

Purpose

The aim of the study reported here was to assess the use of parenteral nutrition (PN) and enteral nutrition (EN), and the prevalence of PN and EN formulas, in the People’s Republic of China.

Methods

Fifty-nine hospitals in the People’s Republic of China participated in a nutrition survey. The resulting information on nutritional support was analyzed.

Results

We received 379,584 nutritional-support prescriptions over 40 days in 2013. PN provided approximately 63.2% and EN provided approximately 36.8% of nitrogen intake. PN provided 63.5% and EN provided 36.5% of lipid intake. There were obvious differences in nitrogen and lipid intake between PN and EN in different regions, departments, and diseases. The percentage of nourishment provided by PN in different regions was highest in Chengdu, followed by the Beijing, Guangzhou, and Hangzhou areas. The percentage of nourishment provided by PN in different departments was highest in general surgery, followed by gastroenterology and the intensive care unit. The percentage of nourishment provided by PN in different diseases/conditions was highest in acute pancreatitis, followed by cancer, and burns. The main source of nitrogen in PN was balanced amino-acid preparations, and in EN, it was protein. The main source of lipids in PN was long- and medium-chain triglyceride lipid emulsion injection.

Conclusion

Despite recent improvements in the application of nutritional support in the People’s Republic of China, a much higher percentage of nitrogen and lipids is delivered through PN than through EN. Furthermore, there are marked regional, departmental, and disease-based differences in the selection of PN versus EN. The rationale for use of nutritional support needs to be improved.

Prevalence of Underprescription or Overprescription of Energy Needs in Critically Ill Mechanically Ventilated Adults as Determined by Indirect Calorimetry: A Systematic Literature Review

BACKGROUND

Underfeeding and overfeeding has been associated with adverse patient outcomes. Resting energy expenditure can be measured using indirect calorimetry. In its absence, predictive equations are used. A systematic literature review was conducted to determine the prevalence of underprescription and overprescription of energy needs in adult mechanically ventilated critically ill patients by comparing predictive equations to indirect calorimetry measurements.

METHODS

Ovid MEDLINE, CINAHL Plus, Scopus, and EMBASE databases were searched in May 2013 to identify studies that used both predictive equations and indirect calorimetry to determine energy expenditure. Reference lists of included publications were also searched. The number of predictive equations that underestimated or overestimated energy expenditure by ±10% when compared to indirect calorimetry measurements were noted at both an individual and group level.

RESULTS

In total, 2349 publications were retrieved, with 18 studies included. Of the 160 variations of 13 predictive equations reviewed at a group level, 38% underestimated and 12% overestimated energy expenditure by more than 10%. The remaining 50% of equations estimated energy expenditure to within ±10 of indirect calorimetry measurements. On an individual patient level, predictive equations underestimated and overestimated energy expenditure in 13-90% and 0-88% of patients, respectively. Differences of up to 43% below and 66% above indirect calorimetry values were observed.

CONCLUSIONS

Large discrepancies exist between predictive equation estimates and indirect calorimetry measurements in individuals and groups. Further research is needed to determine the influence of indirect calorimetry and predictive equation limitations in contributing to these observed differences.

Methicillin-resistant Staphylococcus aureus bloodstream infections are associated with a higher energy deficit than other ICU-acquired bacteremia

PURPOSE

Caloric insufficiency during the first week of intensive care unit (ICU) stay was reported to be associated with increased infection rates, especially ICU-acquired bloodstream infection (ICU-BSI). However, the predisposition to ICU-BSI by a given pathogen remains not well known. We aimed to determine the impact of early energy-calorie deficit on the pathogens responsible for ICU-BSI.

DESIGN

Prospective, observational, cohort study in a 18-bed medical ICU of a tertiary care hospital.

METHODS

Daily energy balance (energy-calorie intakes minus calculated energy-calorie expenditure) was compared according to the microbiological results of the blood cultures of 92 consecutive prolonged (at least 96 h) acute mechanically ventilated patients who developed a first episode of ICU-BSI.

RESULTS

Among the 92 ICU-BSI, nine were due to methicillin-resistant Staphylococcus aureus (MRSA). The cumulated energy deficit of patients with MRSA ICU-BSI was greater than those with ICU-BSI caused by other pathogens (-1,348 ± 260 vs -1,000 ± 401 kcal/day from ICU admission to day of ICU-BSI, p = 0.008). ICU admission, risk factors for nosocomial infections, nutritional status, and conditions potentially limiting feeding did not differ significantly between the two groups. Patients with MRSA ICU-BSI had lower delivered energy and similar energy expenditure, causing higher energy deficits. More severe energy deficit and higher rate of MRSA blood cultures (p = 0.01 comparing quartiles) were observed.

CONCLUSIONS

Early in-ICU energy deficit was associated with MRSA ICU-BSI in prolonged acute mechanically ventilated patients. Results suggest that limiting the early energy deficit could be a way to optimize MRSA ICU-BSI prevention.

When more is better

Nutrition support of critically ill patients with sepsis is one of the most debated issues among intensivists. The latest international sepsis guidelines recommend the prescription of a low volume of feeds through gastric or intestinal enteral nutrition (EN) for 7 days after admission to the ICU. The data to support such recommendations are scarce, and large trials are needed to clarify this issue. As reported in the previous issue of Critical Care, Elke and colleagues have revisited a database containing 13,630 ICU patients, of whom 2,270 met four inclusion criteria: sepsis or pneumonia, ICU stay of at least 3 days, mechanical ventilation within 48 hours after ICU admission, and exclusive EN. The goal of the authors was to assess the impact of various levels of energy and protein administration on mortality at 60 days after ICU admission and on the duration of mechanical ventilation. They found that standard levels of energy and protein recommended by international guidelines for patients in the ICU do also apply to patients with sepsis in the ICU. This is an important finding, which contradicts the current recommendations and beliefs for this subgroup of patients in the ICU and gives a strong rationale for launching a large prospective randomized trial.

Determining energy requirements in the ICU

PURPOSE OF REVIEW

Resting energy expenditure in critically ill patients is highly variable depending on the diagnoses, illness severity, nutritional status, and treatments. The main questions are the following: What is the optimal energy target in my critically ill patient in the ICU at a given time point of the ICU stay? Is measured energy expenditure equivalent with energy requirement?

RECENT FINDINGS

There is uncertainty on the best way to feed the ICU patient; when to start, and what to give, especially concerning the amount of energy. Recent studies indicate that outcome is dependent on provision, components, and route. Indirect calorimetry is considered the gold standard to measure energy requirement and cannot be replaced by assumptions based on weight, height, sex, age, or minute ventilation. A main concern is that an indirect calorimeter with appropriate specifications to a reasonable cost is not available in the market. There are initiatives to solve this matter.

SUMMARY

Nutritionists, intensive care doctors, researchers, and innovators must collaborate to develop an indirect calorimeter to a reasonable cost (less than 10,000 €) that is accurate and handy in the clinical setting. Since this instrument is not yet available, clinicians are left with good clinical practice and predictive formulas.

Gender-specific differences in energy metabolism during the initial phase of critical illness

BACKGROUND/OBJECTIVES

Women and men differ in substrate and energy metabolism. Such differences may affect energy requirements during the acute phase of critical illness.

SUBJECTS/METHODS

Data of 155 critically ill medical patients were reviewed for this study. Indirect calorimetry in each patient was performed within the first 72 h following admission to the medical intensive care unit after an overnight fast.

RESULTS

In overweight (body mass index (BMI) ≥25 kg/m(2)) but not in normal-weight patients, resting energy expenditure (REE) adjusted for body weight (REEaBW) differed significantly between women and men (17.2 (interquartile range (IQR) 15.2-20.7) vs 20.9 (IQR 17.9-23.4) kcal/kg/day, P<0.01). Similarly, REE adjusted for ideal body weight (REEaIBW) was significantly lower in women compared with men (25.5 (IQR 22.6-28.1) vs 28.0 (IQR 25.2-30.0) kcal/kg/day, P<0.05). In overweight patients, gender was identified as an independent predictor of REEaBW in the multivariate regression model (r=-2.57 (95% CI -4.57 to -0.57); P<0.05), even after adjustment for age, simplified acute physiology score (SAPS II), body temperature, body weight and height.

CONCLUSIONS

REEaBW decreases with increasing body mass in both sexes. This relationship differs between women and men. Overweight critically ill women show significantly lower REEaBW and REEaIBW, respectively, compared with men. These findings could affect the current practice of nutritional support during the early phase of critical illness.

Nutritional evaluation and management of AKI patients

Protein-energy wasting is common in patients with acute kidney injury (AKI) and represents a major negative prognostic factor. Nutritional support as parenteral and/or enteral nutrition is frequently needed because the early phases of this are often a highly catabolic state, although the optimal nutritional requirements and nutrient intake composition remain a partially unresolved issue. Nutrient needs of patients with AKI are highly heterogeneous, depending on different pathogenetic mechanisms, catabolic rate, acute and chronic comorbidities, and renal replacement therapy (RRT) modalities. Thus, quantitative and qualitative aspects of nutrient intake should be frequently evaluated in this clinical setting to achieve better individualization of nutritional support, to integrate nutritional support with RRT, and to avoid under- and overfeeding. Moreover, AKI is now considered a kidney-centered inflammatory syndrome; indeed, recent experimental data indicate that specific nutrients with anti-inflammatory effects could play an important role in the prevention of renal function loss after an episode of AKI.

Specialized nutritional support interventions in critically ill patients on renal replacement therapy

PURPOSE OF REVIEW

Optimal nutritional requirements and nutrient intake composition for patients with acute kidney injury remain a partially unresolved issue. Targeting nutritional support to the actual protein and energy needs improves the clinical outcome of critically ill patients, yet very few data are currently available on this topic in acute kidney injury. In this specific clinical condition the risk for underfeeding and overfeeding may be increased by factors interfering on nutrient need estimation, such as rapidly changing body weight due to fluid balance variations, nutrient losses and hidden calorie sources from renal replacement therapy. Moreover, as acute kidney injury is now considered a kidney-centered inflammatory syndrome, the renoprotective role of specific pharmaconutrients with anti-inflammatory properties remains to be fully defined. This review is aimed at discussing recently published results concerning quantitative and qualitative aspects of the nutritional approach to acute kidney injury in critically ill patients.

RECENT FINDINGS

Nutrient needs in patients with acute kidney injury can be difficult to estimate, and should be directly measured, especially in the ICU setting. In fact, recent findings suggest that hidden calorie sources not routinely taken into account - for example, calories from anticoagulants and replacement solutions for renal replacement therapy - could be quantitatively relevant in these patients. Moreover, recent experimental data indicate a possible role for some pharmaconutrients with anti-inflammatory effects (glutamine, and omega-3 fatty acids), in both the prevention of renal function worsening, and in the fostering of renal function recovery after an episode of acute kidney injury.

SUMMARY

Acute kidney injury includes a highly heterogeneous group of patients with widely varying nutrient needs and intakes. Nutritional requirements, in their quantitative and qualitative aspects, should be frequently assessed, individualized, and carefully integrated with renal replacement therapy, in order to avoid both underfeeding and overfeeding, as well as to exploit possible positive pharmacologic effects of specific nutrients.