Metabolic and nutritional support of critically ill patients: consensus and controversies

Volume-Based vs Rate-Based Enteral Nutrition in the Intensive Care Unit: Impact on Nutrition Delivery and Glycemic Control

BACKGROUND

Underfeeding with enteral nutrition (EN) is prevalent in intensive care units (ICUs) and associated with negative outcomes. This study evaluated the impact of volume-based EN (VBEN) vs rate-based EN (RBEN) on delivery of prescribed energy and protein, and glycemic control (GC).

METHODS

This retrospective study included adult patients who require mechanical ventilation within 48 hours of ICU admission and with an RBEN (n = 85) or VBEN (n = 86) order for ≥3 consecutive days during the first 12 ICU days.

RESULTS

Patients receiving VBEN, vs RBEN, received more prescribed energy (RBEN, 67.6%; VBEN, 79.6%; P < .001) and protein (RBEN, 68.6%; VBEN, 79.3%; P < .001). Multiple linear regression analyses confirmed VBEN was significantly associated with an 8.9% increase in energy (P = .002) and 7.7% increase in protein (P = .004) received, after adjusting for age, Acute Physiology and Chronic Health Evaluation II score, duration of and initiation day for EN, and ICU admission location. Presence of hyperglycemia (P = .40) and glycemic variability (GV) (P = .99) were not different between the 2 groups. After adjusting for age, body mass index, diabetes history, primary diagnosis, and percent of days receiving corticosteroids, GC outcomes (presence of hyperglycemia, P = .27; GV, P = .67) remained unrelated to EN order type in multivariable regression models.

CONCLUSION

VBEN, compared with RBEN, was associated with increased energy and protein delivery without adversely affecting GC. These results suggest VBEN is an effective, safe strategy to enhance EN delivery in the ICU.

Multiple Micronutrient Plasma Level Changes Are Related to Oxidative Stress Intensity in Critically Ill Children

OBJECTIVES

Micronutrient supplementation in critically ill adults remains controversial. In the pediatric setting, the impact of oxidative stress on the overall micronutrient status has been poorly explored, due to the limited number of studies and to confounding factors (i.e., malnutrition or extra losses). In order to better understand this phenomenon, we aim to describe micronutrient status, focusing on seven micronutrients, in well-nourished critically ill children presenting with severe oxidative stress.

DESIGN

Prospective, transversal, observational, single-center study.

SETTING

PICU, and anesthesiology department, Lyon, France.

PATIENTS

Three groups of patients were clinically defined: severe oxidative stress PICU group (at least two organ dysfunctions), moderate oxidative stress PICU group (single organ dysfunction), and healthy control group (prior to elective surgery); oxidative stress intensity was controlled by measuring plasma levels of glutathione peroxidase and glutathione. Children presenting any former condition leading to micronutrient deficiency were excluded (malnutrition, external losses).

INTERVENTIONS

Plasma levels of selenium, zinc, copper, vitamin A, vitamin E, vitamin C, and β-carotene were measured in PICU oxidative stress conditions and compared with those of healthy children.

MEASUREMENTS AND MAIN RESULTS

Two hundred one patients were enrolled (51, 48, and 102 in severe, moderate, and healthy control groups, respectively). Median age was 7.1 years (interquartile range, 2.1-13.8 yr). There was a significant trend (p < 0.02) toward plasma level decrease of six micronutrients (selenium, zinc, copper, vitamin E, vitamin C, and β-carotene) while oxidative stress intensity increased. Biological markers of oxidative stress (glutathione peroxidase and glutathione) were in accordance with the clinical definition of the three groups.

CONCLUSIONS

A multiple micronutrient deficiency or redistribution occurs in critically ill children presenting with severe oxidative stress. These findings will help to better identify children who might benefit from micronutrient supplementation and to design adapted supplementation trials in this particular setting.

Feasibility of Exercise Testing in Patients Who Are Critically Ill: A Prospective, Observational Multicenter Study

OBJECTIVE

To evaluate the feasibility and safety of exercise testing and to describe the physiological response to exercise of patients in the Intensive Care Unit (ICU).

DESIGN

A prospective observational multicenter study.

SETTING

Two mixed medical-surgical ICUs.

PARTICIPANTS

Patients (N=37; with no primary neurological disorders, 59% men; median age 50y; ICU length of stay 14.5d; Acute Physiology and Chronic Health Evaluation IV 73.0) who had been mechanically ventilated for more than 48 hours and were hemodynamically stable enough to perform physical exercise.

INTERVENTIONS

A passive or active incremental exercise test, depending on muscle strength, on a bed-based cycle ergometer.

MAIN OUTCOME MEASURES

Feasibility and safety were evaluated based on protocol adherence and adverse events. Physiological responses to exercise quantified as changes in respiratory frequency (RF), oxygen uptake (Vo₂), carbon dioxide output (Vco₂), respiratory exchange ratio (RER), and blood lactate.

RESULTS

Thirty-seven patients of whom 18 were mechanically ventilated underwent the exercise test. The active incremental test was performed by 28, and the passive test by 9 participants. Thirty-three (89%) accomplished the test according to the protocol and 1 moderate severe adverse event (bradycardia; heart rate 44) occurred shortly after the test. RF, Vo₂, Vco₂, and lactate increased significantly, whereas RER did not change during the active incremental exercise test. No changes were observed during the passive exercise test.

CONCLUSIONS

It is safe and feasible to perform exercise testing on a bed-based cycle ergometer in patients who are critically ill and a physiological response could be measured. Future research should investigate the clinical value of exercise testing in daily ICU practice and whether exercise capacity and its limiting factors could be determined by incremental exercise testing.

Novel Metabolomic Comparison of Arterial and Jugular Venous Blood in Severe Adult Traumatic Brain Injury Patients and the Impact of Pentobarbital Infusion

Treatment of severe traumatic brain injury (TBI) in the intensive care unit focuses on controlling intracranial pressure, ensuring sufficient cerebral perfusion, and monitoring for secondary injuries. However, there are limited prognostic tools and no biomarkers or tests of the evolving neuropathology. Metabolomics has the potential to be a powerful tool to indirectly monitor evolving dysfunctional metabolism. We compared metabolite levels in simultaneously collected arterial and jugular venous samples in acute TBI patients undergoing intensive care as well as in healthy control volunteers. Our results show that, first, many circulating metabolites are decreased in TBI patients compared with healthy controls days after injury; both proline and hydroxyproline were depleted by ≥60% compared with healthy controls, as was gluconate. Second, both arterial and jugular venous plasma metabolomic analysis separates TBI patients from healthy controls and shows that distinct combinations of metabolites are driving the group separation in the two blood types. Third, TBI patients under heavy sedation with pentobarbital at the time of blood collection were discernibly different from patients not receiving pentobarbital. These results highlight the importance of accounting for medications in metabolomics analysis. Jugular venous plasma metabolomics shows potential as a minimally invasive tool to identify and study dysfunctional cerebral metabolism after TBI.

Intensive Care Nutrition and Post-Intensive Care Recovery

Intensive care unit (ICU)-acquired weakness frequently complicates critical illness, which prolongs intensive care dependency and causes long-term burden. Observational studies have suggested that prolonged underfeeding could aggravate ICU-acquired weakness and impair outcome. However, recent large randomized controlled trials have failed to show a benefit of early enhanced nutrition to critically ill patients. Moreover, early parenteral nutrition was even shown to increase ICU-acquired weakness and prolong organ failure and intensive care dependency, which may be explained by feeding-induced suppression of autophagy. Currently, the ideal timing of artificial nutrition for critically ill patients as well as the optimal dose and composition remain unclear.

Refeeding syndrome in the frail elderly population: prevention, diagnosis and management

Aging is linked to physiological and pathophysiological changes. In this context, elderly patients often are frail, which strongly correlates with negative health outcomes and disability. Elderly patients are often malnourished, which again is an independent risk factor for both frailty and adverse clinical outcomes. Malnutrition and resulting frailty can be prevented by adequate nutritional interventions. Yet, use of nutritional therapy can also have negative consequences, including a potentially life-threatening metabolic alteration called refeeding syndrome (RFS) in high-risk patients. RFS is characterized by severe electrolyte shifts (mainly hypophosphatemia, hypomagnesemia and hypokalemia), vitamin deficiency (mainly thiamine), fluid overload and salt retention leading to organ dysfunction and cardiac arrhythmias. Although the awareness of malnutrition among elderly people is well established, the risk of RFS is often neglected, especially in the frail elderly population. This partly relates to the unspecific clinical presentation and laboratory changes in the geriatric population. The aim of this review is to summarize recently published recommendations for the management of RFS based on current evidence from clinical studies adapted with a focus on elderly patients.

Is continuing medical education sufficient? Assessing the clinical nutrition knowledge of medical doctors

OBJECTIVES

Provision of nutritional support (NS) can improve disease outcome and shorten hospital length of stay. NS, often prescribed by medical doctors, requires adequate clinical nutrition (CN) expertise. The aim of this study was to investigate self-perceived and actual CN knowledge among medical doctors in Greece.

METHODS

Internal medicine physicians and surgical specialties (residents and specialized) were asked to self-evaluate their CN expertise, via a seven-item questionnaire and to complete a 20-question multiple-choice test on CN topics, with the aim of evaluating their actual CN knowledge. Participants were discouraged from accessing literature/information during the completion of either questionnaire.

RESULTS

Of 182 invited medical doctors, 115 (50.4% surgical specialties) participated in the study (63.2% response rate). The majority of participants (65.2%) demonstrated inadequate CN knowledge, with 30.4% of those scoring low having a high self-perception of their CN expertise. Comparison of perceived and actual CN knowledge revealed that only 56.5% of the participants estimated their knowledge correctly. Those who had participated in CN continuous medical education courses demonstrated increased related expertise (P = 0.002).

CONCLUSIONS

Medical doctors in Greece demonstrate low knowledge of fundamental CN principles, jeopardizing the provision of high-quality and efficient NS. Most importantly, the majority of participants overestimated their CN knowledge and prescribe artificial nutrition or participate in related decision making. Physicians' CN knowledge should be enhanced accordingly, either by attending CN modules during their studies, by participating in basic and advanced courses or CN-specific continuous medical education, or both.

Measuring gastric residual volumes in critically ill burn patients - A systematic review

PURPOSE

Measuring gastric residual volumes (GRV) is common in intensive care units (ICU) in patients receiving enteral nutrition (EN) and are a common source of feeding interruptions. Interruptions in EN yield adverse outcomes and are an area of improvement in burn care. The objectives of this study are to summarize the literature's ICU GRV practices and offer practical suggestions to GRV management in the burn patient.

METHODS

PubMed, SCOPUS, and OvidSP Medline were systematically reviewed using the keywords: burns; thermal injury; gastric residual volume; enteral feeding; tube feeding; enteral nutrition; gastric intolerance; ICU; critical illness. Reviews, case reports, and consensus and opinion papers were excluded.

RESULTS

26 articles were identified. Six burn-specific studies were identified. GRV practices vary widely and are a common cause of EN interruption. Elevated GRVs do not equate to gastrointestinal intolerance and do not always reflect aspiration risk.

CONCLUSIONS

We advocate a GRV threshold of 500mL should be used to optimize the benefits of EN in burn ICUs. A single incident of elevated GRVs should not mandate immediate EN rate reduction or cessation but should prompt a thoughtful examination of secondary causes of gastrointestinal intolerance. Randomized controlled trials are needed to define the ideal GRV threshold and re-evaluate its role in burn care.

Nutritional practices and adequacy in children supported on extracorporeal membrane oxygenation

BACKGROUND AND AIMS

Use of extracorporeal membrane oxygenation (ECMO) in children is increasing. Yet, little is known about optimal nutritional practices in these children. We aim to describe the nutritional adequacy, factors associated with enteral nutrition, and the association between nutritional adequacy and mortality in children supported on ECMO.

METHODS

We conducted a retrospective review of all children (1 month-18 years) requiring ECMO between 2010 and 2016. Data on enteral and parenteral energy and protein intake in the first 7 days of ECMO were collected. Adequacy of nutrition intake was defined as total intake vs. total requirements, expressed as a percentage.

RESULTS

51 patients were included, of which 43 (84.3%) were supported on veno-arterial ECMO. Median ECMO duration was 8.6 days [interquartile range (IQR) 6.1-16.2]. Overall energy and protein adequacy across the first 7 days of ECMO were 48.3% (IQR 28.0-67.4) and 44.8% (IQR 26.9-67.0) respectively. Parenteral nutrition provided majority of calories [median 88.0% (IQR 62.9-100)] and protein [median 91.0% (IQR 62.3-100)] intake. Enteral nutrition (EN) was initiated in 33 (64.7%) patients. Time to EN initiation, vasoactive-inotropic score just before ECMO initiation, veno-arterial ECMO mode and continuous renal replacement therapy in the first week of ECMO were factors associated with EN energy adequacy. Hospital mortality rate was 55% (28/51). Compared to survivors, non-survivors had lower adequacy of EN energy intake [0.5% (IQR 0-4.4) vs. 11.8% (IQR 0-24.5), p = 0.034]. After correcting for ECMO duration, need for continuous renal replacement therapy and number of vasoactive drugs required on ECMO, greater EN energy adequacy remained associated with lower risk of mortality [adjusted odds ratio 0.93 (95% confidence interval: 0.86-0.99), p = 0.048].

CONCLUSIONS

Nutritional adequacy, especially that of EN, remains low in children supported on ECMO. EN energy adequacy was found to be associated with lower mortality. Further studies on nutritional adequacy in pediatric ECMO, as well as strategies to optimize EN in these children, are warranted.

A retrospective evaluation of nutrition support in relation to clinical outcomes in critically ill patients with an open abdomen

BACKGROUND

Optimising nutrition support in critically ill patients with an open abdomen is challenging.

OBJECTIVES

The aims of this study were to (i) quantify the amount and adequacy of nutrition support administered and (ii) determine any relationships that exist between mode of nutrition support delivery and clinical outcomes in critically ill patients with an open abdomen.

METHODS

A retrospective review of critically ill patients mechanically ventilated for at least 48 h with an open abdomen in a mixed quaternary referral intensive care unit. Enteral and parenteral nutrition (ml) administered daily to patients was recorded for up to 21 days. Length of stay in the intensive care unit and hospital and duration of mechanical ventilation (days) were reported.

RESULTS

Thirty patients were studied [14 male, 68 y (15-90 y), body mass index 25 kg/m² (11-51 kg/m²), Acute Physiology and Chronic Health Evaluation II score 20 (7-41), energy goal 1860 kcal/d (1250-2712 kcal/d)]. Patients received 55% (0-117%) of energy goal and 56% (0-105%) protein goal from either enteral or parenteral nutrition. When enteral nutrition was delivered alone or in combination with parenteral nutrition, patients received 48% (0-146%) of their energy and 59% (19-105%) of their protein goal. Patients fed parenteral nutrition, either alone or as supplementary to enteral nutrition (n = 18), received more energy when compared with those who only received enteral nutrition (n = 9) [65 (27-117) vs 49 (15-89) % energy goal, P = 0.025]. Parenteral nutrition was associated with an increased length of stay in hospital [63 (45-156) vs 45 (17-93) d, P = 0.037].

CONCLUSION

Patients with an open abdomen receive about half of their nutrition requirements when fed exclusively via the enteral route. Providing combination enteral and parenteral nutrition to reach nutritional goals may not result in better clinical outcomes for patients with an open abdomen.

Enteral versus parenteral nutrition and enteral versus a combination of enteral and parenteral nutrition for adults in the intensive care unit

BACKGROUND

Critically ill people are at increased risk of malnutrition. Acute and chronic illness, trauma and inflammation induce stress-related catabolism, and drug-induced adverse effects may reduce appetite or increase nausea and vomiting. In addition, patient management in the intensive care unit (ICU) may also interrupt feeding routines. Methods to deliver nutritional requirements include provision of enteral nutrition (EN), or parenteral nutrition (PN), or a combination of both (EN and PN). However, each method is problematic. This review aimed to determine the route of delivery that optimizes uptake of nutrition.

OBJECTIVES

To compare the effects of enteral versus parenteral methods of nutrition, and the effects of enteral versus a combination of enteral and parenteral methods of nutrition, among critically ill adults, in terms of mortality, number of ICU-free days up to day 28, and adverse events.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase on 3 October 2017. We searched clinical trials registries and grey literature, and handsearched reference lists of included studies and related reviews.

SELECTION CRITERIA

We included randomized controlled studies (RCTs) and quasi-randomized studies comparing EN given to adults in the ICU versus PN or versus EN and PN. We included participants that were trauma, emergency, and postsurgical patients in the ICU.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, extracted data, and assessed risk of bias. We assessed the certainty of evidence with GRADE.

MAIN RESULTS

We included 25 studies with 8816 participants; 23 studies were RCTs and two were quasi-randomized studies. All included participants were critically ill in the ICU with a wide range of diagnoses; mechanical ventilation status between study participants varied. We identified 11 studies awaiting classification for which we were unable to assess eligibility, and two ongoing studies.Seventeen studies compared EN versus PN, six compared EN versus EN and PN, two were multi-arm studies comparing EN versus PN versus EN and PN. Most studies reported randomization and allocation concealment inadequately. Most studies reported no methods to blind personnel or outcome assessors to nutrition groups; one study used adequate methods to reduce risk of performance bias.Enteral nutrition versus parenteral nutritionWe found that one feeding route rather than the other (EN or PN) may make little or no difference to mortality in hospital (risk ratio (RR) 1.19, 95% confidence interval (CI) 0.80 to 1.77; 361 participants; 6 studies; low-certainty evidence), or mortality within 30 days (RR 1.02, 95% CI 0.92 to 1.13; 3148 participants; 11 studies; low-certainty evidence). It is uncertain whether one feeding route rather than the other reduces mortality within 90 days because the certainty of the evidence is very low (RR 1.06, 95% CI 0.95 to 1.17; 2461 participants; 3 studies). One study reported mortality at one to four months and we did not combine this in the analysis; we reported this data as mortality within 180 days and it is uncertain whether EN or PN affects the number of deaths within 180 days because the certainty of the evidence is very low (RR 0.33, 95% CI 0.04 to 2.97; 46 participants).No studies reported number of ICU-free days up to day 28, and one study reported number of ventilator-free days up to day 28 and it is uncertain whether one feeding route rather than the other reduces the number of ventilator-free days up to day 28 because the certainty of the evidence is very low (mean difference, inverse variance, 0.00, 95% CI -0.97 to 0.97; 2388 participants).We combined data for adverse events reported by more than one study. It is uncertain whether EN or PN affects aspiration because the certainty of the evidence is very low (RR 1.53, 95% CI 0.46 to 5.03; 2437 participants; 2 studies), and we found that one feeding route rather than the other may make little or no difference to pneumonia (RR 1.10, 95% CI 0.82 to 1.48; 415 participants; 7 studies; low-certainty evidence). We found that EN may reduce sepsis (RR 0.59, 95% CI 0.37 to 0.95; 361 participants; 7 studies; low-certainty evidence), and it is uncertain whether PN reduces vomiting because the certainty of the evidence is very low (RR 3.42, 95% CI 1.15 to 10.16; 2525 participants; 3 studies).Enteral nutrition versus enteral nutrition and parenteral nutritionWe found that one feeding regimen rather than another (EN or combined EN or PN) may make little or no difference to mortality in hospital (RR 0.99, 95% CI 0.84 to 1.16; 5111 participants; 5 studies; low-certainty evidence), and at 90 days (RR 1.00, 95% CI 0.86 to 1.18; 4760 participants; 2 studies; low-certainty evidence). It is uncertain whether combined EN and PN leads to fewer deaths at 30 days because the certainty of the evidence is very low (RR 1.64, 95% CI 1.06 to 2.54; 409 participants; 3 studies). It is uncertain whether one feeding regimen rather than another reduces mortality within 180 days because the certainty of the evidence is very low (RR 1.00, 95% CI 0.65 to 1.55; 120 participants; 1 study).No studies reported number of ICU-free days or ventilator-free days up to day 28. It is uncertain whether either feeding method reduces pneumonia because the certainty of the evidence is very low (RR 1.40, 95% CI 0.91 to 2.15; 205 participants; 2 studies). No studies reported aspiration, sepsis, or vomiting.

AUTHORS' CONCLUSIONS

We found insufficient evidence to determine whether EN is better or worse than PN, or than combined EN and PN for mortality in hospital, at 90 days and at 180 days, and on the number of ventilator-free days and adverse events. We found fewer deaths at 30 days when studies gave combined EN and PN, and reduced sepsis for EN rather than PN. We found no studies that reported number of ICU-free days up to day 28. Certainty of the evidence for all outcomes is either low or very low. The 11 studies awaiting classification may alter the conclusions of the review once assessed.

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.

Prognostic factors for generalized tetanus in adults: A retrospective study in a Chinese hospital

BACKGROUND

We evaluated factors associated with mortality in patients with moderate/severe generalized tetanus.

METHODS

This retrospective study included patients with moderate/severe generalized tetanus admitted to the Affiliated Hospital of Nantong University (China) between January 2005 and January 2017. Clinical data were extracted from medical records. Patients were divided into two groups based on outcome (survival or death). Factors associated with mortality were analyzed using univariate and multivariate logistic regression.

RESULTS

Seventy-five patients were included (57.3% male; age, 57.9 ± 18.4 years; APACHE II score, 10.6 ± 3.4; severe tetanus, 49.3%; mortality, 25.3%). Multivariate analysis identified severe tetanus (odds ratio [OR], 30.364; 95% confidence interval [CI], 2.459-374.896) and APACHE II score (OR, 1.536; 95%CI, 1.051-2.243) as positively associated with mortality, whereas high-calorie nutrition (OR, 0.027; 95%CI, 0.002-0.359) and dexmedetomidine use (OR, 0.035; 95%CI, 0.003-0.467) were negatively associated with mortality (all P < 0.05).

CONCLUSION

Tetanus severity and APACHE II score were associated with mortality in patients with generalized tetanus, whereas high-calorie nutrition and dexmedetomidine use reduced the odds of death. High-calorie nutrition and dexmedetomidine administration may improve prognosis in adult patients with moderate/severe generalized tetanus.

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.

Associations of hyperosmolar medications administered via nasogastric or nasoduodenal tubes and feeding adequacy, food intolerance and gastrointestinal complications amongst critically ill patients: A retrospective study

BACKGROUND

Adequate nutrition is essential during critical illness. However, providing adequate nutrition is often hindered by gastro-intestinal complications, including feeding intolerance. It is suggested that hyperosmolar medications could be causally involved in the development of gastro-intestinal complications. The aims of the present study were 1) to determine the osmolality of common enterally administered dissolved medications and 2) to study the associations between nasogastric and nasoduodenal administered hyperosmolar medications and nutritional adequacy as well as food intolerance and gastro-intestinal symptoms.

METHODS

This retrospective observational cohort study was performed in a medical-surgical ICU in the Netherlands. Adult critically ill patients receiving enteral nutrition and admitted for a minimum ICU duration of 7 days were eligible. The osmolalities of commonly used enterally administrated medications were measured using an osmometer. Patients were divided in two groups: Use of hyperosmolar medications (>500 mOsm/kg) on at least one day during the first week versus none. The associations between the use of hyperosmolar medications and nutritional adequacy were assessed using multiple logistic regression analysis. The associations between hyperosmolar medication and food intolerance as well as gastrointestinal symptoms were assessed using ordinal logistic regression.

RESULTS

In total 443 patients met the inclusion criteria. Of the assessed medications, only three medications were found hyperosmolar. We observed no associations between the use of hyperosmolar medications and nutritional adequacy in the first week of ICU admission (caloric intake β -0.27 95%CI -1.38; 0.83, protein intake β 0.32 95%CI -0.90; 1.53). In addition, no associations were found for enteral feeding intolerance, diarrhea, obstipation, gastric residual volume, nausea and vomiting in ICU patients receiving hyperosmolar medications via a nasogastric tube. A subgroup analysis of patients on duodenal feeding showed that postpyloric administration of hyperosmolar medications was associated with increased risk of diarrhea (OR 138.7 95%CI 2.33; 8245).

CONCLUSIONS

Our results suggest that nasogastric administration of hyperosmolar medication via a nasogastric tube does not affect nutritional adequacy, development of enteral feeding intolerance and other gastro-intestinal complications during the first week after ICU admission. During nasoduodenal administration an increased diarrhea incidence may be encountered.

Diabetes-Specific Formulae Versus Standard Formulae as Enteral Nutrition to Treat Hyperglycemia in Critically Ill Patients: Protocol for a Randomized Controlled Feasibility Trial

Background

During critical illness, hyperglycemia is prevalent and is associated with adverse outcomes. While treating hyperglycemia with insulin reduces morbidity and mortality, it increases glycemic variability and hypoglycemia risk, both of which have been associated with an increase in mortality. Therefore, other interventions which improve glycemic control, without these complications should be explored. Nutrition forms part of standard care, but the carbohydrate load of these formulations has the potential to exacerbate hyperglycemia. Specific diabetic-formulae with a lesser proportion of carbohydrate are available, and these formulae are postulated to limit glycemic excursions and reduce patients’ requirements for exogenous insulin.

Objective

The primary outcome of this prospective, blinded, single center, randomized controlled trial is to determine whether a diabetes-specific formula reduces exogenous insulin administration. Key secondary outcomes include the feasibility of study processes as well as glycemic variability.

Methods

Critically ill patients will be eligible if insulin is administered whilst receiving exclusively liquid enteral nutrition. Participants will be randomized to receive a control formula, or a diabetes-specific, low glycemic index, low in carbohydrate study formula. Additionally, a third group of patients will receive a second diabetes-specific, low glycemic index study formula, as part of a sub-study to evaluate its effect on biomarkers. This intervention group (n=12) will form part of recruitment to a nested cohort study with blood and urine samples collected at randomization and 48 hours later for the first 12 participants in each group with a secondary objective of exploring the metabolic implications of a change in nutrition formula. Data on relevant medication and infusions, nutrition provision and glucose control will be collected to a maximum of 48 hours post randomization. Baseline patient characteristics and anthropometric measures will be recorded. A 28-day phone follow-up will explore weight and appetite changes as well as blood glucose control pre and post intensive care unit (ICU) discharge.

Results

Recruitment commenced in February 2015 with an estimated completion date for data collection by May 2018. Results are expected to be available late 2018.

Conclusions

This feasibility study of the effect of diabetes-specific formulae on the administration of insulin in critically ill patients and will inform the design of a larger, multi-center trial.

Trial Registration

Australian New Zealand Clinical Trial Registry (ANZCTR):12614000166673; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?ACTRN=12614000166673 (Archived by WebCite at http://www.webcitation.org/6xs0phrVu)

Nutritional metabolomics in critical illness

PURPOSE OF REVIEW

Disruption of metabolic homeostasis is universal in the critically ill. Macronutrients and micronutrients are major environmental regulators of metabolite production through their gene regulation effects. The study of large numbers of circulating metabolites is beginning to emerge through the comprehensive profiling of the critically ill. In the critically ill, metabolomic studies consistently show that changes in fatty acids, lipids and tryptophan metabolite pathways are common and are associated with disease state and outcomes.

RECENT FINDINGS

Metabolomics is now being applied in research studies to determine the critical illness response to nutrient deficiency and delivery. Nutritional metabolomics approaches in nutrient deficiency, malnutrition and nutrient delivery have included single time point studies and dynamic studies of critically ill patients over time. Integration of metabolomics and clinical outcome data may create a more complete understanding of the control of metabolism in critical illness.

SUMMARY

The integration of metabolomic profiling with transcription and genomic data may allow for a unique window into the mechanism of how nutrient deficiency and delivery alters cellular homeostasis during critical illness and modulates the regain of cellular homeostasis during recovery. The progress and the challenges of the study of nutritional metabolomics are reviewed here.

The frequency, risk factors, and complications of gastrointestinal dysfunction during enteral nutrition in critically ill patients

BACKGROUND

Gastrointestinal (GI) motility disorders in intensive care patients remain relatively unexplored. Nowadays, the frequency, risk factors and complications of GI dysfunction during enteral nutrition (EN) become more questionable.

AIM

To evaluate the frequency, risk factors and complications of GI dysfunction during EN in the first 2 weeks of the intensive care unit (ICU) stay and to identify precautions to prevent the development of GI dysfunction and avoid complications.

METHODS

In this prospective observational study, we deliberately targeted at-risk patients. A total of 137 patients who received nasogastric tube feeding in an ICU of a tertiary hospital were enrolled.

RESULTS

The incidence of GI dysfunction that was found to be 63% which was associated mainly between MDR bacteria positivity and negative fluid balance. Diarrhea was observed in 36 patients (26%) and on 147 patient-days (incidence rate, 5.5 per 100 patient-days). The median day of diarrhea onset was 6 days after the initiation of EN. Forty patients (29%) presented with constipation (85% during the first week). Fifty patients (36%) exhibited upper digestive intolerance on 212 patient-days (incidence rate, 7.9 per 100 patient-days), after a median EN duration of 6 days (range, 2-14 days). Logistic regression analysis revealed MDR bacteria growth in the culture (OR, 1.75; 95% CI, 1.15-2.67; P=0.008) and negative fluid balance (OR, 0.57; 95% CI, 0.34-0.94; P=0.03) as the risk factors for GI dysfunction. We also showed that GI dysfunction was associated with high SOFA score, hypoalbuminemia, catecholamine use, and prolonged length of stay (LOS). GI dysfunction, on the other hand, can cause some complications including inadequate nutrition, and newly developed decubitus ulcers.

CONCLUSION

GI dysfunction should be considered a clinical predictor of inadequate nutrition and prolonged LOS. In addition, the most dramatic risk for GI dysfunction was observed in patients with MDR bacteria growth in the culture and patients in negative fluid balance. Intensivists provide appropriate nutrition for patients, as well as prompt intervention and the development of treatment strategies in the event of GI dysfunction.

Effect of hypocaloric normoprotein or trophic feeding versus target full enteral feeding on patient outcomes in critically ill adults: a systematic review

Uncertainty surrounds the optimal approach to feeding the critically ill, with increasing interest in the concept of intentional underfeeding to reduce metabolic stress while maintaining gut integrity. Conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, this systematic review evaluates clinical outcomes reported in studies comparing hypocaloric normonitrogenous or trophic feeding (collectively 'intentional underfeeding') targeted full energy feeding administered via enteral nutrition to adult critically ill patients. Electronic databases including PubMed, CINAHL, EMBASE and CENTRAL were searched up to September 2017 for trials evaluating intentional underfeeding versus targeted energy feeding interventions on clinical outcomes (mortality, length of stay, duration of ventilation, infective complications, feeding intolerance and glycaemic control) among critically ill adult patients. Bias of included studies was assessed using the Cochrane risk of bias tool. Of the 595 articles identified, seven studies (six randomised controlled trials, one non-randomised trial) met the inclusion criteria, representing 2,684 patients (hypocaloric normonitrogenous n=668; trophic n=681; full energy feeding n=1335). Across the studies, there was considerable heterogeneity in study methodology, population, feeding strategy and outcomes and their timepoints. We observed no evidence that intentional underfeeding, when compared to targeting full energy feeding, reduced mortality or duration of ventilation or length of stay. However, limited trial evidence is available on the impact of intentional underfeeding on post-discharge functional and quality of life outcomes.

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.

Low caloric and protein intake is associated with mortality in patients with acute kidney injury

BACKGROUND

Acute renal injury (AKI) interferes greatly with nutritional status, affecting the metabolism of all macronutrients and increased mortality rates in hospitalized patients. Our objective was to evaluate the association of nutritional parameters (albumin, cholesterol, caloric and protein intake and nitrogen balance (NB)) with mortality in patients with AKI.

METHODS

This is a prospective observational study that evaluated 595 consecutive patients over the age of 18 years with AKI, requiring enteral or parenteral feeding. At the time of the patient's enrollment, demographic and laboratorial data, caloric and protein supply and NB were recorded on the first day of referral to the nephrologist. All patients were followed throughout the hospital stay and mortality rate was also recorded.

RESULTS

The medium age of patients with AKI was 64 (54-75) years, 64.5% male, 62% admitted to intensive care unit (ICU), 52% on dialysis and the majority (48%) were at stage 3 by AKIN. Length of stay and hospital mortality were 18 (10-31) days and 46%, respectively. Superior age, AKI severity, lower body weight and body mass index (BMI), higher need for dialysis, ICU admission and shorter hospital stay were associated with higher mortality. At logistic regression, caloric (OR: 0.946; CI:95%: 0.901-0.994; p:0.029) and protein intake (OR: 0.947; CI:95%: 0.988-0.992; p = 0.028) and serum albumin (OR: 0.545; CI:95%: 0.401-0741; p < 0.001) were associated with hospital mortality. Cholesterol (OR: 0.995; CI:95%: 0.991-1.000; p = 0.052) was not associated with increased mortality in the adjusted analysis. Analysis of the receiver operating characteristic (ROC) curve showed that calorie intake < 12 kcal/kg (AUC: 0.745; CI:95%: 0.684-0.765; p < 0.001) and protein intake < 0.5 g/kg (AUC: 0.726; CI:95%: 0.686-0.767; p < 0.001) were predictors of hospital mortality, as well as a negative NB < -6.47 g N/day (AUC: 0.745; CI:95%: 0.704-0.786; p < 0.001).

CONCLUSIONS

In conclusion, low caloric and protein intake, negative NB and low albumin value are conditions associated with higher hospital mortality in patients with AKI.

Evaluation of implementation of fasting guidelines for enterally fed critical care patients

BACKGROUND & AIMS

Critically ill adults have increased nutrition risk. Prior to procedures patients are often fasted, leading to nutritional deficits. The use of fasting guidelines may therefore help reduce deficits from accumulating. The aim of this work was to determine the impact on nutrition support delivery following the implementation of fasting guidelines in addition to characterizing staff knowledge of the guidelines.

DESIGN

Retrospective data were collected on n = 74 patients at two different time points; prior to launch of fasting guidelines and post launch, with regards to estimated nutritional requirements, nutritional targets, volume of enteral nutrition (EN) delivered and periods of fasting. Clinical variables of interest were collected for up to 14 days. Questionnaires assessing staff knowledge/barriers to usage of the fasting guidelines were administered to ICU staff.

SETTING

3 ICUs (General, Cardiac and Neurosciences) within University Hospital Southampton NHS Foundation Trust.

PATIENTS

Mechanically ventilated adults in an ICU and receiving exclusive EN.

MEASUREMENTS AND MAIN RESULTS

Comparison was made between pre- and post-guideline implementation with statistically significant improvements in the % EN delivered (76.4 ± 11.8 vs. 84.1 ± 10.8 (p = 0.0009)) and duration of feeds withheld (41.5 ± 26.6 vs. 27.6 ± 20.8 h (p = 0.02)). There were non-significant improvements pre- and post-implementation in the % of energy and protein delivered (80.7 ± 16.4 vs. 86.5 ± 17.3 (p = 0.15 (NS)); 74 ± 18.3 vs. 79 ± 18.5 (p = 0.15 (NS))). 77% of staff were familiar with the guidelines, whilst 42% requested further education. The main barriers to guideline compliance were delays and unpredictable timing of procedures, and differing guidance from senior staff and non-ICU teams.

CONCLUSIONS

Implementation of fasting guidelines led to significant improvements in EN delivery and reduced duration of feed breaks. The use of fasting guidelines is a positive step towards increasing nutrition delivery in the ICU. Further staff education and better planning around procedures is required to promote further adherence to the fasting guidelines.

Adequacy of nutrition support during extracorporeal membrane oxygenation

BACKGROUND

The use of veno-venous extracorporeal membrane oxygenation (vv-ECMO) is increasing in adults with severe respiratory failure. Observational data suggest that there are significant challenges to providing adequate nutrition support for patients on vv-ECMO. We aimed to describe firstly the nutrition support practices in a large single-centre providing vv-ECMO to adults and secondly any association with clinical outcome.

METHODS

We conducted a retrospective review of patients receiving vv-ECMO on the Intensive Care Unit (ICU) of a large London teaching hospital. Adult patients admitted to the ICU with severe respiratory failure between December 2010 and December 2015 were included. Daily energy and protein delivery were compared with estimated targets and reasons for feeding interruptions were collected from electronic medical records. Adequate feeding was defined as 80-110% of estimated targets.

RESULTS

We analysed 203 eligible patients. Median duration of ICU stay was 21.0 (IQR, 15.0-33.0) days and vv-ECMO 10.0 (IQR, 7.0-16.0) days. Although median energy (89.8% (IQR, 80.5-96.0%)) and protein (84.7% (IQR, 74.0-96.7%)) delivery was adequate, underfeeding of either energy or protein occurred on nearly one third (28.3%) of nutrition support days. A higher admission severity of illness score was associated with inadequate protein delivery (p = 0.040). Patients with more severe organ dysfunction on the first day of vv-ECMO received inadequate energy (p = 0.026). The most common reasons for interrupted feeding were medical procedures (39.1%) followed by poor gastric motility (22.8%).

CONCLUSION

Adequate energy and protein delivery during vv-ECMO is possible but underfeeding is still common, especially in those who are more severely ill or who have more severe organ dysfunction. Patients with inadequate energy or protein delivery did not differ in ICU and 6-month survival. Prospective studies investigating optimal feeding in this patient cohort are required.

Feeding the critically ill obese patient: a systematic review protocol

REVIEW QUESTION/OBJECTIVE

The objective of this review is to identify effective enteral nutritional regimens targeting protein and calorie delivery for the critically ill obese patient on morbidity and mortality.More specifically, the review question is:In the critically ill obese patient, what is the optimal enteral protein and calorie target that improves mortality and morbidity?

BACKGROUND

The World Health Organization (WHO) defines obesity as abnormal or excessive fat accumulation that may impair health, or, empirically, as a body mass index (BMI) ≥ 30 kg/m. Twenty-eight percent of the Australian population is obese with the prevalence rising to 44% in rural areas, and there is evidence that rates of obesity are increasing. The prevalence of obese patients in intensive care largely mirrors that of the general population. There is concern, however, that this may also be rising. A recently published multi-center nutritional study of critically ill patients reported a mean BMI of 29 in their sample, suggesting that just under 50% of their intensive care population is obese. It is inevitable, therefore, that the intensivist will care for the critically ill obese patient.Managing the critically ill obese patient is challenging, not least due to the co-morbid diseases frequently associated with obesity, including diabetes mellitus, cardiovascular disease, dyslipidaemia, sleep disordered breathing and respiratory insufficiency, hepatic steatohepatitis, chronic kidney disease and hypertension. There is also evidence that metabolic processes differ in the obese patient, particularly those with underlying insulin resistance, itself a marker of the metabolic syndrome, which may predispose to futile cycling, altered fuel utilization and protein catabolism. These issues are compounded by altered drug pharmacokinetics, and the additional logistical issues associated with prophylactic, therapeutic and diagnostic interventions.It is entirely plausible that the altered metabolic processes observed in the obese intensify and compound the metabolic changes that occur during critical illness. The early phases of critical illness are characterized by an increase in energy expenditure, resulting in a catabolic state driven by the stress response. Activation of the stress response involves up-regulation of the sympathetic nervous system and the release of pituitary hormones resulting in altered cortisol metabolism and elevated levels of endogenous catecholamines. These produce a range of metabolic disturbances including stress hyperglycemia, arising from both peripheral resistance to the effects of anabolic factors (predominantly insulin) and increased hepatic gluconeogenesis. Proteolysis is accelerated, releasing amino acids that are thought to be important in supporting tissue repair, immune defense and the synthesis of acute phase reactants. There is also altered mobilization of fuel stores, futile cycling, and evidence of altered lipoprotein metabolism. In the short term this is likely to be an adaptive response, but with time and ongoing inflammation this becomes maladaptive with a concomitant risk of protein-calorie malnutrition, immunosuppression and wasting of functional muscle tissue resulting from protein catabolism, and this is further compounded by disuse atrophy. Muscle atrophy and intensive care unit (ICU) acquired weakness is complex and poorly understood, but it is postulated that the provision of calories and sufficient protein to avoid a negative nitrogen balance mitigates this process. Avoiding lean muscle mass loss in the obese intuitively has substantial implications, given the larger mass that is required to be mobilized during their rehabilitation phase.There is, in addition, evolving evidence that hormones derived from both the gut and adipose tissue are also involved in the response to stress and critical illness, and that adipose tissue in particular is not a benign tissue bed, but rather should be considered an endocrine organ. Some of these hormones are thought to be pro-inflammatory and some anti-inflammatory; however both the net result and clinical significance of these are yet to be fully elucidated.The provision of adequate nutrition has become an integral component of supportive ICU care, but is complex. There is ongoing debate within critical care literature regarding the optimal route of delivery, the target dose, and the macronutrient components (proportion of protein and non-protein calories) of nutritional support. A number of studies have associated caloric deficit with morbidity and mortality, with the resultant assumption that prescribing sufficient calories to match energy expenditure will reduce morbidity and mortality, although the evidence base underpinning this assumption is limited to observational studies and small, randomized trials.There is research available that suggests hyper-caloric feeding or hyper-alimentation, particularly of carbohydrates, may result in increased morbidity including hyperglycemia, liver steatosis, respiratory insufficiency with prolonged duration of mechanical ventilation, re-feeding syndrome and immune suppression. But the results from studies of hypo-caloric and eucaloric feeding regimens in critically ill patients are conflicting, independent of the added metabolic complexities observed in the critically ill obese patient.Notwithstanding the debate regarding the dose and components of nutritional therapy, there is consensus that nutrition should be provided, preferably via the enteral route, and preferably initiated early in the ICU admission. The enteral route is preferred for a variety of reasons, not the least of which is cost. In addition there is evidence to suggest the enteral route is associated with the maintenance of gut integrity, a reduction in bacterial translocation and infection rates, a reduction in the incidence of stress ulceration, attenuation of oxidative stress, release of incretins and other entero-hormones, and modulation of systemic immune responses. Yet there is evidence that the initiation of enteral nutritional support for the obese critically ill patient is delayed, and that when delivered is at sub-optimal levels. The reasons for this remain obscure, but may be associated with the false assumption that every obese patient has nutritional reserves due to their adipose tissues, and can therefore withstand longer periods with no, or reduced nutritional support. In fact obesity does not necessarily protect from malnutrition, particularly protein and micronutrient malnutrition. It has been suggested by some authors that the malnutrition status of critically ill patients is a stronger predictor of mortality than BMI, and that once malnutrition status is controlled for, the apparent protective effects of obesity observed in several epidemiological studies dissipate. This would be consistent with the large body of evidence that associates malnutrition (BMI < 20 kg/m) with increased mortality, and has led some authors to postulate that the weight-mortality relationship is U-shaped. This has proven difficult to demonstrate, however, due to recognized confounding influences such as chronic co-morbidities, baseline nutritional status and the nature of the presenting critical illness.This has led to interest in nutritional regimens targeting alternative calorie and protein goals to protect the obese critically ill patient from complications arising from critical illness, and particularly protein catabolism. However, of the three major nutritional organizations, the American Society of Parenteral and Enteral Nutrition (ASPEN) is the only professional organization to make specific recommendations about providing enteral nutritional support to the critically ill obese patient, recommending a regimen targeting a hypo-caloric, high-protein goal. It is thought that this regimen, in which 60-70% of caloric requirements are provided promotes steady weight loss, while providing sufficient protein to achieve a neutral, or slightly positive, nitrogen balance, mitigating lean muscle mass loss, and allowing for wound healing. Targeting weight loss is proposed to improve insulin sensitivity, improve nursing care and reduce the risk of co-morbidities, although how this occurs and whether it can occur over the relatively short time frame of an intensive care admission (days to weeks) remains unclear. Despite these recommendations observational data of international nutritional practice suggest that ICU patients are fed uniformly low levels of calories and protein across BMI groups.Supporting the critically ill obese patient will become an increasingly important skill in the intensivist's armamentarium, and enteral nutritional therapy forms a cornerstone of this support. Yet, neither the optimal total caloric goal nor the macronutrient components of a feeding regimen for the critically ill obese patient is evident. Although the suggestion that altering the macronutrient goals for this vulnerable group of patients appears to have a sound physiological basis, the level of evidence supporting this remains unclear, and there are no systematic reviews on this topic. The aim of this systematic review is to evaluate existing literature to determine the best available evidence describing a nutritional strategy that targets energy and protein delivery to reduce morbidity and mortality for the obese patient who is critically ill.

Enteral versus parenteral early nutrition in ventilated adults with shock: a randomised, controlled, multicentre, open-label, parallel-group study (NUTRIREA-2)

BACKGROUND

Whether the route of early feeding affects outcomes of patients with severe critical illnesses is controversial. We hypothesised that outcomes were better with early first-line enteral nutrition than with early first-line parenteral nutrition.

METHODS

In this randomised, controlled, multicentre, open-label, parallel-group study (NUTRIREA-2 trial) done at 44 French intensive-care units (ICUs), adults (18 years or older) receiving invasive mechanical ventilation and vasopressor support for shock were randomly assigned (1:1) to either parenteral nutrition or enteral nutrition, both targeting normocaloric goals (20-25 kcal/kg per day), within 24 h after intubation. Randomisation was stratified by centre using permutation blocks of variable sizes. Given that route of nutrition cannot be masked, blinding of the physicians and nurses was not feasible. Patients receiving parenteral nutrition could be switched to enteral nutrition after at least 72 h in the event of shock resolution (no vasopressor support for 24 consecutive hours and arterial lactate <2 mmol/L). The primary endpoint was mortality on day 28 after randomisation in the intention-to-treat-population. This study is registered with ClinicalTrials.gov, number NCT01802099.

FINDINGS

After the second interim analysis, the independent Data Safety and Monitoring Board deemed that completing patient enrolment was unlikely to significantly change the results of the trial and recommended stopping patient recruitment. Between March 22, 2013, and June 30, 2015, 2410 patients were enrolled and randomly assigned; 1202 to the enteral group and 1208 to the parenteral group. By day 28, 443 (37%) of 1202 patients in the enteral group and 422 (35%) of 1208 patients in the parenteral group had died (absolute difference estimate 2·0%; [95% CI -1·9 to 5·8]; p=0·33). Cumulative incidence of patients with ICU-acquired infections did not differ between the enteral group (173 [14%]) and the parenteral group (194 [16%]; hazard ratio [HR] 0·89 [95% CI 0·72-1·09]; p=0·25). Compared with the parenteral group, the enteral group had higher cumulative incidences of patients with vomiting (406 [34%] vs 246 [20%]; HR 1·89 [1·62-2·20]; p<0·0001), diarrhoea (432 [36%] vs 393 [33%]; 1·20 [1·05-1·37]; p=0·009), bowel ischaemia (19 [2%] vs five [<1%]; 3·84 [1·43-10·3]; p=0·007), and acute colonic pseudo-obstruction (11 [1%] vs three [<1%]; 3·7 [1·03-13·2; p=0·04).

INTERPRETATION

In critically ill adults with shock, early isocaloric enteral nutrition did not reduce mortality or the risk of secondary infections but was associated with a greater risk of digestive complications compared with early isocaloric parenteral nutrition.

FUNDING

La Roche-sur-Yon Departmental Hospital and French Ministry of Health.

Nutrition delivery of a model-based ICU glycaemic control system

BACKGROUND

Hyperglycaemia is commonplace in the adult intensive care unit (ICU), associated with increased morbidity and mortality. Effective glycaemic control (GC) can reduce morbidity and mortality, but has proven difficult. STAR is a proven, effective model-based ICU GC protocol that uniquely maintains normo-glycaemia by changing both insulin and nutrition interventions to maximise nutrition in the context of GC in the 4.4-8.0 mmol/L range. Hence, the level of nutrition it provides is a time-varying estimate of the patient-specific ability to take up glucose.

METHODS

First, the clinical provision of nutrition by STAR in Christchurch Hospital, New Zealand (N = 221 Patients) is evaluated versus other ICUs, based on the Cahill et al. survey of 158 ICUs. Second, the inter- and intra- patient variation of nutrition delivery with STAR is analysed. Nutrition rates are in terms of percentage of caloric goal achieved.

RESULTS

Mean nutrition rates clinically achieved by STAR were significantly higher than the mean and best ICU surveyed, for the first 3 days of ICU stay. There was large inter-patient variation in nutrition rates achieved per day, which reduced overtime as patient-specific metabolic state stabilised. Median intra-patient variation was 12.9%; however, the interquartile range of the mean per-patient nutrition rates achieved was 74.3-98.2%, suggesting patients do not deviate much from their mean patient-specific nutrition rate. Thus, the ability to tolerate glucose intake varies significantly between, rather than within, patients.

CONCLUSIONS

Overall, STAR's protocol-driven changes in nutrition rate provide higher nutrition rates to hyperglycaemic patients than those of 158 ICUs from 20 countries. There is significant inter-patient variability between patients to tolerate and uptake glucose, where intra-patient variability over stay is much lower. Thus, a best nutrition rate is likely patient specific for patients requiring GC. More importantly, these overall outcomes show high nutrition delivery and safe, effective GC are not exclusive and that restricting nutrition for GC does not limit overall nutritional intake compared to other ICUs.

The Retinol Circulating Complex Releases Hormonal Ligands During Acute Stress Disorders

Intensive care workers actively participate in very hot debates aiming at defining the true metabolic, hormonal and nutritional requirements of critically ill patients, the contributory roles played by thyroid and retinoid ligands being largely underestimated. The present article makes up for redressing the balance on behalf of these last hormonal compounds. The retinol circulating complex is transported in the bloodstream in the form of a trimolecular edifice made up of transthyretin (TTR), retinol-binding protein (RBP) and its retinol ligand. TTR reflects the size of the lean body mass (LBM) and is one of the 3 carrier-proteins of thyroid hormones whereas RBP is the sole conveyor of retinol in human plasma. In acute inflammatory disorders, both TTR and RBP analytes experience abrupt cytokine-induced suppressed hepatic synthesis whose amplitude is dependent on the duration and severity of the inflammatory burden. The steep drop in TTR and RBP plasma values releases thyroxine and retinol ligands in their physiologically active forms, creating free pools estimated to be 10-20 times larger than those described in healthy subjects. The peak endocrine influence is reached on day 4 and the freed ligands undergo instant cellular overconsumption and urinary leakage of unmetabolized fractions. As a result of these transient hyperthyroid and hyperretinoid states, helpful stimulatory and/or inhibitory processes are set in motion, operating as second frontlines fine-tuning the impulses primarily initiated by cytokines. The data explain why preexisting protein malnutrition, as assessed by subnormal LBM and TTR values, impairs the development of appropriate recovery processes in critically ill patients. These findings have survival implications, emphasizing the need for more adapted therapeutic strategies in intensive care units.

Practice Guidelines for Nutrition in Critically Ill Patients: A Relook for Indian Scenario

Background and Aim:

Intensive-care practices and settings may differ for India in comparison to other countries. While international guidelines are available to direct the use of enteral nutrition (EN), there are no recommendations specific to Indian settings. Advisory board meetings were arranged to develop the practice guidelines specific to Indian context, for the use of EN in critically ill patients and to overcome challenges in this field.

Methods:

Various existing guidelines, meta-analyses, randomized controlled trials, controlled trials, and review articles were reviewed for their contextual relevance and strength. A systematic grading of practice guidelines by advisory board was done based on strength of the supporting evidence. Wherever Indian studies were not available, references were taken from the international guidelines.

Results:

Based on the literature review, the recommendations for developing the practice guidelines were made as per the grading criteria agreed upon by the advisory board. The recommendations were to address challenges regarding EN versus parenteral nutrition; nutrition screening and assessment; nutrition in hemodynamically unstable; route of nutrition; tube feeding and challenges; tolerance; optimum calorie-protein requirements; selection of appropriate enteral feeding formula; micronutrients and immune-nutrients; standard nutrition in hepatic, renal, and respiratory diseases and documentation of nutrition practices.

Conclusion:

This paper summarizes the optimum nutrition practices for critically ill patients. The possible solutions to overcome the challenges in this field are presented as practice guidelines at the end of each section. These guidelines are expected to provide guidance in critical care settings regarding appropriate critical-care nutrition practices and to set up Intensive Care Unit nutrition protocols.

Time-sensitive therapeutics

Much of what we now do in Critical Care carries an air of urgency, a pressing need to discover and act, with priorities biased toward a reactive response. However, efficacy often depends not simply upon what we do, but rather on whether, when, and how persistently we intervene. The practice of medicine is based upon diagnosis, integration of multiple sources of information, keen judgment, and appropriate intervention. Timing may not be everything, as the well-known adage suggests, but in the intensive care unit (ICU) timing issues clearly deserve more attention than they are currently given. Successfully or not, the patient is continually attempting to adapt and re-adjust to acute illness, and this adaptive  process takes time. Knowing that much of what we do carries potential for unintended harm as well as benefit, the trick is to decide whether the patient is winning or losing the adaptive struggle and whether we can help. Costs of modern ICU care is enormous and the trend line shows no encouraging sign of moderation. To sharpen our effectiveness, reduce hazard, and pare cost we must learn to time our interventions, help the patient adapt, and at times withhold treatment rather than jump in on the impulse to rescue and/or to alter the natural course of disease. Indeed, much of the progress made in our discipline has resulted both from timely intervention when called for and avoidance or moderation of hazardous treatments when not. Time-sensitive ICU therapeutics requires awareness of trends in key parameters, respect for adaptive chronobiology, level-headed evaluation of the need to intervene, and awareness of the costs of disrupting a potentially constructive natural response to illness.

Tailoring nutrition therapy to illness and recovery

Without doubt, in medicine as in life, one size does not fit all. We do not administer the same drug or dose to every patient at all times, so why then would we live under the illusion that we should give the same nutrition at all times in the continuum of critical illness? We have long lived under the assumption that critical illness and trauma lead to a consistent early increase in metabolic/caloric need, the so-called “hypermetabolism” of critical illness. What if this is incorrect? Recent data indicate that early underfeeding of calories (trophic feeding) may have benefits and may require consideration in well-nourished patients. However, we must confront the reality that currently ICU nutrition delivery worldwide is actually leading to “starvation” of our patients and is likely a major contributor to poor long-term quality of life outcomes. To begin to ascertain the actual calorie and protein delivery required for optimal ICU recovery, an understanding of “starvation” and recovery from starvation and lean body mass (LBM) loss is needed. To begin to answer this question, we must look to the landmark Minnesota Starvation Study from 1945. This trial defines much of the world’s knowledge about starvation, and most importantly what is required for recovery from starvation and massive LBM loss as occurs in the ICU. Recent and historic data indicate that critical illness is characterized by early massive catabolism, LBM loss, and escalating hypermetabolism that can persist for months or years. Early enteral nutrition during the acute phase should attempt to correct micronutrient/vitamin deficiencies, deliver adequate protein, and moderate nonprotein calories in well-nourished patients, as in the acute phase they are capable of generating significant endogenous energy. Post resuscitation, increasing protein (1.5–2.0 g/kg/day) and calories are needed to attenuate LBM loss and promote recovery. Malnutrition screening is essential and parenteral nutrition can be safely added following resuscitation when enteral nutrition is failing based on pre-illness malnutrition and LBM status. Following the ICU stay, significant protein/calorie delivery for months or years is required to facilitate functional and LBM recovery, with high-protein oral supplements being essential to achieve adequate nutrition.

Nutritional Supplementation for Diabetic Foot Ulcers: The Big Challenge

Diabetic foot ulcers remain difficult to heal and nutritional supplementation may be an important complementary therapeutic measure. However, we need to clarify many issues before such supplementation is more widely used. Indeed, improvements are needed in the following areas: evaluation of nutritional inadequacy, completion of randomized controlled trials, understanding of patient and ulcer characteristics that favor response to nutritional supplementation, optimal duration of supplementation therapy, and evaluation of patient adherence. The challenge is now to acquire more knowledge in the aforementioned areas.

Does Propofol Sedation Contribute to Overall Energy Provision in Mechanically Ventilated Critically Ill Adults? A Retrospective Observational Study

BACKGROUND

Propofol sedation is common in critically ill patients, providing energy of 1.1 kcal/mL when administered as a 1% solution. We aimed to determine the proportion of energy administered as propofol on days 1-5 in the intensive care unit (ICU) and any association with outcomes.

METHODS

Retrospective observational study in a quaternary ICU from January-December 2012. Inclusion criteria were length of stay (LOS) ≥5 days, age ≥18 years, and provision of mechanical ventilation (MV) for ≥5 days. Outcome measures included proportion of total daily energy provided as propofol, overall energy balance, hospital mortality, duration of MV, and ICU LOS.

RESULTS

Data from 370 patients were analyzed, 87.8% (n = 325) of whom received propofol during days 1-5 in ICU. A median [interquartile range (IQR)] of 119 [50-730] kcal was provided as propofol per patient-day. Proportion of energy provided by propofol as a percentage of total energy delivered was 55.4%, 15.4%, 9.3%, 7.9%, and 9.9% days 1-5, respectively. Patients administered propofol received a greater proportion of their total daily energy prescription compared with those who were not (P < .01). Proportion of energy provided as propofol was not significantly different based on hospital mortality (P = .62), duration of MV (P = .50), or ICU LOS (P = .15).

CONCLUSION

Propofol contributes to overall energy intake on days 1-5 of ICU admission. Energy balance was higher in those receiving propofol. No association was found between the proportion of energy delivered as propofol and outcomes.

Amino acid supplements in critically ill patients

Observational studies have associated a low amino acid intake with adverse outcome of critical illness. Although this finding could theoretically be explained by differences in feeding tolerance related to illness severity, guidelines have recommended to administer sufficient amounts of amino acids from early onwards in the disease course. Recently, however, several high quality randomized controlled trials have not shown benefit by early amino acid supplementation and some trials even found potential harm, thus questioning this recommendation. These negative results could be related to amino acid-induced suppression of autophagy, to the inability to suppress bulk catabolism by exogenous amino acids, or to the administration of an amino acid mixture with an inappropriate composition. Currently, there is no evidence supporting administration of individual amino acid supplements during critical illness and glutamine administration may be harmful. The optimal timing, dose and composition of the amino acid mixture for critically ill patients remain unclear.

Initial nutritional management during noninvasive ventilation and outcomes: a retrospective cohort study

Background

Patients starting noninvasive ventilation (NIV) to treat acute respiratory failure are often unable to eat and therefore remain in the fasting state or receive nutritional support. Maintaining a good nutritional status has been reported to improve patient outcomes. In the present study, our primary objective was to describe the nutritional management of patients starting first-line NIV, and our secondary objectives were to assess potential associations between nutritional management and outcomes.

Methods

Observational retrospective cohort study of a prospective database fed by 20 French intensive care units. Adult medical patients receiving NIV for more than 2 consecutive days were included and divided into four groups on the basis of nutritional support received during the first 2 days of NIV: no nutrition, enteral nutrition, parenteral nutrition only, and oral nutrition only.

Results

Of the 16,594 patients admitted during the study period, 1075 met the inclusion criteria; of these, 622 (57.9%) received no nutrition, 28 (2.6%) received enteral nutrition, 74 (6.9%) received parenteral nutrition only, and 351 (32.7%) received oral nutrition only. After adjustment for confounders, enteral nutrition (vs. no nutrition) was associated with higher 28-day mortality (adjusted HR, 2.3; 95% CI, 1.2–4.4) and invasive mechanical ventilation needs (adjusted HR, 2.1; 95% CI, 1.1–4.2), as well as with fewer ventilator-free days by day 28 (adjusted relative risk, 0.7; 95% CI, 0.5–0.9).

Conclusions

Nearly three-fifths of patients receiving NIV fasted for the first 2 days. Lack of feeding or underfeeding was not associated with mortality. The optimal route of nutrition for these patients needs to be investigated.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1867-y) contains supplementary material, which is available to authorized users.

Nutrition Therapy in Sepsis

Sepsis is characterized by early massive catabolism, lean body mass (LBM) loss, and escalating hypermetabolism persisting for months to years. Early enteral nutrition should attempt to correct micronutrient/vitamin deficiencies, deliver adequate protein and moderated nonprotein calories, as well-nourished patients can generate reasonable endogenous energy. After resuscitation, increasing protein/calories are needed to attenuate LBM loss and promote recovery. Malnutrition screening is essential, and parenteral nutrition can be safely added when enteral nutrition is failing based on preillness malnutrition. Following discharge from intensive care unit, significantly increased protein/calorie delivery is required for months to years to facilitate functional and LBM recovery.

Management and prevention of refeeding syndrome in medical inpatients: An evidence-based and consensus-supported algorithm

OBJECTIVES

Refeeding syndrome (RFS) can be a life-threatening metabolic condition after nutritional replenishment if not recognized early and treated adequately. There is a lack of evidence-based treatment and monitoring algorithm for daily clinical practice. The aim of the study was to propose an expert consensus guideline for RFS for the medical inpatient (not including anorexic patients) regarding risk factors, diagnostic criteria, and preventive and therapeutic measures based on a previous systematic literature search.

METHODS

Based on a recent qualitative systematic review on the topic, we developed clinically relevant recommendations as well as a treatment and monitoring algorithm for the clinical management of inpatients regarding RFS. With international experts, these recommendations were discussed and agreement with the recommendation was rated.

RESULTS

Upon hospital admission, we recommend the use of specific screening criteria (i.e., low body mass index, large unintentional weight loss, little or no nutritional intake, history of alcohol or drug abuse) for risk assessment regarding the occurrence of RFS. According to the patient's individual risk for RFS, a careful start of nutritional therapy with a stepwise increase in energy and fluids goals and supplementation of electrolyte and vitamins, as well as close clinical monitoring, is recommended. We also propose criteria for the diagnosis of imminent and manifest RFS with practical treatment recommendations with adoption of the nutritional therapy.

CONCLUSION

Based on the available evidence, we developed a practical algorithm for risk assessment, treatment, and monitoring of RFS in medical inpatients. In daily routine clinical care, this may help to optimize and standardize the management of this vulnerable patient population. We encourage future quality studies to further refine these recommendations.

Association between adipokines and critical illness outcomes

BACKGROUND

Adipose tissue is an endocrine organ that plays a critical role in immunity and metabolism by virtue of a large number of hormones and cytokines, collectively termed adipokines. Dysregulation of adipokines has been linked to the pathogenesis of multiple diseases, but some questions have arisen concerning the value of adipokines in critical illness setting. The objective of this review was to evaluate the associations between blood adipokines and critical illness outcomes.

METHODS

PubMed, CINAHL, Scopus, and the Cochrane Library databases were searched from inception through July 2016 without language restriction. Studies reporting the associations of adipokines, leptin, adiponectin, resistin, and/or visfatin with critical illness outcomes mortality, organ dysfunction, and/or inflammation were included.

RESULTS

A total of 38 articles were selected according to the inclusion/exclusion criteria of the study. Significant alterations of circulating adipokines have been reported in critically ill patients, some of which were indicative of patient outcomes. The associations of leptin and adiponectin with critical illness outcomes were not conclusive in that blood levels of both adipokines did not always correlate with the illness severity scores or risks of organ failure and mortality. By contrast, studies consistently reported striking increase of blood resistin and visfatin, independently of the critical illness etiology. More interestingly, increased levels of these adipokines were systematically associated with severe inflammation, and high incidence of organ failure and mortality.

CONCLUSIONS

There is strong evidence to indicate that increased levels of blood resistin and visfatin are associated with poor outcomes of critically ill patients, including higher inflammation, and greater risk of organ dysfunction and mortality.

LEVEL OF EVIDENCE

Systematic review, level III.

Evaluation of nutrition support practices: Results from a nationwide survey

BACKGROUND

Multiple clinical guidelines are available to improve and standardize the delivery of nutrition support. However, recommendations are not being universally applied at the bedside due to challenges of resources and barriers of knowledge. Assessing the current level of nutrition support practice is the first step to understand the barriers and ultimately implement potential strategies to increase guideline adherence and promote quality nutrition support in hospitals. There are no published data concerning the practice of nutrition support in Lebanese hospitals.

OBJECTIVES

The objective of our study is to investigate for the first time the current clinical practice pertinent to nutrition support across Lebanon.

METHODS

A survey was developed by The Nutrition Board of the Lebanese Society of Critical Care Medicine (LSCCM) to determine nutrition support practices in hospitals with an Intensive Care Unit (ICU) across Lebanon. The 28-question survey assesses the delivery of feeding methods such as oral nutrition supplements (ONS), enteral nutrition (EN), and parenteral nutrition (PN).

RESULTS

Fourty-one hospitals from 116 total completed the survey. The majority of the hospitals (92.6%) do not systematically use a screening system for malnutrition. Seventy six percent of hospitals reported less than 5% of their patients are kept for more than 7 days with no nutrition support. Early EN is used in preference over PN in ICUs, as 72% of hospitals start early EN (within 48 h) in more than 10% of cases while only 30% of hospitals start early PN (within the first week) in more than 10% of cases. Fifty-one percent of the hospitals use ready prepared formula while the rest (49%) use kitchen prepared formula.

CONCLUSIONS

Our study is the first of its kind in Lebanon aiming at describing the current clinical practice in nutrition support at a national level. Working toward the use of a nutritional screening tool on admission and the exclusive use of ready made formula for enteral feeding will have the most significant and immediate impact on improving quality of nutritional care for hospitalized patients. This can be achieved mainly through the education of the concerned staff.

The role of nutritional support in the physical and functional recovery of critically ill patients: a narrative review

The lack of benefit from randomised controlled trials has resulted in significant controversy regarding the role of nutrition during critical illness in terms of long-term recovery and outcome. Although methodological caveats with a failure to adequately appreciate biological mechanisms may explain these disappointing results, it must be acknowledged that nutritional support during early critical illness, when considered alone, may have limited long-term functional impact.This narrative review focuses specifically on recent clinical trials and evaluates the impact of nutrition during critical illness on long-term physical and functional recovery.Specific focus on the trial design and methodological limitations has been considered in detail. Limitations include delivery of caloric and protein targets, patient heterogeneity, short duration of intervention, inappropriate clinical outcomes and a disregard for baseline nutritional status and nutritional intake in the post-ICU period.With survivorship at the forefront of critical care research, it is imperative that nutrition studies carefully consider biological mechanisms and trial design because these factors can strongly influence outcomes, in particular long-term physical and functional outcome. Failure to do so may lead to inconclusive clinical trials and consequent rejection of the potentially beneficial effects of nutrition interventions during critical illness.

A randomized trial of supplemental parenteral nutrition in underweight and overweight critically ill patients: the TOP-UP pilot trial

Background

Nutrition guidelines recommendations differ on the use of parenteral nutrition (PN), and existing clinical trial data are inconclusive. Our recent observational data show that amounts of energy/protein received early in the intensive care unit (ICU) affect patient mortality, particularly for inadequate nutrition intake in patients with body mass indices (BMIs) of <25 or >35. Thus, we hypothesized increased nutrition delivery via supplemental PN (SPN) + enteral nutrition (EN) to underweight and obese ICU patients would improve 60-day survival and quality of life (QoL) versus usual care (EN alone).

Methods

In this multicenter, randomized, controlled pilot trial completed in 11 centers across four countries, adult ICU patients with acute respiratory failure expected to require mechanical ventilation for >72 hours and with a BMI of <25 or ≥35 were randomized to receive EN alone or SPN + EN to reach 100% of their prescribed nutrition goal for 7 days after randomization. The primary aim of this pilot trial was to achieve a 30% improvement in nutrition delivery.

Results

In total, 125 patients were enrolled. Over the first 7 post-randomization ICU days, patients in the SPN + EN arm had a 26% increase in delivered calories and protein, whereas patients in the EN-alone arm had a 22% increase (both p < 0.001). Surgical ICU patients received poorer EN nutrition delivery and had a significantly greater increase in calorie and protein delivery when receiving SPN versus medical ICU patients. SPN proved feasible to deliver with our prescribed protocol. In this pilot trial, no significant outcome differences were observed between groups, including no difference in infection risk. Potential, although statistically insignificant, trends of reduced hospital mortality and improved discharge functional outcomes and QoL outcomes in the SPN + EN group versus the EN-alone group were observed.

Conclusions

Provision of SPN + EN significantly increased calorie/protein delivery over the first week of ICU residence versus EN alone. This was achieved with no increased infection risk. Given feasibility and consistent encouraging trends in hospital mortality, QoL, and functional endpoints, a full-scale trial of SPN powered to assess these clinical outcome endpoints in high-nutritional-risk ICU patients is indicated—potentially focusing on the more poorly EN-fed surgical ICU setting.

Trial registration

NCT01206166

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1736-8) contains supplementary material, which is available to authorized users.

Omega-3 supplementation in patients with sepsis: a systematic review and meta-analysis of randomized trials

BACKGROUND

Nutritional supplementation of omega-3 fatty acids has been proposed to modulate the balance of pro- and anti-inflammatory mediators in sepsis. If proved to improve clinical outcomes in critically ill patients with sepsis, this intervention would be easy to implement. However, the cumulative evidence from several randomized clinical trials (RCTs) remains unclear.

METHODS

We searched the Cochrane Library, MEDLINE, and EMBASE through December 2016 for RCTs on parenteral or enteral omega-3 supplementation in adult critically ill patients diagnosed with sepsis or septic shock. We analysed the included studies for mortality, intensive care unit (ICU) length of stay, and duration of mechanical ventilation, and used the Grading of Recommendations Assessment, Development and Evaluation approach to assess the quality of the evidence for each outcome.

RESULTS

A total of 17 RCTs enrolling 1239 patients met our inclusion criteria. Omega-3 supplementation compared to no supplementation or placebo had no significant effect on mortality [relative risk (RR) 0.85; 95% confidence interval (CI) 0.71, 1.03; P = 0.10; I ² = 0%; moderate quality], but significantly reduced ICU length of stay [mean difference (MD) -3.79 days; 95% CI -5.49, -2.09; P < 0.0001, I ² = 82%; very low quality] and duration of mechanical ventilation (MD -2.27 days; 95% CI -4.27, -0.27; P = 0.03, I ² = 60%; very low quality). However, sensitivity analyses challenged the robustness of these results.

CONCLUSION

Omega-3 nutritional supplementation may reduce ICU length of stay and duration of mechanical ventilation without significantly affecting mortality, but the very low quality of overall evidence is insufficient to justify the routine use of omega-3 fatty acids in the management of sepsis.

The physician-nurse collaboration in feeding critically ill patients: A multicenter survey

AIMS

Describe physician-nurse collaboration in feeding critically ill patients and explore the influence factors related to this collaboration, which can provide information for clinical practice and future studies.

BACKGROUND

Appropriate nutrition support is essential and significant for critically ill patients, and the importance of physician-nurse collaboration in other fields has been confirmed, yet there are limited studies put insights into the status of physician-nurse collaboration in feeding critically ill patients.

METHODS

A cross-sectional survey with a covering of 15 hospitals was conducted. A 21-item questionnaire was administered to physicians and nurses in critical care units. Descriptive statistics, univariate and multiple stepwise regression analysis were performed to evaluate the physician-nurse collaboration in feeding critically ill patients.

RESULTS

A total of 331 respondents completed the questionnaire. Nurses and physicians were found to have differing perceptions of the physician-nurse collaboration in feeding critically ill patients, with nurses reporting lower levels of collaboration. Nurses consistently gave more negative responses on every survey question compared with physicians. Age, education and clinical experience significantly influenced the nurses' perceptions of cooperation, and age, education, ICU type, and seniority affected the physicians' perceptions of collaboration.

CONCLUSIONS

Physicians, nurses and hospital administrators should highlight the physician-nurse collaboration in feeding critically ill patients and reinforce the cooperation based on potential influencing factors. Further research is required to establish feasible cooperative protocol and evaluate the effectiveness of the approach.

Relationship of energy and protein adequacy with 60-day mortality in mechanically ventilated critically ill patients: A prospective observational study

BACKGROUND & AIMS

The effect of provision of full feeding or permissive underfeeding on mortality in mechanically ventilated critically ill patients in the intensive care unit (ICU) is still controversial. This study investigated the relationship of energy and protein intakes with 60-day mortality, and the extent to which ICU length of stay and nutritional risk status influenced this relationship.

METHODS

This is a prospective observational study conducted among critically ill patients aged ≥18 years, intubated and mechanically ventilated within 48 h of ICU admission and stayed in the ICU for at least 72 h. Information on baseline characteristics and nutritional risk status (the modified Nutrition Risk in Critically ill [NUTRIC] score) was collected on day 1. Nutritional intake was recorded daily until death, discharge, or until the twelfth evaluable days. Mortality status was assessed on day 60 based on the patient's hospital record. Patients were divided into 3 groups a) received <2/3 of prescribed energy and protein (both <2/3), b) received ≥2/3 of prescribed energy and protein (both ≥2/3) and c) either energy or protein received were ≥2/3 of prescribed (either ≥2/3). The relationship between the three groups with 60-day mortality was examined by using logistic regression with adjustment for potential confounders. Sensitivity analysis was performed to examine the influence of ICU length of stay (≥7 days) and nutritional risk status.

RESULTS

Data were collected from 154 mechanically ventilated patients (age, 51.3 ± 15.7 years; body mass index, 26.5 ± 6.7 kg/m²; 54% male). The mean modified NUTRIC score was 5.7 ± 1.9, with 56% of the patients at high nutritional risk. The patients received 64.5 ± 21.6% of the amount of energy and 56.4 ± 20.6% of the amount of protein prescribed. Provision of energy and protein at ≥2/3 compared with <2/3 of the prescribed amounts was associated with a trend towards increased 60-day mortality (Adjusted odds ratio [Adj OR] 2.23; 95% confidence interval [CI], 0.92-5.38; p = 0.074). No difference in mortality status was found between energy and protein provision at either ≥2/3 compared with <2/3 of the prescribed amounts (Adj OR 1.61, 95% CI, 0.58-4.45; p = 0.357). Nutritional risk status, not ICU length of stay, influenced the relationship between nutritional adequacy and 60-day mortality.

CONCLUSIONS

Energy and protein adequacy of ≥2/3 of the prescribed amounts were associated with a trend towards increased 60-day mortality among mechanically ventilated critically ill patients. However, neither energy nor protein adequacy alone at ≥ or <2/3 adequacy affect 60-day mortality. Increased mortality was associated with provision of energy and protein at ≥2/3 of the prescribed amounts, which only affected patients with low nutritional risk.

Significance of admission hypoalbuminemia in acute intracerebral hemorrhage

Low levels of serum albumin may increase the risk of infections and mortality in critically ill patients. We tested the hypothesis that admission hypoalbuminemia predicted infectious complications and poor outcome in subjects with acute intracerebral hemorrhage (ICH). We analyzed a single center cohort of ICH patients collected between 1994 and 2015. Pneumonia, urinary tract infection and sepsis were retrospectively identified, according to validated criteria. Serum albumin was measured on admission and hypoalbuminemia was defined as total albumin ≤3.5 g/dL. The association between albumin levels, infections, and mortality at 90 days was tested with multivariable logistic regression analyses. A total of 2010 patients were included (median age 74 years, 54.5% males) of whom 444 (22.1%) had hypoalbuminemia on admission and 763 (38%) died within 90 days. The frequency of pneumonia, urinary tract infection, and sepsis was 19.9, 15.1, and 2.7%, respectively. Hypoalbuminemic patients had lower admission Glasgow coma scale, higher frequency of intraventricular hemorrhage and were more likely to have a history of chronic kidney or liver disease. After adjustment for potential confounders, hypoalbuminemia was an independent predictor of pneumonia [odds ratio (OR) 1.76, 95% confidence interval (CI) 1.34-2.33, p < 0.001] and sepsis (OR 2.29, 95% CI 1.22-4.30, p = 0.010). Low levels of albumin were also independently associated with higher mortality at 90 days (OR 1.78, 95% CI 1.30-2.44, p < 0.001). In conclusion, early hypoalbuminemia is common and predicts poor outcome in ICH patients. Increased susceptibility to pneumonia and sepsis may be the pathophysiological mechanism underlying this association.

Total parenteral nutrition usage trends in the United States

INTRODUCTION

This study examined how total parenteral nutrition (TPN) usage has changed in recent years, and whether a difference exists between teaching and non-teaching institutions.

MATERIALS AND METHODS

Using the National Inpatient Sample (NIS) database, total discharges of patients who received TPN (ICD-9 99.15) from 2001 to 2014 were determined. The cohort was dichotomized for teaching and non-teaching institutions, and analyzed using the Z-test statistic.

RESULTS

Annual patients receiving TPN at all institutions increased significantly from 25,075 in 2001 to 33,435 in 2014 (P<0.0001), peaking at 43,350 in 2012. Annual patients receiving TPN at teaching institutions increased significantly from 13,231 in 2001 to 24,630 in 2014 (P<0.0001), peaking at 26,935 in 2012. Annual patients receiving TPN at non-teaching institutions decreased significantly from 11,844 in 2001 to 8805 in 2014 (P<0.0001), peaking at 17,920 in 2011.

DISCUSSION

It is unclear why TPN usage trended upward in United States hospitals, and why TPN usage peaked and subsequently decreased in non-teaching institutions while continuing to uptrend in teaching institutions. Further inquiry is indicated to determine the etiology of this discrepancy.

CONCLUSIONS

Utilization of TPN increased in the United States between 2001 and 2014, eventually decreasing in non-teaching institutions but not in teaching institutions.

The intensive care medicine research agenda in nutrition and metabolism

Purpose

The objectives of this review are to summarize the current practices and major recent advances in critical care nutrition and metabolism, review common beliefs that have been contradicted by recent trials, highlight key remaining areas of uncertainty, and suggest recommendations for the top 10 studies/trials to be done in the next 10 years.

Methods

Recent literature was reviewed and developments and knowledge gaps were summarized. The panel identified candidate topics for future trials in critical care nutrition and metabolism. Then, members of the panel rated each one of the topics using a grading system (0–4). Potential studies were ranked on the basis of average score.

Results

Recent randomized controlled trials (RCTs) have challenged several concepts, including the notion that energy expenditure must be met universally in all critically ill patients during the acute phase of critical illness, the routine monitoring of gastric residual volume, and the value of immune-modulating nutrition. The optimal protein dose combined with standardized active and passive mobilization during the acute phase and post-acute phase of critical illness were the top ranked studies for the next 10 years. Nutritional assessment, nutritional strategies in critically obese patients, and the effects of continuous versus intermittent enteral nutrition were also among the highest-ranking studies.

Conclusions

Priorities for clinical research in the field of nutritional management of critically ill patients were suggested, with the prospect that different nutritional interventions targeted to the appropriate patient population will be examined for their effect on facilitating recovery and improving survival in adequately powered and properly designed studies, probably in conjunction with physical activity.

Electronic supplementary material

The online version of this article (doi:10.1007/s00134-017-4711-6) contains supplementary material, which is available to authorized users.