Nutritional support in critical illness and recovery

Small peptide formulas versus standard polymeric formulas in critically ill patients with acute gastrointestinal injury: a systematic review and meta-analysis

Small peptide formulas versus standard polymeric formulas for enteral nutrition in critically ill patients with acute gastrointestinal injury (AGI) have been a topic of debate. A systematic review and meta-analysis were conducted to compare their clinical and nutritional outcomes. Relevant studies from January 1980 to June 2022 were searched in PubMed, Cochrane, and Embase databases. Randomized controlled trials involving AGI grade I-IV patients were included, while children, non-AGI patients, and non-critically ill patients were excluded. Results indicated no significant difference in all-cause mortality. Patients receiving small peptide formulas showed higher daily protein intake, greater albumin growth, and higher prealbumin levels. They also had shorter lengths of stay in the intensive care unit and hospital. Conversely, patients receiving standard polymeric formulas had a higher daily calorie intake. In conclusion, the choice of formula may not affect mortality in critically ill patients with AGI. Small peptide formulas were more conducive to increase daily protein intake, decrease intensive care unit and hospital length of stay. Further large-scale randomized controlled trials evaluating the effects of these two nutritional formulas on clinical and nutritional outcomes in critically ill patients with AGI are needed to confirm these results.

Prevalence and Associated Factors of Coexistence of Malnutrition and Sarcopenia in Geriatric Rehabilitation

Malnutrition and sarcopenia often coexist in rehabilitation patients, although they are often overlooked and undertreated in clinical practice. This cross-sectional study aimed to clarify the prevalence of the coexistence of malnutrition and sarcopenia (Co-MS) and its associated factors in convalescent rehabilitation wards in Japan. Consecutive patients aged ≥ 65 years in convalescent rehabilitation wards between November 2018 and October 2020 were included. Malnutrition and sarcopenia were determined by the Global Leadership Initiative on Malnutrition (GLIM) criteria and the Asian Working Group for Sarcopenia (AWGS 2019) criteria, respectively. Patients who presented both with malnutrition and sarcopenia were classified as Co-MS. Potentially associated factors included age, sex, days from onset to admission of rehabilitation wards, reason for admission, pre-morbid functional dependency, comorbidity, activities of daily living, swallowing ability, and oral function and hygiene. The prevalence of malnutrition, sarcopenia, and Co-MS was calculated. Binary logistic regression analyses were performed to compute odds ratios (ORs) and the 95% confidence interval (CI) of possible associated factors for each condition. Overall, 601 patients were eligible for the analysis (median 80 years old, 355 female patients, 70% cerebrovascular disease). Co-MS, malnutrition, and sarcopenia were found in 23.5%, 29.0%, and 62.4% of the enrolled patients, respectively. After adjustment, onset–admission interval (OR = 1.04; 95% CI = 1.02 to 1.06), hospital-associated deconditioning (OR = 4.62; 95% CI = 1.13 to 18.8), and swallowing ability (Food Intake LEVEL Scale) (OR = 0.83; 95% CI = 0.73 to 0.93) were identified as independent explanatory factors of Co-MS. In conclusion, Co-MS was prevalent in geriatric rehabilitation patients; thus, healthcare professionals should be aware of the associated factors to detect the geriatric rehabilitation patients who are at risk of both malnutrition and sarcopenia, and to provide appropriate treatments.

Modulation of cerebral ketone metabolism following traumatic brain injury in humans

Adaptive metabolic response to injury includes the utilization of alternative energy substrates - such as ketone bodies (KB) - to protect the brain against further damage. Here, we examined cerebral ketone metabolism in patients with traumatic brain injury (TBI; n = 34 subjects) monitored with cerebral microdialysis to measure total brain interstitial tissue KB levels (acetoacetate and β-hydroxybutyrate). Nutrition - from fasting vs. stable nutrition state - was associated with a significant decrease of brain KB (34.7 [10th-90th percentiles 10.7-189] µmol/L vs. 13.1 [6.5-64.3] µmol/L, p < 0.001) and blood KB (668 [168.4-3824.9] vs. 129.4 [82.6-1033.8] µmol/L, p < 0.01). Blood KB correlated with brain KB (Spearman's rho 0.56, p = 0.0013). Continuous feeding with medium-chain triglycerides-enriched enteral nutrition did not increase blood KB, and provided a modest increase in blood and brain free medium chain fatty acids. Higher brain KB at the acute TBI phase correlated with age and brain lactate, pyruvate and glutamate, but not brain glucose. These novel findings suggest that nutritional ketosis was the main determinant of cerebral KB metabolism following TBI. Age and cerebral metabolic distress contributed to brain KB supporting the hypothesis that ketones might act as alternative energy substrates to glucose. Further studies testing KB supplementation after TBI are warranted.

Epidemiological Study on the Status of Nutrition-Support Therapies by Emergency Physicians in China

Objectives

This study aimed to investigate the current status of nutrition-support therapies by emergency physicians in China and to provide an evidence-based case to improve the regulation of enteral and parenteral nutrition-support therapies.

Methods

Physicians from the Emergency Branch of the China Geriatrics Society were enrolled in the present survey. A questionnaire related to nutrition-support therapy, including the time, location, ways, indications, complications, and nutrition-support training for physicians was answered.

Results

527 questionnaires were collected from over 300 hospitals in 25 provinces of China. The time to initiation of emergency nutrition support was often delayed. Furthermore, the treatment intensity and standardized training of physicians are weaknesses concerning nutrition support. Treatment standardization has been significantly improved, including blood glucose monitoring, precaution and management of complications, and the use of immunomodulators.

Conclusions

Emergency physicians should pay attention to early identifying and providing nutrition support to those patients who need it. Finally, standardized training should be developed for emergency nutrition-support therapy.

The Effect of Nutrition on Early Stress-Induced Hyperglycemia, Serum Insulin Levels, and Exogenous Insulin Administration in Critically Ill Patients With Septic Shock: A Prospective Observational Study

BACKGROUND

Stress-induced hyperglycemia is common among septic shock patients. Nutritional support influences glucose homeostasis but this effect has never been studied in septic shock. We aimed to determine the course of hyperglycemia and serum insulin levels in critically ill septic shock patients and to address the effects of caloric intake on glycemia, insulin levels, and exogenous insulin requirements.

METHODS

A prospective observational study of 24 ventilated septic shock patients during 72 h after ICU admission. Every 4 h nutritional variables, exogenous insulin administration, serum insulin, and glucose levels were recorded.

RESULTS

Stress-induced hyperglycemia was found in 96.2% of patients. Exogenous insulin requirements increased gradually and were most pronounced at 36 h (mean 4.64 IU/h). Total serum insulin levels were lowest at the point of most exogenous insulin requirements (mean 2.75 mIU/L). Total caloric intake and insulin requirements were positively associated (Pearson correlation coefficient 0.210).

CONCLUSIONS

In patients with septic shock marked reduced serum insulin levels can be observed during the first 36 h after intensive care unit (ICU) admission that have to be compensated by exogenous insulin administration, a phenomenon gradually improving after 36 h. Feeding is positively associated with exogenous insulin requirements. These results suggest that strategies to manage stress-induced hyperglycemia in patients with septic shock should consider frequent glycemic monitoring, conservative insulin dosing to prevent hypoglycemia when insulin resistance disappears, and slow progressive nutrition support during the early ICU phase as caloric loading may worsen hyperglycemia. This approach may attenuate the risk of glucose variability, hypo- and hyperglycemia and associated poor outcomes.

Is refeeding syndrome relevant for critically ill patients?

PURPOSE OF REVIEW

To summarize recent relevant studies regarding refeeding syndrome (RFS) in critically ill patients and provide recommendations for clinical practice.

RECENT FINDINGS

Recent knowledge regarding epidemiology of refeeding syndrome among critically ill patients, how to identify ICU patients at risk, and strategies to reduce the potential negative impact on outcome are discussed.

SUMMARY

RFS is a potentially fatal acute metabolic derangement that ultimately can result in marked morbidity and even mortality. These metabolic derangements in ICU patients differ from otherwise healthy patients with RFS, as there is lack of anabolism. This is because of external stressors inducing a hypercatabolic response among other reasons also reflected by persistent high glucagon despite initiation of feeding. Lack of a proper uniform definition complicates diagnosis and research of RFS. However, refeeding hypophosphatemia is commonly encountered during critical illness. The correlations between risk factors proposed by international guidelines and the occurrence of RFS in ICU patients remains unclear. Therefore, regular phosphate monitoring is recommended. Based on recent trials among critically ill patients, only treatment with supplementation of electrolytes and vitamins seems not sufficient. In addition, caloric restriction for several days and gradual increase of caloric intake over days is recommendable.

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.

Role of Glucagon in Catabolism and Muscle Wasting of Critical Illness and Modulation by Nutrition

RATIONALE

Critical illness is hallmarked by muscle wasting and disturbances in glucose, lipid, and amino acid homeostasis. Circulating concentrations of glucagon, a catabolic hormone that affects these metabolic pathways, are elevated during critical illness. Insight in the nutritional regulation of glucagon and its metabolic role during critical illness is lacking.

OBJECTIVES

To evaluate whether macronutrient infusion can suppress plasma glucagon during critical illness and study the role of illness-induced glucagon abundance in the disturbed glucose, lipid, and amino acid homeostasis and in muscle wasting during critical illness.

METHODS

In human and mouse studies, we infused macronutrients and manipulated glucagon availability up and down to investigate its acute and chronic metabolic role during critical illness.

MEASUREMENTS AND MAIN RESULTS

In critically ill patients, infusing glucose with insulin did not lower glucagon, whereas parenteral nutrition containing amino acids increased glucagon. In critically ill mice, infusion of amino acids increased glucagon and up-regulated markers of hepatic amino acid catabolism without affecting muscle wasting. Immunoneutralizing glucagon in critically ill mice only transiently affected glucose and lipid metabolism, did not affect muscle wasting, but drastically suppressed markers of hepatic amino acid catabolism and reversed the illness-induced hypoaminoacidemia.

CONCLUSIONS

These data suggest that elevated glucagon availability during critical illness increases hepatic amino acid catabolism, explaining the illness-induced hypoaminoacidemia, without affecting muscle wasting and without a sustained impact on blood glucose. Furthermore, amino acid infusion likely results in a further breakdown of amino acids in the liver, mediated by increased glucagon, without preventing muscle wasting. Clinical trial registered with www.clinicaltrials.gov (NCT 00512122).

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.

Who Dies after ICU Discharge? Retrospective Analysis of Prognostic Factors for In-Hospital Mortality of ICU Survivors

We investigated the causes of inpatient death after intensive care unit (ICU) discharge and determined predictors of in-hospital mortality in Korea. Using medical ICU registry data of Seoul National University Hospital, we performed a retrospective cohort study involving patients who were discharged alive from their first ICU admission with at least 24 hours of ICU length of stay (LOS). From January 2011 to August 2013, 723 patients were admitted to ICU and 383 patients were included. The estimated in-hospital mortality rate was 11.7% (45/383). The most common cause of death was respiratory failure (n = 25, 56%) followed by sepsis and cancer progression; the causes of hospital death and ICU admission were the same in 64% of all deaths; sudden unexpected deaths comprised about one-fifth of all deaths. In order to predict in-hospital mortality among ICU survivors, multivariate analysis identified presence of solid tumor (odds ratio [OR], 4.06; 95% confidence interval [CI], 2.01-8.2; P < 0.001), hematologic disease (OR, 4.75; 95% CI, 1.51-14.96; P = 0.013), Sequential Organ Failure Assessment (SOFA) score upon ICU admission (OR, 1.08; 95% CI, 0.99-1.17; P = 0.075), and hemoglobin (Hb) level (OR, 0.67; 95% CI, 0.52-0.86; P = 0.001) and platelet count (Plt) (OR, 0.99; 95% CI, 0.99-1.00; P = 0.033) upon ICU discharge as significant factors. In conclusion, a significant proportion of in-hospital mortality is predictable and those who die in hospital after ICU discharge tend to be severely-ill, with comorbidities of hematologic disease and solid tumor, and anemic and thrombocytopenic upon ICU discharge.

Protein Requirements of the Critically Ill Pediatric Patient

This article includes a review of protein needs in children during health and illness, as well as a detailed discussion of protein metabolism, including nitrogen balance during critical illness, and assessment and prescription/delivery of protein to critically ill children. The determination of protein requirements in children has been difficult and challenging. The protein needs in healthy children should be based on the amount needed to ensure adequate growth during infancy and childhood. Compared with adults, children require a continuous supply of nutrients to maintain growth. The protein requirement is expressed in average requirements and dietary reference intake, which represents values that cover the needs of 97.5% of the population. Critically ill children have an increased protein turnover due to an increase in whole-body protein synthesis and breakdown with protein degradation leading to loss of lean body mass (LBM) and development of growth failure, malnutrition, and worse clinical outcomes. The results of protein balance studies in critically ill children indicate higher protein needs, with infants and younger children requiring higher intakes per body weight compared with older children. Monitoring the side effects of increased protein intake should be performed. Recent studies found a survival benefit in critically ill children who received a higher percentage of prescribed energy and protein goal by the enteral route. Future randomized studies should evaluate the effect of protein dosing in different age groups on patient outcomes, including LBM, muscle structure and function, duration of mechanical ventilation, intensive care unit and hospital length of stay, and mortality.

Intensive care unit-acquired weakness

When critically ill, a severe weakness of the limbs and respiratory muscles often develops with a prolonged stay in the intensive care unit (ICU), a condition vaguely termed intensive care unit-acquired weakness (ICUAW). Many of these patients have serious nerve and muscle injury. This syndrome is most often seen in surviving critically ill patients with sepsis or extensive inflammatory response which results in increased duration of mechanical ventilation and hospital length of stay. Patients with ICUAW often do not fully recover and the disability will seriously impact on their quality of life. In this chapter we discuss the current knowledge on the pathophysiology and risk factors of ICUAW. Tools to diagnose ICUAW, how to separate ICUAW from other disorders, and which possible treatment strategies can be employed are also described. ICUAW is finally receiving the attention it deserves and the expectation is that it can be better understood and prevented.

Gastrointestinal failure in the ICU

PURPOSE OF REVIEW

The current review summarizes different aspects of assessment of gastrointestinal function and provides a practical approach to management of adult patients with gastrointestinal dysfunction in the ICU.

RECENT FINDINGS

Different ways to define gastrointestinal failure have been used in the past. Recently, the term 'acute gastrointestinal injury (AGI)' has been proposed to specifically describe gastrointestinal dysfunction as a part of multiple organ dysfunction syndrome. Possible pathophysiological mechanisms and different aspects in assessment of gastrointestinal function in adult ICU patients are presented. Currently, there is no single marker that could reliably describe gastrointestinal dysfunction. Therefore, monitoring and management is still based on complex assessment of different gastrointestinal symptoms and feeding intolerance, even though this approach includes a large amount of subjectivity. The possible role of biomarkers (citrulline, enterohormones, etc.) and additional parameters like intra-abdominal pressure remains to be clarified.

SUMMARY

Defining gastrointestinal failure remains challenging but broad consensus needs to be reached and disseminated soon to allow conduct of interventional studies. A systematic approach to management of gastrointestinal problems is recommended.

Intake of Dietary Supplements and Malnutrition in Patients in Intensive Care Unit

Background:

Malnutrition is prevalent among patients hospitalized in Intensive Care Units (ICUs) and causes various complications. Dietary supplementation to provide appropriate nutritional support may reduce the malnutrition and complications through improvement in nutritional status. This study was carried out to assess the association between dietary supplementation and malnutrition among patients in ICUs.

Methods:

A case–control study was conducted on 180 male patients aged 20–60 years in the ICUs of the hospitals in Ahvaz, Iran in 2013. Data of two groups including 83 patients (cases) who had consumed regular hospital meals and dietary supplements and 97 patients (controls) who had received regular hospital meals were compared. Anthropometric measurements, laboratory values, and dietary intakes were extracted from medical records, and Maastricht index (MI) was calculated. Data were analyzed using the IBM SPSS Statistics 21. T-test and paired-sample t-test were used to determine the difference between groups.

Results:

Taking supplements increased daily energy intake, carbohydrate, and protein in case group (n = 83) significantly (P < 0.05). MI changed to 3.1 ± 3.8 and 4.3 ± 4.2 in case (n = 83) and control (n = 97) groups, respectively. Although the MI fell in both groups, it showed a greater reduction in case group (from 6.3 ± 5.3 to 3.1 ± 3.8).

Conclusions:

Since consuming dietary supplements besides the regular hospital meals increased intake of energy and macronutrients and reduced the MI significantly, it was concluded that it helped supply nutritional requirements more effectively and improved the malnutrition in ICU.

Chronic critical illness: the price of survival

BACKGROUND

The evolution of the techniques used in the intensive care setting over the past decades has led on one side to better survival rates in patients with acute conditions and severely impaired vital functions. On the other side, it has resulted in a growing number of patients who survive an acute event, but who then become dependent on one or more life support techniques. Such patients are called chronically critically ill patients.

MATERIALS & METHODS

No absolute definition of the disease is currently available, although most patients are characterized by the need for prolonged mechanical ventilation. Mortality rates are still high even after dismissal from intensive care unit (ICU) and transfer to specialized rehabilitation care settings.

RESULTS

In recent years, some studies have tried to clarify the pathophysiological characteristics underlying chronic critical illness (CCI), a disease that is also characterized by severe endocrine and inflammatory impairments, partly accounting for the almost constant set of symptoms.

DISCUSSION

Currently, no specific treatment is available. However, a strategic early therapeutic approach on ICU admission might try to prevent the progress of the acute disease towards chronic critical illness.

Editorial on the original article entitled "Permissive underfeeding of standard enteral feeding in critically ill adults" published in the New England Journal of Medicine on June 18, 2015

On June 18, 2015, the New England Journal of Medicine published an article entitled "Permissive underfeeding of standard enteral feeding in critically ill adults", which reports the results of a study that examined the impact of prolonged nutritional energy restriction for critically ill patients. The study design was unique in the sense that patients in both groups received similar doses of protein during the intervention, while the non-protein energy intake was reduced in the intervention group. The study showed no differences in outcome between the two study groups. These results add to a growing body of high quality evidence against the dogmatic belief that full enteral or parenteral feeding should be given as early as possible during critical illness to prevent complications. Further research is now needed to address the question of the optimal timing to provide more nutritional support for the benefit of the patients, possibly guided by improved biomarkers that need to be developed and validated, and to investigate underlying mechanisms.