Controversies in Critical Care Nutrition Support

Bolus Versus Continuous Enteral Feeding for Critically Ill Patients: A Systematic Review and Meta-Analysis

Enteral feeding is a crucial aspect of nutritional support for critically ill patients. However, the optimal feeding approach, whether bolus or continuous, remains a subject of debate. This systematic review and meta-analysis aimed to compare the outcomes of bolus feeding and continuous enteral feeding in critically ill patients. A systemic search was carried out in PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL) Ultimate, Web of Science, Scopus, and Google Scholar to identify relevant studies. To ensure that we obtain the latest evidence on the topic, the search was limited to the last five years. Risk of bias assessments and meta-analyses were performed for relevant clinical outcomes. A total of nine randomized controlled trials (RCTs) were included, involving a total of 863 patients. All the studies were published between 2020 and 2023. High-risk performance bias was observed in seven studies, with unclear risk in two studies. In terms of clinical outcomes, no statistically significant differences were found between bolus and continuous enteral feeding in terms of diarrhea (odds ratio {OR} 0.60, 95% CI 0.27 to 1.30, p=0.20), constipation (OR 1.52, 95% CI 0.91 to 2.53, p=0.11), vomiting (OR 0.74, 95% CI 0.36 to 1.49, p=0.39), distention (OR 0.70, 95% CI 0.14 to 3.58, p=0.66), aspiration (OR 0.61, 95% CI 0.16 to 2.73, p=0.48), and gastric residual volume (GRV) (OR 0.80, 95% CI 0.30 to 2.15, p=0.66). Furthermore, no significant differences between bolus and continuous feeding were observed in terms of intensive care unit (ICU) mortality (OR 0.66, 95% CI 0.42 to 1.04, p=0.07), hospital mortality (OR 0.57, 95% CI 0.31 to 1.03, p=0.06), ICU length of stay (OR 0.70, 95% CI 0.50 to 1.90, p=0.25), and hospital length of stay (OR -0.86, 95% CI -3.04 to 1.33, p=0.44). This systematic review and meta-analysis suggest that bolus and continuous enteral feeding methods exhibit comparable outcomes in critically ill patients. However, both ICU mortality and hospital mortality outcomes were close to achieving statistical significance, which favored the continuous feeding approach.

Early enteral versus early parenteral nutrition in critically ill patients with respiratory distress: a case–control study

Background

Nutritional support is essential as enteral or parenteral nutrition to reduce catabolism, to lower the complications rate, and to improve outcomes in critically ill patients.

Results

The median, range age of the cohort was (median 10, range 6–18.8 months). One-hundred thirteen (62.8%) were males, and 67 (37.2%) were females. The higher frequency of sepsis, ventilator-acquired pneumonia (VAP), and mortality founded in the group received PN. Frequency of sepsis was 15 (16.7%), VAP was 5 (5.6%), and the mortality rate was 11.1% in EN group, while frequency of sepsis was 37 (41.1%), VAP was 23 (25.6%), and the mortality rate was 27.8% in PN group (P = 0.001, 0.001, 0.01, respectively). Median of weight gain on the EN group was 0.17 kg at 2nd week which was more than those in PN group (P = 0.001). The mean ± SD time for reaching the caloric target for those receiving early EN was 4.0 ± 1.9 days which is earlier than that of PN group (6.2 ± 1.7 days) (P = 0.001). There is no significant difference between both groups as regard pediatric intensive care unit (PICU) stay length and mechanical ventilation stay length.

Conclusion

Early EN remains the preferred route for nutrient delivery as the PN route was accompanied by a lot of complication such as sepsis, VAP, and high mortality rate.

Impact of an interdisciplinary nutrition support team (NST) on the clinical outcome of critically ill patients. A pre/post NST intervention study

BACKGROUND

Intensive care unit (ICU) patients are at particular risk for malnutrition with major impact for outcome and prognosis. Nutrition support teams (NST) have been proposed to improve nutrition care in ICU patients.

OBJECTIVE

To assess the effectiveness of an interdisciplinary NST on anthropometry and clinical outcome of ICU patients.

METHODS

Before NST implementation, we assessed 120 patients (before NST group; SAPS II score 44 ± 16), afterwards 60 patients (after NST group), of whom 29 received NST guidance (after NST + group; SAPS II 65 ± 19) and 31 not (after NST - group; SAPS II, 54 ± 16). The primary outcome parameter was length of stay in the hospital (hospital-LOS). Severity of disease was assessed by the APACHE II score and the nutritional risk (NUTRIC) score.

RESULTS

NST intervention resulted in a more pronounced improvement of disease severity (APACHE II, from 27 ± 8 to 18 ± 6, p < 0.001; NUTRIC, from 7 ± 2 to 4 ± 2, p < 0.001) compared to no NST intervention (APACHE II from 24 ± 7 to 21 ± 7, p < 0.05; NUTRIC from 6 ± 2 to 5 ± 2, p < 0.01). The mean hospital-LOS was not reduced, neither in the NST intervention group nor in the control group without NST intervention. NST intervention failed to improve nutritional status or mortality compared to no NST intervention.

CONCLUSION

In our study the NST intervention had a positive effect on disease severity, but failed to improve mortality, hospital-LOS or nutritional status in ICU patients, likely because of a large patient heterogeneity.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT02200874).

Nutritional composition and cost of home-prepared enteral tube feeding

BACKGROUND & AIMS

To aid in dietary prescription and contribute to the promotion of food and nutritional safety of individuals, this study's objective was to compare the nutritional composition and cost of homemade preparations, blended preparations, and commercial enteral formula prescribed for adults and elderly people at hospital discharge.

METHODS

All hospitals in a Brazilian city that prescribed the three types of enteral formulations provide information about enteral formulations prescribed for home use. Enteral formulations were estimated in relation to energy content, macronutrients, micronutrients, and cost.

RESULTS

Homemade diets, blended and commercial enteral formulations showed, on average, normoproteic, normoglicidic and normolipidic features, with average daily costs (US$/2000 kcal) of US$ 29.77, 50.56 and 154.44, respectively. The cost was higher in the commercial enteral formulas (P < .001); vitamin and mineral content were poorer in homemade preparations.

CONCLUSIONS

The homemade and blended enteral preparations cost less, but were generally lower in micronutrients, calling for more adequate dietary prescription.

Should I Start With A Postpyloric Enteral Nutrition Modality?

Nutrition therapy is a key element in the management of malnourished and critically ill patients. Although many aspects of enteral nutrition (EN) have been well defined by research, with clear recommendations by 3 major society guidelines, EN delivery method remains a topic for debate. The goal of this manuscript is to concisely review gastric vs postpyloric enteral feeding in critically ill adult patients and provide a set of recommendations to individualize EN delivery method based on patient characteristics and specific needs.

Are Classic Bedside Exam Findings Required to Initiate Enteral Nutrition in Critically Ill Patients: Emphasis on Bowel Sounds and Abdominal Distension

The general physical examination of a patient is an axiom of critical care medicine, but evidence to support this practice remains sparse. Given the lack of evidence for a comprehensive physical examination of the entire patient on admission to the intensive care unit, which most clinicians consider an essential part of care, should clinicians continue the practice of a specialized gastrointestinal system physical examination when commencing enteral nutrition in critically ill patients? In this review of literature related to gastrointestinal system examination in critically ill patients, the focus is on gastrointestinal sounds and abdominal distension. There is a summary of what these physical features represent, an evaluation of the evidence regarding use of these physical features in patients after abdominal surgery, exploration of the rationale for and against using the physical findings in routine practice, and detail regarding what is known about each feature in critically ill patients. Based on the available evidence, it is recommended that an isolated symptom, sign, or bedside test does not provide meaningful information. However, it is submitted that a comprehensive physical assessment of the gastrointestinal system still has a role when initiating or administering enteral nutrition: specifically, when multiple features are present, clinicians should consider further investigation or intervention.

Novel Resolution Mediators of Severe Systemic Inflammation

Nonresolving inflammation, a hallmark of underlying severe inflammatory processes such as sepsis, acute respiratory distress syndrome and multiple organ failure is a major cause of admission to the intensive care unit and high mortality rates. Many survivors develop new functional limitations and health problems, and in cases of sepsis, approximately 40% of patients are rehospitalized within three months. Over the last few decades, better treatment approaches have been adopted. Nevertheless, the lack of knowledge underlying the complex pathophysiology of the inflammatory response organized by numerous mediators and the induction of complex networks impede curative therapy. Thus, increasing evidence indicates that resolution of an acute inflammatory response, considered an active process, is the ideal outcome that leads to tissue restoration and organ function. Many mediators have been identified as immunoresolvents, but only a few have been shown to contribute to both the initial and resolution phases of severe systemic inflammation, and these agents might finally substantially impact the therapeutic approach to severe inflammatory processes. In this review, we depict different resolution mediators/immunoresolvents contributing to resolution programmes specifically related to life-threatening severe inflammatory processes.

Increased intestinal permeability exacerbates sepsis through reduced hepatic SCD-1 activity and dysregulated iron recycling

Inflammatory bowel disease is associated with changes in the mucosal barrier, increased intestinal permeability, and increased risk of infections and sepsis, but the underlying mechanisms are incompletely understood. Here, we show how continuous translocation of gut microbial components affects iron homeostasis and facilitates susceptibility to inflammation-associated sepsis. A sub-lethal dose of lipopolysaccharide results in higher mortality in Mucin 2 deficient (Muc2^-/-) mice, and is associated with elevated circulatory iron load and increased bacterial translocation. Translocation of gut microbial components attenuates hepatic stearoyl CoA desaturase-1 activity, a key enzyme in hepatic de novo lipogenesis. The resulting reduction of hepatic saturated and unsaturated fatty acid levels compromises plasma membrane fluidity of red blood cells, thereby significantly reducing their life span. Inflammation in Muc2^-/- mice alters erythrophagocytosis efficiency of splenic macrophages, resulting in an iron-rich milieu that promotes bacterial growth. Our study thus shows that increased intestinal permeability triggers a cascade of events resulting in increased bacterial growth and risk of sepsis.

The gut in trauma

PURPOSE OF REVIEW

The purpose of this review is to describe established and emerging mechanisms of gut injury and dysfunction in trauma, describe emerging strategies to improve gut dysfunction, detail the effect of trauma on the gut microbiome, and describe the gut-brain connection in traumatic brain injury.

RECENT FINDINGS

Newer data suggest intraluminal contents, pancreatic enzymes, and hepatobiliary factors disrupt the intestinal mucosal layer. These mechanisms serve to perpetuate the inflammatory response leading to multiple organ dysfunction syndrome (MODS). To date, therapies to mitigate acute gut dysfunction have included enteral nutrition and immunonutrition; emerging therapies aimed to intestinal mucosal layer disruption, however, include protease inhibitors such as tranexamic acid, parenteral nutrition-supplemented bombesin, and hypothermia. Clinical trials to demonstrate benefit in humans are needed before widespread applications can be recommended.

SUMMARY

Despite resuscitation, gut dysfunction promotes distant organ injury. In addition, postresuscitation nosocomial and iatrogenic 'hits' exaggerate the immune response, contributing to MODS. This was a provocative concept, suggesting infectious and noninfectious causes of inflammation may trigger, heighten, and perpetuate an inflammatory response culminating in MODS and death. Emerging evidence suggests posttraumatic injury mechanisms, such as intestinal mucosal disruption and shifting of the gut microbiome to a pathobiome. In addition, traumatic brain injury activates the gut-brain axis and increases intestinal permeability.

Controversies Surrounding Critical Care Nutrition: An Appraisal of Permissive Underfeeding, Protein, and Outcomes

Over the past few years, numerous studies have called into question the optimal dose, timing, composition, and advancement rate of nutrition during the early acute phase of critical illness. These studies suggest permissive underfeeding with slow advancement may be more beneficial than aggressive full feeding. These counterintuitive results were possibly explained by enhanced autophagy, less hyperglycemia, or prevention of refeeding syndrome. This review underscores the controversies surrounding permissive underfeeding, aims to answer whether permissive underfeeding is appropriate for all critically ill patients, describes the impact of optimal protein delivery on critical care outcomes, discusses nutrition risk, and cogitates on the impact of nutrition on critical care outcomes.

Resolution of inflammation and sepsis survival are improved by dietary Ω-3 fatty acids

Critical conditions such as sepsis following infection or traumatic injury disturb the complex state of homeostasis that may lead to uncontrolled inflammation resulting in organ failure, shock and death. They are associated with endogenous mediators that control the onset of acute inflammatory response, but the central problem remains the complete resolution of inflammation. Omega-3 enriched lipid emulsions (Ω-3⁺ LEs) were used in experimental studies and clinical trials to establish homeostasis, yet with little understanding about their role on the resolution of inflammation and tissue regeneration. Here, we demonstrate that Ω-3 lipid emulsions (LEs) orchestrate inflammation-resolution/regeneration mechanism during sterile peritonitis and murine polymicrobial sepsis. Ω-3⁺ LEs recessed neutrophil infiltration, reduced pro-inflammatory mediators, reduced the classical monocyte and enhanced the non-classical monocytes/macrophages recruitment and finally increased the efferocytosis in sepsis. The actions of Ω-3⁺ LE were 5-lipoxygenase (5-LOX) and 12/15-lipoxygenase (12/15-LOX) dependent. Ω-3⁺ LEs shortened the resolution interval by 56%, stimulated the endogenous biosynthesis of resolution mediators lipoxin A4, protectin DX and maresin 1 and contributed to tissue regeneration. Ω-3⁺ LEs protected against hypothermia and weight loss and enhanced survival in murine polymicrobial sepsis. We highlighted a role of Ω-3⁺ LEs in regulating key mechanisms within the resolution terrain during murine sepsis. This might form the basis for a rational design of sepsis specific clinical nutrition.

Critical Care Nutrition: Where's the Evidence?

The surgical critically ill patient is subject to a variable and complex metabolic response, which has detrimental effects on immunity, wound healing, and preservation of lean body muscle. The concept of nutrition support has evolved into nutrition therapy, whereby the primary objectives are to prevent oxidative cell injury, modulate the immune response, and attenuate the metabolic response. This review outlines the metabolic response to critical illness, describes nutritional risk; reviews the evidence for the role, dose, and timing of enteral and parenteral nutrition, and reviews the evidence for immunonutrition in the surgical intensive care unit.

Updates in Nutrition Support for Critically Ill Adult Patients

Specialized nutrition support is often employed in critically ill patients who are unable to maintain volitional intake. The Society of Critical Care Medicine (SCCM) and American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.) recently updated guidelines for the provision of nutrition support in critically ill patients. The purpose of this review is to summarize key changes from the previous guidelines as they relate to recently published literature, which will aid the hospital pharmacist in optimizing nutrition support therapies in the critical care setting.

Protein Requirements for Critically Ill Patients With Renal and Liver Failure

Diseases leading to critical illness induce proteolysis resulting in muscle wasting and negative nitrogen balance. Muscle wasting has been associated with poor intensive care unit (ICU)-related outcomes, including an increased risk for mortality. Acute kidney injury (AKI) represents a common organ dysfunction associated with ICU-related disorders, such as sepsis, trauma, and respiratory failure. AKI and renal replacement therapy lead to amino acid loss. Decompensated liver cirrhosis (DLC) and acute liver failure (ALF) represent more severe forms of liver dysfunction leading to ICU admission. DLC and ALF are associated with proteolysis and amino acid loss. AKI, DLC, and ALF uniquely contribute to negative nitrogen balance. The purpose of this review is to outline proteolysis associated with critical illness; define specific protein abnormalities in AKI, DLC, and ALF; define protein requirements in AKI, DLC, and ALF; and discuss barriers associated with optimal protein supplementation in these disorders.