Enteral nutrition in septic shock: a call for a paradigm shift.

PURPOSE OF REVIEW: The purpose of this review is to identify contemporary evidence evaluating enteral nutrition in patients with septic shock, outline risk factors for enteral feeding intolerance (EFI), describe the conundrum of initiating enteral nutrition in patients with septic shock, appraise current EFI definitions, and identify bedside monitors for guiding enteral nutrition therapy. RECENT FINDINGS: The NUTRIREA-2 and NUTRIREA-3 trial results have better informed the dose of enteral nutrition in critically ill patients with circulatory shock. In both trials, patients with predominant septic shock randomized to receive early standard-dose nutrition had more gastrointestinal complications. Compared to other contemporary RCTs that included patients with circulatory shock, patients in the NUTRIREA-2 and NUTRIREA-3 trials had higher bowel ischemia rates, were sicker, and received full-dose enteral nutrition while receiving high baseline dose of vasopressor. These findings suggest severity of illness, vasopressor dose, and enteral nutrition dose impact outcomes. SUMMARY: The provision of early enteral nutrition preserves gut barrier functions; however, these benefits are counterbalanced by potential complications of introducing luminal nutrients into a hypo-perfused gut, including bowel ischemia. Findings from the NUTRIREA2 and NUTRIREA-3 trials substantiate a 'less is more' enteral nutrition dose strategy during the early acute phase of critical illness. In the absence of bedside tools to guide the initiation and advancement of enteral nutrition in patients with septic shock, the benefit of introducing enteral nutrition on preserving gut barrier function must be weighed against the risk of harm by considering dose of vasopressor, dose of enteral nutrition, and severity of illness.

Personalized nutrition therapy in critical care: 10 expert recommendations.

Personalization of ICU nutrition is essential to future of critical care. Recommendations from American/European guidelines and practice suggestions incorporating recent literature are presented. Low-dose enteral nutrition (EN) or parenteral nutrition (PN) can be started within 48 h of admission. While EN is preferred route of delivery, new data highlight PN can be given safely without increased risk; thus, when early EN is not feasible, provision of isocaloric PN is effective and results in similar outcomes. Indirect calorimetry (IC) measurement of energy expenditure (EE) is recommended by both European/American guidelines after stabilization post-ICU admission. Below-measured EE (~ 70%) targets should be used during early phase and increased to match EE later in stay. Low-dose protein delivery can be used early (~ D1-2) (< 0.8 g/kg/d) and progressed to ≥ 1.2 g/kg/d as patients stabilize, with consideration of avoiding higher protein in unstable patients and in acute kidney injury not on CRRT. Intermittent-feeding schedules hold promise for further research. Clinicians must be aware of delivered energy/protein and what percentage of targets delivered nutrition represents. Computerized nutrition monitoring systems/platforms have become widely available. In patients at risk of micronutrient/vitamin losses (i.e., CRRT), evaluation of micronutrient levels should be considered post-ICU days 5-7 with repletion of deficiencies where indicated. In future, we hope use of muscle monitors such as ultrasound, CT scan, and/or BIA will be utilized to assess nutrition risk and monitor response to nutrition. Use of specialized anabolic nutrients such as HMB, creatine, and leucine to improve strength/muscle mass is promising in other populations and deserves future study. In post-ICU setting, continued use of IC measurement and other muscle measures should be considered to guide nutrition. Research on using rehabilitation interventions such as cardiopulmonary exercise testing (CPET) to guide post-ICU exercise/rehabilitation prescription and using anabolic agents such as testosterone/oxandrolone to promote post-ICU recovery is needed.

Nutrition, defecation, and the lower gastrointestinal tract during critical illness.

PURPOSE OF REVIEW: The goal of this report is to delineate the correlation between constipation as a manifestation of impaired gastrointestinal transit with adverse clinical outcomes, to identify risk factors, which predispose to this condition, and outline a management scheme for prophylactic treatment. RECENT FINDINGS: Constipation is common in the ICU, affecting upwards of 60-85% of critically ill patients. As suggested by case series and observational studies, constipation may be an independent prognostic factor identifying patients with greater disease severity, higher likelihood of organ dysfunction, longer duration of mechanical ventilation, prolonged hospital length of stay, and possibly reduced survival. Treating constipation is a low priority for intensivists often relegated to the nursing service, and few ICUs have well designed protocols in place for a bowel regimen. Small randomized controlled trials show improvement in certain outcome parameters in response to a daily lactulose therapy; hospital length of stay, sequential organ failure assessment scores, and duration of mechanical ventilation. However, aggregating the data from these studies in two separate meta-analyses showed that the effect of a bowel regimen on these three endpoints were not statistically different. SUMMARY: No causal relationship can be determined between constipation and adverse outcomes. Nonetheless, a clinical correlation seems to exist. Whether constipation is an epiphenomenon or simply a reflection of greater severity of critical illness, at some point it may contribute to worsening morbidity in the ICU. A graded prophylactic bowel regimen should help reverse impairment of the gastrointestinal transit and aid in reducing its deleterious impact on the hospital course of the critically ill patient.

Preparative Fasting Orders for Medical/Surgical Interventions and Imaging Studies: Time to Review and Revise!

PURPOSE OF THE REVIEW: Preparative fasting orders arose out of a purported need to enhance imaging studies, reduce interference of food with intended medical/surgical interventions, and protect the patient from vomiting and aspiration pneumonia. This review discusses the frequency, appropriateness, and efficacy of fasting orders in meeting those needs and whether their use should be modified in the future. RECENT FINDINGS: Nil per os (NPO) orders are overused, as they are often inappropriate, typically excessive, and routinely create barriers which may increase risk for patients. Fasting orders are used more often for medical procedures than for surgical operations or imaging studies. One fourth of NPO orders are inappropriate, and the intended procedure or study is canceled 20% of the time usually for a change in plans or scheduling error and rarely because of patient eating. Nausea/vomiting associated with contrast media or imaging studies is rare, self-limited, and not linked to preparatory fluid or food ingestion. Prolonged fasting reduces patient cooperation and satisfaction, and may contribute to a higher rate of complications. Each institution should review and revise preparative fasting orders. Drinking of fluids should be allowed without restriction. Truncated periods of solid food restriction may be required due to technical reasons related to specific imaging studies, and for procedures or surgical operations which require sedation or general anesthesia. Inappropriate and prolonged fasting should be avoided, as they create barriers to adequate nutritional therapy and impose added risk with regard to patient outcomes.

A guide to enteral nutrition in intensive care units: 10 expert tips for the daily practice.

The preferential use of the oral/enteral route in critically ill patients over gut rest is uniformly recommended and applied. This article provides practical guidance on enteral nutrition in compliance with recent American and European guidelines. Low-dose enteral nutrition can be safely started within 48 h after admission, even during treatment with small or moderate doses of vasopressor agents. A percutaneous access should be used when enteral nutrition is anticipated for ≥ 4 weeks. Energy delivery should not be calculated to match energy expenditure before day 4-7, and the use of energy-dense formulas can be restricted to cases of inability to tolerate full-volume isocaloric enteral nutrition or to patients who require fluid restriction. Low-dose protein (max 0.8 g/kg/day) can be provided during the early phase of critical illness, while a protein target of > 1.2 g/kg/day could be considered during the rehabilitation phase. The occurrence of refeeding syndrome should be assessed by daily measurement of plasma phosphate, and a phosphate drop of 30% should be managed by reduction of enteral feeding rate and high-dose thiamine. Vomiting and increased gastric residual volume may indicate gastric intolerance, while sudden abdominal pain, distension, gastrointestinal paralysis, or rising abdominal pressure may indicate lower gastrointestinal intolerance.

Clinical nutrition for the gastroenterologist: the physiologic rationale for providing early nutritional therapy to the hospitalized patient.

PURPOSE OF REVIEW: Conflicting reports in the literature have been misinterpreted by clinicians, who conclude that nutritional therapy for the hospitalized patient is of marginal value. The true benefit of such therapy is derived from the provision of early enteral nutrition. This article describes the physiologic response to enteral feeding, which accounts for the outcome benefits, and illustrates how use of the gut alters immune responses and the intestinal microbiota. RECENT FINDINGS: The provision of early enteral nutrition has been shown to reduce infection and mortality in high-risk hospitalized patients (compared with not providing such therapy). Early feeding maintains gut integrity, reduces permeability, promotes tolerance and appropriate immune responses, and supports commensalism of the intestinal microbiota. Early enteral nutrition influences cross-talk signaling between luminal bacteria and the intestinal epithelium. Failure to utilize the gut in acute illness can amplify the systemic inflammatory response syndrome and worsen disease severity, while at the same time promoting antibiotic resistance and increased septic morbidity. SUMMARY: Appropriate nutritional therapy does change outcomes in the hospitalized patient, especially for those who are at risk on the basis of disease severity and/or poor nutritional status. Greatest benefit is seen from those therapeutic regimens that specifically target gut defenses and the intestinal microbiome.

Clinical nutrition for the gastroenterologist: bedside strategies for feeding the hospitalized patient.

PURPOSE OF REVIEW: The timing, advancement, and use of appropriate monitors determine whether the hospitalized patient experiences the full benefit of nutritional therapy. This article reviews management strategies in delivering the optimal nutrition regimen capable of improving outcomes in the hospitalized patient. RECENT FINDINGS: Enteral nutrition should be initiated in the first 24-36 h after admission. Determination of nutritional risk helps guide the urgency with which nutritional therapy is provided and predicts the likelihood for difficulties in delivering the prescribed regimen. Feeds should be advanced slowly over 3-4 days to meet 70-80% of goal for calories (20 kcal/kg/day) and 100% for protein (2.0 gm/kg/day). Reaching protein goals early on may be more important than achieving energy goals. Patients should be monitored for hemodynamic stability, evidence of refeeding syndrome, and tolerance in the setting of gastrointestinal dysfunction. Parenteral nutrition should be utilized in select high-risk patients where the feasibility of full enteral nutrition is questioned. SUMMARY: Timing with early initiation of enteral nutrition, avoidance of overfeeding, and step-wise advancement of feeds are required to safely realize the benefits of such therapy.

Does the Intestinal Microbiome Impact Athletic Performance?

PURPOSE OF REVIEW: To analyze current research involving elite athletes and the gut microbiome, with the goal to expand knowledge of potential sports performance strategies and interventions. RECENT FINDINGS: Most of the current research focuses on theoretical applications from microbiome research and known characteristics of performance, as few studies have actually been conducted in elite athletes. However, of the studies that have been conducted, the research is promising that dietary strategies may provide targeted interventions in the future. The majority of sports nutrition takes an external approach to diet: manipulating macronutrient intake based on type of training and performance goals. However, shifting to an internal focus, prioritizing the health of the gut microbiome, could be a new frontier for a competitive edge in athletics.

Gastrointestinal Dysfunction and Feeding Intolerance in Critical Illness: Do We Need an Objective Scoring System?

PURPOSE OF REVIEW: Efforts to provide early enteral nutrition in critical illness are thwarted by gastrointestinal dysfunction and feeding intolerance. While many of the signs and symptoms of this dysfunction reflect gastroparesis and intestinal dysmotility, other symptoms which may or may not be related are often included such as diarrhea, bleeding, and intra-abdominal hypertension. This paper discusses the need to monitor tolerance of nutritional therapy in the critical care setting and reviews the results of those clinical trials which have helped establish objective measures, define feeding intolerance, and provide a tool to guide continued delivery of the enteral regimen. RECENT FINDINGS: While definitions vary, the presence of gastrointestinal dysfunction and feeding intolerance correlates with adverse clinical outcomes, including prolonged duration of mechanical ventilation, greater length of stay in the intensive care unit, and increased mortality. Despite their prognostic value, it is not clear to what extent these scoring systems should direct nutritional therapy. The clinician should be astute in the careful selection of monitors, in identifying and addressing signs and symptoms of intolerance, and by responding appropriately with feeding strategies that are effective and safe. Early enteral feeding in critical illness has been shown to be optimized by following protocols which allow monitoring patient tolerance while providing individualized care.

Metabolic support in the critically ill: a consensus of 19.

Metabolic alterations in the critically ill have been studied for more than a century, but the heterogeneity of the critically ill patient population, the varying duration and severity of the acute phase of illness, and the many confounding factors have hindered progress in the field. These factors may explain why management of metabolic alterations and related conditions in critically ill patients has for many years been guided by recommendations based essentially on expert opinion. Over the last decade, a number of randomized controlled trials have been conducted, providing us with important population-level evidence that refutes several longstanding paradigms. However, between-patient variation means there is still substantial uncertainty when translating population-level evidence to individuals. A cornerstone of metabolic care is nutrition, for which there is a multifold of published guidelines that agree on many issues but disagree on others. Using a series of nine questions, we provide a review of the latest data in this field and a background to promote efforts to address the need for international consistency in recommendations related to the metabolic care of the critically ill patient. Our purpose is not to replace existing guidelines, but to comment on differences and add perspective.

Should fecal microbial transplantation be used in the ICU?

PURPOSE OF REVIEW: Maintaining gut barrier defenses, modulating immune responses, and supporting the role of commensal microbiota are major factors influencing outcome in critical illness. Of these, maintaining a commensal 'lifestyle' and preventing the emergence of a virulent pathobiome may be most important in reducing risk of infection and multiple organ failure. RECENT FINDINGS: The polymeric formulas utilized for enteral nutrition in the ICU are absorbed high in the gastrointestinal tract and may not reach the microbial burden in the cecum where their effect is most needed. The provision of a few select probiotic organisms may be insufficient to refaunate the gut and establish a 'recovery pattern,' propelling the patient toward health and homeostasis. Use of fecal microbial transplantation (FMT) appears to be a more successful strategy for replenishing the intestinal microbiome and maintaining its commensal phenotypic expression. SUMMARY: FMT has become an attractive option to mitigate multiple organ dysfunction in the ICU. This article discusses the physiology, rationale, early experience, and expectations for such therapy in the critically ill patient.

Technical Aspects of Fecal Microbial Transplantation (FMT).

PURPOSE OF REVIEW: Fecal microbial transplantation (FMT) has become established as an effective therapeutic modality in the treatment of antibiotic-refractory recurrent Clostridium difficile colitis. A number of formulations and methods of delivery of FMT are currently available, each with distinct advantages. This review aims to review donor and patient selection for FMT as well as procedural aspects of FMT to help guide clinical practice. RECENT FINDINGS: FMT can be obtained in fresh, frozen, lyophilized, and capsule-based formulations for delivery by oral ingestion, nasoenteric tube, colonoscopy, or enema (depending on the formulation used). Choosing the optimal method relies heavily on patient-related factors, including underlying pathology and severity of illness. As potential applications for FMT expand, careful donor screening and patient selection are critical to minimizing risk to patients and physicians. FMT represents an excellent therapeutic option for treatment of recurrent Clostridium difficile colitis and holds promise as a possible treatment modality in a variety of other conditions. The wide array of delivery methods allows for its application in various disease states in both the inpatient and outpatient setting.

Assessing the value of endoscopic ultrasound in predicting symptom severity and long-term clinical course in chronic pancreatitis.

BACKGROUND: To date, no studies have evaluated the correlation between number of endoscopic ultrasound (EUS) criteria met for chronic pancreatitis (CP) and symptom severity over the course of the disease. This study assessed the relationship between number of EUS-based diagnostic criteria for CP and CP severity over time. METHODS: A University of Louisville database was queried for patients undergoing EUS due to concern for chronic pancreatitis between 2005 and 2016. Patients were grouped based on EUS criteria met for CP and groups were compared along outcome and procedural variables. RESULTS: Of a total of 243 patients, 24, 129, and 90 patients met 1-3, 4-5, and ≥6 EUS diagnostic criteria, respectively. Median follow-up time was 33 months. Along all follow-up parameters, number of diagnostic criteria was positively correlated with an increased percentage of patients requiring operative intervention for chronic pancreatitis on univariate and multivariate analysis. CONCLUSIONS: In addition to the role of EUS criteria in establishing the diagnostic severity of patients with symptomatic chronic pancreatitis, the number of EUS-based criteria may help predict patients who will eventually require operative intervention and thus prompt referral to a pancreatobiliary surgeon earlier in the course of a patient's disease.

ACG Clinical Guideline: Nutrition Therapy in the Adult Hospitalized Patient.

The value of nutrition therapy for the adult hospitalized patient is derived from the outcome benefits achieved by the delivery of early enteral feeding. Nutritional assessment should identify those patients at high nutritional risk, determined by both disease severity and nutritional status. For such patients if they are unable to maintain volitional intake, enteral access should be attained and enteral nutrition (EN) initiated within 24-48 h of admission. Orogastric or nasogastric feeding is most appropriate when starting EN, switching to post-pyloric or deep jejunal feeding only in those patients who are intolerant of gastric feeds or at high risk for aspiration. Percutaneous access should be used for those patients anticipated to require EN for >4 weeks. Patients receiving EN should be monitored for risk of aspiration, tolerance, and adequacy of feeding (determined by percent of goal calories and protein delivered). Intentional permissive underfeeding (and even trophic feeding) is appropriate temporarily for certain subsets of hospitalized patients. Although a standard polymeric formula should be used routinely in most patients, an immune-modulating formula (with arginine and fish oil) should be reserved for patients who have had major surgery in a surgical ICU setting. Adequacy of nutrition therapy is enhanced by establishing nurse-driven enteral feeding protocols, increasing delivery by volume-based or top-down feeding strategies, minimizing interruptions, and eliminating the practice of gastric residual volumes. Parenteral nutrition should be used in patients at high nutritional risk when EN is not feasible or after the first week of hospitalization if EN is not sufficient. Because of their knowledge base and skill set, the gastroenterologist endoscopist is an asset to the Nutrition Support Team and should participate in providing optimal nutrition therapy to the hospitalized adult patient.

Does the use of specialized proresolving molecules in critical care offer a more focused approach to controlling inflammation than that of fish oils?

PURPOSE OF REVIEW: The literature regarding the use of fish oils in the critically ill to limit the inflammatory and catabolic response have been inconsistent. The objective of this manuscript is to review a newly discovered class of specialized proresolving molecules (SPMs), which could help elucidate the discrepancies reported in the critical care literature regarding the anti-inflammatory benefits of fish oil/ω-3 fatty acids. RECENT FINDINGS: Although use of fish oil has traditionally been thought to reduce or limit the inflammatory process in the critical ill, a new class of endogenously produced highly active lipid mediators derived from arachidonic acid and ω-3 fatty acids (lipoxins, resolvins, protectins, and maresins) have been shown to actively enhance resolution of inflammation. These SPMs stimulate the cardinal signs of resolution of inflammation, which include the cessation of leukocytic infiltration, a countering of the effects of proinflammatory mediators, stimulation of the uptake of apoptotic neutrophils, promotion of the clearance of necrotic cellular debris, and enhancement of the host's ability to eliminate microbial invasion. SUMMARY: By actively turning off inflammation (instead of simply attenuating its natural course), SPMs have shown more consistent effects in decreasing pain and risk of sepsis, increasing epithelialization and wound healing, promoting tissue regeneration, potentiating the effects of antibiotics, and enhancing adaptive immunity.

Common Medications Which Lead to Unintended Alterations in Weight Gain or Organ Lipotoxicity.

Obesity is one of the most common chronic conditions in the world. Its management is difficult, partly due to the multiple associated comorbidities including fatty liver, diabetes, hypertension, and hyperlipidemia. As a result, the choice of prescription medications in overweight and obese patients has important implications as some of them can actually worsen the fat accumulation and its associated metabolic complications. Several prescription medications are associated with weight gain with mechanisms that are often poorly understood and under-recognized. Even less data are available on the distribution of fat and lipotoxicity (the organ damage related to fat accumulation). The present review will discuss the drugs associated with weight gain, their mechanism of action, and the magnitude and timing of their effect.

Can Nutritional Assessment Tools Predict Response to Nutritional Therapy?

Traditional tools and scoring systems for nutritional assessment have focused solely on parameters of poor nutritional status in the past, in an effort to define the elusive concept of malnutrition. Such tools fail to account for the contribution of disease severity to overall nutritional risk. High nutritional risk, caused by either deterioration of nutritional status or greater disease severity (or a combination of both factors), puts the patient in a metabolic stress state characterized by adverse outcome and increased complications. Newer scoring systems for determining nutritional risk, such as the Nutric Score and the Nutritional Risk Score-2002 have created a paradigm shift connecting assessment and treatment with quality outcome measures of success. Clinicians now have the opportunity to identify high risk patients through their initial assessment, provide adequate or sufficient nutrition therapy, and expect improved patient outcomes as a result. These concepts are supported by observational and prospective interventional trials. Greater clinical experience and refinement in these scoring systems are needed in the future to optimize patient response to nutrition therapy.