Influence of enteral nutrition-induced splanchnic hyperemia on the septic origin of splanchnic ischemia

Ischemic insular damage and stress ulcer in patients of acute ischemic stroke

BACKGROUND AND AIMS

Stress ulcer (SU) is a common complication in patients with acute ischemic stroke. The relationship of infarction location and the incidence of SU was unclear. Herein, we aim to investigate the association between ischemic insular damage and the development of SU.

METHODS

Data were retrieved from the SPARK study (Effect of Cardiac Function on Short-Term Functional Prognosis in Patients with Acute Ischemic Stroke). We included the patients who had experienced an ischemic stroke within 7 days. The diagnosis of SU was based on clinical manifestations, including hematemesis, bloody nasogastric tube aspirate, or hematochezia. Evaluation of ischemic insular damage was conducted through magnetic resonance imaging. Cyclo-oxygenase regression analysis and Kaplan-Meier survival curves were used to assess the relationship between ischemic insular damage and the occurrence of SU.

RESULTS

Among the 1357 patients analyzed, 110 (8.1%) developed SUs during hospitalization, with 69 (6.7%) experiencing infarctions in the anterior circulation. After adjusting for potential confounders, patients with ischemic insular damage exhibited a 2.16-fold higher risk of developing SUs compared to those without insular damage (p = .0206). Notably, among patients with infarctions in the anterior circulation, those with insular damage had a 2.21-fold increased risk of SUs (p = .0387). Moreover, right insular damage was associated with a higher risk of SUs compared to left insular damage or no insular damage (p for trend = .0117). Kaplan-Meier curves demonstrated early separation among groups, persisting throughout the follow-up period (all p < .0001).

CONCLUSIONS

This study identified a significant independent correlation between ischemic insular damage, particularly on the right side, and the development of SU during hospitalization, indicating the need to consider prophylactic acid-suppressive treatment for patients with ischemic insular damage.

REVISE: Re-Evaluating the Inhibition of Stress Erosions in the ICU: a randomised trial protocol

INTRODUCTION

The Re-Evaluating the Inhibition of Stress Erosions (REVISE) Trial aims to determine the impact of the proton pump inhibitor pantoprazole compared with placebo on clinically important upper gastrointestinal (GI) bleeding in the intensive care unit (ICU), 90-day mortality and other endpoints in critically ill adults. The objective of this report is to describe the rationale, methodology, ethics and management of REVISE.

METHODS AND ANALYSIS

REVISE is an international, randomised, concealed, stratified, blinded parallel-group individual patient trial being conducted in ICUs in Canada, Australia, Saudi Arabia, UK, US, Kuwait, Pakistan and Brazil. Patients≥18 years old expected to remain invasively mechanically ventilated beyond the calendar day after enrolment are being randomised to either 40 mg pantoprazole intravenously or an identical placebo daily while mechanically ventilated in the ICU. The primary efficacy outcome is clinically important upper GI bleeding within 90 days of randomisation. The primary safety outcome is 90-day all-cause mortality. Secondary outcomes include rates of ventilator-associated pneumonia, Clostridioides difficile infection, new renal replacement therapy, ICU and hospital mortality, and patient-important GI bleeding. Tertiary outcomes are total red blood cells transfused, peak serum creatinine level in the ICU, and duration of mechanical ventilation, ICU and hospital stay. The sample size is 4800 patients; one interim analysis was conducted after 2400 patients had complete 90-day follow-up; the Data Monitoring Committee recommended continuing the trial.

ETHICS AND DISSEMINATION

All participating centres receive research ethics approval before initiation by hospital, region or country, including, but not limited to - Australia: Northern Sydney Local Health District Human Research Ethics Committee and Mater Misericordiae Ltd Human Research Ethics Committee; Brazil: Comissão Nacional de Ética em Pesquisa; Canada: Hamilton Integrated Research Ethics Board; Kuwait: Ministry of Health Standing Committee for Coordination of Health and Medical Research; Pakistan: Maroof Institutional Review Board; Saudi Arabia: Ministry of National Guard Health Affairs Institutional Review Board: United Kingdom: Hampshire B Research Ethics Committee; United States: Institutional Review Board of the Nebraska Medical Centre. The results of this trial will inform clinical practice and guidelines worldwide.

TRIAL REGISTRATION NUMBER

NCT03374800.

Renal Injuries after Cardiac Arrest: A Morphological Ultrastructural Study

BACKGROUND

This study aims to investigate the probable lesions and injuries induced in the renal tissue after a cardiac arrest. The renal ischemia-reperfusion model in cardiac arrest describes the effects of ischemia in the kidneys, alongside a whole-body ischemia-reperfusion injury. This protocol excludes ischemic conditions caused by surgical vascular manipulation, venous injury or venous congestion.

METHODS

For the experimental study, 24 swine were subjected to cardiac arrest. Seven minutes later, the cardiopulmonary resuscitation technique was performed for 5 min. Afterwards, advanced life support was provided. The resuscitated swine consisted one group and the non-resuscitated the other. Tissue samples were obtained from both groups for light and electron microscopy evaluation.

RESULTS

Tissue lesions were observed in the tubules, parallel to destruction of the microvilli, reduction in the basal membrane invaginations, enlarged mitochondria, cellular vacuolization, cellular apoptosis and disorganization. In addition, fusion of the podocytes, destruction of the Bowman's capsule parietal epithelium and abnormal peripheral urinary space was observed. The damage appeared more extensive in the non-resuscitated swine group.

CONCLUSIONS

Acute kidney injury is not the leading cause of death after cardiac arrest. However, evidence suggests that the kidney damage after a cardiac arrest should be highly considered in the prognosis of the patients' health outcome.

Post-Cardiac Arrest Syndrome Is Not Associated With an Early Bacterial Translocation

BACKGROUND

The aim of this study was to investigate bacterial translocation and its possible role in the development of post-resuscitation inflammatory response following Cardio-Pulmonary Resuscitation (CPR) after cardiac arrest.

METHODS

Munich female swine were employed for a model of cardiac arrest via application of electrical current. After 7 min, CPR was initiated, and animals were either successfully return to spontaneous circulation (ROSC) within 40 min or not (no-ROSC). At the end of experimental period and prior to sacrifice, samples from the intestine, mesenteric lymph nodes (MLN), liver and portal vein blood were obtained. Evaluation of inflammation and gut permeability was performed; MLN, liver and portal vein samples were analyzed for 16 s rRNA detection and cytokine mRNA expression.

RESULTS

A decreased expression of the tight junction protein Occludin, with higher levels of inflammation, greater epithelial disintegration, ulceration, loss of crypts and villi height were found in the intestines of the ROSC swine in comparison to no-ROSC. The macrophage surface antigen CD-14 staining was relatively more intense in the ROSC than in no-ROSC. Higher levels of TNF-α mRNA expression were present in the liver of the ROSC group. Finally, despite the inflammatory response and the gut mucosal alterations in ROSC group, no bacterial translocation was detected in liver, MLN and portal vein.

CONCLUSIONS

We show that resuscitation from cardiac arrest induces inflammatory response and intestinal permeability in swine 4h after resuscitation, but not a bacterial translocation. Bacterial translocation is not an early phase phenomenon but probably part of the pathophysiologic sequelae.

The adaptive immune response in cardiac arrest resuscitation induced ischemia reperfusion renal injury

BACKGROUND

The present study aims to investigate, immunohistochemically, the role of the adaptive immune response in cardiac arrest/resuscitation-induced ischemia-reperfusion renal injury (IRI), namely to assess the presence of lymphocytes in renal tissue samples and the connection between the extent of the damage and the concentration of the lymphocytes by comparing the kidneys of non resuscitated swine with the kidneys of resuscitated swine.

METHODS

Twenty four swine underwent cardiac arrest (CA) via a pacemaker wire. After 7 min, without any intervention, Cardiopulmonary Resuscitation, CPR, was commenced. Five min after CPR was commenced advanced life-support, ALS. Animals were divided into resuscitated animals and non resuscitated animals. Tissue samples obtained from the two groups for immunohistological study aiming to detect T-cells, B-cells and plasma cells using CD3 + , CD20 + , and CD138 + antibodies.

RESULTS

There seems to be a strong concentration of T lymphocytes in the kidney tissues after ischemia of both non-resuscitated and resuscitated swine. B lymphocytes, also, appear to have infiltrated the ischemic kidneys of both animal groups; nevertheless, the contribution of T lymphocytes to the induction of injury remains greater. There is no strong evidence of correlation between the plasma cells and the damage.

CONCLUSION

The adaptive immune response seems to have a strong association with kidney injury and acute tubular necrosis after cardiac arrest/ resuscitation-induced ischemia-reperfusion. However, the extent to which the adaptive immune cells are involved in the induction of renal injury remains uncertain and there are many questions about the mechanism of function of these cells, the answers of which require further studies.

Pathophysiology and protective approaches of gut injury in critical illness

The gut is a complex organ that has played an important role in digestion, absorption, endocrine functions, and immunity. The gut mucosal barriers consist of the immunologic barrier and nonimmunologic barrier. During critical illnesses, the gut is susceptible to injury due to the induction of intestinal hyperpermeability. Gut hyperpermeability and barrier dysfunction may lead to systemic inflammatory response syndrome. Additionally, gut microbiota are altered during critical illnesses. The etiology of such microbiome alterations in critical illnesses is multifactorial. The interaction or systemic host defense modulation between distant organs and the gut microbiome is increasingly studied in disease research. No treatment modality exists to significantly enhance the gut epithelial integrity, permeability, or mucus layer in critically ill patients. However, multiple helpful approaches including clinical and preclinical strategies exist. Enteral nutrition is associated with an increased mucosal barrier in animal and human studies. The trophic effects of enteral nutrition might help to maintain the intestinal physiology, prevent atrophy of gut villi, reduce intestinal permeability, and protect against ischemia-reperfusion injury. The microbiome approach such as the use of probiotics, fecal microbial transplantation, and selective decontamination of the digestive tract has been suggested. However, its evidence does not have a high quality. To promote rapid hypertrophy of the small bowel, various factors have been reported, including the epidermal growth factor, membrane permeant inhibitor of myosin light chain kinase, mucus surrogate, pharmacologic vagus nerve agonist, immune-enhancing diet, and glucagon-like peptide-2 as preclinical strategies. However, the evidence remains unclear.

Safety and Tolerance of Enteral Nutrition in the Medical and Surgical Intensive Care Unit Patient Receiving Vasopressors

BACKGROUND

Multiple societal guidelines recommend enteral nutrition (EN) be initiated within 24 to 48 hours of admission to the intensive care unit (ICU) once a patient is hemodynamically stable. Gastrointestinal intolerance and occurrence of bowel ischemia have been a concern for patients receiving vasopressors while concurrently receiving luminal nutrients. The study objective was to determine whether patients receiving vasopressors while concomitantly receiving enteral nutrients had more incidences of bowel ischemia and intolerance than those receiving EN without vasopressor agents.

METHODS

This retrospective study included 319 medical and surgical ICU patients from a level 1 trauma center. The patients were either receiving vasopressors simultaneously with EN (n = 178) or EN alone (n = 141). Data regarding gastric residual volume (GRV), new abdominal pain, emesis, and bowel ischemia were collected.

RESULTS

There were more patients who had elevated GRV in the group that received vasopressors than patients who did not (20% vs 7%; P-value < .01). There were no differences between rates of bowel ischemia, emesis, or new abdominal pain between the 2 groups.

CONCLUSION

Based on our findings, EN is generally well tolerated and safe for those patients simultaneously receiving vasopressors.

Effects of oral/enteral nutrition alone versus plus pantoprazole on gastrointestinal bleeding in critically ill patients with low risk factor: a multicenter, randomized controlled trial

Background/aim

Critically ill patients are at risk of developing gastrointestinal (GI) bleeding due to stress causing mucosal damage. Aim of the study was to determine the effect of oral/enteral nutrition with or without concomitant pantoprazole on upper GI bleeding in low risk critically ill patients.

Materials and methods

This was a prospective, randomized, open-label, multicenter study conducted with intensive care unit (ICU) patients receiving oral/enteral nutritional support. Patients were randomly assigned into two groups including intervention group (received oral/EN plus pantoprazole) and control group (received only oral/EN).

Results

A total of 300 patients (intervention group: 152, control group: 148) participated in the study. Overall, 226 (75%) patients were fed by orally and 74 (25%) patients fed by enteral tube feeding. Median duration of nutritional support 4 (range: 2–33) days. Overt upper GI bleeding was noted only in one patient (0.65%) who was in the intervention group. The overall length of ICU stay of 4 (2–105) days, while ICU stay was significantly longer in the intervention group than in the control group (P = 0.006).

Conclusions

Our findings seems to indicate that in patients who are at low risk for GI bleeding and under oral/enteral nutritional support, the use of PPIs may not reduce the risk of bleeding, however these results are imprecise because of low event (GI bleeding) rate and limited power.

Safety and Outcomes of Early Enteral Nutrition in Circulatory Shock

Circulatory shock is one of the most common reasons for an intensive care unit admission, has been shown to impair gut barrier and immune functions, and promotes dysbiosis. The exact timing and dose of enteral nutrition (EN) in circulatory shock remains unclear. In fact, because of fear of complications such as nonocclusive mesenteric ischemia and bowel necrosis and splanchnic steal phenomenon, clinicians may hesitate to start EN in critically ill patients with circulatory shock. In this narrative review, we identify and appraise contemporary evidence evaluating the safety and outcomes of EN in circulatory shock.

Vasopressors and Nutrition Therapy: Safe Dose for the Outset of Enteral Nutrition?

Background and Aims

Patients with hemodynamic instability need to receive intensive treatment as fluid replacement and vasoactive drugs. In the meantime, it is supposed to initiate nutritional therapy within 24 to 48 hours after admission to the intensive care unit (ICU), as an essential part of patient's intensive care and better outcomes. However, there are many controversies tangential to the prescription of enteral nutrition (EN) concomitant to the use of vasopressor and its doses. In this way, the present study aimed to identify what the literature presents of evidence to guide the clinical practice concerning the safe dose of vasopressors for the initiation of nutritional therapy in critically ill patients.

Methods

This review was carried out in PubMed, ProQuest, Web of Science, and Medline databases. The descriptors were used to perform the search strategy: Critical Care, Intensive Care Units, Vasoconstrictor Agents, and Enteral Nutrition. Inclusion criteria were patients of both genders, over 18 years of age, using vasoactive drugs, with the possibility of receiving EN therapy, and articles written in English, Portuguese, and Spanish. In addition, exclusion criteria were case reports, non-papers, and repeated papers.

Results

10 articles met our inclusion criteria.

Conclusion

It was observed that there are many controversies about the supply of EN in critically ill patients using vasopressor, especially about the safe dose, and it was not possible to identify a cutoff value for the beginning therapy. Despite the drug doses, clinical signs are still the most important parameters in the evaluation of EN tolerance.

Circulatory effects of dexmedetomidine in early sepsis: a randomised controlled experimental study

We designed this experimental study with a view to evaluate the effects of dexmedetomidine (DEX) on cardiac performance and systemic and peripheral hemodynamics in healthy and early-stage endotoxemia swine models. Our study hypothesis was that DEX can ensure hemodynamic stability during the course of endotoxemia. Thirty-two male pigs (25-27 kg) were assigned into four groups: (1) no intervention (group A), (2) DEX 0.8 μg/kg was administered in non-septic animals (group B), (3) sepsis induced by intravenous Escherichia coli endotoxin (group C) and (4) DEX 0.8 μg/kg was administered in septic animals (group D). Hemodynamic parameters such as heart rate, mean blood pressure, central venous pressure, pulmonary artery pressures, pulmonary artery occlusion pressure, pulmonary vascular resistance and cardiac output were continuously recorded. Central venous oxygen saturation was also measured in order to obtain a complete evaluation of cardiovascular response to sepsis. Heart rate was decreased, whilst mean arterial pressure decrease was alleviated after DEX administration in septic animals. In addition, central venous pressure was stable in animals with sepsis after DEX infusion. Sepsis dramatically elevated pulmonary function indicators but DEX succeeded in ameliorating this effect. The important decrease measured in central venous oxygen saturation in both sepsis groups reflected the decreased perfusion of tissues that takes place at the end of early sepsis. Our findings support the hypothesis that DEX has beneficial effects on heart rate and pulmonary artery pressure, whilst reduction in systemic blood pressure occurs at acceptable levels.

Gut rest strategy and trophic feeding in the acute phase of critical illness with acute gastrointestinal injury

Critically ill patients frequently suffer from gastrointestinal dysfunction as the intestine is a vulnerable organ. In critically ill patients who require nutritional support, the current guidelines recommend the use of enteral nutrition within 24-48 h and advancing towards optimal nutritional goals over the next 48-72 h; however, this may be contraindicated in patients with acute gastrointestinal injury because overuse of the gut in the acute phase of critical illness may have an adverse effect on the prognosis. We propose that trophic feeding after 72 h, as a partial gut rest strategy, should be provided to critically ill patients during the acute phase of illness as an organ-protective strategy, especially for those with acute gastrointestinal injury.

Combined Enteral and Parenteral Glutamine Supplementation in Endotoxemic Swine: Effects on Portal and Systemic Circulation Levels

OBJECTIVE

To measure plasma glutamine (GLN) levels in systemic and portal circulation after combined enteral and parenteral administration in early endotoxemic swine. We hypothesized that this combination will be more efficient than intravenous administration alone in restoring plasma levels during the course of endotoxemia.

MATERIALS AND METHODS

Endotoxemia was induced with Escherichia coli O111:B4 lipopolysaccharide (LPS) (250 μg/kg body weight) in 16 anes-thetized, fasted swine and maintained by constant infusion (2 μg/kg/h) over 180 min. Another 16 swine served as controls. After infusion with LPS or placebo, GLN was administered intravenously, enterally or in combination (0.5 g/kg i.v. plus 0.5 g/kg enterally) over 30 min. At 0, 15, 30, 45, 60, 120 and 180 min, blood was drawn from the systemic and portal circulation for colorimetric assessment of GLN.

RESULTS

In healthy, placebo-alone swine, GLN levels remained stable throughout the study. Intravenous and combined infusion increased systemic levels (p = 0.001), but after enteral administration alone, a smaller effect was observed (p = 0.026). Portal levels were increased after combined, enteral and intravenous administration (p = 0.001). In endotoxemia, systemic and portal levels decreased significantly. Intravenous and, to a greater extent, combined administration increased systemic levels (p = 0.001), while enteral administration only had a small effect (p = 0.001). In the portal vein, intravenous and combined treatment increased plasma levels (p = 0.001), whereas enteral supplementation alone had again a small, yet significant effect (p = 0.001).

CONCLUSIONS

The findings indicate that combined GLN supplementation is superior to intravenous treatment alone, in terms of enhanced availability in systemic and portal circulations. Thus, combined treatment at the onset of endotoxemia is a beneficial practice, ensuring adequate GLN to compensate for the resulting intracellular shortage.

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.

Stress ulcer prophylaxis in intensive care unit patients receiving enteral nutrition: a systematic review and meta-analysis

Background

Pharmacologic stress ulcer prophylaxis (SUP) is recommended in critically ill patients with high risk of stress-related gastrointestinal (GI) bleeding. However, as to patients receiving enteral feeding, the preventive effect of SUP is not well-known. Therefore, we performed a meta-analysis of randomized controlled trials (RCTs) to evaluate the effect of pharmacologic SUP in enterally fed patients on stress-related GI bleeding and other clinical outcomes.

Methods

We searched PubMed, Embase, and the Cochrane database from inception through 30 Sep 2017. Eligible trials were RCTs comparing pharmacologic SUP to either placebo or no prophylaxis in enterally fed patients in the ICU. Results were expressed as risk ratio (RR) and mean difference (MD) with accompanying 95% confidence interval (CI). Heterogeneity, subgroup analysis, sensitivity analysis and publication bias were explored.

Results

Seven studies (n = 889 patients) were included. There was no statistically significant difference in GI bleeding (RR 0.80; 95% CI, 0.49 to 1.31, p = 0.37) between groups. This finding was confirmed by further subgroup analyses and sensitivity analysis. In addition, SUP had no effect on overall mortality (RR 1.21; 95% CI, 0.94 to 1.56, p = 0.14), Clostridium difficile infection (RR 0.89; 95% CI, 0.25 to 3.19, p = 0.86), length of stay in the ICU (MD 0.04 days; 95% CI, −0.79 to 0.87, p = 0.92), duration of mechanical ventilation (MD −0.38 days; 95% CI, −1.48 to 0.72, p = 0.50), but was associated with an increased risk of hospital-acquired pneumonia (RR 1.53; 95% CI, 1.04 to 2.27; p = 0.03).

Conclusions

Our results suggested that in patients receiving enteral feeding, pharmacologic SUP is not beneficial and combined interventions may even increase the risk of nosocomial pneumonia.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1937-1) contains supplementary material, which is available to authorized users.

Enteral nutrition as stress ulcer prophylaxis in critically ill patients: A randomized controlled exploratory study

PURPOSE

We investigated whether early enteral nutrition alone may be sufficient prophylaxis against stress-related gastrointestinal (GI) bleeding in mechanically ventilated patients.

MATERIALS AND METHODS

Prospective, double blind, randomized, placebo-controlled, exploratory study that included mechanically ventilated patients in medical ICUs of two academic hospitals. Intravenous pantoprazole and early enteral nutrition were compared to placebo and early enteral nutrition as stress-ulcer prophylaxis. The incidences of clinically significant and overt GI bleeding were compared in the two groups.

RESULTS

124 patients were enrolled in the study. After exclusion of 22 patients, 102 patients were included in analysis: 55 patients in the treatment group and 47 patients in the placebo group. Two patients (one from each group) showed signs of overt GI bleeding (overall incidence 1.96%), and both patients experienced a drop of >3 points in hematocrit in a 24-hour period indicating a clinically significant GI bleed. There was no statistical significant difference in the incidence of overt or significant GI bleeding between groups (p=0.99).

CONCLUSION

We found no benefit when pantoprazole is added to early enteral nutrition in mechanically ventilated critically ill patients. The routine prescription of acid-suppressive therapy in critically ill patients who tolerate early enteral nutrition warrants further evaluation.

Feeding the Open Abdomen

BACKGROUND

The purpose of this study was to determine if early enteral nutrition improves outcome for trauma patients with an open abdomen (OA).

METHODS

Retrospective review was used to identify 78 patients who required an OA for >or=4 hospital days, survived, and had available nutrition data. Demographic data and nutrition data comprising enteral nutrition initiation day and daily % target goal were collected. Patients were divided into 2 groups: early enteral feeding (EEN), initiated <or=4 days within celiotomy; and late enteral feeding (LEN; >4 days). Outcomes included infectious complications, early closure of the abdominal cavity (<8 days from original celiotomy), and fistula formation.

RESULTS

Fifty-three of 78 (68%) patients were men, with a mean age of 35 years; 74% had blunt trauma. Forty-three of 78 (55%) patients had EEN, whereas 35 of 78 (45%) had LEN. There was no difference with respect to demographics, injury severity, or infectious complication rates. Thirty-two of 43 (74%) patients with EEN had early closure of the abdominal cavity, whereas 17 of 35 (49%) patients with late feeding had early closure (p = .02). Four of 43 (9%) patients with EEN demonstrated fistula formation, whereas 9 of 35 (26%) patients with late feeding formed fistulae (p = .05). The EEN group had lower hospital charges (p = .04) by more than $50,000.

CONCLUSIONS

EEN in the OA was associated with (1) earlier primary abdominal closure, (2) lower fistula rate, (3) lower hospital charges.

Tolerability of Enteral Nutrition in Mechanically Ventilated Patients With Septic Shock Who Require Vasopressors

Purpose:

Enteral nutrition (EN) is often held in patients receiving vasopressor support for septic shock. The rationale for this practice is to avoid mesenteric ischemia. The objective of this study is to evaluate the tolerability of EN in patients with septic shock who require vasopressor support and determine factors associated with tolerance of EN.

Materials and Methods:

This was a single-center retrospective review of adult patients admitted to the intensive care unit with a diagnosis of septic shock and an order for EN. The primary outcome was EN tolerance. Secondary outcomes included time to initiation of EN from the start of vasopressor(s), length of stay, and mortality.

Results:

A total of 120 patients were included. Sixty-two percent of patients tolerated EN. The most common reason for intolerance of EN was gastric residuals > 250 mL (74%). No reports of mesenteric ischemia were observed. A multivariate analysis demonstrated that patients with septic shock initiating EN within 48 hours and receiving norepinephrine-equivalent doses of 0.14 μg/kg/min or less were more likely to tolerate EN.

Conclusion:

Based on our observation, early EN may be tolerated and safely administered in patients with septic shock who are adequately fluid resuscitated and receive doses of < 0.14 μg/kg/min of norepinephrine equivalents.

When Is It Appropriate to Use Glutamine in Critical Illness?

Glutamine is a nonessential amino acid, which under trauma or critical illness can become essential. A number of historic small single-center randomized controlled trials (RCTs) have demonstrated positive treatment effects on clinical outcomes with glutamine supplementation. Meta-analyses based on these trials demonstrated a significant reduction in hospital mortality, intensive care unit (ICU) length of stay (LOS), and hospital LOS with intravenous (IV) glutamine. Similar results were not noted in 2 large multicenter RCTs (REDOXS and MetaPlus) assessing the efficacy of glutamine supplementation in ventilated ICU patients. The REDOXS trial of 40 ICUs randomized 1223 ventilated ICU patients to glutamine (IV and enteral), antioxidants, both glutamine and antioxidants, or placebo. The main conclusions were a trend toward increased 28-day mortality and significant increased hospital and 6-month mortality in those who received glutamine. The MetaPlus trial of 14 ICUs, which randomized 301 ventilated ICU patients to glutamine-enriched enteral vs an isocaloric diet, noted increased 6-month mortality in the glutamine-supplemented group. Newer RCTs have focused on specific populations and have demonstrated benefits in burn and elective surgery patients with glutamine supplementation. Whether larger studies will confirm these findings is yet to be determined. Recent American Society for Parenteral and Enteral Nutrition guidelines recommend that IV and enteral glutamine should not be used in the critical care setting based on the moderate quality of evidence available. We agree with these recommendations and would encourage larger multicenter studies to evaluate the risks and benefits of glutamine in burn and elective surgery patients.

Immune enhancing nutrition in traumatic brain injury - A preliminary study

Traumatic brain injury (TBI) is a major cause of death and disability worldwide. Certain patients appear to benefit when they receive immune enhancing additives, such as glutamine, arginine, and omega-3 fatty acids. We hypothesized that TBI patients given enteral feedings containing these supplements may have improved nutrition measures and infection rates when compared to standard tube feedings. This is a retrospective review of patients from a Level-One trauma center from July 2009 to July 2013. A total of 240 TBI patients received either an immune enhancing nutrition (IEN) formula (n = 126), or a standard formula (SF) (n = 114) based on the attending surgeon's preference. Data collected included demographic information, infection information and outcome measures. Patients were similar in terms of age, ISS, head AIS, and initial prealbumin level. Patients receiving IEN were found to have lower rates of blood stream infections (10.3% vs 19.3%, p < 0.05), whereas pneumonia and UTI rates were similar between groups. In addition, both groups had similar rates of all-cause mortality and hospital length of stay, however IEN patients spent longer in the ICU and on ventilators. In TBI patients receiving IEN, prealbumin levels were higher at the second, third, and fourth week of admission (week 2 - 22.2 vs 17.4, p = 0.006; week 3 - 24.6 vs 20.1, p = 0.04; week 4 - 26.3 vs 22.1, p = 0.19; week 5 - 25.8 vs 20.3, p = 0.21). This study suggests that patients with traumatic brain injury who receive IEN are more likely to have increased prealbumin levels perhaps reflecting improved nutrition throughout their hospital stay and may show some benefit in rates of infections, particularly in bacteremia.

Early enteral nutrition in critically ill patients with hemodynamic instability: an evidence-based review and practical advice

Early enteral nutrition (EEN) in critically ill patients is associated with significant benefit as well as elevated risk of complications. Concomitant use of EEN with vasopressors has been associated with nonocclusive bowel necrosis in critically ill patients with hemodynamic instability. The decision when to initiate enteral nutrition in hemodynamically unstable patients that require vasoactive substances remains a clinical dilemma. This review summarizes the effect of EEN and vasoactive agents on gastrointestinal blood flow and perfusion in critically ill patients, based on current evidence. Animal and clinical data involving simultaneous administration of EEN and vasoactive agents for hemodynamic instability are reviewed, and the factors related to the safety and effectiveness of EEN support in this patient population are analyzed. Moreover, practical recommendations are provided. Additional randomized clinical trials are warranted to provide cutting-edge evidence-based guidance about this issue for practitioners of critical care.

Safety of Enteral Feedings in Critically Ill Children Receiving Vasoactive Agents

BACKGROUND

The objective of this retrospective study was to evaluate the safety of enteral feeding in children receiving vasoactive agents (VAs).

METHODS

Patients aged 1 month to 18 years with a pediatric intensive care unit stay for ≥96 hours during 2007 and 2008 who received any VA (epinephrine, norepinephrine, vasopressin, milrinone, dopamine, and dobutamine) were included and categorized into fed and nonfed groups. Their demographics, clinical characteristics, type and dose of VA, and presence of gastrointestinal (GI) outcomes were obtained. GI outcomes were compared between the groups by the χ(2) test, Mann-Whitney test, and logistic regression.

RESULTS

In total, 339 patients were included. Of these, 55% were in the fed group and 45% in the nonfed group. Patients in the fed group were younger (median age, 1.05 vs 2.75 years, respectively; P < .001) and tended to have a lower Pediatric Index of Mortality 2 (PIM2) risk of mortality (ROM) than those in the nonfed group (median, 3.33% vs 3.52%, respectively; P = .106). Mortality was lower in the fed group than the nonfed group (6.9% vs 15.9%, respectively; odds ratio [OR], 0.39; 0.18-0.84; P < .01, 95% CI), while GI outcomes did not differ between the groups. The vasoactive-inotropic score (VIS) did not differ between the groups except on day 1 (P = .017). The ROM did not differ between the groups after adjusting for age, PIM2 ROM, and VIS on day 1 (OR, 0.58; 0.26-1.28; P = .18, 95% CI).

CONCLUSIONS

Enteral feeding in patients receiving VAs is associated with no difference in GI outcomes and a tendency towards lower mortality. Prospective studies are required to confirm the safety of enteral feedings in patients receiving VAs.

Nutrition in the ICU: an evidence-based approach

Providing artificial nutrition is an important part of caring for critically ill patients. However, because of a paucity of robust data, the practice has been highly variable and often based more on dogma than evidence. A number of studies have been published investigating many different aspects of critical care nutrition. Although the influx of data has better informed the practice, the results have often been conflicting or counter to prevailing thought, resulting in discordant opinions and different interpretations by experts in the field. In this article, we review and summarize the data from a number of the published studies, including studies investigating enteral vs parenteral nutrition, supplementing enteral with parenteral nutrition, and use of immunonutrition. In addition, published studies informing the practice of how best to provide enteral nutrition will be reviewed, including the use of trophic feedings, gastric residual volumes, and gastric vs postpyloric tube placement.

Enteral nutrition in the hemodynamically unstable critically ill patient

The benefit of enteral nutrition in critically ill patients has been demonstrated by several studies, especially when it is started early, in the first 24-48h of stay in the Intensive Care Unit, and this practice is currently advised by the main clinical guidelines. The start of enteral nutrition is controversial in patients with hemodynamic failure, since it may trigger intestinal ischemia. However, there are data from experimental studies in animals, as well as from observational studies in humans that allow for hypotheses regarding its beneficial effect and safety. Interventional clinical trials are needed to confirm these findings.

Nutrition therapy for the critically ill surgical patient with aortic aneurysmal rupture: defining and improving current practice

BACKGROUND

Our goal is to define nutrition therapy in critically ill patients after surgical repair of acute ruptured or dissecting aortic aneurysm to identify opportunities for quality improvement.

METHODS

International, prospective studies in 2007-2009 and 2011 were combined. Sites provided institutional and patient characteristics including from intensive care units (ICUs) admission to ICU discharge for a maximum of 12 days. We selected patients with aortic aneurysmal rupture or acute dissection staying in the ICU for ≥ 3 days.

RESULTS

There were 104 eligible patients from 72 distinct ICUs analyzed. Overall, 86.5% received artificial nutrition. There were 50.0% patients who received enteral nutrition (EN) only, 29.8% patients received a combination of EN and parenteral nutrition (PN), 6.7% patients received PN only, and 13.5% did not receive any nutrition. The mean time from admission to initiation of EN was 3.0 days (SD ± 2.4 days). The adequacy of calories from nutrition support was 46.8% (range 0%-111%) with a mean of 10.0 kcal/kg/day. Of the total of 83 patients who received EN, 53 patients (63.8%) had interruption of EN. The reasons included fasting, intolerance, patients deemed too sick for enteral feeding, and loss of enteral feeding route. For patients with gastrointestinal intolerance, 3/30 patients (10%) received small bowel feeding and 23/30 patients (76.7%) of patients received motility agents.

CONCLUSION

Postoperative critically ill patients with aortic aneurysmal rupture or acute dissection are at high risk for inadequate nutrition therapy, and there may be inadequate utilization of strategies to improve nutrition uptake.

Nutrition and the open abdomen

Adequate nutrition support is critical in the management of patients with an open abdomen. Despite the literature supporting its use in trauma patients, provider concerns and clinical controversies remain regarding the early administration and long-term sequelae of enteral nutrition (EN) therapy in these patients. The purpose of this article is to review the clinical concepts behind the use of the open abdomen, as well as examine the altered nutrition requirements associated with the maintenance of a temporary laparostomy. The rationale for early EN is described, as well as the pros and cons surrounding the use of supplemental parenteral nutrition in those patients unable to meet nutrition goals enterally in a reasonable time frame. Finally, an open abdomen nutrition support algorithm is provided as part of the critical care plan in these patients who represent the sickest of surgical patients.

Drivers of oxidative stress in acute pancreatitis: the role of nutrition therapy

Severe acute pancreatitis is a disease process distinguished by increasing oxidative stress and potential destruction of the pancreatic gland. An initial injury to the acinar cell initiates a sentinel event, which leads to a vicious cycle of inflammation and cell death by either apoptosis or necrosis. Whether the acute inflammation resolves or goes on to a pattern of chronicity may be related to genetic predisposition, failure to remove injurious agents, and innate systems for antioxidant defense. The degree to which nutrition therapy can modulate oxidative stress, maintain intestinal function, and preserve the structure of the acinar cell is truly amazing. Understanding the mechanisms involved in this complex disease process and the manner in which these mechanisms are influenced by dietary agents affords new and exciting therapeutic options for the future.

Nutrition therapy for the critically ill surgical patient: we need to do better!

BACKGROUND

To identify opportunities for quality improvement, the nutrition adequacy of critically ill surgical patients, in contrast to medical patients, is described.

METHODS

International, prospective, and observational studies conducted in 2007 and 2008 in 269 intensive care units (ICUs) were combined for purposes of this analysis. Sites provided institutional and patient characteristics and nutrition data from ICU admission to ICU discharge for maximum of 12 days. Medical and surgical patients staying in ICU at least 3 days were compared.

RESULTS

A total of 5497 mechanically ventilated adult patients were enrolled; 37.7% had surgical ICU admission diagnosis. Surgical patients were less likely to receive enteral nutrition (EN) (54.6% vs 77.8%) and more likely to receive parenteral nutrition (PN) (13.9% vs 4.4%) (P < .0001). Among patients initiating EN in ICU, surgical patients started EN 21.0 hours later on average (57.8 vs 36.8 hours, P < .0001). Consequently, surgical patients received less of their prescribed calories from EN (33.4% vs 49.6%, P < .0001) or from all nutrition sources (45.8% vs 56.1%, P < .0001). These differences remained after adjustment for patient and site characteristics. Patients undergoing cardiovascular and gastrointestinal surgery were more likely to use PN, were less likely to use EN, started EN later, and had lower total nutrition and EN adequacy rates compared with other surgical patients. Use of feeding and/or glycemic control protocols was associated with increased nutrition adequacy.

CONCLUSIONS

Surgical patients receive less nutrition than medical patients. Cardiovascular and gastrointestinal surgery patients are at highest risk of iatrogenic malnutrition. Strategies to improve nutrition performance, including use of protocols, are needed.

Enteral refeeding rapidly restores PN-induced reduction of hepatic mononuclear cell number through recovery of small intestine and portal vein blood flows

BACKGROUND

Absence of enteral nutrition (EN) reduces hepatic mononuclear cell (MNC) numbers and impairs their functions. However, enteral refeeding (ER) for as little as 12 hours following parenteral nutrition (PN) rapidly restores hepatic MNC numbers. We hypothesized that changes in small intestine and portal vein blood flows related to feeding route might be responsible for this phenomenon.

METHODS

In experiment 1, mice (n = 19) were randomized to Chow (n = 5), PN (n = 7) or ER (n = 7) groups. The Chow group was given chow ad libitum with intravenous (IV) saline for 5 days. The PN group was fed parenterally for 5 days, while the ER group was re-fed with chow for 12 hours following 5 days of PN. Then, small intestine and portal vein blood flows were monitored and hepatic MNCs were isolated and counted. In experiment 2, the effects of intravenous administration of prostaglandin E(1) (PGE(1)) on hepatic MNC numbers were examined in fasted mice for 12 hours. Mice (n = 28) were randomized to Control (n = 8), PG0 (n = 10), or PG1 (n = 10) groups. The Control group was fed chow ad libitum with IV saline, while the PG0 and PG1 groups were fasted for 12 hours with infusions, respectively, of saline and PGE(1) at 1 microg/kg/minute. Blood flows and hepatic MNC numbers were examined.

RESULTS

Experiment 1: ER restored PN-induced reductions in small intestine and portal vein blood flows and hepatic MNC number to the levels in the Chow group. Small intestine and portal vein blood flows correlated positively with hepatic MNC number. Experiment 2: Fasting decreased small intestine and portal vein blood flows and hepatic MNC number. However, PGE(1) restored portal vein blood flow to the level of the Control group, and moderately increased hepatic MNC number. There was a positive correlation between portal blood flow and hepatic MNC number.

CONCLUSIONS

Reduced small intestine and portal vein blood flows may contribute to impaired hepatic immunity in the absence of EN. ER quickly restores hepatic MNC number through recovery of blood flow in both the small intestine and the portal vein.

Oxidative stress due to anesthesia and surgical trauma: importance of early enteral nutrition

Anesthesia and surgical trauma are considered major oxidative and nitrosative stress effectors resulting in the development of SIRS. In this study we evaluated the usefulness of early enteral nutrition after surgical trauma. Sixty male Wistar rats were subjected to midline laparotomy and feeding-gastrostomy. Twenty of these rats served as controls after recovering from the operation stress. The remaining rats received, through gastrostomy, enteral nutrition or placebo-feeding for 24 h. Oxidative stress markers and CC chemokine production were evaluated in rat serum and liver tissue. The operation itself was found to increase nitric oxide (NO) and malondialdehyde (MDA) and to decrease superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), as well as liver tissue energy charge (EC) in relation to controls. The rats receiving enteral feeding exhibited statistically significantly lower levels of NO and MDA, and higher levels of SOD, GSH-Px, and liver EC, in relation to placebo feeding rats. The operation significantly increased the chemokines monocyte chemoattractant protein (MCP)-1 and regulated upon activation, normal T-cell expressed, and secreted (RANTES) in rat serum, while enteral nutrition caused a further significant increase in chemokine levels in serum. mRNA chemokine expression in liver was increased in a similar pattern. These findings indicate that early enteral feeding might play an important role after surgery ameliorating oxidative stress, affecting positively the hepatic EC and regulating, via chemokine production, cell trafficking, and healing process.

The patient with circulatory shock: to feed or not to feed?

Controversy continues to surround the appropriate form and timing of nutrition support for the patient with circulatory shock. Clinical studies have demonstrated improvements in outcome with the administration of enteral nutrition to critically ill patients; however, the provision of enteral nutrition to critically ill patients with ongoing shock remains controversial. This article reviews gut perfusion during normal states and during circulatory shock as well as alterations in perfusion when enteral feeding is provided. Pharmaconutrients studied during ischemia and reperfusion are discussed.

Enteral glutamine during active shock resuscitation is safe and enhances tolerance of enteral feeding

BACKGROUND

Feeding the hemodynamically unstable patient is increasingly practiced, yet few data exist on its safety. Because enteral glutamine is protective to the gut in experimental models of shock and improves clinical outcomes, it may benefit trauma patients undergoing shock resuscitation and improve tolerance if administered early. This pilot study aimed to evaluate gastrointestinal tolerance and safety of enteral feeding with glutamine, beginning during shock resuscitation in severely injured patients.

METHODS

In a prospective randomized trial, 20 patients were randomly assigned to either an enteral glutamine group (n = 10) or a control group (n = 10). Patients with severe trauma meeting standardized shock resuscitation criteria received enteral glutamine 0.5 g/kg/d during the first 24 hours of resuscitation and 10 days thereafter. Immune-enhancing diet began on postinjury day 1, with a target of 25 kcal/kg/d. Control patients received isonitrogenous whey powder plus immune-enhancing diet. Tolerance (vomiting, nasogastric output, diarrhea, and distention) was assessed throughout the study.

RESULTS

Glutamine was well tolerated and no adverse events occurred. Treated patients had significantly fewer instances of high nasogastric output (5 vs 23; p = .010), abdominal distention (3 vs 12; p = .021), and total instances of intolerance (8 vs 42; p = .011). Intensive care unit (ICU) and hospital length of stay were comparable. Control patients required supplemental parenteral nutrition (PN) to meet goals at day 7.

CONCLUSIONS

Enteral glutamine administered during active shock resuscitation and through the early postinjury period is safe and enhances gastrointestinal tolerance. A large clinical trial is warranted to determine if enteral glutamine administered to the hemodynamically unstable patient can reduce infectious morbidity and mortality.

Enteral nutrition affects nitric oxide production in peripheral blood and liver after a postoperative lipopolysaccharide-induced endotoxemia in rats

OBJECTIVES

Sepsis is a common complication in the early postoperative period, leading to the augmentation of oxidative and nitrosative stresses. The present study investigated the role of enteral nutrition on nitric oxide (NO) production after a lipopolysaccharide (LPS)-induced endotoxemia as an index of nitrosative stress.

METHODS

Fifty rats were subjected to midline laparotomy and feeding gastrostomy. Ten rats served as controls after recovering from operative stress. The remaining rats received, through gastrostomy, enteral nutrition or placebo feeding for 24 h, after which they were injected intraperitoneally with LPS or equal volume of saline. Two hours later blood and liver tissue were collected. NO production was quantified in serum samples and homogenates of liver tissue by a modification of Griess's reaction. NO synthase (NOS) mRNA expression was examined in homogenate of liver tissue by reverse transcription-polymerase chain reaction.

RESULTS

The operation significantly increased basal NO production in rat serum. LPS induced a further significant increase of NO levels. Enteral feeding of rats significantly decreased NO levels in both groups. In contrast, enteral nutrition was found to increase significantly NO levels in liver homogenates from rats treated with LPS. A constitutive endothelial NOS mRNA expression was found in liver tissue, whereas LPS administration induced inducible NOS mRNA expression in liver tissue regardless of enteral feeding.

CONCLUSION

These findings indicate that early enteral feeding leads to a reduction in circulating NO levels induced by operation and endotoxemia, but increases hepatic NO levels in endotoxemia probably by the effect of LPS-induced inducible NOS on the increased L-arginine uptake.