Postinjury enteral tolerance is reliably achieved by a standardized protocol

Caloric Intake with High Ratio of Enteral Nutrition Associated with Lower Hospital Mortality for Patients with Acute Respiratory Distress Syndrome Using Prone Position Therapy

Positioning patients in the prone position leads to reduced hospital mortality rates for those with severe acute respiratory distress syndrome (ARDS). What constitutes the optimal feeding strategy for prone patients with ARDS is controversial. We conducted a retrospective study that enrolled 110 prone patients with ARDS in two medical intensive care units (ICUs) from September 2015 to November 2018. Inclusion criteria were as follows: age ≥20 years, diagnosis of respiratory failure requiring mechanical ventilation, diagnosis of ARDS within 72 h of ICU admission, placement in a prone position within the first 7 days of ICU admission, and ICU stay of more than 7 days. Exclusion criteria were as follows: nil per os orders because of gastrointestinal bleeding or hemodynamic instability, and ventilator dependency because of chronic respiratory failure. The consecutive daily enteral nutrition(EN)/EN + parenteral nutrition(PN) ratio could predict hospital mortality rates within the first 7 days of admission when using generalized estimating equations (p = 0.013). A higher average EN/EN + PN ratio within the first 7 days predicted (hazard ratio: 0.97, confidence interval: 0.96-0.99) lower hospital mortality rates. To reduce hospital mortality rates, caloric intake with a higher EN ratio may be considered for patients in prone positions with ARDS.

Volume-Based Protocol Improves Delivery of Enteral Nutrition in Critically Ill Trauma Patients

BACKGROUND

Critically ill patients on enteral nutrition (EN) often do not receive goal nutrition support. Factors impeding delivery of EN include interruption for procedures, tube dislodgement, and high gastric residuals. A volume-based feeding protocol (VP) is designed to adjust the infusion rate to compensate for interruptions. We hypothesize that implementation of a VP would increase delivery of EN over the conventional hourly rate method (CM).

METHODS

This study compared patients on CM to those on VP. The primary outcome measured was percentage of goal EN delivered during the entire intensive care unit (ICU) stay. Inclusion criteria for the study consisted of patients aged >18 years, traumatic mechanism of injury and admission to the ICU >72 hours, hemodynamic stability to receive EN per the trauma ICU standard of practice, and EN via nasogastric or post-pyloric feeding tube.

RESULTS

We evaluated 227 patients over a 20-month period. Seventy-nine patients in the VP group were compared with the control group of 148 patients. Patients on VP received a significantly higher percentage of goal EN than those on CM (73.3% vs 65%, P = .0002). There was no difference in the incidence of diarrhea (CM 4.16% vs VP 5.19%; P = .29) or tube dislodgment (CM 2.04% vs VP 1.61%; P = .51).

CONCLUSION

Implementation of a VP significantly increased delivery of EN by 8.3% over that given by the CM in critically ill trauma patients with no difference in feeding-related complications.

Autophagy: should it play a role in ICU management?

PURPOSE OF REVIEW

This review is to discuss the role of autophagy in the critically ill patient population. As the understanding of autophagy continues to expand and evolve, there are certain controversies surrounding whether intensivist should allow the benefit of autophagy to supersede gold standard of insulin therapy or early nutritional support.

RECENT FINDINGS

The review is relevant as the current literature seems to support under-feeding patients, and perhaps the reason these studies were positive could be prescribed to the mechanisms of autophagy. It is well understood that autophagy is a physiologic response to stress and starvation, and that the inducible form could help patients with end-organ dysfunction return to homeostasis.

SUMMARY

The jury is still out as to how autophagy will play into clinical practice as we review several gold standard therapies for the critically ill.

Enteral tolerance in critically ill patients

Enteral nutrition (EN) can maintain the structure and function of the gastrointestinal mucosa better than parenteral nutrition. In critically ill patients, EN must be discontinued or interrupted, if gastrointestinal complications, particularly vomiting and bowel movement disorders, do not resolve with appropriate management. To avoid such gastrointestinal complications, EN should be started as soon as possible with a small amount of EN first and gradually increased. EN itself may also promote intestinal peristalsis. The measures to decrease the risk of reflux and aspiration include elevation the head of the bed (30° to 45°), switch to continuous administration, administration of prokinetic drugs or narcotic antagonists to promote gastrointestinal motility, and switch to jejunal access (postpyloric route). Moreover, the control of bowel movement is also important for intensive care and management. In particular, prolonged diarrhea can cause deficiency in nutrient absorption, malnutrition, and increase in mortality. In addition, diarrhea may cause a decrease the circulating blood volume, metabolic acidosis, electrolyte abnormalities, and contamination of surgical wounds and pressure ulcers. If diarrhea occurs in critically ill patients on EN management, it is important to determine whether diarrhea is EN-related or not. After ruling out the other causes of diarrhea, the measures to prevent EN-related diarrhea include switch to continuous infusion, switch to gastric feeding, adjustment of agents that improve gastrointestinal peristalsis or laxative, administration of antidiarrheal drugs, changing the type of EN formula, and semisolidification of EN formula. One of the best ways to success for EN management is to continue as long as possible without interruption and discontinuation of EN easily by appropriate measures, even if gastrointestinal complications occur.

The Efficacy of an Enteral Access Protocol for Feeding Trauma Patients

BACKGROUND

Proper enteral access to deliver specialized nutrition support in critically injured patients can be difficult, time consuming, and costly. We designed a protocol with interdisciplinary input to facilitate early enteral access in our trauma patients. Our primary objective was to determine if the protocol improved our ability to obtain small-bowel access in patients within 48 hours of their admission to the surgical intensive care unit (SICU). Secondary objectives were to examine the efficacy of the protocol by evaluating parenteral nutrition (PN) use, adequacy of enteral caloric delivery, and clinical outcomes including pneumonia and sepsis rates, SICU length of stay (LOS), hospital LOS, and mortality before and after its implementation.

METHODS

The medical records of 51 trauma patients admitted to the SICU, who met inclusion criteria, were reviewed retrospectively and divided into 2 groups. Patients in group 1 were admitted before protocol implementation (1997-1998, n = 17). Patients in group 2 were admitted after protocol implementation (1998-2000, n = 34).

RESULTS

Small-bowel access was achieved earlier in group 2 compared with group 1 [2.2 +/- 2 days vs 5.4 +/- 8 days, respectively (p = .04)]. PN was used less frequently in group 2 at 41.2% (14/34) as opposed to 64.7% (11/17) in group 1 (p = .05). There was a reduction in the number of days to reach caloric goal from 4.9 days in group 1 to 3.9 days in group 2 (n.s.). Clinical outcomes were similar in both groups.

CONCLUSIONS

The use of a protocol was effective in the achievement of prompt small bowel access. The number of days to reach caloric goal decreased after protocol implementation, but not to a statistically significant degree. However, we were able to detect a significant reduction in the use of PN.

Defining and Assessing Tolerance in Enteral Nutrition

Nutrition support has become widely recognized as an essential component of optimal care for acutely ill patients. Enteral nutrition is preferred over parenteral routes when possible. However, prescribed enteral nutritional regimens are sometimes met with side effects and even complications. These adverse events have been collectively termed "intolerance," and forms of intolerance occur in a spectrum from bothersome at least to life threatening when most severe. Here we discuss nutritional access and its maintenance, introduce and define intolerance, and then review the current literature with regard to principal forms of enteral nutrition intolerance.

Gastric Feeding as an Extension of an Established Enteral Nutrition Protocol

BACKGROUND

Indiscriminate gastric feeding in ICU patients imposes unacceptable risks of aspiration. Believing that a subset of ICU patients can be fed safely via the stomach, we have developed a protocol to identify appropriate patients and guide the bedside clinician in how to safely and effectively feed via the stomach.

METHODS

A literature search was done to identify appropriate medical literature. High grade evidence along with local expert opinions were used to develop a protocol. This protocol has been refined and implemented.

RESULTS

Based on perceived risk of aspiration, patients are assigned enteral access (ie, stomach vs. distal post-pyloric). Enteral formula is selected based on patient characteristics. It is then advanced by a standard protocol with specific precautions while monitoring for symptoms of intolerance. Management of intolerance is dictated by the type and severity of intolerance.

CONCLUSION

We have implemented a gastric feeding into a subset of our ICU patients. Gastric feeding requires certain precautions but appears to be safe. With more experience and better understanding of the pathogenesis gastroparesis, we believe that most ICU patients should be able to safely feed into the stomach. This is logistically easier than post-pyloric feeding and offers physiologic advantages.

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.

Usefulness of a real-time bowel sound analysis system in patients with severe sepsis (pilot study)

Healthy bowel function is an important factor when judging the advisability of early enteral nutrition in critically ill patients, but long-term observation and objective evaluation of gastrointestinal motility are difficult. In the study, real-time continuous measurement of gastrointestinal motility was performed in patients with severe sepsis using a developed bowel sound analysis system, and the correlation between bowel sounds and changes over time in blood concentrations of interleukin (IL)-6, which is associated with sepsis severity, was evaluated. The subjects were five adult patients in the acute phase of severe sepsis on a mechanical ventilator, with IL-6 blood concentrations ≥100 pg/mL, who had consented to participate in the study. Gastrointestinal motility was measured for a total of 62,399 min: 31,544 min in 3 subjects in the no-steroids group and 30,855 min in 2 subjects in the steroid treatment group. In the no-steroids group, the bowel sound counts were negatively correlated with IL-6 blood concentration, suggesting that gastrointestinal motility was suppressed as IL-6 blood concentration increased. However, in the steroid treatment group, gastrointestinal motility showed no correlation with IL-6 blood concentration (r = -0.25, p = 0.27). The IL-6 blood concentration appears to have decreased with steroid treatment irrespective of changes in the state of sepsis, whereas bowel sound counts with the monitoring system reflected the changes in the state of sepsis, resulting in no correlation. This monitoring system provides a useful method of continuously, quantitatively, and non-invasively evaluating gastrointestinal motility in patients with severe sepsis. Gastrointestinal motility might be useful as a parameter reflecting disease severity, particularly in patients treated with steroids.

Evaluation of nutrition deficits in adult and elderly trauma patients

BACKGROUND

As metabolism is often escalated following injury, severely injured trauma patients are at risk for underfeeding and adverse outcomes.

METHODS

From an international database of 12,573 critically ill, adult mechanically ventilated patients, who received a minimum of 3 days of nutrition therapy, trauma patients were identified and nutrition practices and outcomes compared with nontrauma patients. Within the trauma population, we compared nutrition practices and outcomes of younger vs older patients.

RESULTS

There were 1279 (10.2%) trauma patients. They were younger, were predominantly male, had lower Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, and had an overall lower body mass index compared with nontrauma patients. Eighty percent of trauma patients received enteral feeding compared with 78% of nontrauma patients. Trauma patients were prescribed more calories and protein yet received similar amounts as nontrauma patients. Nutrition adequacy was reduced in both trauma and nontrauma patients. Survival was higher in trauma patients (86.6%) compared with nontrauma patients (71.8%). When patients who died were included as never discharged, trauma patients were more rapidly discharged from the intensive care unit (ICU) and hospital. Within the trauma population, 17.5% were elderly (≥65 years). The elderly had increased days of ventilation, ICU stay, and mortality compared with younger trauma patients. In a multivariable model, age and APACHE II score, but not nutrition adequacy, were associated with time to discharge alive from the hospital.

CONCLUSION

Significant nutrition deficits were noted in all patients. Elderly trauma patients have worse outcomes compared with younger patients. Further studies are necessary to evaluate whether increased nutrition intake can improve the outcomes of trauma patients, especially geriatric trauma patients.

Can the intestinal dysmotility of critical illness be differentiated from postoperative ileus?

Gastrointestinal dysmotility is commonly noted in the intensive care unit and postoperative settings. Characterized by delayed passage of stool and flatus, nausea, vomiting, and abdominal distention, the condition is associated with nutritional deficiencies, risk of aspiration, and considerable allocation of health care resources. Knowledge of gastrointestinal function in health and illness continues to expand. While the factors that precipitate ileus differ between postoperative and critically ill patients, the two clinical scenarios seem to have similar mechanisms and share many of the same pathophysiologic patterns. By reviewing and comparing the literature on the respective mechanisms and contributing factors generated in these separate clinical settings, a common more comprehensive management strategy may be derived with the potential for newer innovative therapeutic options.

Enteral nutrition in patients with severe traumatic brain injury: reasons for intolerance and medical management

Approximately, 50% of patients with severe traumatic brain injury (TBI) exhibit intolerance to enteral nutrition (EN). This intolerance hampers the survival and rehabilitation of this subpopulation to a great extent, and poses various difficulties for clinicians due to its complex underlying mechanisms. This review discusses the possible reasons for intolerance to EN following severe TBI, current trends in medical management, as well as other related issues that are experienced by many clinicians.

Impact of enteral feeding protocols on enteral nutrition delivery: results of a multicenter observational study

BACKGROUND

To evaluate the effect of enteral feeding protocols on key indicators of enteral nutrition in the critical care setting.

METHODS

International, prospective, observational, cohort studies conducted in 2007 and 2008 in 269 intensive care units (ICUs) in 28 countries were combined for the purposes of this analysis. The study included 5497 consecutively enrolled, mechanically ventilated, adult patients who stayed in the ICU for at least 3 days. Sites recorded the presence or absence of a feeding protocol operational in their ICU. They provided selected nutritional data on enrolled patients from ICU admission to ICU discharge for a maximum of 12 days. Sites that used a feeding protocol were compared with those that did not.

RESULTS

On average, protocolized sites used more enteral nutrition (EN) alone (70.4% of patients vs 63.6%, P = .0036), started EN earlier (41.2 hours from admission to ICU vs 57.1, P = .0003), and used more motility agents in patients with high gastric residual volumes (64.3% of patients vs 49.0%, P = .0028) compared with sites that did not use a feeding protocol. Overall nutritional adequacy (61.2% of patients' caloric requirements vs 51.7%, P = .0003) and adequacy from EN were higher in protocolized sites compared with nonprotocolized sites (45.4% of requirements vs 34.7%, P < .0001). EN adequacy remained significantly higher after adjustment for pertinent patient and ICU level baseline characteristics.

CONCLUSIONS

The presence of an enteral feeding protocol is associated with significant improvements in nutrition practice compared with sites that do not use such a protocol.

Presidential address: imagination trumps knowledge

Multiple organ failure (MOF) emerged 30 years ago and became our research focus. Over the years, we have proposed a series of cartoons that rallied multidisciplinary translational research teams around common themes to generate "win-win" hypotheses that when tested (right or wrong) have advanced our understanding of MOF. MOF has a bimodal trajectory, and the gut plays a role in both trajectories. Early MOF occurs because of excessive proinflammation (ie, systemic inflammatory response syndrome [SIRS]), and early gut ischemia-reperfusion can amplify SIRS and contribute to the early fulminant SIRS-MOF trajectory. Fortunately, most patients survive early SIRS, but some develop excessive anti-inflammation (ie, compensatory anti-inflammatory response syndrome). The gut also plays a role in this late indolent compensatory anti-inflammatory response syndrome-MOF trajectory. Multiple factors cause progressive gut dysfunction such that the gut (an important immunologic organ) worsens compensatory anti-inflammatory response syndrome and becomes the reservoir for pathogens and toxins that cause late sepsis.

Safe practices for enteral nutrition in critically ill patients

Promoting patient safety in the enterally fed critically ill patient is dependent on nursing surveillance and recognition of potential areas of patient harm and medical errors. Identifying areas for potential human error, administrative and organizational conditions that are conducive to error, and the patient's own tolerance to EN need to be recognized by the critical care nurse if the risk for EN complications is to be minimized.

Fasting exacerbates and feeding diminishes LPS-induced liver injury in the rat

INTRODUCTION

Enteral nutrition improves clinical outcomes. The effects of feeding on LPS induced liver injury are unknown. We hypothesized that feeding would attenuate liver injury from LPS.

METHODS

Fasted or fed rats were given LPS (20 mg/kg i.p.) or saline for 5 h and sacrificed. Serum aminotransferases and cytokines (immunoassay) were measured. Oxidative stress protein (iNOS, COX2, and HO1) assessments (Western immunoblot) were also obtained.

RESULTS

In fasted rats, LPS significantly increased serum aminotransferase levels, enhanced hepatic COX2, iNOS, and HO1 immunoreactivity, and increased serum cytokine levels when compared to controls. While feeding diminished liver enzymes, attenuated expression of COX2 and iNOS, and blunted production of pro-inflammatory cytokines, it did not modulate LPS-induced expression of the anti-inflammatory markers HO1 and IL-10.

CONCLUSION

These data suggest that feeding decreases liver injury by attenuating expression of pro-inflammatory mediators while maintaining expression of anti-inflammatory mediators, both systemically and locally.

Feeding the injured intestine: enteral nutrition in the critically ill patient

PURPOSE OF REVIEW

The utilization of enteral nutrition in critically ill patients is frequently suboptimal. This may be due, in part, to ongoing controversies regarding appropriate use of enteral support, but there are also perceived barriers to its use even when there is good evidence that it can be given. This review was undertaken to outline some of these controversies and barriers to use of enteral nutrition in the ICU.

RECENT FINDINGS

Although the advantages of enteral nutrition may have been overstated, it remains preferable to parenteral nutrition for support of critically ill patients. Early initiation of enteral support is a reasonable approach. Many patients with perceived contraindications to enteral therapy are actually good candidates for its use. Frequent interruptions in enteral nutrition lead to suboptimal nutrient delivery, but might be overcome by use of specific protocols emphasizing safe and effective utilization of enteral support.

SUMMARY

Use of enteral nutritional support is recommended for critically ill patients requiring specialized nutritional support. Barriers to its use could be overcome by better educating providers about indications for use and by developing methods to avoid undue interruption of therapy.

Nutrition support of the traumatically injured warfighter

Major trauma induces metabolic alterations that contribute to the systemic immune suppression in severely injured patients and increase the risk of infection and posttraumatic organ failure. Nutrition modulation of cellular processes has evolved into a high-priority therapy, backed by substantial scientific evidence. The appropriate selection, timing, and dose of nutrients required for metabolic resuscitation must be individualized and goal directed. Ideally, the nutritional interventions for warfighters will be developed strategically based on the extent of injuries and underlying deficiencies and will be designed to provide the nutrients necessary to balance hypermetabolic processes, heal wounds, and promote optimal recovery.

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.

Management of perioperative nutrition support

PURPOSE OF REVIEW

Perioperative nutrition has been extensively studied, but numerous questions remain unanswered. This review focuses on new developments in nutrient delivery in the immediate perioperative period. Issues specifically addressed include which patients are most likely to benefit from perioperative nutritional supplementation, and the optimal route, timing, and quantity of nutrient delivery.

RECENT FINDINGS

Visceral proteins, particularly albumin, play an important role in nutritional and perioperative risk assessment. Although the recommendation to use the enteral route for delivery of nutrition whenever possible is clear, the cautious introduction of enteral feeds in the labile group of patients with circulatory failure is essential. Preoperative use of immune-modulating enteral formulas, preoperative carbohydrate loading, and the concept of early enteral feeding are important developments. Supplementary arginine, glutamine, and omega-3 fats play a potential role in nutritional management, as does 'permissive' hypocaloric feeding.

SUMMARY

The particulars of nutritional support for perioperative and critically ill patients remain controversial. Recent studies addressing specific issues in this diverse discipline perhaps raise more questions than are answered. However, each new contribution to the literature brings us closer to an understanding of optimal nutritional management in the metabolically stressed patient.

Peroxisome proliferator-activated receptor gamma mediates protection against cyclooxygenase-2-induced gut dysfunction in a rodent model of mesenteric ischemia/reperfusion

Cyclooxygenase (COX)-2 has been identified as an important mediator elaborated during ischemia/reperfusion, with pro- and anti-inflammatory properties having been reported. As the role of COX-2 in the small intestine remains unclear, we hypothesized that COX-2 expression would mediate mesenteric ischemia/reperfusion-induced gut injury, inflammation, and impaired transit and that these deleterious effects could be reversed by the selective COX-2 inhibitor, N-[2-(cyclohexyloxy)-4-nitrophenyl] methanesulphanamide (NS-398). Additionally, we sought to determine the role of peroxisome proliferator-activated receptor gamma (PPARgamma) in mediating protection by NS-398 in this model. Rats underwent sham surgery or were pretreated with NS-398 (3, 10, or 30 mg/kg) intraperitoneally 1 h before 60 min of superior mesenteric artery occlusion and 30 min to 6 h of reperfusion. In some experiments, NS-398 (30 mg/kg) was administered postischemia. Ileum was harvested for COX-2 mRNA and protein, PGE2, myeloperoxidase (inflammation), histology (injury), intestinal transit and PPARgamma protein expression, and DNA-binding activity. COX-2 expression and PGE2 production increased after mesenteric ischemia/reperfusion and were associated with gut inflammation, injury, and impaired transit. Inhibition of COX-2 by NS-398 (30 mg/kg, but not 3 or 10 mg/kg) not only reversed the deleterious effects of COX-2, but additionally induced expression and nuclear translocation of PPARgamma. NS-398 given postischemia was equally protective. In conclusion, COX-2 may function as a proinflammatory mediator in a rodent model of mesenteric ischemia/reperfusion. Reversal of gut inflammation, injury, and impaired transit by high-dose NS-398 is associated with PPAR activation, suggesting a potential role for PPAR-gamma in shock-induced gut protection.

The impact of implementing an enteral tube feeding protocol on caloric and protein delivery in intensive care unit patients

BACKGROUND

The purpose of this study was to determine the effect of an enteral tube feeding protocol on caloric and protein delivery to intensive care unit (ICU) patients.

METHODS

This prospective study consisted of 2 phases: before and after the implementation on an enteral-feeding protocol. The following data were collected: demographics, Acute Physiology and Chronic Health Evaluation II score and Simplified Acute Physiology Score II, caloric and protein requirements, the location of the feeding tube tip, and prokinetic agents use. The primary endpoint was caloric and protein intake as a percentage of the requirement. Secondary endpoints were gastric residuals >150 mL, vomiting episodes, ICU and hospital lengths of stay, mechanical ventilation duration, and ICU and hospital mortality.

RESULTS

There were no significant differences between the control (n = 100) and protocol groups (n = 103) in baseline characteristics. The protocol was associated with significant improvement in the 7-day average of caloric intake/requirement (53.9 +/- 2.3% vs 64.5 +/- 2.2%, p = .001) and protein intake/requirement (56.7 +/- 2.6% vs 67.4% +/- 2.7%, p = .005). Caloric and protein intake improved whether the patient was receiving prokinetic agent or not. There was a trend toward lower gastric residual volumes and vomiting episodes in the protocol group. Patients receiving gastric feeding showed significant improvement in caloric intake to levels comparable to patients with postpyloric feeding.

CONCLUSIONS

Enteral tube feeding protocol is effective in improving feeding delivery in ICU patients independent of prokinetic agent use. Protocol for enteral tube feeding should be considered in the management of ICU patients, given the positive impact of this nonpharmacologic, non-interventional tool.

Immune-enhancing enteral nutrients differentially modulate the early proinflammatory transcription factors mediating gut ischemia/reperfusion

BACKGROUND

Recent reports suggest that enteral diets enriched with arginine may be harmful by enhancing inflammation. This is consistent with our gut ischemia/reperfusion (I/R) model in which arginine induced the proinflammatory mediator inducible nitric oxide synthase and resulted in injury and inflammation whereas glutamine was protective. We now hypothesize that arginine and glutamine differentially modulate the early proinflammatory transcription factors activated by gut I/R.

METHODS

At laparotomy, jejunal sacs were filled with either 60 mmol/L glutamine, arginine, or an iso-osmotic control followed by 60 minutes of superior mesenteric artery occlusion and 6 hours of reperfusion and compared with shams. Jejunum was harvested for nuclear factor (NF)-kappaB and activator protein-1 (AP-1) measured by electrophoretic mobility shift assay and c-jun and c-fos (AP-1 family) by supershift.

RESULTS

Both NF-kappaB and AP-1 were activated by gut I/R. Arginine and glutamine had no differential effect on NF-kappaB, whereas AP-1 expression (c-jun but not c-fos) was markedly enhanced by arginine and significantly lessened by glutamine.

CONCLUSION

Arginine enhanced expression of the early proinflammatory transcription factor AP-1 but not NF-kappaB. This represents a novel mechanism by which arginine may be harmful when administered to critically ill patients.

Postinjury abdominal compartment syndrome does not preclude early enteral feeding after definitive closure

BACKGROUND

Critically injured patients are susceptible to the abdominal compartment syndrome (ACS), which requires decompressive laparotomy with delayed abdominal closure. Previous work by the University of Texas Houston group showed impaired gut function after resuscitation-associated gut edema. The purpose of this study was to determine if enteral nutrition was precluded by the intra-abdominal hypertension and bowel edema of the ACS.

METHODS

Patients developing postinjury ACS from January 1996 to August 2003 at our level-I trauma center were reviewed. Patient demographics, time to definitive abdominal closure, and institution and tolerance of enteral nutrition were evaluated.

RESULTS

Thirty-seven patients developed postinjury ACS during the study period; 26 men and 11 women with a mean age of 36 +/- 4 and injury severity score of 33 +/- 4. Mean intra-abdominal pressure before decompression was 32 +/- 3 mm Hg, and concurrent mean peak airway pressure was 50 +/- 4 cm oxygen. Enteral feeding was never started in 12 patients; 4 died within 48 hours of admission, 7 required vasoactive agents until their death, and 1 developed an enterocutaneous fistula requiring parenteral nutrition. Enteral feeding was initiated in the remaining 25 patients: 13 had feeds started within 24 hours of abdominal closure; 5 were fed with open abdomens; and 7 had a delay because of vasopressors (n = 2), multiple trips to the operating room (n = 2), paralytics (n = 2), and increased intra-abdominal pressures (n = 1). Once advanced, enteral feeding was tolerated in 23 (92%) of the 25 patients with attainment of goal feeds in a mean of 3.1 +/- 1 days.

CONCLUSIONS

Despite the bowel edema and intra-abdominal hypertension related to the ACS, early enteral feeding is feasible after definitive abdominal closure.

Hypertonic saline prevents inflammation, injury, and impaired intestinal transit after gut ischemia/reperfusion by inducing heme oxygenase 1 enzyme

BACKGROUND

Hypertonic saline (HTS) has been shown to modulate the inflammatory response after shock. We have previously demonstrated that heme oygenase-1 (HO-1) induction is protective against gut dysfunction in models of shock-induced gut ischemia/reperfusion (I/R). We therefore hypothesized that HTS prevents gut inflammation, injury, and impaired transit by inducing HO-1 in a model of gut I/R.

METHODS

Rats underwent 60 minutes of superior mesenteric artery occlusion (SMAO) and then were resuscitated with 4 mL/kg of HTS, an equal volume of lactated Ringer's (LR) solution (4 mL/kg, low volume), or equal salt LR solution (32 mL/kg, high volume) and compared with SMAO alone or shams. A separate group was pretreated with the HO-1 blocker Sn protoporphyrin IX (SNP IX) before SMAO plus HTS. At 6 hours of reperfusion, transit was determined and ileum harvested for HO-1 (anti-inflammatory) and inducible nitric oxide synthase (proinflammatory) immunoreactivity, myeloperoxidase (MPO) activity, and histologic injury. Data are expressed as mean +/- SEM (analysis of variance).

RESULTS

Intestinal transit was severely impaired after SMAO (2.5 +/- 0.1), improved with low- and high-volume LR solution (3.2 +/- 0.2 and 3.1 +/- 0.1, not significant), but returned to sham (4.6 +/- 0.2) with HTS (4.8 +/- 0.2). Pretreatment with SNP abrogated this protective effect. Myeloperoxidase activity was significantly increased by SMAO (SMAO, 2.3 +/- 0.3; sham, 0.4 +/- 0.05), lessened by low- and high-volume LR solution (1.5 +/- 0.3 and 1.7 +/- 0.4), but returned to sham levels with HTS (1.0 +/- 0.01). Activity with SNP IX pretreatment was significantly increased (4.04 +/- 0.8). Mucosal injury followed a similar pattern. Inducible nitric oxide synthase was increased by SMAO and low- and high-volume LR solution (0.8 +/- 0.2, 0.8 +/- 0.03, and 0.8 +/- 0.02, respectively; sham, 0.5 +/- 0.02), but significantly reduced by HTS (0.7 +/- 0.02). HO-1 was induced by SMAO and low- and high-volume LR solution (0.33 +/- 0.02, 0.32 +/- 0.03, and 0.37 +/- 0.4, respectively; sham, 0.0 +/- 0.0), but was further increased with HTS (0.49 +/- 0.04).

CONCLUSION

HTS resuscitation protects against inflammation, injury, and impaired intestinal transit after gut I/R in part by inducing HO-1. This is a novel mechanism of HO-1 protection.

When is the seriously ill patient ready to be fed?

BACKGROUND

After assessing the critically ill patient for risk of aspiration, the clinician still must decide if the patient is ready to be fed. The goal is to identify critically ill patients who are likely to tolerate enteral nutrition and attempt to minimize complications.

METHODS

A synthesis of the both clinical and animal studies to identify factors related to patient readiness for enteral nutrition.

RESULTS

The key issue to be resolved is adequacy of resuscitation and restoration of mesenteric perfusion. Currently, there is no reliable clinical tool to measure gut perfusion. The best indicators currently are stabilization of vital signs, decreasing fluid and blood requirements, normalization of the base deficit, and lactate and removal of inotropic or vasopressor support.

CONCLUSIONS

Most critically ill patients should be ready for enteral nutrition within 24 to 48 hours of intensive care unit admission. Critically ill patients who need catecholamine support, heavy sedation, or therapeutic neuromuscular blockade should probably not receive enteral nutrition until they have been stabilized.