Intolerance to enteral feeding in the brain-injured patient

Risk factors for aspiration

BACKGROUND

There are numerous risk factors for aspiration in tube-fed critically ill patients. However, there is confusion about the extent to which these factors actually contribute to aspiration. The purpose of this literature review was to summarize findings from selected research studies.

METHODS

A nonexhaustive literature search was conducted to identify risk factors for aspiration in tube-fed, critically ill patients. The most commonly cited factors were decreased level of consciousness, supine position, presence of a nasogastric tube, tracheal intubation and mechanical ventilation, bolus or intermittent feeding delivery methods, high-risk disease and injury conditions, and advanced age.

RESULTS

Many studies of aspiration risk factors have relatively small sample sizes and used equivocal definitions of aspiration. Although some addressed aspiration as an outcome, others considered gastroesophageal reflux or pneumonia as outcomes. Despite these variations, authors almost uniformly agree that a decreased level of consciousness and a sustained supine position are major risk factors for aspiration. There is less agreement regarding the effect of a nasogastric tube (or its size) on aspiration and on the effect of various formula delivery methods.

CONCLUSIONS

A decreased level of consciousness is a major risk factor for aspiration, as is a sustained supine position. Although some authors favor using small-bore feeding tubes to prevent aspiration, there seems to be insufficient data to warrant this action. Although strong data are lacking regarding feeding delivery methods, there are more data to support continuous feedings than bolus/intermittent feedings in high-risk patients.

Nutritional support for head-injured patients

BACKGROUND

Head injury increases the body's metabolic responses, and therefore nutritional demands. Provision of an adequate supply of nutrients is associated with improved outcome. The best route for administering nutrition (parenterally (TPN) or enterally (EN)), and the best timing of administration (e.g early versus late) of nutrients needs to be established.

OBJECTIVES

To quantify the effect on mortality and morbidity of alternative strategies of providing nutritional support following head injury.

SEARCH STRATEGY

Trials were identified by computerised searches of the Injuries Group specialised register, Cochrane Controlled Trials Register, MEDLINE, EMBASE and BIDS Index to Scientific and Technical Proceedings, and by checking the reference lists of trials and review articles.

SELECTION CRITERIA

Randomised controlled trials of timing or route of nutritional support following acute traumatic brain injury.

DATA COLLECTION AND ANALYSIS

Two reviewers independently abstracted data and assessed trial quality. Information was collected on death, disability, and incidence of infection. If trial quality was unclear, or if there were missing outcome data, trialists were contacted in an attempt to get further information.

MAIN RESULTS

The timing of support: early versus delayed Of the seven trials addressing the timing of support, data on mortality were obtained for all seven trials (284 participants). The relative risk (RR) for death with early nutritional support was 0.67 (95% CI 0.41 to 1.07). Data on disability were available for three trials. The RR for death or disability at the end of follow-up was 0.75 (0.50 to 1.11). The route of feeding: parenteral versus enteral Seven trials compared parenteral versus enteral nutrition. Because early support often involves parenteral nutrition, three of the trials are also included in the previous analyses. Five trials (207 participants) reported mortality. The RR for mortality at the end of follow-up period was 0.66 (0.41 to 1.07). Two trials provided data on death and disability. The RR was 0.69 (95%Cl 0.40 to 1.19). 3. Enteral nutrition: jejunal versus gastric. There was one trial with no deaths and the RR is not estimable.

REVIEWER'S CONCLUSIONS

This review suggests that early feeding may be associated with a trend towards better outcomes in terms of survival and disability. Further trials are required. These trials should report not only nutritional outcomes but also the effect on death and disability.

Enteral nutrition in the critically ill: a prospective survey in an Australian intensive care unit

Nutritional support is routine practice in critically ill patients and enteral feeding is preferred to the parenteral route. However this direct delivery of nutrients to the gut is potentially ineffective for a variety of reasons. We performed a prospective audit of 40 consecutive intensive care patients to determine whether enteral feeding met the nutritional requirements of our patients. The ideal requirements for each patient were calculated using the Harris-Benedict equation with an adjustment determined by the patient's diagnosis. We compared the amount of feed delivered with the daily requirements over a seven-day period Successful feeding was defined as the achievement of 90% of the ideal calorie requirement for two consecutive days. The mean calculated (+/- SD) energy requirement was 9,566 kJ (+/- 2,586). Patients received only 51% (SD 38) of their energy requirements throughout the study period. Only 10 patients (25%) were successfully fed for at least any two-day period in the seven days. Feeding was limited mainly by gastrointestinal dysfunction or by the need to fast the patient for medical, surgical and airway procedures. Success of feeding was not related to the use of sedative orparalysing agents and had no correlation with plasma albumin concentration. There was no difference in the volume of feed delivered to patients who survived or died. Prokinetic agents were used in 25 patients and in these patients there was a trend towards improved delivery of feed.

Comparison of gastrointestinal tolerance to two enteral feeding protocols in critically ill patients: a prospective, randomized controlled trial

BACKGROUND

The purpose of this study was to compare gastrointestinal tolerance to two enteral feeding protocols in critically ill patients.

METHODS

A prospective, randomized controlled trial, that involved 96 consecutive patients expected to stay in the intensive care unit for > or =3 days and who had no contraindications to enteral feeding. The patients were randomized to either the current protocol (group I; gastric residual volume threshold, 150 mL, optional prokinetic) or proposed feeding protocol (group II; gastric residual volume threshold 250 mL, mandatory prokinetic). Gastrointestinal intolerance was recorded as episodes of high gastric residual volume, emesis, or diarrhea. The time to reach the goal rate of feeding and the percentage of nutritional requirements received during the study period were also recorded.

RESULTS

Nineteen of 36 patients (19/36 = 0.53) in group I had one or more episodes of high gastric residual volume, compared with 10 of 44 patients (10/44 = 0.23) in group II (p < .005). There was no statistical difference between the two protocols with regards to emesis, diarrhea, or the total episodes of intolerance. The patients in group II reached their goal rates on average in 15 hours and received 76% of their nutritional requirements, compared with 22 hours and 70% in group I; however, these differences were not statistically significant.

CONCLUSIONS

The incidence of enteral feeding intolerance was reduced by using a gastric residual volume of 250 mL along with the mandatory use of prokinetics. The study showed a trend of improved enteral nutrition provision and reduced the time to reach the goal rate in group II. These improvements support the adoption of the proposed feeding protocol for critically ill patients.

The nutritional management of patients with head injuries

Severe head injuries tend to be associated with hypermetabolism and hypercatabolism resulting in negative nitrogen balances which may exceed 30 grams day-1. Enteral feeding should begin as soon as the patient is hemodynamically stable, attempting to reach a non-protein caloric intake of at least 30-35 kcal kg-1 day-1 and a protein intake of 2.0-2.5 g kg-1 day-1 as soon as possible. With severe head injuries (Glasgow Coma Scale < 8), there is an increased tendency for gastric feeding to regurgitate into the upper airway. Keeping the patient upright and checking residuals is important in such patients. Jejunal feedings are less apt to be aspirated. If it is apparent that the gastro-intestinal tract cannot be used to reach the nutritional goals within three days, total parental nutrition is begun within 24-48 h so as to reach these nutrition goals by either one or both routes by the third or fourth day. Blood glucose levels exceeding 150-200 mg dl-1 tend to increase the severity of the neurologic problems and efforts should be made to prevent hyperglycemia by carefully regulating the glucose and insulin intake. Indirect calorimetry to determine the respiratory quotient and resting energy expenditure should be determined twice weekly. To determine N2 balance, urinary urea nitrogen should be measured in 24-h specimens. These tests should be performed once or twice weekly until it is clear that the nutrition is adequate.

Intolerance to intragastric enteral nutrition in critically ill patients: complications and management

Compared with parenteral nutrition, early administration of enteral nutrition (EN) to critically ill patients improves clinical outcomes and reduces infection rates. Intragastric EN often is complicated by intolerance, as indicated by elevated volumes of aspirated gastric residuals. Conflicting data are available for the volume of residual that represents intolerance, but most clinicians use 150-200 ml to signify gastrointestinal motility dysfunction. Intolerance is associated with mortality. Data support an association between intragastric EN and aspiration pneumonia, but little information is available regarding the contributory effect of intolerance. Transpyloric migration of the feeding tube may facilitate tolerance but does not reduce the likelihood of aspiration pneumonia. Prokinetic agents (cisapride, erythromycin, metoclopramide) promote gastric emptying. Results of most studies are limited because patients did not receive or tolerated intragastric EN. Metoclopramide is the agent of choice for treating intolerance. Further studies are necessary before prokinetic drugs can be recommended for preventing intragastric EN-associated aspiration pneumonia.

Nutrition

The use of nutrition for the medical patient, in the inpatient setting and at home, will likely continue to increase in the future. Each patient should be evaluated in an individualized but systematic fashion. Each patient in whom malnourishment is suspected should undergo a thorough assessment for the presence and degree of malnutrition with an accurate calculation of nutritional requirements. It is important to choose the correct method of delivery of nutrition, to monitor and recognize any complications or problems that may arise, and to tailor the nutritional therapy to the unique diseases that are encountered in medicine. Although increasingly new advances and changes are occurring in the field of nutrition, nutritional support and therapy are best delivered and supplied to the patient with a network of health care workers, including the physician, the nurse, the dietitian, the social worker, and pharmacist.

The paracetamol absorption test: a useful addition to the enteral nutrition algorithm?

BACKGROUND

Enteral nutrition in critically ill patients given via the nasogastric route is often decreased or stopped because of large gastric residual volumes.

AIM

To assess the effect of continuing enteral nutrition in patients with an elevated gastric residual volume but normal gastric emptying by the paracetamol absorption test.

METHODS

The paracetamol absorption test was performed on all patients receiving enteral nutrition via a nasogastric tube who had a residual volume (assessed every 8 hours) of >150 ml or more than twice the hourly infusion rate. Patients were then divided into 2 groups according to the result of the test: Group 1 (n=8), normal gastric emptying; and Group II (n=24), abnormal gastric emptying. Group I continued to receive enteral nutrition. In Group II feeding was interrupted in 18 patients and prokinetic agents administered, while a subgroup of six patients continued to receive enteral nutrition without prokinetic agents. All patients were followed for evidence of delayed gastric emptying and aspiration.

RESULTS

Residual volumes were similarly elevated in both groups (p=0.25). Enteral nutrition was continued in Group I with no adverse effects. Prokinetic agents allowed enteral nutrition to be resumed in 88% of the 18 Group II patients. Enteral nutrition in the subgroup had to be stopped because of persistently elevated residual volumes.

CONCLUSION

The paracetamol absorption test may be normal in patients with relatively high gastric residual volumes. These patients may continue to receive enteral nutrition.

The incidence of ventilator-associated pneumonia and success in nutrient delivery with gastric versus small intestinal feeding: a randomized clinical trial

BACKGROUND

Enteral feeding provides nutrients for patients who require endotracheal tubes and mechanical ventilation. There is a presumed increase in the risk of ventilator-associated pneumonia (VAP) with tube feeding. This has stimulated the development of procedures for duodenal intubation and small intestinal (SI) feeding as primary prophylaxes to prevent VAP.

OBJECTIVE

To investigate the rate of VAP and adequacy of nutrient delivery with gastric (G) vs. SI feeding.

DESIGN

A prospective, randomized, controlled trial.

SETTING

A medical intensive care unit of a county hospital.

PATIENTS

A total of 44 endotracheally intubated, mechanically ventilated patients requiring enteral nutrition.

INTERVENTION

Subjects were randomized to receive enteral nutrition via G or SI feeding. Protocols directed the placement of the feeding tube and the infusion of enteral nutrition and defined the radiographic and clinical criteria for a diagnosis of VAP.

MEASUREMENTS AND OUTCOMES

The incidence of VAP and the adequacy of nutritional supplementation were prospectively followed. The relative risk of VAP with SI was 1.1 (95% confidence interval 0.96-2.44) compared with G. The SI group received a greater percentage of their caloric requirements (SI 69 +/- 7% vs. G 47 +/- 7%, mean +/- SEM, p < .05). Mortality did not differ between G (26 +/- 9%) and SI (24 +/- 10, p = .86).

CONCLUSIONS

There is no clear difference in the incidence of VAP in SI compared with G enteral nutrition. Patients given feeding into the SI do receive higher calorie and protein intakes.

The intensive care unit as an operating room

This article is an overview of the different procedures currently performed on the ICU patient and emphasizes percutaneous tracheostomy and percutaneous gastrotomy. The steps necessary to prepare the patient, the ICU staff, and intensivist to achieve a safe and successful procedure are described, as are the indications, technique, complications, safety, and advantages to perform these techniques in the ICU.

The Brain Trauma Foundation. The American Association of Neurological Surgeons. The Joint Section on Neurotrauma and Critical Care. Nutrition

Data show that starved head-injured patients lose sufficient nitrogen to reduce weight by 15% per week. Class II data show that 100-140% replacement of resting metabolism expenditure with 15-20% nitrogen calories reduces nitrogen loss. Data in non-head injured patients show that a 30% weight loss increased mortality rate. Class I data suggests that nonfeeding of head-injured patients by the first week increases mortality rate. The data strongly support feeding at least by the end of the first week. It has not been established that any method of feeding is better than another or that early feeding prior to 7 days improves outcome. Based on the level of nitrogen wasting documented in head-injured patients and the nitrogen sparing effect of feeding, it is a guideline that full nutritional replacement be instituted by day 7.

Routine intragastric feeding following traumatic brain injury is safe and well tolerated

BACKGROUND

Delayed gastric emptying following traumatic brain injury (TBI) has led some to advocate jejunal feeding. Our purpose was to review our experience with percutaneous endoscopic gastrostomy (PEG) and intragastric feeding in TBI patients to assess safety and effectiveness.

METHODS

All patients on a TBI clinical pathway at our institution were targeted for early PEG. After PEG, standard enteral nutrition was initiated. Abdominal examination and gastric residual volumes were used to assess tolerance.

RESULTS

There were 118 patients with moderate to severe TBI. The average age was 36 years. Mean Injury Severity Score (ISS) was 25. Enteral access was obtained and intragastric feeding was initiated on day 3. 6. Intragastric feeding was tolerated without complication in 111 of 114 (97%) patients. Five patients aspirated, but had no evidence of intolerance prior to the event.

CONCLUSIONS

PEG provided reliable enteral access in moderate to severe TBI patients. Intragastric feeding was well tolerated with a low complication rate (4%).

Prospective, randomized, controlled trial to determine the effect of early enhanced enteral nutrition on clinical outcome in mechanically ventilated patients suffering head injury

OBJECTIVE

To determine the effect of early enhanced enteral nutrition (EN) on clinical outcome of head-injured patients.

DESIGN

Prospective, randomized, controlled trial.

SETTING

Tertiary neurosurgical and trauma center.

PATIENTS

Eighty-two patients suffering head injury and requiring mechanical ventilation.

INTERVENTIONS

Patients were randomized to receive standard EN (gradually increased from 15 mL/hr up to estimated energy and nitrogen requirements) or enhanced EN (started at a feeding rate that met estimated energy and nitrogen requirements) from day 1. Good neurologic outcome (Glasgow Outcome Scale score of 4 or 5) was determined at 3 and 6 months after injury, and the incidence of infective and total complications was determined during the hospital stay up to 6 months.

MEASUREMENTS AND MAIN RESULTS

Disease severity assessed by best preintubation Glasgow Coma Scale score, pupillary responses, Injury Severity Score, Acute Physiology and Chronic Health Evaluation II score, computed tomographic scan categorization, and age was similar in both groups. Intervention patients had a higher percentage of energy (p = .0008) and nitrogen (p<.0001) requirements met by EN in the first week after injury. Neurologic outcome at 6 months was similar between groups, but there was a tendency for more intervention patients to have a good neurologic outcome at 3 months than control patients (61% vs. 39%, p = .08). Fewer intervention patients had an infective complication (61% vs. 85%, p = .02) or more than one total complication (37% vs. 61%, p = .046) compared with control patients. Enhanced EN was associated with a reduction in the ratio of serum concentration of C-reactive protein to albumin up to day 6 after injury (p = .004).

CONCLUSIONS

Enhanced EN appears to accelerate neurologic recovery and reduces both the incidence of major complications and postinjury inflammatory responses.

The metabolic response to acute traumatic brain injury and implications for nutritional support

An overview of the metabolic response to acute traumatic brain injury is presented. The consequences of hypermetabolism, hypercatabolism, and an altered immune function are discussed. Once a person with acute traumatic brain injury develops this hyperdynamic state, the resultant excessive protein breakdown ensues. This can lead to malnutrition. The feeding methods used to prevent malnutrition are discussed, along with the proper alimentation to provide to diminish the hyperdynamic state and improve immune function.

Acute intracranial hypertension-induced inhibition of gastric emptying: evaluation in conscious rats

To study the effect of raised intracranial pressure (ICP)-induced alterations in gastric emptying, and their modulation by pharmacological interventions, an experimental model was standardized in rats. A test meal of methylcellulose and phenol red was administered intragastrically. ICP was raised to 40, 60 and 80 mmHg by connecting a buffered saline pressure head to an intracerebroventricular (i.c.v.) cannula. Gastric emptying was estimated after killing the animals, from the residual stomach phenol red content. Inhibition of gastric emptying was observed when ICP was raised, the maximum being at 80 mmHg ICP (percent gastric emptying 26.5%+/-2.8 vs. 83.4+/-4.7 in sham-ICP). Pretreatment with clonidine, prazosin or ondansetron did not modify the raised ICP-induced inhibition of gastric emptying. Cisapride was ineffective at 1 mg/kg but caused a partial reversal at the 5- and 10-mg/kg doses (46.9+/-3.1% and 42.6+/-4.0%, respectively). Carbachol at a lower dose of 0.1 mg/kg i.p., produced a greater reversal (78.3+/-6.0%) than did the high dose (52.8+/-4.1). Bretylium partially reversed the inhibition of gastric emptying (45.7+/-4.3%). The protective effect of carbachol and cisapride suggests that suppression of vagal activity due to increased ICP may play an important role in the inhibition of gastric emptying due to intracranial hyper-tension.

Metabolic assessment and enteral tube feeding usage in children with acute neurological diseases

OBJECTIVE

To report on acquired experience of metabolic support for children with acute neurological diseases, emphasizing enteral tube feeding usage and metabolic assessment, and also to recommend policies aimed towards improving its implementation.

DESIGN

Retrospective analysis.

SETTING

Pediatric Intensive Care Unit of Hospital do Servidor Público Estadual de São Paulo.

SUBJECTS

44 patients consecutively admitted to the Pediatric ICU over a period of 3 years who were given nutrition and metabolic support for at least 72 hours. Head trauma, CNS infections and craniotomy post-operative period following tumor exeresis were the main diagnoses.

MEASUREMENTS

Records of protein-energy intake, nutrient supply route, nitrogen balance and length of therapy.

RESULTS

From a total of 527 days of therapy, single parenteral nutrition was utilized for 34.3% and single enteral tube feeding for 79.1% of that period. 61.4% of the children were fed exclusively via enteral tube feeding, 9.1% via parenteral and 39.5% by both routes. The enteral tube feeding was introduced upon admission and transpyloric placement was successful in 90% of the cases. Feeding was started 48 hours after ICU admission. The caloric goal was achieved on the 7th day after admission, and thereafter parenteral nutrition was interrupted. The maximum energy supply was 104.2 +/- 23.15 kcal/kg. The median length of therapy was 11 days (range 4-38). None of the patients on tube feeding developed GI tract bleeding, pneumonia or bronchoaspiration episodes and, of the 4 patients who were given exclusive TPN, 2 developed peptic ulcer. The initial urinary urea nitrogen was 7.11 g/m2 and at discharge 6.44 g/m2. The protein supply increased from 1.49 g/kg to 3.65 g/kg (p < 0.01). The nitrogen balance increased from--7.05 to 2.2 g (p < 0.01).

CONCLUSIONS

Children with acute neurological diseases are hypercatabolic and have high urinary nitrogen losses. The initial negative nitrogen balance can be increased by more aggressive feeding regimes than the usual ones. Early tube feeding was well tolerated, which permits the conclusion that it is a safe and effective method for nutrition support. Recommendations of basic rules for metabolic support are made.

[Nutritional aspects of cranial trauma]

In head-injured patients the nutritional support is aimed to prevent denutrition status usually observed. The adequate amount of calories depends on the basal metabolism (as calculated with the Harris Benedict equation). It has to be increased in case of fever (by a 0.1 factor per degree above 37 degrees C), sepsis (by a 0.1 to 0.2 factor) or when sedation is discontinued (by a 0.3 factor). The increased proteolysis is not modified by the associated treatment and results in an inevitable protein loss, whatever the qualitative change in nutritional support. In clinical practice, the nutritional support has to be adjusted continuously to the needs of the patient, to avoid a more pronounced denutrition due to the summation of daily nutritional deficits.

Gastric emptying in head-injured patients

OBJECTIVE

Most patients with moderate to severe head injury (HI) initially do not tolerate enteral feedings. Intolerance to nasogastric feeding is also commonly observed after HI. Quantitative measurements of gastric emptying (GE), to determine a possible mechanism for intolerance to enteral feeding, are lacking.

METHODS

We prospectively evaluated gastric emptying half-time (GET1/2) of liquid meals in 35 patients with moderate to severe HI.

RESULTS

In comparison with 16 age-matched healthy control subjects (29.4 +/- 3.7 min), GET1/2 was significantly prolonged (57.2 +/- 20.8 min, p < 0.05) and abnormal in 80% of the HI patients. A prolonged GET1/2 and higher incidence of abnormal GET1/2 were observed in female patients, older patients, and patients with low Glasgow coma scale (GCS) scores, when compared with male patients, younger patients, and patients with high GCS scores. However, the differences for the means of GET1/2 and the incidences of abnormal GET1/2 between the subgroup patients were not significant (p > 0.05). In addition, significantly prolonged GET1/2 and higher incidence of abnormal GET1/2 (p < 0.05) were observed in patients with short injury duration, in comparison with patients with long injury duration.

CONCLUSION

Head injury can cause significant prolonged GE of liquid meals, especially in patients with short injury duration.

Metabolic profiles of patients with subarachnoid hemorrhage treated by early surgery

OBJECTIVE

This study was conducted to evaluate the metabolic response of patients with subarachnoid hemorrhage (SAH) and to determine whether the severity of hemorrhage influenced the response.

METHODS

Resting energy expenditure, nitrogen balance, and serum rapid-turnover proteins were studied for 3-day periods at Day 4, Day 10, and before discharge in patients with SAH who underwent surgical clipping within 2 days after the onset. The patients were divided into two groups according to the Hunt and Hess classification system; there were 17 patients with Grade I or II (mild group) and 19 patients with Grade III, IV, or V (severe group).

RESULTS

The mean resting energy expenditures (mean+/-standard deviation) were highest on Day 10, which were 146+/-24% and 198+/-78% of basal energy expenditure in the mild and severe groups, respectively. The nitrogen balance levels of the mild group on Days 4 and 10 were -3.0+/-3.5 g per day and -4.5+/-2.9 g per day, and those of the severe group were -7.5+/-3.2 g per day and -9.2+/-4.1 g per day, respectively. There was a significant difference in the nitrogen balance over time between the two groups (P=0.0037). Serum transferrin, prealbumin, and retinol-binding protein levels were lowest on Day 4 and gradually increased. There were no significant differences in these parameters between the two groups.

CONCLUSION

SAH treated by surgery induces a profound stress response. A significant difference of increased catabolism but not decreased anabolism between the mild and severe groups was noted.

The principles and practical application of enteral nutrition

The enteral route is the preferred method of nutritional support in patients with functional gastrointestinal tracts. Many techniques for obtaining enteral access are available, and the decision regarding which one to use depends on several issues, including the functional integrity of each part of the gastrointestinal tract, the duration of anticipated nutritional support, and the risk of aspiration and gastroesophageal reflux. Nasoesophageal tubes are useful for short-term supplementation; however, patients needing nutritional support for longer than 2 weeks may be better served with a more permanent tube. Blenderized pet food diets are recommended for nutritional support because these diets do not need to be supplemented with protein or micronutrients. Commercial human enteral formulas provide a useful alternative for patients with specific nutrient requirements or for feeding via nasoesophageal or jejunostomy tubes.

Percutaneous endoscopic gastrostomy for patients with severe cerebral injury

Early enteral nutrition improves the outcome of severely injured patients. To provide enteral nutrition, various methods are available. In a restrospective study we analysed the outcome of 24 severely traumatized patients (mean ISS = 44), in whom a percutaneous endoscopic gastrostomy (PEG) was used for enteral nutrition. All patients had been admitted to the intensive care unit with major cerebral injury. The mean duration of intensive care treatment and the in hospital stay were 28 and 71 days, respectively. PEG was introduced 14 days after hospital admittance. Enteral nutrition through the PEG was administered for 45 days. Four patients died, 8 patients were discharged from the hospital while being fed via the PEG and 12 patients resumed normal feeding and the PEG was removed. Three severe complications occurred; 1 patient aspirated massively and died; in 2 patients intra-abdominal leakage of the enteral nutrition occurred. Both patients recovered from this complication. We conclude that because of the advantages of early enteral nutrition on the one hand and the drawbacks of nasogastric feeding tubes on the other, in injured patients with severe cerebral damage, PEG placement is justified, despite the risk of complications.

Physiologic hypoalbuminemia is well tolerated by severely burned children

BACKGROUND

Physiologic hypoalbuminemia, defined as a plasma albumin (pl-ALB) of 1.0 to 2.5 g/dL, is a component of the injury response. A consensus on the need for albumin supplementation in this setting is lacking.

METHODS

We examined 27 consecutive children (age, 7 +/- 6 years) with > 40% body surface burns (mean, 59 +/- 18%) during their initial 4 weeks of care. Patients were managed with an albumin-supplementation protocol that tolerated profound physiologic hypoalbuminemia. Intravenous albumin was administered by infusion of 1 to 2 g/kg/d when pl-ALB fell below 1.0 g/dL, or below 1.5 g/dL in the presence of enteral feeding intolerance or pulmonary dysfunction. Supplementation was stopped when pl-ALB reached 2.0 g/dL.

RESULTS

Mean pl-ALB was 1.7 g/dL overall. Infusion for pl-ALB < 1.0 g/dL was needed for 70% (n = 19) of the patients. Profound physiologic hypoalbuminemia was constant, that is, mean weekly pl-ALB never exceed 2.5 g/dL in any patient. Mean plasma globulin rose during the 4 week period from 2.3 +/- 0.1 at week 1 to 3.1 +/- 0.1 at week 4. Diarrhea was negligible (19 of 756 patient days), nasogastric feedings were well tolerated, PaO2/FiO2 ratios remained well above 150, wounds healed satisfactorily, and all children survived and have been discharged home.

CONCLUSIONS

Profound physiologic hypoalbuminemia (pl-ALB of 1.0-2.5 g/dL) does not have adverse effects on pulmonary or gut function, wound healing, or outcome in severely burned children, perhaps because of a compensatory increase in acute-phase proteins reflected in plasma globulin.

Nutritional management of the critically ill neurologic patient

To summarize, the event of severe neurologic injury results in significant metabolic changes. These changes cause increased requirements for protein and nonprotein calories, micronutrients, and small bowel feedings or TPN. Early feeding has been shown to improve survival. Therefore, every effort should be made to provide aggressive nutritional support within the first 72 hours after injury. Specific guidelines are as follows: Provide full-strength, full-rate feedings within 72 hours. Provide enteral nutrients via nasojejunal or percutaneous endoscopic jejunostomy feeding tube if access is available; attempt gastric feedings if not. Provide TPN within 48 hours if enteral access is not available and begin enteral feeding as soon as possible. Provide 2 to 2.3 g protein/kg/d if renal function is normal. Provide 40% to 70% above basal needs as total calories, with 30% to 40% of calories as lipid to minimize hyperglycemia. Provide protein as small peptides to improve tolerance, absorption, utilization, and gut integrity. Provide a lipid source with 50% to 70% medium-chain triglycerides and an omega-6 to omega-3 ratio of 2:1 to 8:1 to minimize negative effects of omega-6 fatty acids and provide an easily absorbed and utilized source of lipid.

Cisapride as a treatment for gastroparesis in traumatic brain injury

Gastroparesis is a well-documented finding among patients with severe traumatic brain injuries. The treatment of choice has been metoclopramide, but it is less than ideal given its central dopaminergic blocking activity. Cisapride is a newer prokinetic agent without side effects on the central nervous system and might be a superior treatment. The case of a healthy 22-year-old man who suffered a severe traumatic brain injury and multiple trauma in a motor vehicle accident is reported. The patient required gastrostomy tube placement but developed recurrent aspiration pneumonia once feedings were initiated. Despite receiving metoclopramide, barium studies revealed gastroparesis, a significant decrease in gastric peristalsis, and reflux. A jejunostomy tube was placed to prevent further aspiration. The administration of cisapride was begun, and 2 days later the patient was changed back to G-tube feedings with no evidence of residual aspirates. Repeat barium study showed definite improvement in peristalsis. This case demonstrates the potential usefulness of cisapride in patients with traumatic brain injury. Although further research is necessary, efficacy without central dopamine blockage may make cisapride the treatment of choice for gastroparesis and reflux in traumatic brain injury.

Enteral feeding associated gastroesophageal reflux and aspiration pneumonia: a review

Hospital malnutrition continues to be a serious problem. Although enteral feeding of hospitalized patients is safe and less expensive than parenteral feeding, it is associated with side effects involving the gastrointestinal tract and respiratory systems.

Observations on the patterns of 24-hour energy expenditure changes in body composition and gastric emptying in head-injured patients receiving nasogastric tube feeding

BACKGROUND

Although intolerance to nasogastric feeding is commonly observed after head injury, quantitative measurements of gastric emptying are lacking. Concepts about energy requirements are limited by the lack of long-term measurements of total energy expenditure.

METHODS

Six male subjects with severe head injury had their gastric emptying measured by the phenol red technique. N and energy balances were measured by classic balance techniques, which included continuous indirect calorimetry for up to 24 hours (days 3 to 5). Measurements of body composition were made on days 3 to 5 and 12 to 19 (4 subjects only).

RESULTS

The subjects lost a mean of 9.8 kg of which 2.3 kg was estimated to be due to fat (equivalent to -14 g N/d and -1690 kcal/d). On days 3 to 5, basal metabolic rate (BMR) was 130% to 135% of predicted. The low dietary intake (650 kcal and 4.2g N/d) was associated with negative energy (-1710 +/- 520 kcal/d) and N balances (-19 +/- 5 g N/d). Gastric emptying was delayed twofold (days 3 to 5) compared with controls (p < .001) and was associated with significant regurgitation of feed into the mouth (16 of 31 saliva samples contained glucose at a concentration of > 0.5 mmol/L compared with control values of < 0.2 mmol/L.

CONCLUSIONS

The large negative energy balance in the subjects studied was largely due to the inadequate nasogastric feeding, which was associated with a twofold reduction in the rate of gastric emptying and frequent regurgitation of feed. The large negative N balance and the high contribution of protein oxidation to total energy expenditure (25% to 28%) was predominantly due to the injury sustained and immobility. An increase in BMR is not necessarily associated with increased total energy expenditure or energy requirements.

Early nutrition support modifies immune function in patients sustaining severe head injury

BACKGROUND

Immunosuppression after severe head injury has been characterized by a depressed CD4 (T-helper/inducer)-CD8 (T-suppressor/cytotoxic) ratio and decreased T-lymphocyte responsiveness. Some investigators propose that this immunocompromized state is the result of an injury-associated hypermetabolic response and inadequate nutrient delivery during the immediate postinjury recovery phase. Previous observations from our institution demonstrated a preserved CD4-CD8 ratio in severe closed-head injury (CHI) patients receiving early parenteral nutrition (PN). It was unclear whether early PN or other aspects of patient care eliminated the characteristic depression in cellular immunity. The purpose of this study was to further investigate the effect of early PN on the immune function of CHI patients.

METHODS

Nine patients sustaining severe CHI were prospectively randomized to either early PN (n = 4) at day 1 or delayed PN (n = 5) at day 5. Total nutrient administration was delivered at 2 g of protein/kg per day and 40 nonprotein kcal/kg per day for at least the first 14 days of hospitalization. Analysis for T-lymphocyte expression of CD4 and CD8 cell surface antigens and interleukin-6 was performed on days 1, 3, 7, and 14 of hospitalization. T-lymphocyte activation in response to stimulation by concanavalin A (Con A), phytohemagglutinin (PHA), and pokeweed mitogens (PWM) was also assessed on these days.

RESULTS

Significant increases in total CD4 cell counts (2048 +/- 194 to 2809 +/- 129 vs 1728 +/- 347 to 1825 +/- 563, p < .05) and CD4% (42.6 +/- 4.4% to 56.2 +/- 2.6% vs 36.6 +/- 6.6% to 36.6 +/- 11.3%, p < .05) were observed at day 14 in patients receiving early vs delayed PN. An improved lymphocyte response from baseline to day 14 after Con A stimulation was demonstrated in the early PN group (3850 +/- 1596 to 16144 +/- 5024 cpm, p < .05). A significant rise in the CD4-CD8 ratio over baseline to day 14 was also noted in the early PN group (1.43 +/- 0.17 to 2.38 +/- 0.54, p < .05).

CONCLUSIONS

The early aggressive nutrition support of CHI patients appears to modify immunologic function by increasing CD4 cells, CD4-CD8 ratios, and T-lymphocyte responsiveness to Con A.

Long-term enteral access in aspiration-prone patients

Aspiration pneumonia is a serious complication of enteral feeding. Many critically ill patients are particularly at risk for aspiration. Few studies have rigorously compared various access devices. Risk factors for aspiration and studies examining aspiration associated with enteral feeding devices are reviewed. We recommend a surgical jejunostomy for all patients at high risk for aspiration who require more than 3 weeks of enteral nutrition support.

Gastric emptying following brain injury: effects of choice of sedation and intracranial pressure

OBJECTIVE

To compare the effects of opioid and non-opioid sedation on gastric emptying.

DESIGN

Prospective, randomized trial.

SETTING

University teaching hospital ICU.

PATIENTS

21 brain injured patients requiring sedation, mechanical ventilation and intracranial pressure (ICP) monitoring for > 24 h.

INTERVENTIONS

Patients were randomized to receive infusions of either morphine plus midazolam (M), or propofol (P). Gastric emptying was assessed by the paracetamol absorption technique and by residual volumes following a 200 ml test feed.

MEASUREMENTS AND RESULTS

Pre-sedation Glasgow Coma Score, mean ICP and the presence of bowel sounds were noted. Plasma concentrations of paracetamol were measured over 3 h following a 1 g gastric dose. There were no differences in median peak paracetamol concentration (M, 18.5 versus P, 20.8 mg/l), median time to peak concentration (M, 20 versus P, 25 min), median area under the concentration-time curve (AUC), or in the median residual volumes at 1 h (M, 14 versus P, 10.5 ml) and 2 h (M, 5 versus P, 3 ml). In patients with ICP > 20 mmHg, paracetamol concentrations were lower (p < 0.05), and AUC after 30 min was lower (165 mg.min/l versus 411 mg.min/l, p = 0.023). Mean ICP was correlated with AUC (Kendall rank p = 0.027). Gastric emptying did not correlate with initial Glasgow Coma Score or presence of bowel sounds.

CONCLUSIONS

Gastric emptying is not improved in patients with brain injury by avoiding morphine (1-8 mg/h) in the sedative regimen. Intracranial hypertension is associated with reduced gastric emptying.

Enteral nutrition in the critically ill patient: a prospective survey

OBJECTIVES

To describe current enteral nutrition-prescribing practices for critically ill patients, and to identify factors associated with initiation of, and tolerance to, enteral nutrition.

DESIGN

A prospective, cohort study.

SETTING

Two tertiary care medical-surgical intensive care units (ICU) in Ontario, Canada.

PATIENTS

We enrolled 99 consecutive patients who were expected to stay in the ICU for > 3 days and who were unable to tolerate oral nutrition. We followed patients for 21 days or until they tolerated enteral nutrition, tolerated oral nutrition, were discharged from the ICU, or died.

MEASUREMENTS AND MAIN RESULTS

We recorded time elapsed from ICU admission to initiation and tolerance of enteral feedings, and examined factors associated with these events. We defined tolerance as receiving 90% of estimated daily energy requirements for > 48 hrs without gastrointestinal dysfunction (i.e., high gastric residuals, vomiting, diarrhea, abdominal distention). Seventy-three (74%) of 99 patients were started on enteral feedings an average 3.1 days (range 1 to 18) after ICU admission. Of 26 patients never started on enteral nutrition, three (12.5%) patients eventually tolerated oral nutrition, 14 (54.0%) patients were discharged from the ICU, and seven (27.0%) patients died. Reasons for not initiating enteral nutrition included absence of bowel sounds (27.0%), high nasogastric drainage (16.9%), contraindication to enteral nutrition (16.7%), tolerance of oral nutrition (6.8%), and no apparent reason (5.1%). Abdominal surgery, use of vasoactive drugs, and admission to one hospital made initiation of enteral nutrition less likely, whereas presence of bowel sounds and admission to the other hospital made initiation of enteral nutrition more likely. Thirty-five (42.9%) of 73 patients started on enteral nutrition achieved tolerance of the regimen. The average time from ICU admission to tolerance of feedings was 5.8 days (range 1 to 14). Once started on enteral nutrition, the most common reasons for decreasing or discontinuing feedings included high gastric residuals (51.0%), mechanical feeding tube problems (15.4%), medical or surgical procedures (5.4%), and vomiting (5.1%). Use of paralytic agents and the presence of high gastric residuals were associated with intolerance. Of 38 patients who did not achieve tolerance, 20 (52.6%) patients were discharged from the ICU, eight (21.0%) patients died, and eight (21.0%) patients eventually tolerated oral nutrition.

CONCLUSIONS

Enteral nutrition is not started in all eligible ICU patients. Approximately half of those patients receiving enteral nutrition achieved tolerance of the regimen. Gastrointestinal dysfunction causing intolerance to enteral nutrition is a common reason for not starting, or discontinuing, feedings.

Intravenous albumin and nutrition support: going for the quick fix

BACKGROUND

IV albumin has been advocated as adjunctive therapy for hypoalbuminemic patients who are receiving nutrition support. This discussion will critically consider the rationale for this recommendation as well as the evidence available in the medical literature.

METHODS

The medical literature was reviewed.

RESULTS

Randomized controlled trials have shown that IV albumin improves serum albumin levels. However such therapy does not improve clinical outcome in patients receiving parenteral nutrition. Although no trials exist that test the hypothesis in hypoalbuminemic patients receiving enteral nutrition, the purported "supportive evidence" in the medical literature is actually weak and contradictory. IV albumin does have some associated toxicity, and it is expensive.

CONCLUSIONS

There is reason to believe that IV albumin is not effective in improving the clinical outcome of hypoalbuminemic patients who are receiving nutrition support. Until more compelling data become available, it is not reasonable to adopt a policy of routinely correcting the hypoalbuminemia in this way. In fact, hypoalbuminemia may be a manifestation of a serious disease state rather than a marker of deficient protein stores.

Pentobarbital coma in neurosurgical patients: nutrition considerations

Neurosurgical patients in pentobarbital coma are a complex nutrition support population. Physiologic changes associated with the primary injury to the brain, combined with the pharmacodynamic influences of barbiturate therapy, contribute to the difficulties of initiating aggressive nutrition support. Early nutritional repletion is important to the overall outcome of traumatically injured patients. Consequently, factors that influence nutrition support decisions must be understood to assure appropriate intervention. The metabolic changes associated with traumatic head injury, pentobarbital therapy, and nutrition support strategies are reviewed.

Nutrition support in critical illness

Sepsis, shock, multiple trauma, and burns are often associated with altered metabolism characterized by severe catabolism, wasting of the lean body mass, immune dysfunction, and compromised wound healing. Nutrition support is one of the mainstays in the management of these critically ill patients and is aimed at minimizing these complications. The purpose of this article is to compare stress hypermetabolism and starvation metabolism, to review current recommendations for the provision of energy and substrate to the critically ill patient, and to review pertinent literature regarding enteral vs parenteral nutrition. Finally, this article will provide a brief overview of new and future therapies with emphasis on specific substrates and growth factors and the potential for their use in the critically ill patient.

Limitations of percutaneous endoscopic jejunostomy

Thirty-six patients at the University of Kentucky Medical Center underwent percutaneous endoscopic jejunostomy placement between January 1 and December 31, 1989. We retrospectively reviewed their charts for indications and complications of the procedure. Experience and outcome with the initial placement of the percutaneous jejunostomy tube was evaluated. Primary diagnoses at the time of insertion included central nervous system disorders (28), ventilator dependence (5), cancer (2), and gastroparesis (1). The follow-up period ranged from 2 to 131 days (median 16 days). Tube dysfunction or dislodgment occurred in 31% of patients. Other complications included pulmonary aspiration (11%) and bleeding at the insertion site (3%). The 30-day mortality rate was 19% with all but one death caused by the severity of the underlying primary illness. It is concluded that problems with the currently performed technique of percutaneous endoscopic jejunostomy, along with tube-related problems, seriously limit the usefulness of this technique. Improvements in technology, along with routine postprocedure radiographs to allow early detection of malpositioned jejunostomy tubes, may improve the outcome of this procedure. Newer techniques that have a higher success of distal small intestinal placement need to be evaluated.