Applied nutrition in ICU patients. A consensus statement of the American College of Chest Physicians

Parenteral glucose and glucose control in the critically ill: a kinetic appraisal

BACKGROUND

We investigated the influence of parenteral glucose infusion on insulin-driven tight glucose control (4.4-6.1 mmol/liter) in the critically ill by appraising kinetic characteristics of the glucoregulatory system.

METHODS

Turnover characteristics of the glucoregulatory system associated with constant 0, 1.2, and 2.4 mg/kg/min parenteral glucose infusion were obtained by literature review and mass-balance calculations.

RESULTS

Without parenteral glucose infusion, the achievement of tight glucose control is hampered by long time delays with an anticipated glucose equilibration half-time (T((1/2))) of 185 min. The constant parenteral glucose infusions of 1.2 and 2.4 mg/kg/min reduce T((1/2)) to 80 and 40 min, respectively. This follows on from the accelerated glucose turnover brought about by the insulin-modulated glucose uptake, which increases in response to increasing exogenous insulin required to achieve tight glucose control. However, large variations exist among glucose turnover characteristics in the critically ill.

CONCLUSIONS

The constant parenteral glucose infusion greater or equal to 2.4 mg/kg/min is expected to simplify the achievement of tight glucose control by reducing system delays and may facilitate the development of more intuitive, efficacious, and safer insulin-titration guidelines.

Poor agreement between continuous measurements of energy expenditure and routinely used prediction equations in intensive care unit patients

BACKGROUND & AIMS

A wide variation in 24h energy expenditure has been demonstrated previously in intensive care unit (ICU) patients. The accuracy of equations used to predict energy expenditure in critically ill patients is frequently compared with single or short-duration indirect calorimetry measurements, which may not represent the total energy expenditure (TEE) of these patients. To take into account this variability in energy expenditure, estimates have been compared with continuous indirect calorimetry measurements.

METHODS

Continuous (24h/day for 5 days) indirect calorimetry measurements were made in patients requiring mechanical ventilation for 5 days. The Harris-Benedict, Schofield and Ireton-Jones equations and the American College of Chest Physicians recommendation of 25 kcal/kg/day were used to estimate energy requirements.

RESULTS

A total of 192 days of measurements, in 27 patients, were available for comparison with the different equations. Agreement between the equations and measured values was poor. The Harris-Benedict, Schofield and ACCP equations provided more estimates (66%, 66% and 65%, respectively) within 80% and 110% of TEE values. However, each of these equations would have resulted in clinically significant underfeeding (<80% of TEE) in 16%, 15% and 22% of patients, respectively, and overfeeding (>110% of TEE) in 18%, 19% and 13% of patients, respectively.

CONCLUSIONS

Limits of agreement between the different equations and TEE values were unacceptably wide. Prediction equations may result in significant under or overfeeding in the clinical setting.

Feeding Practices of Severely Ill Intensive Care Unit Patients: An Evaluation of Energy Sources and Clinical Outcomes

OBJECTIVE

The quantity of nutrition that is provided to intensive care unit (ICU) patients has recently come under more scrutiny in relation to clinical outcomes. The primary objective of this study was to assess energy intake in severely ill ICU patients and to evaluate the relationship of energy intake with clinical outcomes.

DESIGN

Prospective cohort study.

SUBJECTS/SETTINGS

Seventy-seven adult surgery and medical ICU patients with length of ICU stay of at least 5 days.

STATISTICAL ANALYSES PERFORMED

Student's t test and chi2 tests were used to examine ICU populations. To determine the relationship of patient variables to hospital length of stay and ICU, length of stay regression trees were calculated.

RESULTS

Both groups were underfed with 50% of goal met in surgical ICU and 56% of goal met in medical ICU. Medical ICU patients received less propofol and significantly less dextrose-containing intravenous fluids when compared to surgical ICU patients (P=0.013). From regression analysis, approaching full nutrient requirements during ICU stay was associated with greater hospital length of stay and ICU length of stay. For combined groups, if % goal was > or =82%, the estimated average value for ICU length of stay was 24 days; whereas, if the % goal was <82%, the average ICU length of stay was 12 days. This relationship held true for hospital length of stay.

CONCLUSIONS

Medical and surgical ICU patients were insufficiently fed during their ICU stay when compared with registered dietitian recommendations. Medical ICU patients received earlier nutrition support, on average more enteral nutrition, with fewer kilocalories supplied from lipid-based sedatives and intravenous fluid relative to surgical ICU patients. Based upon length of stay, the data suggest that the most severely ill patient may not benefit from delivery of full nutrient needs in the ICU.

Accurate Determination of Energy Needs in Hospitalized Patients

OBJECTIVE

To evaluate the accuracy of seven predictive equations, including the Harris-Benedict and the Mifflin equations, against measured resting energy expenditure (REE) in hospitalized patients, including patients with obesity and critical illness.

DESIGN

A retrospective evaluation using the nutrition support service database of a patient cohort from a similar timeframe as those used to develop the Mifflin equations.

SUBJECTS/SETTING

All patients with an ordered nutrition assessment who underwent indirect calorimetry at our institution over a 1-year period were included.

INTERVENTION

Available data was applied to REE predictive equations, and results were compared to REE measurements.

MAIN OUTCOME MEASURES

Accuracy was defined as predictions within 90% to 110% of the measured REE. Differences >10% or 250 kcal from REE were considered clinically unacceptable.

STATISTICAL ANALYSES PERFORMED

Regression analysis was performed to identify variables that may predict accuracy. Limits-of-agreement analysis was carried out to describe the level of bias for each equation.

RESULTS

A total of 395 patients, mostly white (61%) and African American (36%), were included in this analysis. Mean age+/-standard deviation was 56+/-18 years (range 16 to 92 years) in this group, and mean body mass index was 24+/-5.6 (range 13 to 53). Measured REE was 1,617+/-355 kcal/day for the entire group, 1,790+/-397 kcal/day in the obese group (n=51), and 1,730+/-402 kcal/day in the critically ill group (n=141). The most accurate prediction was the Harris-Benedict equation when a factor of 1.1 was multiplied to the equation (Harris-Benedict 1.1), but only in 61% of all the patients, with significant under- and over-predictions. In the patients with obesity, the Harris-Benedict equation using actual weight was most accurate, but only in 62% of patients; and in the critically ill patients the Harris-Benedict 1.1 was most accurate, but only in 55% of patients. The bias was also lowest with Harris-Benedict 1.1 (mean error -9 kcal/day, range +403 to -421 kcal/day); but errors across all equations were clinically unacceptable.

CONCLUSIONS

No equation accurately predicted REE in most hospitalized patients. Without a reliable predictive equation, only indirect calorimetry will provide accurate assessment of energy needs. Although indirect calorimetry is considered the standard for assessing REE in hospitalized patients, several predictive equations are commonly used in practice. Their accuracy in hospitalized patients has been questioned. This study evaluated several of these equations, and found that even the most accurate equation (the Harris-Benedict 1.1) was inaccurate in 39% of patients and had an unacceptably high error. Without knowing which patient's REE is being accurately predicted, indirect calorimetry may still be necessary in difficult to manage hospitalized patients.

Nutrition support and the chronic critical illness syndrome

Critical illness can be viewed as consisting of 4 distinct stages: (1) acute critical illness (ACI), (2) prolonged acute critical illness, (3) chronic critical illness, and (4) recovery. ACI represents the evolutionarily programmed response to a stressor. In ACI, substrate is shunted away from anabolism and toward vital organ support and inflammatory proteins. Nutrition support in this stage is unproven and may ultimately prove detrimental. As critical illness progresses, there is no evolutionary precedent, and man owes his life to modern critical care medicine. It is at this point that nutrition and metabolic support become integral to the care of the patient. This paper (1) delineates and develops the 4 stages of critical illness using current evidence, clinical experience, and new hypotheses; (2) defines the chronic critical illness syndrome (CCIS); and (3) details an approach to the metabolic and nutrition support of the chronically critically ill patient using the metabolic model of critical illness as a guide. It is our hope that this clinical model can generate testable hypotheses that can improve the outcome of this unique population of patients.

Overview of glycemic control in critical care: relating performance and clinical results

BACKGROUND

Hyperglycemia is prevalent in critical care and tight control can save lives. Current ad-hoc clinical protocols require significant clinical effort and produce highly variable results. Model-based methods can provide tight, patient specific control, while addressing practical clinical difficulties and dynamic patient evolution. However, tight control remains elusive as there is not enough understanding of the relationship between control performance and clinical outcome.

METHODS

The general problem and performance criteria are defined. The clinical studies performed to date using both ad-hoctitration and model-based methods are reviewed. Studies reporting mortality outcome are analysed in terms of standardized mortality ratio (SMR) and a 95(th) percentile (+/-2sigma) standard error (SE(95%)) to enable better comparison across cohorts.

RESULTS

Model-based control trials lower blood glucose into a 72-110 mg/dL band within 10 hours, have target accuracy over 90%, produce fewer hypoglycemic episodes, and require no additional clinical intervention. Plotting SMR versus SE(95%) shows potentially high correlation (r=0.84) between ICU mortality and tightness of control.

SUMMARY

Model-based methods provide tighter, more adaptable one method fits all solutions, using methods that enable patient-specific modeling and control. Correlation between tightness of control and clinical outcome suggests that performance metrics, such as time in a relevant glycemic band, may provide better guidelines. Overall, compared to the current one size fits all sliding scale and ad-hoc regimens, patient-specific pharmacodynamic and pharmacokinetic model-based, or one method fits all control, utilizing computational and emerging sensor technologies, offers improved treatment and better potential outcomes when treating hyperglycemia in the highly dynamic critically ill patient.

Advances in Surgical Nutrition

Dr. Stanley Dudrick invented total parenteral nutrition in 1968, providing a desperately needed therapy to those patients who could not eat. It has since saved thousands of patients worldwide. Nutrition interventions (NI) in surgical/trauma and critically ill patients have evolved dramatically during the last 20 years from a supportive therapy to a clear therapeutic role. Like any other form of therapy, NI will benefit patients when adequately indicated and prescribed. NI, however, may cause significant side effects and harm when poorly ordered. This article reviews the indications for the prescription of the different forms of NI available to the clinician caring for the surgical patient.

Ventilator associated pneumonia

Hospital acquired or nosocomial infections continue to be an important cause of morbidity and mortality. The critically ill patient is at particular risk of developing intensive care unit acquired infection, with the lungs being especially vulnerable. Nosocomial bacterial pneumonia occurring after two days of mechanical ventilation is referred to as ventilator associated pneumonia, and is the most common nosocomial infection seen in the intensive care unit. Intubation of the trachea and mechanical ventilation is associated with a 7-fold to 21-fold increase in the incidence of pneumonia and up to 28% of patients receiving mechanical ventilation will develop this complication. Its development is associated with an attributable increase in morbidity and mortality. The establishment of an accurate diagnosis of ventilator associated pneumonia remains problematic and as yet there is still no accepted "gold standard" for diagnosis. The responsible pathogens vary according to case mix, local resistance patterns, and methodology of sampling. However, there is general agreement that rapid initiation of appropriate antimicrobial therapy improves outcome.

Risks and benefits of nutritional support during critical illness

Critically ill patients who depend on intensive care for more than a few days reveal profound erosion of lean body mass, which is thought to contribute to high morbidity and mortality. Despite a shortfall of evidence that supplemental feeding actually alters clinical outcome of these life-threatening disease states, this observation evoked an almost universal, albeit often inappropriate, use of nutritional support (NS) in the critically ill, administered via the parenteral or the enteral route. Lack of knowledge and overenthusiasm subsequently resulted in complications associated with both parenteral nutrition (PN) and enteral nutrition (EN), which led to the standing controversy over which should be preferred. With time, however, it became clear that EN and PN are not mutually exclusive and that critically ill patients requiring NS should be fed according to the functional status of the gastrointestinal tract. In addition, tight blood glucose control with insulin is advised in fed critically ill patients because overall metabolic control appears to surpass any outcome benefit attributed to the route of feeding. Recently, various special nutritional formulas have been suggested to prevent or treat multiorgan failure in the critically ill, among other pathways via modulation of immune function. Although special nutritional formulas may be promising in a variety of clinical settings, based on currently available data, these cannot be recommended for routine use in critically ill patients.

Early enteral immunonutrition vs. parenteral nutrition in critically ill patients without severe sepsis: a randomized clinical trial

OBJECTIVES

We compared early parenteral nutrition (PN) and early enteral immunonutrition (iEN) in critically ill patients, distinguishing those with and without severe sepsis or septic shock (SS) on admission to intensive care units (ICUs).

DESIGN AND SETTING

Multicenter, randomized, unblinded clinical trial in 33 Italian general ICUs.

PATIENTS AND PARTICIPANTS

The study included 326 patients, 287 of whom did not have SS on ICU admission. Eligibility criteria excluded the two tails in the spectrum of critical conditions, i.e., patients either too well or too ill. Of the patients recruited 160 were randomized to iEN (142 without SS) and 166 to PN (145 without SS).

INTERVENTIONS

Patients were randomized to two arms: early iEN or early PN.

MEASUREMENTS AND RESULTS

Primary endpoint was 28-day mortality for all patients and the occurrence of SS during ICU stay for patients admitted without such condition. While 28-day mortality did not differ between iEN and PN (15.6% vs. 15.1%), patients without SS who received iEN had fewer episodes of severe sepsis or septic shock (4.9% vs. 13.1%). ICU length of stay was 4 days shorter in patients given iEN.

CONCLUSIONS

Compared to parenteral nutrition iEN appears to be beneficial in critical patients without severe sepsis or septic shock. Parenteral nutrition in these patients should be abandoned, at least when enteral nutrition can be administered, even at an initial low caloric content.

Preventing Respiratory Complications of Tube Feedings: Evidence-Based Practice

The most dreaded complication of tube feedings is tracheobronchial aspiration of gastric contents. Strong evidence indicates that most critically ill tube-fed patients receiving mechanical ventilation aspirate gastric contents at least once during their early days of tube feeding. Those who aspirate frequently are about 4 times more likely to have pneumonia develop than are those who aspirate infrequently. Although a patient’s illness might not be modifiable, some risk factors for aspiration can be controlled; among these are malpositioned feeding tubes, improper feeding site, large gastric volume, and supine position. A review of current research-based information to support modification of these risk factors is provided.

Energy expenditure in hospitalized patients: implications for nutritional support

An understanding of energy expenditure in hospitalized patients is necessary to determine optimal energy supply in the care of individuals who require nutritional support. A review was conducted of 19 studies in which resting energy expenditure (REE) had been measured using indirect calorimetry and compared with estimated basal energy expenditure (BEE) from the Harris-Benedict equation. Studies of patients with burns, head injuries, and fever were excluded because REE is known to be increased in these conditions. The studies reported data on 1256 patients with the following diagnoses: postoperative (28%), trauma or sepsis (26%), cancer (18%), pulmonary disease (9%), cardiovascular disease (2%), miscellaneous (9%), and unspecified (6%). The average REE in the 19 studies was 113% of the BEE. The mean +/- SD REE/BEE ratio was higher in 11 studies in which the REE was measured during feeding than in 5 studies in which the measurement was made during fasting (117% +/- 3% vs 105% +/- 4%; P = .047). In those 11 studies, overfeeding may have contributed to higher REE values than otherwise would have been observed. Some evidence indicated that the REE/BEE ratio is higher in more severe illness, but results were inconsistent. Unfortunately, little information is available concerning total energy expenditure, which includes the contribution of physical activity. It appears that most patients can be fed adequately with energy equal to 100% to 120% of estimated BEE. Hypoenergetic feeding may be appropriate in some overweight and obese individuals. Additional research in hospitalized patients on total energy expenditure and on the relationship between severity of illness and energy expenditure is needed.

Effects of early enteral feeding on the outcome of critically ill mechanically ventilated medical patients

STUDY OBJECTIVES

To determine the impact of early enteral feeding on the outcome of critically ill medical patients.

DESIGN

Retrospective analysis of a prospectively collected large multi-institutional ICU database.

PATIENTS

A total of 4,049 patients requiring mechanical ventilation for > 2 days.

MEASUREMENTS AND RESULTS

Patients were classified according to whether or not they received enteral feeding within 48 h of mechanical ventilation onset. The 2,537 patients (63%) who did receive enteral feeding were labeled as the "early feeding group," and the remaining 1,512 patients (37%) were labeled as the "late feeding group." The overall ICU and hospital mortality were lower in the early feeding group (18.1% vs 21.4%, p = 0.01; and 28.7% vs 33.5%, p = 0.001, respectively). The lower mortality rates in the early feeding group were most evident in the sickest group as defined by quartiles of severity of illness scores. Three separate models were done using each of the different scores (acute physiology and chronic health evaluation II, simplified acute physiology score II, and mortality prediction model at time 0). In all models, early enteral feeding was associated with an approximately 20% decrease in ICU mortality and a 25% decrease in hospital mortality. We also analyzed the data after controlling for confounding by matching for propensity score. In this analysis, early feeding was again associated with decreased ICU and hospital mortality. In all adjusted analysis, early feeding was found to be independently associated with an increased risk of ventilator-associated pneumonia (VAP) developing.

CONCLUSION

Early feeding significantly reduces ICU and hospital mortality based mainly on improvements in the sickest patients, despite being associated with an increased risk of VAP developing. Routine administration of such therapy in medical patients receiving mechanical ventilation is suggested, especially in patients at high risk of death.

Successful long-term jejunostomy feedings in relapsing pancreatitis: a case report

Relapsing pancreatitis is characterized by repeated episodes of acute inflammation of the pancreas, with either a localized or a systemic organic response that may progress to chronic pancreatitis. Enteral jejunal feedings have been shown to be effective in the management of acute pancreatitis, but long-term use of jejunal feedings as treatment of relapsing pancreatitis has not been reported. We describe the case of a young patient treated with long-term jejunal feedings to induce remission and prevent recurrence of acute relapsing pancreatitis. An 18-year-old Hispanic man had well-documented recurrent episodes of acute pancreatitis. Multiple studies were performed as part of the diagnostic workup of the patient's relapsing pancreatitis, including endoscopic ultrasound, endoscopic retrograde cholangiopancreatography with biliary sphincterotomy, and laparoscopic cholecystectomy. Despite medical therapy, endoscopic and surgical procedures, the patient continued having episodes of pancreatitis on a monthly basis, with over 13 distinct documented episodes of pancreatitis during a 15-month period. A jejunostomy tube was inserted surgically, and long-term jejunal feedings were instituted, with excellent control of the patient's symptoms. There was only 1 episode of pancreatitis in the ensuing 24 months associated with the resumption of oral feedings and a weight gain of 20 pounds during this time period. Chronic jejunal feedings seem to be an effective alternative for treatment and prevention of acute relapsing pancreatitis. To our knowledge, this is the first report of long-term enteral feedings in acute relapsing pancreatitis.

Weight-adjusted resting energy expenditure is not constant in critically ill patients

OBJECTIVE

In critically ill patients, energy requirements are frequently calculated as a multiple of total body weight presuming a linear relationship between total body weight and resting energy expenditure (REE); however, it is doubtful if this estimation of energy needs should be applied to all patients, particularly to overweight patients, since adipose tissue has a low contribution to REE. This study was undertaken to test the hypothesis that REE adjusted for total body weight decreases with increasing body mass index in critically ill patients. Additionally, measured REE was compared with three predictive equations.

DESIGN AND SETTING

Clinical study in a university hospital intensive care unit.

PATIENTS

One hundred critically ill patients admitted to the intensive care unit.

MEASUREMENTS AND RESULTS

Patients were included into four groups according to their body mass index (normal weight, pre-obese, obese, and morbidly obese). Measured REE was assessed using indirect calorimetry. Energy needs were calculated using the basal metabolic rate, the Consensus Statement of the American College of Chest Physicians (REEacs), and 25[Symbol: see text]kcal/kg of ideal body weight (REEibw). Adjusted REE was 24.8 +/- 5.5 kcal/kg in normal weight, 22.0 +/- 3.7 kcal/kg in pre-obese, 20.4 +/- 2.6 kcal/kg in obese, and 16.3 +/- 2.3 kcal/kg in morbidly obese patients (p < 0.01). Basal metabolic rate underestimated measured REE in normal weight and pre-obese patients. REEacs and REEibw over- and underestimated measured REE in overweight patients, respectively.

CONCLUSIONS

Predictive equations were not able to estimate measured REE adequately in all the patients. Adjusted REE decreased with increasing body mass index; thus, a body mass index group-specific adaptation for the estimation of energy needs should be applied.

Assessing Nutritional Status in Chronically Critically Ill Adult Patients

• Background Numerous methods are used to measure and assess nutritional status of chronically critically ill patients.

• Objectives To discuss the multiple methods used to assess nutritional status in chronically critically ill patients, describe the nutritional status of chronically critically ill patients, and assess the relationship between nutritional indicators and outcomes of mechanical ventilation.

• Methods A descriptive, longitudinal design was used to collect weekly data on 360 adult patients who required more than 72 hours of mechanical ventilation and had a hospital stay of 7 days or more. Data on body mass index and biochemical markers of nutritional status were collected. Patients’ nutritional intake compared with physicians’ orders, dieticians’ recommendations, and indirect calorimetry and physicians’ orders compared with dieticians’ recommendations were used to assess nutritional status. Relationships between nutritional indicators and variables of mechanical ventilation were determined.

• ResultsInconsistencies among nurses’ implementation, physicians’ orders, and dieticians’ recommendations resulted in wide variations in patients’ calculated nutritional adequacy. Patients received a mean of 83% of the energy intake ordered by their physicians (SD 33%, range 0%–200%). Patients who required partial or total ventilator support upon discharge had a lower body mass index at admission than did patients with spontaneous respirations (Mann-Whitney U = 8441, P = .001).

• Conclusions In this sample, the variability in weaning progression and outcomes most likely reflects illness severity and complexity rather than nutritional status or nutritional therapies. Further studies are needed to determine the best methods to define nutritional adequacy and to evaluate nutritional status.

Frequency of under- and overfeeding in mechanically ventilated ICU patients: causes and possible consequences

INTRODUCTION

In critically ill patients enteral nutrition (EN) is frequently associated with underfeeding and intolerance, whilst parenteral nutrition (PN) has been associated with a greater risk of infectious complications and overfeeding.

MATERIALS AND METHODS

The adequacy of nutritional support provided to critically ill patients was prospectively recorded and compared with estimated requirements. The incidence of, and practices contributing to, under- (<80% of energy requirements) and overfeeding (>110% of energy requirements) were identified.

RESULTS

Overall patients received approximately 81% and 76% of prescribed energy and protein intakes respectively. Underfeeding occurred on 50.3% of days. Reasons for patients failing to achieve adequate intakes included, fasting for airway management procedures (21%) and gastrointestinal intolerance (14%). Overfeeding, although less common (18.6% of days), was more likely to occur in patients with a tracheostomy requiring prolonged mechanical ventilation (>16 days). The combination of oral and nasogastric feeding or use of nutrient-dense feeds were most frequently associated with overfeeding. Discussion The overall adequacy of nutritional intakes in the present study was similar to those reported elsewhere. However, the incidence of overfeeding was greater than anticipated and occurred in patients already experiencing delayed weaning from mechanical ventilation.

Physicochemical stability of highly concentrated total nutrient admixtures for fluid-restricted patients

PURPOSE

The physicochemical stability of highly concentrated total nutrient admixtures (TNAs) for fluid-restricted patients was studied.

METHODS

Five TNAs made from lipid injectable emulsions (50:50 mixture of medium-chain and long-chain triglycerides) designed to meet the full nutritional needs of adults with body weights of 40-80 kg were chosen. Protein was included in the TNAs at 1.5 g/kg for each body weight and was supplied from a concentrated 16% mixture containing the essential and non-essential amino acids. All admixtures were contained in ethylene vinyl acetate bags and were aseptically prepared. Triplicate preparations of each TNA were investigated over 30 hours at room temperature by dynamic light scattering (DLS) and light extinction with single-particle optical sensing (LE-SPOS).

RESULTS

No significant changes in the physicochemical stability of the TNAs were observed by DLS (mean droplet size) or LE-SPOS (large-diameter tail) from time 0 (immediately after compounding) to 30 hours. All TNAs met the mean-droplet-size criteria outlined by USP for 20% lipid injectable emulsions.

CONCLUSION

Concentrated TNA formulations made from lipid injectable emulsions were stable for 30 hours at room temperature.

Endoscopic approaches to enteral nutritional support

Enteral is preferred to parenteral nutritional support for acute and chronic diseases because it is more physiological and associated with fewer infection complications. Nasal tube feedings are generally used for 30 days or less and percutaneous access for the longer-term. Feeding by naso-gastric tubes is appropriate for most critically ill patients. However, trans-pyloric feeding is indicated for those with regurgitation and aspiration of gastric feeds. Deep naso-jejunal tube feeding is appropriate for patients with severe acute pancreatitis. There are several methods for endoscopic placement of naso-enteric tubes. Percutaneous endoscopic gastrostomy is used for most persons requiring long-term support. Long-term jejunal feeding is most often used for persons with chronic aspiration of gastric feeds, chronic pancreatitis intolerant to eating, or persons in need of concomitant gastric decompression. Percutaneous endoscopic gastrostomy with a jejunal tube extension is fraught with tube dysfunction and dislocation. Direct percutaneous endoscopic jejunostomy tubes may be more robust, but are less commonly performed.

Efficacy of medium-chain triglycerides compared with long-chain triglycerides in total parenteral nutrition in patients with digestive tract cancer undergoing surgery

The objectives of this prospective, randomized study were to evaluate the efficacy and tolerability of the short-term use of medium-chain triglyceride/long-chain triglyceride (MCT/LCT) fat emulsions, and to compare the hematologic and biochemical effects of MCT/LCT fat emulsions with LCT fat emulsions in gastrointestinal (GI) tract cancer patients following surgery. Thirty patients with GI tract cancer requiring total parenteral nutrition (TPN) were equally randomized to receive MCT/LCT or LCT emulsions for 7 days. After 7 days, no sign of complications directly related to administration of fat emulsions was observed and there were no marked differences in anthropometry, length of hospital stay, and surgical complication rates between the two groups. However, MCT/LCT significantly improved plasma prealbumin concentration (p = 0.005). Changes in complements C3 and C4, total lymphocyte count, and immunoglobulins after TPN were not significantly different between the groups. Serum triglyceride and cholesterol levels remained constant. The serum insulin level in the MCT/LCT group was higher than in the LCT group (p = 0.048). Our data revealed that MCT/LCT fat emulsions significantly enhanced nutritional status in patients with GI tract cancer, indicated by higher prealbumin levels, which might be partially due to the higher circulating insulin levels in the MCT/LCT group.

Nutritional support of the obese patient

Overweight and obesity is the most common chronic disease in the United States and is associated with an increased risk for morbidity and mortality. For the hospitalized patient, the mechanical, metabolic, and inflammatory physiologic changes induced by obesity necessitate additional considerations for care. Calculation of nutritional requirements is problematic and challenging due to difficulty in measuring body composition and energy expenditure. Provision of selective hypocaloric feeding in this population may be particularly beneficial in reducing complications of hyperglycemia, fluid overload, and reduction in fat mass. Clinical care should incorporate a team approach that addresses the special nutritional and metabolic needs of this population.

Give your patient a fast hug (at least) once a day

OBJECTIVE

To introduce the Fast Hug mnemonic (Feeding, Analgesia, Sedation, Thromboembolic prophylaxis, Head-of-bed elevation, stress Ulcer prevention, and Glucose control) as a means of identifying and checking some of the key aspects in the general care of all critically ill patients.

DESIGN

Not applicable.

SETTING

Any intensive care unit at any time.

PATIENTS

All intensive care unit patients.

INTERVENTIONS

Dependent on the results of applying the Fast Hug.

MEASUREMENTS AND MAIN RESULTS

Not applicable.

CONCLUSIONS

Application of this simple strategy encourages teamwork and may help improve the quality of care received by our intensive care unit patients.

Variation in enteral nutrition delivery in mechanically ventilated patients

OBJECTIVE

We determined the variability in enteral feeding practices in mechanically ventilated patients in four adult intensive care units of a tertiary-care, referral hospital.

METHODS

Patients who had been mechanically ventilated for at least 48 h and received enteral nutrition were prospectively followed.

RESULTS

Fifty-five of 101 consecutive mechanically ventilated patients received enteral nutrition; in 93% of patients, feedings were infused into the stomach. Patients who were cared for in the medical intensive care unit, where a nutritional protocol was operational, received enteral nutrition earlier in their ventilatory course (P=0.004) and feedings were advanced to target rates faster (P=0.043) than those who received care in other units. The number (P=0.243) and duration (P=0.668) of interruptions in feeding did not differ by patient location. On average, patients received only 50% to 70% of their targeted caloric goals during the first 6 days of enteral nutrition. Most feeding discontinuations (41%) were secondary to procedures. Gastrointestinal intolerances, including vomiting, aspiration, abdominal distention, and increased gastric residuals, were uncommon despite allowing gastric residuals up to 300 mL.

CONCLUSIONS

The practice of providing enteral feeds to mechanically ventilated patients varies widely, even within one hospital. A protocol enhanced early initiation of enteral feeds and advancement to target feeding rates but did not alter the number or duration of interruptions in enteral feedings. Procedures represented the most common reason for stopping enteral feeds, and gastrointestinal intolerances (vomiting, aspiration, and increased gastric residuals) caused few feeding interruptions. The gastric route was safe and well tolerated for early enteral feeding in most mechanically ventilated patients.

Hyperglycemia enhances the cytokine production and oxidative responses to a low but not high dose of endotoxin in rats

OBJECTIVE

The aim of this study was to investigate whether hyperglycemia enhances the systemic inflammatory response and oxidative stress induced by endotoxin.

DESIGN

Laboratory investigation.

SETTING

University medical school.

SUBJECTS

Forty-one male Sprague-Dawley rats.

INTERVENTIONS

A hyperglycemic condition was produced in rats by glucose clamp for 3 hrs. Immediately on stopping the glucose infusion, animals received different doses of endotoxin injection (0, 0.2, or 1 mg/kg), and then blood glucose concentration was monitored over the ensuing 2 hrs. At the end of 2 hrs, levels of tumor necrosis factor-alpha, interleukin-1beta, interleukin-6, corticosterone, and alpha-1 acid glycoprotein were determined in serum, and malondialdehyde and total glutathione content were determined in the liver.

MEASUREMENTS AND MAIN RESULTS

Over the 2-hr period, blood glucose concentrations returned to normal in initially hyperglycemic rats. However, the levels of cytokines, corticosterone, and alpha-1 acid glycoprotein were significantly higher in these animals compared with nonhyperglycemic controls, demonstrating an extended effect of prior hyperglycemia on markers of systemic inflammation. With low-dose (0.2 mg/kg) but not high-dose (1 mg/kg) endotoxin administration, hyperglycemic animals had significantly higher levels of cytokines compared with controls, indicating that prior hyperglycemia can enhance the systemic inflammatory response to a moderate endotoxin dose, but that the maximum effects of endotoxin on production of inflammatory cytokines are not altered by transient high glucose exposure.

CONCLUSIONS

Systemic inflammation persists for a period following hyperglycemia, and this can enhance the systemic inflammatory response to a subsequent moderate stress.

Nutritional Adequacy in Patients Receiving Mechanical Ventilation Who Are Fed Enterally

• Background Inadequate nutritional intake in critically ill patients can lead to complications resulting in increased mortality and healthcare costs. Several factors limit adequate nutritional intake in intensive care unit patients given enteral feedings.

• Objective To examine the adequacy of enteral nutritional intake and the factors that affect its delivery in patients receiving mechanical ventilation.

• Methods A prospective, descriptive design was used to study 60 patients receiving enteral feedings at target or goal rate. Energy requirements were determined for the entire sample by using the Harris-Benedict equation; energy requirements for a subset of 25 patients were also determined by using indirect calorimetry. Energy received via enteral feeding and reason and duration of interruptions in feedings were recorded for 3 consecutive days.

• Results Mean estimated energy requirements (8996 kJ, SD 1326 kJ) and mean energy intake received (5899 kJ, SD 3058 kJ) differed significantly (95% CI 3297-3787; P &lt; .001). A total of 41 patients (68.3%) received less than 90% of their required energy intake, 18 (30.0%) received within ±10%, and 1 (1.7%) received more than 110%. Episodes of diarrhea, emesis, large residual volumes, feeding tube replacements, and interruptions for procedures accounted for 70% of the variance in energy received (P&lt;.001). Procedural interruptions alone accounted for 45% of the total variance. Estimated energy requirements determined via indirect calorimetry and mean energy received did not differ.

• Conclusions Most critically ill patients receiving mechanical ventilation who are fed enterally do not receive their energy requirements, primarily because of frequent interruptions in enteral feedings.

Metabolic, Electrolytes, and Nutritional Concerns in Critical Illness

This article discusses metabolic, electrolyte, and nutritional concerns in critical illness.

Caloric requirements in patients with necrotizing fasciitis

Patients with necrotizing fasciitis (NF) and other soft tissue infections are often treated in burn centers due to the extent of wound care and surgical intervention needed. Sepsis and surgery increase metabolic needs and may limit oral intake and necessitate enteral (TEN) or parenteral (TPN) nutrition. We reviewed the records of patients admitted with necrotizing fasciitis or surgical soft tissue infections from January 1993 to June 1998 who had indirect calorimetry (IC) measurements performed. Records were also reviewed for surgical/medical management and nutritional intervention. Twenty-six patients were admitted with 17 of these having IC measurements (133 total IC measurements). The IC group had more surgeries (mean 4.9 versus 2.7) and 82% required mechanical ventilation (mean 17.9 days). Energy expenditure showed a moderate but significant increase in energy needs (mean 23.8 kcal/kg/day, 124% BEE) with large variations (10.7-42.4 kcal/kg/day, 60%-199% BEE) in individual energy requirements. Caloric intake averaged 73% of needs based on IC (range 53%-104%). Nearly all patients (94%) required TEN (82%) and/or TPN (41%) nutrition for a mean of 24 days (range 1-68 days). NF presents a broad range of metabolic and surgical needs. Our data indicates patients with NF have increased energy requirements and suggests provision of calories at 124% basal or 25 kcal/kg actual wt/d; but due to the large individual variation, routine assessment using IC is recommended. Clinicians need to recognize the likely need for nutritional support and possibly lengthy clinical course for these patients.

Hypocaloric feeding of obese patients in the intensive care unit

PURPOSE OF REVIEW

Given the increased awareness of the detrimental complications of overfeeding, particularly hyperglycemia, the safety and efficacy of specialized nutritional support for the critically ill obese patient is of major concern. The intent of this review is to provide the scientific foundation, supporting and conflicting literature, for the implementation of hypocaloric, high-protein specialized nutritional support for acutely ill, hospitalized patients with obesity.

RECENT FINDINGS

Similar anabolic equivalencies can be achieved with hypocaloric, high-protein nutritional support compared with a more traditional higher calorie, lower protein regimen. The provision of additional calories worsens hyperglycemia, results in a further accumulation of fat mass, and increases the potential for overfeeding without significant net protein anabolism gain.

SUMMARY

The current literature indicates that hypocaloric, high-protein enteral or parenteral nutrition is promising as the standard of practice for the metabolic support of the critically ill obese patient. The achievement of net protein anabolism and the avoidance of overfeeding complications are the primary goals, with fat weight loss a welcome secondary benefit.

Guidelines for nutritional support in intensive care unit patients: a critical analysis

PURPOSE OF REVIEW

Guidelines are supposed to be helpful in clinical practice. Guidelines are also supposed to rest upon the evidence that there is. In the field of clinical nutrition the problem is that many clinical trials are not conclusive because they are underpowered and sometimes have an inferior design.

RECENT FINDINGS

The publication of the Canadian guidelines one year ago initiated a lively debate. The Canadian guidelines used meta-analysis as a tool to review the literature. This resulted in both a sound evaluation of studies as well as some controversial recommendations. The Canadian guidelines are here put in a perspective in which the older type of guidelines are compared, and some of the points of recommendation are scrutinized.

SUMMARY

What all guidelines agree upon is the shortage of solid knowledge, the conviction that complications related to nutritional therapy in the intensive care unit are not acceptable, and that enteral nutrition is preferable if it can be given without risk. Beyond that, many controversies remain and the need for high quality prospective studies must be emphasized. In addition, such studies must address the clinically important questions that the guidelines try to answer.

A review of the nursing care of enteral feeding tubes in critically ill adults: part I

Enteral tubes are frequently used in critically ill patients for feeding and gastric decompression. Many of the nursing guidelines to facilitate the care of patients with enteral tubes have not been based on current research, but on ritual and opinion. Using a computerised literature search and an evidence-based classification system as described by the Joanna Briggs Institute for Evidence Based Nursing and Midwifery (JBI), a comprehensive review was undertaken of enteral tube management. Several nursing practices related to enteral tube management are described. Evidence to support alternate methods of tube placement assessment other than abdominal X-ray was inconclusive. Enteral feeding should continue if gastric residual volumes are not considered excessive, as feeding is often withheld unnecessarily. Frequency of checking gastric residual volumes is largely opinion based and varies considerably, but prokinetics that aid gastric emptying should be used if absorption of feeds is problematic. Other recommendations include continuous rather than intermittent feeding, semi-recumbent positioning to reduce the risk of airway aspiration and diligent artificial airway cuff management. Contamination of feeds can be minimised by minimal, meticulous handling and the use of closed rather than open systems. Generally, there was little high quality evidence to support practice recommendations leaving significant scope for further research by nurses in the management of patients with enteral tubes.

Retrospective Evaluation of Commonly Used Equations to Predict Energy Expenditure in Mechanically Ventilated, Critically Ill Patients

STUDY OBJECTIVE

To determine which of four commonly used equations to estimate energy expenditure is precise and unbiased compared with energy expenditure as measured by indirect calorimetry.

DESIGN

Retrospective, observational study.

SETTING

Adult medical intensive care unit in a research hospital of the National Institutes of Health Clinical Center.

PATIENTS

Seventy-six adult, mechanically ventilated, critically ill patients.

INTERVENTION

Indirect calorimetry reports generated by the National Institutes of Health Critical Care Medicine Department's Metabolic Cart Consult Service were reviewed. Bias and precision of resting energy expenditure (REE) estimated by equations were computed using mean prediction error (ME) and root mean squared prediction error (MSE). Equations were considered precise if the 95% confidence interval for MSE was within 15% of the measured energy expenditure (MEE) determined by indirect calorimetry. Equations were considered unbiased if the 95% confidence interval for ME included zero. Paired t tests were used to compare estimated REE values for each predictive equation with MEE values determined by indirect calorimetry. Data were stratified into regions of bias using classification and regression tree analysis, as well as visual inspection of estimated REE-versus-MEE curves for each equation.

MEASUREMENTS AND MAIN RESULTS

The Harris-Benedict equation multiplied by an activity factor of 1.2 was unbiased and precise. The Ireton-Jones equation was precise but biased. The American College of Chest Physicians' consensus recommendation was biased and imprecise. The Harris-Benedict equation without an activity factor also demonstrated bias and imprecision.

CONCLUSIONS

The Harris-Benedict equation multiplied by an activity factor of 1.2 is suitable for predicting REE and may be used in the absence of indirect calorimetry.

Validation of the Canadian clinical practice guidelines for nutrition support in mechanically ventilated, critically ill adult patients: Results of a prospective observational study*

OBJECTIVE

Recently, evidence-based clinical practice guidelines for the provision of nutrition support in the critical care setting have been developed. To validate these guidelines, we hypothesized that intensive care units whose practice, on average, was more consistent with the guidelines would have greater success in providing enteral nutrition.

DESIGN

Prospective observational study.

SETTING

Fifty-nine intensive care units across Canada.

PATIENTS

Consecutive cohort of mechanically ventilated patients.

INTERVENTIONS

In May 2003, participating intensive care units recorded nutrition support practices on a consecutive cohort of mechanically ventilated patients who stayed for a minimum of 72 hrs. Sites enrolled an average of 10.8 (range, 4-18) patients for a total of 638. Patients were observed for an average of 10.7 days.

MEASUREMENTS AND MAIN RESULTS

We examined the association between five recommendations from the clinical practice guidelines most directly related to the provision of nutrition support (use of parenteral nutrition, feeding protocol, early enteral nutrition, small bowel feedings, and motility agents) and adequacy of enteral nutrition. We defined adequacy of enteral nutrition as the percent of prescribed calories that patients actually received. Across sites, the average adequacy of enteral nutrition over the observed stay in intensive care unit ranged from 1.8% to 76.6% (average 43.0%). Intensive care units with a greater than median utilization of parenteral nutrition (>17.5% patient days) had a much lower adequacy of enteral nutrition (32.9 vs. 52.7%, p < .0001). Intensive care units that used a feeding protocol tended to have a higher adequacy of enteral nutrition than those that did not (44.9 vs. 38.5%, p = .03). Intensive care units that initiated enteral nutrition on >50% of their patients within the first 48 hrs had a higher adequacy of enteral nutrition than those that did not (48.1 vs. 34.4%, p < .0001). Intensive care units that had a >50% utilization of motility agents and/or any small bowel feedings in patients with high gastric residuals tended to have a higher adequacy of enteral nutrition than those intensive care units that did not (45.6 vs. 39.2%, p = .04, and 48.4 vs. 41.8%, p = .16, respectively).

CONCLUSIONS

Intensive care units that were more consistent with the Canadian clinical practice guidelines were more likely to successfully feed patients via enteral nutrition. Adoption of the Canadian clinical practice guidelines should lead to improved nutrition support practice in intensive care units. This may translate into better outcomes for critically ill patients receiving nutrition support.

Effect of gastrointestinal motility and feeding tube site on aspiration risk in critically ill patients: a review

OBJECTIVE

The purpose of this literature review is to examine the effect of the interaction between gastrointestinal motility and feeding site on the aspiration risk in critically ill, tube-fed patients.

METHODS AND RESULTS

A single answer to the question of the preferred feeding site is not likely to be found because the degree of aspiration risk varies significantly according to individual variations in gastrointestinal motility and multiple pre-existing and treatment-related risk factors. However, regardless of the feeding site, it is ultimately regurgitated gastric contents that are aspirated into the lungs. For this reason, the clinical assessment of greatest interest is the evaluation of gastric emptying, usually monitored clinically by measuring gastric residual volumes.

CONCLUSION

Current recommendations for monitoring residual volumes and preventing aspiration are provided.

The pragmatics of feeding the pediatric patient with acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) represents the ultimate pulmonary response to a wide range of injuries, from septicemia to trauma. Optimal nutrition is vital to enhancing oxygen delivery, supporting adequate cardiac contractility and respiratory musculature, eliminating fluid and electrolyte imbalances, and supporting the proinflammatory response. Research is providing a better understanding of nutrients that specifically address the complex physiologic changes in ARDS. This article highlights the pathophysiology of ARDS as it relates to nutrition, relevant nutritional assessment, and important enteral and parenteral considerations for the pediatric patient who has ARDS.

Establishment of enteral nutrition: prokinetic agents and small bowel feeding tubes

PURPOSE OF REVIEW

Nutritional support is vital to improving the clinical outcomes in patients in the intensive care unit. Enteral nutrition should be administered early and aggressively, thereby reducing the need for parenteral nutrition. Because nasogastric feeding is often associated with gastrointestinal intolerance, recent research has focused on the use of prokinetic agents or small bowel feeding tubes to enhance the successful establishment and maintenance of enteral nutrition.

RECENT FINDINGS

Prokinetic agents (such as metoclopramide and erythromycin) improve markers of gastric emptying and appear to improve tolerance of enteral nutrition, although their effects on clinical outcomes are not as well established. In comparison with nasogastric feeding, small bowel feeding allows the dysfunctional stomach of the critically ill to be bypassed, thereby reducing the rate of gastrointestinal complications and probably the risk of pneumonia. Small bowel tubes are more difficult to place than nasogastric tubes, although the new Tiger tube appears very promising.

SUMMARY

Nasogastric feeding is preferred for almost all patients in the intensive care unit. Metoclopramide is the preferred prokinetic agent, although whether it or erythromycin should be administered to all patients in the intensive care unit or only those with gastrointestinal intolerance remains unknown. Small bowel feeding is not currently recommended for all patients in the intensive care unit because the benefits do not appear to outweigh the logistic and cost considerations. Nevertheless, when gastrointestinal intolerance develops in a nasogastrically fed patient, a small bowel feeding tube should be inserted at the earliest opportunity.

Optimum treatment of severe sepsis and septic shock: evidence in support of the recommendations

Severe sepsis and septic shock are among the most common causes of death in noncoronary intensive care units. The incidence of sepsis has been increasing over the past two decades, and is predicted to continue to rise over the next 20 years. While our understanding of the complex pathophysiologic alterations that occur in severe sepsis and septic shock has increased greatly asa result of recent clinical and preclinical studies, mortality associated with the disorder remains unacceptably high. Despite these new insights, the cornerstone of therapy continues to be early recognition, prompt initiation of effective antibiotic therapy, and source control, and goal-directed hemodynamic, ventilatory,and metabolic support as necessary. To date, attempts to reduce mortality with innovative, predominantly anti-inflammatory therapeutic strategies have been extremely disappointing. Observations of improved outcomes with physiologic doses of corticosteroid replacement therapy and activated protein C (drotrecogin alfa[activated]) have provided new adjuvant therapies for severe sepsis and septic shock in selected patients. This article reviews the components of sepsis management and discusses the available evidence in support of these recommendations. In addition, there is a discussion of some promising new strategies.

Gastric tonometry and monitoring gastrointestinal perfusion: using research to support nursing practice

The principles and physiological underpinnings of gastric tonometry are reviewed. Tonometric variables, including the PtCO2, pHi and CO2 gap, are described and critiqued as measurements of gastrointestinal perfusion. Increases in gastrointestinal CO2 unrelated to gastrointestinal hypoperfusion are discussed within different clinical contexts. The technical limitations of gastric tonometry, including procedural errors and PtCO2 measurement are discussed in relation to the accuracy of tonometric measurements. Tonometric measurement using semi-continuous air tonometry is introduced as a strategy to minimize technical limitations.

Outcomes in critically ill patients before and after the implementation of an evidence-based nutritional management protocol

OBJECTIVE

To determine whether the implementation of a nutritional management protocol in the ICU leads to the increased use of enteral nutrition, earlier feeding, and improved clinical outcomes in patients.

DESIGN

Prospective evaluation of critically ill patients before and after the introduction of an evidence-based guideline for providing nutritional support in the ICU.

SETTING

The medical-surgical ICUs of two teaching hospitals.

PATIENTS

Two hundred critically ill adult patients who remained npo > 48 h after their admission to the ICU. One hundred patients were enrolled into the preimplementation group, and 100 patients were enrolled in the postimplementation group.

INTERVENTION

Implementation of an evidence-based ICU nutritional management protocol.

MEASUREMENT AND RESULTS

Nutritional outcome measures included the number of patients who received enteral nutrition, the time to initiate nutritional support, and the percent caloric target administered on day 4 of nutritional support. Clinical outcomes included the duration of mechanical ventilation, ICU and in-hospital length of stay (LOS), and in-hospital mortality rates. Patients in the postimplementation group were fed more frequently via the enteral route (78% vs 68%, respectively; p = 0.08), and this difference was statistically significant after adjusting for severity of illness, baseline nutritional status, and other factors (odds ratio, 2.4; 95% confidence interval [CI], 1.2 to 5.0; p = 0.009). The time to feeding and the caloric intake on day 4 of nutritional support were not different between the groups. The mean (+/- SD) duration of mechanical ventilation was shorter in the postimplementation group (17.9 +/- 31.3 vs 11.2 +/- 19.5 days, respectively; p = 0.11), and this difference was statistically significant after adjusting for age, gender, severity of illness, type of admission, baseline nutritional status, and type of nutritional support (p = 0.03). There was no difference in ICU or hospital LOS between the two groups. The risk of death was 56% lower in patients who received enteral nutrition (hazard ratio, 0.44; 95% CI, 0.24 to 0.80; p = 0.007).

CONCLUSION

An evidence-based nutritional management protocol increased the likelihood that ICU patients would receive enteral nutrition, and shortened their duration of mechanical ventilation. Enteral nutrition was associated with a reduced risk of death in those patients studied.

Low caloric intake is associated with nosocomial bloodstream infections in patients in the medical intensive care unit

OBJECTIVE

To determine whether caloric intake is associated with risk of nosocomial bloodstream infection in critically ill medical patients.

DESIGN

Prospective cohort study.

SETTING

Urban, academic medical intensive care unit.

PATIENTS

Patients were 138 adult patients who did not take food by mouth for > or =96 hrs after medical intensive care unit admission.

MEASUREMENTS

Daily caloric intake was recorded for each patient. Participants subsequently were grouped into one of four categories of caloric intake: <25%, 25-49%, 50-74%, and > or =75% of average daily recommended calories based on the American College of Chest Physicians guidelines. Simplified Acute Physiology Score II and serum albumin were measured on medical intensive care unit admission. Serum glucose (average value and maximum value each day) and route of feeding (enteral, parenteral, or both) were collected daily. Nosocomial bloodstream infections were identified by infection control surveillance methods.

MAIN RESULTS

The overall mean (+/-sd) daily caloric intake for all study participants was 49.4 +/- 29.3% of American College of Chest Physicians guidelines. Nosocomial bloodstream infection occurred in 31 (22.4%) participants. Bivariate Cox analysis revealed that receiving > or =25% of recommended calories compared with <25% was associated with significantly lower risk of bloodstream infection (relative hazard, 0.24; 95% confidence interval, 0.10-0.60). Simplified Acute Physiology Score II also was associated with risk of nosocomial bloodstream infection (relative hazard, 1.27; 95% confidence interval, 1.01-1.60). Average daily serum glucose, admission serum albumin, time to initiating nutritional support, and route of nutrition did not affect risk of bloodstream infection. After adjustment for Simplified Acute Physiology Score II in a multivariable analysis, receiving > or =25% of recommended calories was associated with a significantly lower risk of bloodstream infection (relative hazard, 0.27; 95% confidence interval, 0.11-0.68).

CONCLUSIONS

In the context of reducing risk of nosocomial bloodstream infections, failing to provide > or =25% of the recommended calories may be harmful. Higher caloric goals may be necessary to achieve other clinically important outcomes.

Management of post traumatic respiratory failure

Acute respiratory distress syndrome (ARDS) is a severe and common complication of major trauma. The most important early management principle is to identify the inciting event and remove the ongoing insult aggressively. It is important to immediately resuscitate the patients and prepare them for a complex and difficult hospitalization. Avoiding secondary insults is the cornerstone of supportive care, and this is based primarily on aggressive immune surveillance, full nutrition, and unrelenting oxygen delivery. The use of aggressive immune surveillance, nutritional support, and fluid management is critical to support ventilator management for oxygenation and ventilation. In general, although essential, the ventilator has great potential for harm in patients who are compromised seriously with ARDS. Physicians must establish reasonable therapeutic goals based on oxygen delivery rather than arbitrary normal values of blood gas measurement. The impact of the ventilator should be limited with regard to aspiratory pressure, tidal volume, inspired oxygen, and levels of expiratory end expiratory pressure. Use of pulmonary toilet, including therapeutic bronchoscopy; patient positioning, including intermittent prone positioning, and recruitment maneuvers are useful therapeutic complements for maintaining functional residual capacity and decreasing shunt. Overall, ARDS represents a clear indication that the patient is failing to meet the demands of their stress and without prompt attention likely will die. It is a challenge and an opportunity to identify the underlying situation and to manage the patient while not causing additional harm as the patient's intrinsic resources can bring about the healing necessary to recover from the situation of extremis.

Nutritional intake in the critically ill: Improving practice through research

Enteral feeding is the preferred method of nutritional support in the critically ill; however, evidence suggests that many critically ill patients do not meet their nutritional goals. The implementation of enteral feeding protocols has improved nutritional delivery, although protocols can be widely variable. Similarly, enteral feeding related nursing practice is also inconsistent within and between intensive care units (ICUs). These variations in enteral feeding practice can be linked to the shortage of reliable and valid research into the many issues associated with the effective delivery of enteral nutrition. In the absence of a strong research tradition and practice, rituals are embraced and rarely challenged, further contributing to the wide variations in enteral feeding practice. Of particular importance are practice issues related to the commencement of enteral feeding and the assessment of feeding tolerance. This article seeks to review the literature related to commencing enteral feeding, with particular reference to the suitability of enteral nutrition, methods of enteral feeding and adjustment of enteral feeding rates. Issues relating to feeding intolerance, including the assessment of gastric residual volume and the development of diarrhoea, will also be explored.

Enteral Administration of Naloxone for Treatment of Opioid-Associated Intragastric Feeding Intolerance

Intragastric enteral feeding intolerance, common in the intensive care setting, is attributed to many causes. Opioid antagonists such as naloxone may have a role in reversing the intolerance when it is associated with intravenous opioid infusions. A 38-year-old woman hospitalized for acute respiratory distress syndrome was supported with low tidal volume mechanical ventilation. She required lorazepam and morphine administered by continuous intravenous infusion to achieve ventilator synchrony and pain control. While receiving these therapies, the patient developed persistent intolerance to intragastric feeding. Intravenous metoclopramide and laxatives did not decrease gastric volume residuals, and insertion of a jejunal tube was deemed unsafe due to worsening of her respiratory status. Total parenteral nutrition was begun to meet her caloric needs, but she experienced repeated catheter-related bloodstream infections. Naloxone 2 mg by gastric tube every 8 hours for 8 days was started; the dosage then was increased to 4 mg every 8 hours. Tube feeding was restarted, which provided the patient with more than 90% of her daily caloric needs and allowed for discontinuation of parenteral nutrition. With this dosage of naloxone, tolerance to intragastric feeding was maintained until the patient's death due to refractory respiratory failure. Enterally administered naloxone is an effective, noninvasive means of reversing intolerance to intragastric feeding associated with opioids.

Catheter-Related Infections in Continuous Hemodiafiltration in Intensive Care Patients

BACKGROUND/AIMS

Infection control is of key importance especially in the application of long-term continuous hemodiafiltration (CHDF) involving invasive vascular catheterization to critically ill patients. We investigated hemodialysis catheter-related infections in long-term CHDF.

METHODS

We examined catheter infections in 54 patients who were admitted to the intensive care unit and underwent CHDF for 2 weeks or longer.

RESULTS

With a total of 155 catheters (1,071 catheter days) studied, catheter colonization and catheter-related bloodstream infection were noted with an incidence rate of 4.8 and 2.7 per 1,000 catheter days, respectively. No difference in catheter colonization rate was observed depending on the catheterization sites or duration of catheterization. Infections were identified in 39 patients (72%) and blood culture positivity was noted in 25 patients (46%).

CONCLUSIONS

Since the majority of cases requiring long-term CHDF are complicated with a variety of infections, it is difficult to control infections associated with hemodialysis catheters separately from infections of other types. Systemic infection control should serve as a strategy finally leading to successful control of catheter-related infection.