Are patients fed appropriately according to their caloric requirements?

BACKGROUND: Specific morbidity related to underfeeding and overfeeding necessitates the design of nutrition support regimens that provide calories equal to those required on the basis of energy expenditure. This prospective multicenter trial was designed to determine what percent of patients in long-term acute care facilities receive feeding appropriate to their needs and whether accuracy of feeding has an impact on patient clinical status. METHODS: Patients on mechanical ventilation who were hospitalized at 32 Vencor Hospitals over a 9-week period and who were receiving only enteral nutrition by continuous infusion at a presumed goal rate were evaluated once by indirect calorimetry (IC) while on feeding. Caloric intake over the preceding 24 hours was determined by physician orders and by patient intake/output (I/O) record. Caloric requirements were defined by measured resting energy expenditure (REE) + 10% for activity. Degree of metabolism was defined by the ratio: (measured REE/Harris-Benedict predicted REE) x 100, and the degree of feeding by the ratio: (calories provided/calories required) x 100. RESULTS: IC was performed on 335 patients (mean, 11.2 patients per center; range, 1 to 32), of which 72 were excluded for nonphysiological results or failure to achieve steady state, 21 for receiving parenteral nutrition, and 29 for not being on mechanical ventilation at time of testing. The 213 study patients were 58.7% male with mean age 70.1 years (range, 20 to 90 years). Measured REE was <25 kcal/kg in 66.2% of patients and 25 to 35 kcal/kg in 28.6%. Barely half (48.4%) of this patient population was hypermetabolic. Based on physician orders, the majority of patients (58.2%) were overfed, receiving >110% of required calories, and 12.2% were underfed, receiving <90% of requirements. Discrepancies based on I/O records, however, suggested that 36.1% of patients received <90% of those calories ordered. By either basis, only about 25% of patients received feeding within 10% of required calories. The percent of patients being overfed varied between centers, ranging from 32.2% to 92.8%, and was not affected by years of facility IC experience or volume of IC studies per month. The pattern of caloric provision as measured by degree of feeding correlated inversely to degree of metabolism (p < .0001, R2 = .24). Accuracy of feeding had an impact on ventilatory status, as degree of feeding correlated inversely with minute ventilation (p = .001, R2 = .05). Degree of overfeeding also led to significant increases in azotemia (p = .033, R2 = .02). Extrapolating study data over 1 year, reduction in excess volume of enteral formula would have resulted in a cost savings of up to $1.3 million for the Vencor system. CONCLUSIONS: Because energy expenditure is difficult to predict on the basis of conventional equations, patients in long-term acute care facilities routinely are overfed and underfed, with only 25% receiving calories within 10% of required needs. Measuring a patient's energy requirement at least once by IC is important, because the degree of metabolism predicts how easily a patient will be underfed or overfed. The amount of infused calories should be compared with caloric requirements measured by IC, because the accuracy or degree of underfeeding or overfeeding has an impact on ventilatory status and the likelihood for developing azotemia. Although physician practice or bias may reduce the optimal clinical effect, the use of IC to determine caloric requirements may result in significant cost savings.

Use of residual volume as a marker for enteral feeding intolerance: prospective blinded comparison with physical examination and radiographic findings.

High gastric residual volumes (RVs) are a frequent cause for cessation of total enteral nutrition (TEN). This study was designed to determine the RV that indicates intolerance or inadequate gastric emptying and to compare the RV findings in a blinded fashion with those findings obtained on physical examination and radiography. Twenty healthy normal volunteers (HNV), 8 stable patients with gastrostomy tubes (GTP), and 10 critically ill patients (CIP) were evaluated prospectively for 8 hours while receiving TEN. No subjects were clearly intolerant (ie, vomiting, aspiration). Of the total RVs recorded, 13.1% were greater than or equal to 150 mL in the CIP group, whereas only 2.4% of the RVs were greater than or equal to 150 mL in the HNV group. None of the RVs in the GTP group were greater than or equal to 150 mL. Objective scores on physical examination failed to correlate with RV (p = .397), as did objective scores on radiography (p = .742). However, objective scores on physical examination were significantly related to scores on radiography (p = .016). Abnormal physical examination findings were found in 4 out of 11 patients (GTP + CIP) with RVs less than 100 mL and in 6 out of 7 with RVs greater than or equal to 100 mL. Abnormal radiographic results were found in 6 out of 11 patients with RVs less than 100 mL, in 7 out of 7 patients with RVs greater than or equal to 100 mL, and in 4 out of 20 HNVs. There was no difference in RVs obtained from the supine or right lateral decubitus positions.(ABSTRACT TRUNCATED AT 250 WORDS)

Nutritional support in patients with inflammatory bowel disease.

Total parenteral nutrition with bowel rest has been used as primary therapy to reduce disease activity and achieve remission in patients with inflammatory bowel disease (IBD). However, results are short-lived and similar success can be attained through total enteral nutrition with highly specialized elemental or semielemental formulas. Enteral nutrition costs less than parenteral nutrition, maintains gut integrity, stimulates immunocompetence, and helps to control symptoms and overall disease activity. Increased use of enteral formulas can be expected in the future. The role of diet in management of IBD is currently under scrutiny. No one diet is appropriate for all patients, but restriction of fat, fiber, lactose, or oxalate may be necessary to help alleviate symptoms and minimize the risk of complications.

Indirect calorimetry: can this technology impact patient outcome?

This review of 23 papers involving indirect calorimetry published over the past 18 months shows how our understanding of the metabolic response to injury has changed, highlights the problems introduced by use of predictive equations and alterations in indirect calorimetry testing protocol, and emphasizes the need to monitor cumulative energy balance by comparing daily caloric intake to energy expenditure.

Immunonutrition and enteral hyperalimentation of critically ill patients.

Physicians need to be maximally aggressive in their use of total enteral nutrition (TEN) in the critically ill patient, due to its lower cost, better physiology, and lower complication rate when compared to parenteral therapy. Various components in TEN such as glutamine, arginine, RNA nucleotides, omega-3 fish oils, and fiber, may have important roles in immunonutrition by maintaining gut integrity, stimulating the immune system, and preventing bacterial translocation from the gut. For each patient, the physician must choose the optimal enteral formula for that particular disease or organ failure state to maximize nutrient substrate assimilation and tolerance. Total parenteral nutrition (TPN) should be used only when a true contraindication to enteral feedings exists or as adjunctive therapy when full nutritional requirements cannot be met by TEN alone.