Journal of Parenteral and Enteral Nutrition

Although nutritional support is vital to treatment of severe sepsis, the septic patient does not respond normally to glucose infusion. We have used the hyperglycemic glucose clamp technique to investigate the initial hormonal and metabolic responses of the septic patient to glucose under controlled conditions. The plasma glucose concentration was raised to and maintained at 12 mmol/liter for 2 hr in 12 septic patients and 11 normal controls. Glucose utilization, assessed from the amount infused, was significantly depressed in the patients, despite similar plasma insulin concentrations in the two groups. Forearm glucose uptake was similarly impaired. Despite very similar plasma free fatty acid concentrations in the two groups, which were suppressed equally by the glucose infusion, whole-body fat oxidation was elevated in the patients compared with the controls, and suppressed to a lesser extent in response to glucose. Glycerol and ketone body concentrations were elevated in the patients in keeping with a picture of accelerated release, clearance, and oxidation of fatty acids.

Plasma cortisol, epinephrine, and norepinephrine concentrations were elevated in the septic patients in a severity-related manner, but not to high levels compared with experimental work. Norepinephrine showed no response to the glucose infusion in either group. Plasma glucagon concentrations were not significantly elevated in the septic patients.

We conclude that the hyperglycemic glucose clamp provides a useful model for studying glucose intolerance in sepsis. Impaired glucose utilization in septic patients is associated with increased fat oxidation, although the hormonal basis for these changes is still unclear. (Journal of Parenteral and Enteral Nutrition 11: 345-353, 1987)

Resting metabolic rate (RMR) usually is measured by indirect calorimetry for a brief interval, and the results are then extrapolated to 24-hr resting energy production. The aim of the current study was to examine the validity of this approach by measuring the within- and between-day variability in RMR. The RMR was measured hourly in 14 healthy adults from 8:00 am to 4:00 pm after an overnight fast on two separate days. The results indicated that, during day 1, RMR remained unchanged from early morning to late afternoon, and there was no significant difference between RMR measurements 1 through 8. Based upon analysis of variance and intraclass correlation coefficients, the averages of the first and the last three RMR measurements were found to be unreliable. RMR reliability was improved by averaging all measurements taken during the day, and maximum reliability was obtained by averaging the middle three RMR measurements. A similar pattern of results was observed during day 2, although the overall trend was for the reliability of RMR measurements to improve relative to day 1. The average RMRs on days 1 and 2 were not significantly different. These results indicate that the current practice of establishing a patient's RMR based upon a single measurement potentially can lead to large errors in determining energy needs. Measurement reliability can be improved by serially measuring RMR, eliminating the initial measurement, and averaging the remaining two to three values. (Journal of Parenteral and Enteral Nutrition 11:354-359, 1987)

Serum albumin was measured in 126 men (average age 70.6; range 40 to 96) of a Veterans Administration Nursing Home, and was correlated with other items in an extensive clinical data base, including death or survival during the year after the analysis. The reason for institutionalization was chronic neurologic disease or other disabling physical condition in 63 men (group A), and psychiatric disorder in 63 men (group B).

In group A, the proportions of men with albumin <3.5, 3.5-4.0, and >4.0 g/dl were 6%, 37%, and 57%, respectively. In this group, the serum albumin level was significantly (p < 0.05) correlated with death rate, hemoglobin, hematocrit, serum cholesterol, and serum lactic dehydrogenase. The death rate in group A during the year after the albumin analysis was 25%. For the patients with albumin level <3.5, 3.5-4.0, and >4.0 g/ dl, the death rates were 50%, 43%, and 11 % respectively ( p < 0.01 for comparison of the former two groups with the latter). The subgroup with albumin 3.5-4.0 g/dl represented only 37% of the men in group A, but accounted for 63% of the group's deaths.

In group B, serum albumin level was not significantly correlated with any other clinical variable. Death rate during the year after the albumin analysis was only 2% in group B, and did not correlate with the albumin level.

These data indicate that, in nonpsychiatric Nursing Home men, the desirable level for the serum albumin concentration is higher than 3.5 g/dl. (Journal of Parenteral and Enteral Nutrition 11:360-363, 1987)

Hypomagnesemia is reportly a common complication of care during the early period of recovery from major trauma. Aminoglycoside treatment, by provoking inappropriate renal magnesium wasting, may contribute to the frequency of hypomagnesemia. We examined the magnesium (Mg) status of six severely burned adolescents during the early phase of recovery. Although provision of Mg met recommended levels, hypomagnesemia occurred in every patient. Two of five of our patients were hypomagnesemic during gentamycin treatment, and five of five during subsequent tobramycin therapy (including the three not affected by gentamycin). Additional episodes occurred in five patients in the absence of aminoglycosides. An interrelationship between Mg status and efficacy of potassium repletion is detailed for one patient. Hypomagnesemia during tobramycin treatment was associated with refractoriness to potassium repletion. Recurrence of hypokalemia during a subsequent diuresis-induced hypomagnesemia was prevented by Mg supplementation. The Mg requirement is increased during recovery from severe burns and appears to exceed that provided by commercially available enteral formulations. (Journal of Parenteral and Enteral Nutrition 11:364-367, 1987)

The optimum composition and concentration of crystalline amino acid solutions necessary for growth and brain maturation in critically ill infants requiring total parenteral nutrition (TPN) are unknown. Either an excess or a deficiency of amino acids could theoretically impair normal brain development in the neonate. The purpose of this study was to compare the toxicity and efficacy of two intravenous amino acid solutions, Neopham, modeled after the amino acid pattern found in human breast milk, and Aminosyn, a marketed product, designed for general usage.

Sixteen infants and children requiring continuous intravenous nutrition for at least 7 days received the Neopham amino acid solution, and eight infants and children received the Aminosyn amino acid solution as part of a total parenteral nutrition regimen which included glucose, the fat emulsion Intralipid, as well as routine mineral and vitamin additives.

There were no significant differences in mean gestational age, body weight, postnatal age, or mean daily nutrient intake between the patients receiving Aminosyn or Neopham. The daily nitrogen intake, excretion, and retention were similar in both groups. In addition, there were no statistically significant differences in either hematological or biochemical parameters between the two study groups.

The plasma levels of three essential amino acids, isoleucine, methionine, and valine, rose significantly higher in the Aminosyn-treated patients. The plasma levels of all the essential amino acids increased in both study groups. (Journal of Parenteral and Enteral Nutrition 11:368-377, 1987)

We report here our clinical experiences of "fine bore" nasogastric feeding tubes. Data have been collated over a 7-year period (1978-1985). A total of 403 patients were intubated on 809 occasions. In the first retrospective study, the clinical use of 491 unweighted tubes was compared with that of fifty 3.5-g weighted tubes. No advantage was found in the use of the weighted tubes. In the second prospective controlled clinical trial, these results were confirmed. Forty-six patients were intubated on 76 occasions with an 85-cm open-ended, unweighted nasogastric feeding tube (Prima, Portex UK), and 57 patients were intubated on 79 occasions with a 91-cm 3.0-g weighted tube (Entriflex, Biosearch, Raritan, NJ). Mean duration of placement was similar in each case, and 62% of both types of tubes were inadvertently removed. Without exception, all the tubes remained in the stomach throughout. Disappointed with the similar and overall performance of both types of tubes, we initiated a design program which resulted in the development of two new nasogastric tubes, one weighted and one unweighted. The tubes were manufactured with polyurethane, rather than polyvinychloride (PVC), which permitted an increase in diameter of the internal lumen which, in turn, was coated with water-activated lubricant to ease removal of the introducer wire. A specially modeled outflow port was incorporated into the tips of both tubes. The performance of the two new polyurethane nasogastric feeding tubes was assessed under controlled trial conditions; as a reference, a widely used PVC unweighted open-ended tube was used. Although intubation times were similar in patients without concurrent endotracheal intubation, it took a significantly shorter time to intubate patients with concurrent endotracheal intubation with the new weighted tube. After tube intubation, it was possible to aspirate gastric contents significantly more often through the new polyurethane tubes ( p < 0.001) than through the PVC tube, and the unweighted polyurethane tube stayed in situ longer (p < 0.05) than the PVC tube. The newly designed polyurethane nasogastric feeding tubes are the first tubes that have been shown to have advantages over the simpler type of open-ended, unweighted PVC nasogastric feeding tubes. (Journal of Parenteral and Enteral Nutrition 11:378-383, 1987)

The stability of total nutrient admixture (TNA) systems containing a soybean oil emulsion (Soyacal) has been reported with only one amino acid (AA) solution. This study was conducted to compare the physical stability of 10 TNA systems varied only by the AA solution used. All systems contained electrolytes, vitamins, trace elements, and heparin. The volume ratios of AA, dextrose 70% and lipid emulsion 20% were 1:1:1. Solutions were stored at 4°C for 14 days and then held at ambient temperature for an additional 4 days. Each TNA was serially analyzed on days 0, 1, 3, 5, 7, 14, 15, 16, 17, and 18 for gross visual appearance, pH, osmolality, mean particle diameter, and particle size distribution. The AA solutions evaluated include: Travasol 8.5% and 10%; Aminosyn 8.5% and 10%, Aminosyn RF 5.2%; FreAmine III 8.5% and 10%; FreAmine HBC 6.9%; HepatAmine 8.0%; and NephrAmine 5.4%. The pH values of the Aminosyn solutions were lower than those of other products; however, the pH values of all TNA systems were >5.7, which supported particle stability. The osmolality was not affected by the AA solutions. Based upon particle size distribution, 95% of all particles were <0.608 μm in diameter, with means ranging from 0.286 μm to 0.309 μm. The largest particle observed by light microscopy was 6.9 μm. These data indicate that TNA systems prepared with the 10 AA solutions and Soyacal 20% are physically stable. (Journal of Parenteral and Enteral Nutrition 11:384-388, 1987)

This study was designed to determine, on intestinal function, the comparative effects of a fat emulsion, a carbohydrate solution, and a mixture of lipids and carbohydrates given for 4 days to adult rats either intragastrically or intravenously. The rats were separated into three groups (n = 24 in each group). Each group was divided into two populations fed either intragastrically or intravenously. Each group received one of the following nutrients: a 20% Intralipid emulsion, a mixture (1:1, V/V) of Intralipid 20% and Vamine N containing 25% glucose (W/V), a solution of Vamine-glucose supplemented with fructose to reach a final concentration of 20% (W/V). Sham-operated rats that received laboratory chow orally were used as controls. The daily caloric intake was 0.21 to 0.22 kcal/g body weight. The studies on villus morphology and on brush border enzyme activities were performed on the proximal part of the jejunum. For all nutrients, intragastric infusion provoked an increase in the villus height. The lipids were the only nutrients to cause villus lengthening by the intravenous route. Intragastric or intravenous infusion of fat provoked a deficiency in intestinal disaccharidases: the presence of carbohydrates in the diet inhibited this effect slightly. Carbohydrates given alone, either intragastrically or intravenously, caused an elevation of lactase activity. Independent of diet composition, aminopeptidase activity was reduced after intravenous feeding.

In conclusion, the disaccharidase activities are largely dependent on changes occurring in the nutrient composition given either intragastrically or intravenously, whereas aminopeptidase activity was related to the route of diet administration. (Journal of Parenteral and Enteral Nutrition 11:389-393, 1987)

Total nutrient admixtures (TNAs) containing glucose, amino acids, and lipid emulsion in one container and amino acid/dextrose solutions [conventional total parenteral nutrition (TPN) formulations] were studied in a controlled laboratory experiment for their ability to support the growth of microorganisms. Both TNA and conventional TPN formulations for peripheral and central venous administration with standard additives were inoculated with microorganisms to provide 10¹-10² colony-forming units/ml (CFU/ml) of Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Klebsiella penumoniae, and Candida albicans. The admixtures were stored at room temperature and samples for quantitative microbiology were taken at time 0, 6, 12, 24, 48, 72, and 96 hr. K. pneumoniae, E. coli, and P. aeruginosa were able to proliferate in central TNAs, but the growth of these organisms was retarded in conventional TPN solutions. In the peripheral formulations, K. pneumoniae and E. coli proliferated in both the TNA and conventional TPN systems, whereas P. aeruginosa grew well only in the peripheral TNA. S. epidermidis was not able to grow in any admixtures tested; however, C. albicans grew well in all admixtures, but growth was slower in the conventional central TPN. In conclusion, peripheral and central TNAs supported the growth of microorganisms significantly better than conventional TPN solutions. (Journal of Parenteral and Enteral Nutrition 11:394-397, 1987)

Chronically uremic patients appear to have an increased nutritional requirement for vitamin B6, and vitamin B6 deficiency occurs frequently when such individuals do not receive supplements of this vitamin. Since manifestations of vitamin B6 deficiency in renal failure are not well defined, this study examined two aspects of the chronic renal failure syndrome which might be influenced by vitamin B₆: impaired growth and progressive loss of renal function. We examined food intake, weight gain, the food efficiency ratio, degree of azotemia, and renal function in chronically azotemic rats pair-fed for 6 weeks either a vitamin B₆-deficient diet or a diet containing a surfeit of vitamin B₆. In the azotemic vitamin B₆deficient rats, as compared to the azotemic B₆-replete rats, there was evidence of reduced appetite, decreased weight gain, a lower food efficiency ratio, increased azotemia, and a reduced glomerular filtration rate as estimated from the urea clearance or the mean of the urea and creatinine clearances. These findings suggest that vitamin B₆ deficiency may contribute to decreased food intake, reduced growth, and lower renal function in animals with chronic renal insufficiency. (Journal of Parenteral and Enteral Nutrition 11:398-402, 1987)

To explore whether nurses in academic institutions are being adequately educated to care for patients' nutritional needs, we conducted a survey of National League for Nursing accredited baccalaureate programs in the United States and their associated graduate programs. Data indicate that nutrition content is an integral part of baccalaureate nursing programs. Less emphasis is reported on nutrition content at the graduate level. Recommendations include revision of the substantive nutritive content and increased clinical experience in nutrition in both undergraduate and graduate nursing education. (Journal of Parenteral and Enteral Nutrition 11:406-411, 1987)

The patient described in this case report had anorexia nervosa, which ultimately was fatal. She presented with complete serous atrophy of the bone marrow associated with pancytopenia. After 2 weeks of intensive nutritional support, her peripheral blood counts had returned to normal. At autopsy on day 24, the serous atrophy had resolved and the bone marrow was populated by normal numbers of hematopoietic precursors. This case is unique in demonstrating that starvation-induced severe serous atrophy of the bone marrow is reversible with nutritional intervention. (Journal of Parenteral and Enteral Nutrition 11:422-423, 1987)

The delivery of safe and nutritionally successful total parenteral nutrition (TPN), including intravenous lipid emulsion, to a pregnant woman with Crohn's disease and short bowel syndrome from conception to delivery is reported. Maternal nutritional status improved during the pregnancy. Fetal development was normal, and a healthy, full-term infant was delivered. The placenta was normal. Specific intravenous macronutrient and micronutrient requirements during pregnancy are not well defined. Our experience has resulted in the generation of additional recommendations to optimize the intravenous nutritional therapy of this high-risk population. (Journal of Parenteral and Enteral Nutrition 11:424-427, 1987)