A probable endocrine basis for the depression of ketone bodies during infectious or inflammatory state in rats.

The effects of infection with Streptococcus pneumoniae, Francisella tularensis, and Venezuelan equine encephalitis virus as well as inflammatory stress induced by the administration of turpentine and endotoxin on plasma ketone bodies and insulin were studied in white rats. All of the infectious/inflammatory stresses caused a significant decrease in the ketonemia of fasting and an elevation of plasma insulin. When a pneumococcal infection was initiated in a diabetic rat, inhibition of fasting ketonemia did not occur. Similarly, pneumococcal infection in the hypophysectomized rat did not result in a noticeable depression of either fasting ketonemia or plasma FFA. The increase in circulating insulin appears to be closely correlated with the inhibition of fasting ketonemia noted in the infectious/inflammatory stress.

Trace metal profile of parenteral nutrition solutions.

Zinc, copper, iron, magnesium, and chromium were analyzed in commercially prepared total parenteral nutrition solutions of amino acid/protein hydrolysate, dextrose, lipid, and water from several manufacturers. Concentrations of each varied with both the manufacturer and the solution lot number, with the greatest differences observed for zinc (0.026 to 4.04 mg/liter) and iron (0.025 to 1.370 mg/liter). Since the consequences of prolonged total parenteral nutrition with trace-metal-deficient solutions are dependent upon the physical state of the patients, the duration of hyperalimentation and problems associated with trauma, it is recommended that the endogenous concentrations described be supplemented as needed for each patient. This need is difficult to determine, however, because little is known about the clinical effect of any trace-metal-deficiency state developing in patients receiving long-term total parenteral nutrition.

Home enteral and parenteral nutritional support: a comparison.

Eighteen patients requiring intensive outpatient nutritional support were prospectively reviewed to compare the application of enteral and parenteral approaches. Nine patients received home enteral nutritional support (HEN) for a period of 2 to 15 months via Micro Feeding jejunostomy (MFJ) tubes. The other nine patients received home parenteral nutritional support (HPN) for a period of 3 of 32 months via Broviac catheters. The nine patients on HEN for a period of 2 to 15 months had a mean increase in weight, tricep skinfold thickness, arm muscle circumference, and serum albumin of 9.9 kg (p less than 0.001), 2.5 mm (p less than 0.01), 3.7 cm (p less than 0.05), and 0.73 g/dl (p less than 0.02), respectively. One patient suffered accidental loss of the MFJ tube; otherwise there were no significant complications. The nine patients on HPN for a period of 3 to 32 months had a mean increase in weight, triceps skinfold thickness, arm muscle circumference, and serum albumin of 8.5 kg (p less than .001), 3.5 mm (p less than 0.05), 3.4 cm (p less than 0.05), and 1.09 g/dl (p less than 0.001), respectively. Three patients each experienced one episode of catheter sepsis. These complications were far more serious than arising from the MFJ tube. In addition, the average cost of HPN was found to be 10 to 20 times greater than that of HEN. It is concluded that HEN should be selected over HPN as the course of therapy in all possible cases and that the MFJ tube is a safe, useful, and cost-effective approach.

Effect of inflammatory and noninflammatory stress on ketone bodies and free fatty acids in rats.

Both bacterial and viral infections prevented or reversed the expected ketogenic response induced in rats by starvation. In contrast, ketogenesis was not inhibited by stresses such as aseptic femoral fracture or immobilization by screen restraint. Infection had no effect on mitochondrial enzymes of terminal respiration and fatty acid oxidation.

Specific metabolic effects imposed by Streptococcus pneumoniae upon the response to femoral fracture in the rat.

The possible potentiation of an infection upon the metabolic consequences of trauma was tested in rats using a 2 X 2 block design which included control, femoral fracture, pneumococcal infection, and fracture plus infection groups. Infection introduced unique metabolic effects different from those of starvation, femoral fracture, or both together. Infection-induced effects included an accelerated conversion of 14C-alanine to glucose, higher serum haptoglobin, alpha2-macrofetoprotein, copper, and ceruloplasmin values, and lower serum iron, zinc, and transferrin concentrations. The first three of these infection-induced effects were diminished in rats with a femoral fracture. No measured effect of infection was increased in traumatized rats.

Correlation of pressure sores and nutritional status.

As life expectancy increases, so do the problems of the elderly population. One major problem is that of protein calorie malnutrition; another is the susceptibility of this population to pressure sores. The purpose of this study was to determine if a correlation exists between deteriorating nutritional status and the development of pressure sores. The nutritional status of 232 nursing home patients (mean age 72.9 +/- 12 years) was determined using biochemical and anthropometric measurements. Overall, the incidence of some degree of malnutrition was 59%. Seventeen of the patients were found to have pressure sores and were all malnourished. When classified as mild, moderate, or severe malnutrition, the patients with pressure sores were in the severe group. There was a significant difference (P less than .001) between the nutritional status of pressure sore patients and the malnourished patients. It appears that the development of pressure sores correlates with nutritional deficiencies. The authors' findings suggest a need for more aggressive nutritional support in the elderly, especially those with pressure sores.

A protocol for nutritional assessment in a community hospital.

A nutritional assessment protocol established by the Metabolic Support Service of three Chicago community hospitals has aided the support teams in providing optimal nutritional care. The assessment procedure described includes evaluation of the somatic and visceral protein compartments, cell-mediated immunity, and nitrogen balance. Through weekly repetitions of these indexes, nutritional assessment has become the objective basis for the diagnosis of the type and degree of malnutrition as well as the basis for the selection of the appropriate nutritional support and the evaluation of its effectiveness.

Total parenteral nutrition.

Total parenteral nutrition has evolved as a distinct therapeutic reality within the past decade. Starvation or malnutrition need no longer be accepted as a necessary component of prolonged illness. Though current TPN techniques can be both safe and effective, the prevention of potential complications must always have a high priority. Changes in technique are to be anticipated as further knowledge and improved materials allow the pursuit of more basic clinical problems. The recent experience with the use of high caloric TPN solutions for prolonged gastrointestinal failure in 73 patients at the Loyola University Medical Center has been summarized. The need for the involvement of an experienced TPN team in the care of these patients cannot be overemphasized if the numerous and diverse potential complications of the TPN system are to be minimized.

A review of hypersomolar hyperglycemic nonketotic dehydration (HHND): etiology, pathophysiology and prevention during intravenous hyperalimentation.

The records of 200 patients, nutritionally supported by synthetic means, were reviewed for evidence of clinical hyperosmolar hyperglycemic nonketotic dehydration (HHND). There was a 3% incidence of morbidity, with a single mortality. Laboratory values demonstrated a positive correlation between persistent glucosuria and HHND. The pathophysiology of HHND demonstrated a relative insulin lack with sufficient insulin to prevent lipolysis, but insufficient to prevent hyperglycemia, glucosuria and osmotic diuresis. The mechanism and management of the pseudodiabetes of stress is reviewed. It is concluded that HHND is an avoidable iatrogenic morbidity. Prevention of osmotic diuresis secondary to glucosuria and, therefore, prevention of HHND is achieved by providing exogenous insulin sufficient to prevent glucosuria.

Vitamin C supplementation of total parenteral nutrition formulas.

The effect of a wide range of daily vitamin C intake (350-2250 mg, mean 975 mg) on the serum and urine vitamin C levels was studied in 20 adult hospitalized patients receiving total parenteral nutrition for a period greater than 15 days. Serum vitamin C levels increased with vitamin C administration, but remained within the normal range. Urine vitamin C levels were above normal during total parenteral nutrition in all but one patient. A positive vitamin C "balance" was achieved in all patients. The vitamin C intake positively correlated with the vitamin C urine concentration and vitamin C "balance." Maximal vitamin C retention was 800 mg/day. It is concluded that administration of vitamin C in doses greater than 1000 mg/day is unjustified in those patients receiving total parenteral nutrition who are not hypermetabolic.

Visceral protein increase associated with interrupt versus continuous enteral hyperalimentation.

Periodic parenteral hyperalimentation, the interruption of feeding for a period of time each day, parallels the fasted vs fed state in the meal eater. The fasted state appears to be more physiologic and seems to be associated with an increase of visceral proteins. Intravenous hyperalimentation data that have been published seem to confirm this fact. The purpose of this study was to compare the effect of continuous enteral hyperalimentation and interrupt enteral hyperalimentation on the visceral protein compartment. Two groups of 10 afebrile matched control patients (group 1) were on continuous enteral hyperalimentation for 19 +/- 6 days with no improvement in serum albumin or serum transferrin levels. No changes were made in the feeding schedules of 10 of the patients. Feeding schedules of the other 10 patients were changed to an 8-hr interrupt enteral hyperalimentation with calories, protein, and volume being provided remaining the same. Repeat serum albumin and transferrin levels were obtained after 10 days. There was a significant increase in albumin and transferrin levels (p less than 0.005) in those patients changed to an interrupt feeding schedule.

A new method for long-term intravenous alimentation in unrestrained rats.

Existing equipment for long-term iv alimentation in small laboratory animals is somewhat cumbersome and quite costly. Although a one-time expense, the cost of this equipment may not be economically viable for many researchers. Herein we present a novel method for long-term iv alimentation in unrestrained rats that is practical, inexpensive, and easily assembled from readily available materials. This new "proxy" set was tested and compared with the standard swivel assembly set. Statistical analysis showed no difference in measured parameters in rats infused by either method. However, the cost of the new set (excluding pump) was almost 90 times less than its commercially available counterpart. This self-constructed approach should bring small animal research within the economic means of most investigators.

Parenteral nutrition with essential amino acids in pretransplantation anephrics.

The effect of intravenous hyperalimentation with essential amino acids and hypertonic dextrose on nitrogen metabolism, total body urea and creatinine was studied in 16 patients with end-stage renal disease prior to and after bilateral nephrectomy, splenectomy and appendectomy. Parenteral essential amino acids and hypertonic dextrose are effective in lowering blood urea nitrogen in anephric patients who are incapable of improving renal function. The inclusion of essential amino acids in hypertonic dextrose increases nutritional value far beyond that which can be attributed to the caloric concentration of the amino acids themselves.

Enteral nutrition: frequency of formula modification.

A retrospective study was undertaken to determine with what frequency one of the 12 standard enteral formulations routinely used by the Metabolic Support Service could not be used without modification. Forty-three percent of the 83 patients studied required modification of one or more of the 5 individual components of the enteral product being utilized (ie, carbohydrate, protein, fat, electrolytes, and vitamins). Organ dysfunction was the reason for 31% of those changes in formula, other conditions included vitamin deficiencies (30%), electrolyte imbalances (27%), and essential fatty acid deficiencies (12%). The results of the study confirm the fact that no single formula can be effective in meeting every patient's fluid and electrolyte requirements while addressing the specific nutritional aspects of their disease. It would appear that a totally modular system for enteral nutrition similar to that used in parenteral nutritional support would allow maximum flexibility in the preparation of formulae that conform to patient's needs.

Unique effects of infectious or inflammatory stress on fat metabolism in rats.

Infectious or inflammatory stress in the rat causes very typical functional and metabolic alterations. Among the most typical are elevation in body temperature, insulin, and glucagon and depression in the concentrations of plasma ketones and free fatty acids. These changes occur only with infectious or inflammatory stress and not with noninflammatory stresses such as femoral fracture, screen restraint, or exercise. It appears that the depression in plasma ketone bodies during infection or inflammation is closely related to the rise in plasma insulin. During infection imposed on experimentally induced diabetes, inhibition of plasma ketones is not apparent. In a similar fashion, infection in hypophysectomized rats causes no elevation in plasma insulin and no depression in plasma ketones. Discussion concerning the implications of these observations in the rat and primate is included.

Comparative study of clearance of 10% and 20% fat emulsion.

The rate of fat emulsion clearance from the blood of 10 healthy adult male volunteers administered 0.1 gram of fat per kilogram body weight as 10% or 20% safflower oil emulsion (Liposyn) was studied. The subjects were hospitalized for 2 days and each was given the predetermined amount of one of the two fat emulsions (10% or 20%) by rapid injection into a peripheral vein and the rate of clearance of the emulsion determined over a 60-minute period, beginning when half of the emulsion had been injected. There was no significant difference in the clearance rate between the two emulsions. It is concluded that 20% fat emulsion is a safe as 10% fat emulsion for use in intravenous nutritional support.

Protein-sparing therapy during pneumococcal infection in rhesus monkeys.

A model was developed in the rhesus monkey to determine if the marked wasting of body proteins associated with sepsis could be prevented by an intravenous supply of various nutritional substrates. All monkeys were given a basic infusion of 0.5 gm of amino acid nitrogen/kg body weight via an indwelling catheter in the jugular vein. Three groups were given diets with no added calories, 85 calories/kg from dextrose or 85 calories from lipid. In each group, six monkeys were inoculated with 3 x 10(8) Streptococcus pneumoniae and four with heatkilled organisms. In the monkeys infused with the amino acids alone, pneumococcal sepsis resulted in a fourfold increase in loss of body proteins compared with calorie-restricted controls. Addition of 85 calories/kg/day of either dextrose or lipid reduced body wasting associated with infectious disease. The calories from lipid were utilized bythe septic host as a source of energy, with a slightly reduced efficiency when compared with the isocaloric infusion of dextrose. The nitrogen sparing of the fat emulsion could not be accounted for by its glycerol content. Therefore, the septic monkey seemed to utilize fatty acids as an energy substrate. It appears that the carbohydrate calories tend to favor the synthesis of peripheral proteins (associated mainly with skeletal muscle), while lipid calories favor synthesis of visceral proteins such as plasma albumin and acute-phase proteins.

Specific muscle protein-sparing postoperative dextrose-free amino acid infusions.

The protein-sparing and ketogenic effect of postoperative infusion of maintenance solutions containing either 3.5% amino acids or 5% dextrose in 0.33 normal (N) saline was compared by nitrogen balance and urinary acetone determination in 31 patients. A specific muscle protein sparing effect was determined by quantitation of excretion of 3-methylhistidine in seven patients of the amino acid group and eight patients in the dextrose group. In addition, an extensive hormone and substrate profile was determined. It was found that amino acid infusions not only produce a less negative nitrogen balance but also significantly reduce excretion of 3-methylhistidine indicating specific preservation of the muscle compartment.

Metabolic and nutritional support of the intensive care patient. Ascending the learning curve.

The learning curve of nutritional support in the critically ill began with the amelioration of the effects of starvation in patients with a disabled intestine. Next, there was an appreciation that feeding formulas could be tailored to support patients with specific organ insufficiencies. Then it was realized that feeding enterally has distinct advantages over feeding parenterally. In addition to a decrease in catheter-related sepsis, there was noted a distinct decrease in "remote site" sepsis. In fact, good scientific reasons have been identified to explain why this occurs, such as maintaining the competency of the intestine against a translocation of endotoxin and bacteria and "turn-on" of the stress response. Further, we now know that specific nutrients can produce desirable pharmacologic effects. In the future, feeding formulae will be devised that continue to modify the patient's response to illness favorably. Another important consideration is to begin nutritional support as soon as possible--i.e., on the day of admission, if appropriate. The critical care specialist should be expert in these techniques, with the goal of eliminating malnutrition as a confounding variable in the clinical course of the intensive care unit patient.

Albumin and colloid osmotic pressure implications for fluid resuscitation.

This article reviews basic physiologic principles governing fluids in spaces. Starling's law is presented, and its interpolation into a dynamic clinical setting is discussed. These principles are further described through a case presentation.