Nutrition and Fluid Balance

Longer-term studies in rats (Schwartz, Tornaben, and Boxhill 1973 Oishi, Ishi, and Hiraga 1979 Levin, Semler, and Ruben 1993 Slaughter et al. 1998), mice (Dancla and Nachbaur 1981), and cynomolgus monkeys (Yoshida et al. 1994) show effects 

Unlike fats and carbohydrates, which are stored within the body, protein gains or losses can be more immediate indicators of nutritional changes affecting the animal. However, given that more than 50% of the body s albumin is located in extravascu-lar spaces and the half-life of albumin, plasma albumin may take some time to fall, while some other smaller proteins synthesized in the liver may fall more quickly because they have shorter half-lives. Increased gluconeogenesis may occur following dietary alterations and lead to changes of the plasma aminotransferases. 

Severe dehydration and reduction of plasma volume may become apparent through increased plasma protein and hematocrit values (Boyd 1981 Kutscher 

Alterations of fluid intake affect plasma electrolyte balance (Clausing and Gottschalk 1989 Boemke et al. 1990 Single et al. 1998). Simple observations of water intake together with urinary output are important when examining subjects for fluid balance perturbations. 

Treatment prior to sequential blood sampling in toxicology studies should be similar in respect to food and water intake, and any effects on dietary and fluid intake should be considered when biochemical changes are interpreted. Any major changes of animal diets should be monitored for possible effect on plasma and urine chemistry. 

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The parameters of interest in body composition analysis (bioelectric impedance analysis, BIA) are (a) TBW, (b) extracellular/intracellular fluid balance, (c) muscle mass, and (d) fat mass. Application areas are as diversified as sports, medicine, nutrition, and fluid balance in renal dialysis and transplantations. 

Commonly administered LVPs include such products as Lactated Ringers Injection USP, Sodium Chloride Injection USP (0.9%), which replenish fluids and electrolytes, and Dextrose Injection USP (5%), which provides fluid plus nutrition (calories), or various combinations of dextrose and saline. In addition, numerous other nutrient and ionic solutions are available for clinical use, the most popular of which are solutions of essential amino acids or lipid emulsions. These solutions are modified to be hypertonic, isotonic, or hypotonic to aid in maintaining both fluid, nutritional, and electrolyte balance in a particular patient according to need. Indwelling needles or catheters are required in LVP administration. Care must be taken to avoid local or systemic infections or thrombophlebitis owing to faulty injection or administration technique. 

CHLORIDE (Biological Aspects). Sodium chloride, potassium chloride, and other chloride salts, when ingested by animals from feedstuffs and humans from various food substances, reduce to a consideration of the cation involved (Na", K h. etc.) and the Cl (chloride) ion. Generally, in terms of animal and human nutrition, more research has been conducted and more is known about the role of cations in metabolism than that of the chloride ion. Some physiologists and nutritionists in the pasi have described chloride as playing a "passive role" in maintaining the body s ionic and fluid balance. With exception of the chloride shift" in venous blood, the movements of chloride have usually been considered secondary to those of the cations. 

Implement fluid/nutrition therapy, taking into account the nature of injuries and/or agents exposed to and monitoring hydration and fluid balance accordingly. 

Saltin, B. Costill, D.L. (1988). Fluid and electrolyte balance during prolonged exercise. In Exercise, Nutrition, and Energy Metabolism (Horton, E.S. Teijung, R.L., ed), pp. 150-158, MacMillan. New York. 

O Parenteral nutrition (PN), also called total parenteral nutrition (TPN), is the intravenous administration of fluids, macronutrients, electrolytes, vitamins, and trace elements for the purpose of weight maintenance or gain, to preserve or replete lean body mass and visceral proteins, and to support anabolism and nitrogen balance when the oral/enteral route is not feasible or adequate. 

PN should provide a balanced nutritional intake, including macronutrients, micronutrients, and fluid. Macronutrients, including amino acids, dextrose, and intravenous lipid emulsions, are important sources of structural and energy-yielding substrates. A balanced PN formulation includes 10% to 20% of total daily calories from amino acids, 50% to 60% of total daily calories from dextrose, and 20% to 30% of total daily calories from intravenous lipid emulsion. Micronutrients, including electrolytes, vitamins, and trace elements, are required to support essential biochemical reactions. Parenteral... 

Severe cases of tetanus generally require admission to an intensive care unit for 3-5 weeks. Weight loss is universal in tetanus and these patients require enteral nutrition. Other important measures include close control of fluid balance, chest physiotherapy to prevent pneumonia, prophylaxis of thromboembolism and intensive nursing care to prevent pressure sores. 

The most common interventions that must be made when treating patients with ARF involve fluid and electrolyte management. Most patients with ARF are fluid overloaded, and fluids must be restricted. This means maximally concentrated drug infusions and nutrition solutions. So-called keep vein open or maintenance intravenous infusions should be halted unless the patient is euvolemic or is receiving renal replacement solution that is able to maintain fluid balance. 

McDonald JTand Margen S (1979) Wine versus ethanol in human nutrition. II. Fluid, sodium, and potassium balance. Am J Clin Nutr 32 817-822. 

The many factors that can alter Vss and/or Cl, and thereby shorten or prolong T1/2 are discussed in detail elsewhere. They include altered fluid balance, nutritional status, percentage of body fat, species, hormonal status, age of animal, and disease status. For example, renal and/or hepatic disease can reduce Cl and therefore prolong Ti/2 for the therapeutic phase, while infectious diseases may either increase or decrease Cl and/or Vss- In contrast, the main factor controlling the slope of the very late terminal phase is the redistribution of the drug from a deep compartment to plasma. 

Description. Potassium is an essential mineral micronutrient in human nutrition it is the major cation inside animal cells, and it is thus important in maintaining fluid and electrolyte balance in the body. Potassium is also important in allowing muscle contraction and the sending of all nerve impulses in animals. 

Essential Fatty Acids. The higher unsaturated fatty acids are indispensable for the rat. Deprivation of these fatty acids results in loss of hair, disturbances of fluid balance, loss of reproductive faculty, and ultimately in death. Similar deficiency symptoms have not been observed in man, because the amounts required are so small (in the rat only 20 mg linoleic acid per day) and an absolutely fat-free diet is practically unknown. It is established, however, that man cannot synthesize the higher unsaturated fatty acids either. They should be particulary important in the nutrition of infants the adult organism has large reserves to draw on. 

Table 9.6 gives the concentrations of some typical electrolytes in blood plasma. There is a charge balance because the total number of positive charges is equal to the total number of negative charges. The use of a specific intravenous solution depends on the nutritional, electrolyte, and fluid needs of the individual patient. Examples of var ious types of solutions are given in Table 9.7. 

Armstrong LE (2002) Caffeine, body fluid-electrolyte balance and exercise performance. International Journal of Sport Nutrition and Exercise Metabolism 12 205-222. 

Severe negative nitrogen balance may occasionally have to be corrected by hyperalimentation or total parenteral nutrition (TPN). Intravenous solutions used in TPN contain essential and nonessential amino acids, plus a source of calories in the form of fat and carbohydrate. They "spare" the administered amino acids and allow them to be used for tissue repair. The TPN fluid must also contain all other nutritional factors required for life, including essential fatty acids, vitamins, and minerals. Severe metal and essential fatty acid deficiencies have been observed in situations in which such inclusions had not been made. 

Minerals dissolved in the body fluids are responsible for nerve impulses and the contraction of muscles, as well as for water- and acid-base balance. They play an important role in maintaining the respiration, heart rate, and blood pressure in normal limits. Deficiency of minerals in the diet may lead to severe, chronic clinical signs of diseases, frequently reversible after their supplementation in the diet, or following the total parenteral nutrition. Their influence on biochemical reactions in living systems also makes it possible to use them intentionally in many food processes. 

Major differences exist between the metabolic, fluid, and electrolyte management of patients with acute versus chronic kidney disease (CKD). For example, positive nitrogen balance is more difficult to achieve in patients with acute renal failure (ARF) due to the increased rate of protein catabolism. Additionally, patients with acute renal failure are more likely to develop hyperglycemia during nutritional support and frequently are dialyzed by modalities that are not used commonly for the patient with end-stage kidney disease (ESKD). Because of these differences, the nutritional management of patients with ARF is discussed separately. 

Only one study (Ibrahim et ai, 2003) has reported iodine balances in a cohort of extreme preterm infants who were (initially) parenterally fed. Iodine intakes and urinary iodine outputs were determined for 13 infants over four separate 24h periods at postnatal day 1, 6, 13 and 27. The types and volumes of all enteral and parenteral nutrition fluids used for each infant were accurately recorded. 

Table 40.1 The types and volumes of enteral and parenteral nutrition fluids at balance days (Ibrahim et al., 2003) ...

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