fluid balance

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an instrument for weighing.
equilibrium (def. 1).
acid-base balance see acid-base balance.
analytical balance a balance used in the laboratory, sensitive to variations of the order of 0.05 to 0.1 mg.
fluid balance see fluid balance.
negative balance a state in which the amount of water or an electrolyte excreted from the body is greater than that ingested.
nitrogen balance see nitrogen balance.
positive balance a state in which the amount of water or an electrolyte excreted from the body is less than that ingested.
water balance fluid balance.
zero balance a state in which the amount of water or an electrolyte excreted from the body is exactly equal to that ingested; see equilibrium (def. 1).

fluid balance1

a state of equilibrium in which the amount of fluid consumed equals the amount lost in urine, feces, perspiration, and exhaled water vapor.

fluid balance2

a nursing outcome from the Nursing Outcomes Classification (NOC) defined as water balance in the intracellular and extracellular compartments of the body. See also Nursing Outcomes Classification.

water balance

the state when the amount of water consumed in food and drink plus that generated by metabolism equals the amount of water excreted. Intake is regulated by behavioural mechanisms, including thirst and salt cravings. While almost a litre of water per 24 hours is unavoidably lost via the skin, lungs and faeces, the kidneys are the site of regulated excretion of water in the urine. In a moderate climatic environment, to achieve water balance a sedentary individual should consume ∼2 litres of water daily; in hot dry environments up to 4 litres may be needed. Athletes require additional intake to match the loss due to a high sweating rate, depending in turn on the type and severity of exercise, on the temperature and humidity, and on heat acclimatization. See also hydration status, posterior pituitary, sports drinks, thirst. Fig facing .

hydration status

refers to body fluid levels. euhydration the normal state of body water content (typically about 40 litres). hypohydration reduced total body water which may develop by the process of dehydration due to excessive sweating under exercise heat stress. Athletes may lose 2-6% body weight during prolonged exercise. Hypohydration is detrimental to both exercise performance and health and should be prevented by provision of fluids to match water loss. In several sports (e.g. boxing, power lifting, wrestling) athletes may purposely induce dehydration to achieve weight loss prior to competition. hyperhydration increased total body water. It has been proposed that prior hyperhydration may improve thermoregulation during exercise heat stress, but studies have had inconsistent results. See also water balance.


1. an instrument for weighing.
2. harmonious adjustment of different elements or parts; harmonious performance of functions. Used to describe symmetry and proportion of conformation.

acid-base balance
the proportion of acid and base required to keep the blood and body fluids neutral. See also acid-base balance.
analytical balance
a laboratory balance sensitive to very small variations of the order of 0.001 mg.
balance examination
simultaneous palpation of muscles on both sides of the body of Greyhounds attempting to locate areas of soreness or spasm.
fluid balance
the state of the body in relation to ingestion and excretion of water and electrolytes (see also fluid balance).
nitrogen balance
the state of the body in regard to ingestion and excretion of nitrogen. In negative nitrogen balance the amount of nitrogen excreted is greater than the quantity ingested. In positive nitrogen balance the amount excreted is smaller than the amount ingested. See also nitrogen balance.
posture balance
disturbances of balance, including falling to one side, rotation of the head, walking in circles. These are usually indications of disturbances of the organs of balance in the semicircular canals.
water balance
fluid balance.


1. a liquid or gas; any liquid of the body.
2. composed of molecules which freely change their relative positions without separation of the mass.

allantoic fluid
the fluid contained within the allantois.
amniotic fluid
the fluid within the amnion that bathes the developing fetus and protects it from mechanical injury.
ascitic fluid
see ascites.
fluid balance
a state in which the volume of body water and its solutes (electrolytes and nonelectrolytes) are within normal limits and there is normal distribution of fluids within the intracellular and extracellular compartments. The total volume of body fluids should be about 60% of the body weight, and it should be distributed so that one-third is extracellular fluid and two-thirds intracellular fluid. Although this distribution remains constant in a healthy animal, there is continuous movement of fluid into and out of the various compartments. See also dehydration, water intoxication.
body f's
the fluids within the body, composed of water, electrolytes and nonelectrolytes. The volume and distribution of body fluids vary with age, sex and amount of adipose tissue. Throughout life there is a slow decline in the volume of body fluids; obesity decreases the relative amount of water in the body.
Although the body fluids are continuously in motion, moving in and out of the cells, tissue spaces and vascular system, physiologists consider them to be 'compartmentalized'. Fluid within the cell membranes is called intracellular fluid and comprises about two-thirds of the total body fluids. The remaining one-third is outside the cell and is called extracellular fluid. The extracellular fluid can be further divided into tissue fluid (interstitial fluid), which is found in the spaces between the blood vessels and surrounding cells, and intravascular fluid, which is the fluid component of blood.
The maintenance of a proper balance between the intracellular and extracellular fluid volumes is essential to health. In patients with heart failure and renal failure the balance becomes upset, producing either localized or generalized edema. Excessive fluid loss produces fluid volume deficit causing cellular dehydration and impaired cellular function.
Bouin's fluid
a histological fixative.
cerebrospinal fluid
the fluid contained within the ventricles of the brain, the subarachnoid space, and the central canal of the spinal cord. See also cerebrospinal fluid.
fluid dram
see fluid dram.
fluid extract
a liquid preparation of a vegetable drug, containing alcohol as a solvent or preservative, or both, of such strength that each milliliter contains the therapeutic constituents of 1 gram of the standard drug it represents.
fetal fluid
allantoic plus amniotic fluids.
interstitial fluid
the extracellular fluid bathing the cells in most tissues, excluding the fluid within the lymph and blood vessels.
isotonic fluid
having the same tonicity or osmotic pressure as blood.
lacrimal fluid
aqueous fluid secreted by the lacrimal glands; called also tears.
fluid line
in radiographs, the interface between fluid and gas, as in the gastrointestinal tract, will show as a straight line.
fluid loss
by vomiting, diarrhea, polyuria, water deprivation. See dehydration.
fluid mosaic model
the modern concept of the structure of a biological membrane developed by S.J. Singer and G.L. Nicolson. In it the membrane consists of protein molecules partly embedded in a discontinuous bilayer of phospholipids that form the matrix of a mosaic of functional cell units.
fluid ounce
see fluid ounce.
pericardial, pleural, peritoneal fluid
normally present in amounts sufficient only to lubricate the movement of viscera within the respective cavities. Composition similar to blood serum.
fluid replacement
see fluid therapy (below).
fluid restriction
the limitation of oral fluid intake to a prescribed amount for each 24-hour period.
fluid retention
see edema.
spinal fluid
the fluid within the spinal canal.
fluid splashing sounds
audible when gas and fluid are free in a cavity, e.g. abomasum in cases of abomasal displacement; can be elicited by shaking a small animal or part of a large animal (i.e. succussion) or by simultaneous percussion and auscultation.
synovial fluid
fluid therapy
aims to replace fluids lost by disease process or by restriction of intake, or to maintain a high rate of fluid excretion to ensure removal of toxins, or to administer therapeutic or anesthetic agents slowly over a long period. The amounts and route of administration vary with the need of the patient. Normal solutions include 5% dextrose and Ringer's solution; alkalinizing fluids include lactated Ringer's and 1.3% sodium bicarbonate; acidifying solutions include isotonic saline and 1.9% ammonium chloride.
fluid thrill
see thrill.
fluid volume deficit
an imbalance in fluid volume in which there is loss of fluid from the body not compensated for by an adequate intake of water. The major causes are: (1) insufficient fluid intake, and (2) excessive fluid loss from vomiting, diarrhea, suctioning of gastric contents, or drainage through operative wounds, burns or fistulae. Decreased volume in the intravascular compartment is called hypovolemia. Because water moves freely between the compartments, extracellular fluid deficit causes intracellular fluid deficit (cellular dehydration), which leaves the cells without adequate water to carry on normal function.
fluid volume excess
an overabundance of water in the interstitial fluid spaces or body cavities (edema) or an excess of fluid within the blood vessels (hypervolemia) and water intoxication.
Factors that contribute to the accumulation of edematous fluid are: (1) dilatation of the arteries, as occurs in the inflammatory process; (2) reduced effective osmotic pressure, as in hypoproteinemia, lymphatic obstruction and increased capillary permeability; (3) increased venous pressure, as in congestive heart failure, thrombophlebitis and cirrhosis of the liver; and (4) retention of sodium due to increased reabsorption of sodium by the renal tubules.
fluid wave
see thrill.
References in periodicals archive ?
9] Chapter 2, section 2(i) of these regulations identifies that fluid balance monitoring is part of the scope of practice of a registered nurse.
776 1-3 Systemic volume Change in 24-hour fluid balance (mL) -0.
Thus potentially resulting in the average dosage of caffeine we ingest having no effect on fluid balance or hydration levels.
This concept of fluid balance is one of the most difficult concepts for patients to understand (Baillod, 1995), and research demonstrates that peritoneal dialysis patients have difficulty controlling their fluid balance (Cocchi et al.
We calculated fluid balance (total input-total output) each day of IAP measurement.
Coffee consumption and total body water homeostasis as measured by fluid balance and bioelectrical impedance analysis.
Electrolytes, including magnesium, potassium, sodium and chloride, are essential for heat tolerance, fluid balance, muscle function, and every form of energy conversion and utilization in the body.
Preliminary materials explain the structural and functional differences between adults and children, including the special problems associated with fluid balance, anesthesia, and intraoperative care, as well as the special techniques involved in operating on neonates and infants and the problems of postoperative care.
Salt, or more precisely sodium, is required to regulate fluid balance in the body.
Because caffeine is a known diuretic, its effects on body fluid balance and heat storage are potentially negative.
Vata governs bodily functions concerning movement; pitta governs heat, metabolism and energy production; and kapha governs fluid balance and physical structure, such as fat, tissue and muscle.
The fluid balance between bone, sinew, and bronze ignored.