Fluid replacement
Encyclopedia
Fluid replacement or fluid resuscitation is the medical practice of replenishing bodily fluid lost through sweating, bleeding, fluid shifts or other pathologic processes. Fluids can be replaced via oral administration (drinking), intravenous administration, rectally, or hypodermoclysis, the direct injection of fluid into the subcutaneous tissue. Fluids administered by the oral and hypodermic routes are absorbed more slowly than those given intravenously.
associated with diarrhea
, particularly gastroenteritis
/gastroenteropathy, such as that caused by cholera
or rotavirus
. ORT consists of a solution
of salt
s and sugars which is taken by mouth. It is used around the world, but is most important in the developing world
, where it saves millions of children a year from death due to diarrhea
—the second leading cause of death in children under five.
, intravenous fluid replacement is preferred, and may be lifesaving. It is especially useful where there is depletion of fluid both in the intracellular space and the vascular spaces.
Fluid replacement is also indicated in fluid depletion due to hemorrhage, extensive burns and excessive sweating (as from a prolonged fever), and prolonged diarrhea (cholera).
The table to the right shows daily requirements for some major fluid components. If these cannot be given parenterally, they may need to be given entirely intravenously. If continued long-term (more than approx. 2 days), a more complete regimen of total parenteral nutrition
may be required.
In addition, during e.g. surgical procedures, fluid requirement increases by e.g. increased evaporation, fluid shifts and/or excessive urine production. Even a small surgery may cause a loss of approx. 4 ml/kg/hour, and a large surgery approximately 8 ml/kg/hour, in addition to the basal fluid requirement.
s. Physiologic saline solution
, or 0.9% sodium chloride
solution, is often used because it is isotonic
, and therefore will not cause potentially dangerous fluid shifts. Also, if it is anticipated that blood will be given, normal saline is used because it is the only fluid compatible with blood administration.
Blood transfusion
is the only approved fluid replacement capable of carrying oxygen.
Lactated Ringer's solution
is another isotonic crystalloid solution and it is designed to match most closely blood plasma. If given intravenously, isotonic crystalloid fluids will be distributed among remains the intravascular and interstitial spaces.
Blood products, non-blood products and combinations are used in fluid replacement, including colloid and crystalloid solutions. Colloids are increasingly used but they are more expensive than crystalloids. A systematic review
found no evidence that resuscitation with colloids, instead of crystalloids, reduces the risk of death in patients with trauma, burns or following surgery.
(low urine production). Oliguria has various limits, but a urine output of 0.5mL/kg/hr in adults is usually considered adequate and suggests adequate organ perfusion. The parkland formula is not perfect and fluid therapy will need to be titrated to hemodynamic values and urine output.
The speed of fluid replacement may differ between procedures. The planning of fluid replacement for burn victims is based on the Parkland formula (4mL Lactated Ringers/kg/% TBSA burned). The parkland formula gives the minimum amount to be given in 24 hours. Half of the value is given over the first eight hours after the time of the burn (not from time of admission to ED) and the other half over the next 16 hours. In dehydration, 2/3 of the deficit may be given in 4 hours, and the rest during approx. 20 hours.
The initial volume expansion period is called the fluid challenge, and may be distinguished from succeeding maintenance administration of fluids. During the fluid challenge, large amounts of fluids may be administered over a short period of time under close monitoring to evaluate the patient’s response. Fluid challenge, as the procedure of giving large amounts of fluid in a short time, may be reserved for hemodynamically unstable patients, distinguished from conventional fluid administration for patients who are not acutely ill, who receive fluids as part of a diagnostic study, or for less acutely ill patients in whom fluid administration can be guided by fluid intake and output recordings.
Oral
Oral rehydration therapy (ORT) is a simple treatment for dehydrationDehydration
In physiology and medicine, dehydration is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism...
associated with diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
, particularly gastroenteritis
Gastroenteritis
Gastroenteritis is marked by severe inflammation of the gastrointestinal tract involving both the stomach and small intestine resulting in acute diarrhea and vomiting. It can be transferred by contact with contaminated food and water...
/gastroenteropathy, such as that caused by cholera
Cholera
Cholera is an infection of the small intestine that is caused by the bacterium Vibrio cholerae. The main symptoms are profuse watery diarrhea and vomiting. Transmission occurs primarily by drinking or eating water or food that has been contaminated by the diarrhea of an infected person or the feces...
or rotavirus
Rotavirus
Rotavirus is the most common cause of severe diarrhoea among infants and young children, and is one of several viruses that cause infections often called stomach flu, despite having no relation to influenza. It is a genus of double-stranded RNA virus in the family Reoviridae. By the age of five,...
. ORT consists of a solution
Solution
In chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.- Types of solutions :...
of salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
s and sugars which is taken by mouth. It is used around the world, but is most important in the developing world
Developing country
A developing country, also known as a less-developed country, is a nation with a low level of material well-being. Since no single definition of the term developing country is recognized internationally, the levels of development may vary widely within so-called developing countries...
, where it saves millions of children a year from death due to diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
—the second leading cause of death in children under five.
Indications
In severe dehydrationDehydration
In physiology and medicine, dehydration is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism...
, intravenous fluid replacement is preferred, and may be lifesaving. It is especially useful where there is depletion of fluid both in the intracellular space and the vascular spaces.
Fluid replacement is also indicated in fluid depletion due to hemorrhage, extensive burns and excessive sweating (as from a prolonged fever), and prolonged diarrhea (cholera).
| Daily requirements | |
|---|---|
| Water | 30 ml/kg/24hrs |
| Na+ Sodium Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride... |
~ 1 mmol/kg/24hrs |
| K+ Potassium Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are... |
0.5 - 1 mmol/kg/24hrs |
| Glucose Glucose Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate... |
5 (3 to 8) g/hour |
The table to the right shows daily requirements for some major fluid components. If these cannot be given parenterally, they may need to be given entirely intravenously. If continued long-term (more than approx. 2 days), a more complete regimen of total parenteral nutrition
Total parenteral nutrition
Parenteral nutrition is feeding a person intravenously, bypassing the usual process of eating and digestion. The person receives nutritional formulae that contain nutrients such as glucose, amino acids, lipids and added vitamins and dietary minerals...
may be required.
In addition, during e.g. surgical procedures, fluid requirement increases by e.g. increased evaporation, fluid shifts and/or excessive urine production. Even a small surgery may cause a loss of approx. 4 ml/kg/hour, and a large surgery approximately 8 ml/kg/hour, in addition to the basal fluid requirement.
Types of fluids used
The types of intravenous fluids used in fluid replacement are generally within the class of volume expanderVolume expander
A volume expander is a type of intravenous therapy that has the function of providing volume for the circulatory system. It may be used for fluid replacement.-Physiology:...
s. Physiologic saline solution
Saline (medicine)
In medicine, saline is a general term referring to a sterile solution of sodium chloride in water but is only sterile when it is to be placed intravenously, otherwise, a saline solution is a salt water solution...
, or 0.9% sodium chloride
Sodium chloride
Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...
solution, is often used because it is isotonic
Isotonic
The term isotonic may refer to;*Isotonic for the term associated with muscle contraction*An isotone in nuclear physics*Sports drinks are sometimes designed in an isotonic way to assist athletes rehydrate while balancing electrolytes...
, and therefore will not cause potentially dangerous fluid shifts. Also, if it is anticipated that blood will be given, normal saline is used because it is the only fluid compatible with blood administration.
Blood transfusion
Blood transfusion
Blood transfusion is the process of receiving blood products into one's circulation intravenously. Transfusions are used in a variety of medical conditions to replace lost components of the blood...
is the only approved fluid replacement capable of carrying oxygen.
Lactated Ringer's solution
Lactated Ringer's solution
Lactated Ringer's solution is a solution that is isotonic with blood and intended for intravenous administration. It may also be given subcutaneously....
is another isotonic crystalloid solution and it is designed to match most closely blood plasma. If given intravenously, isotonic crystalloid fluids will be distributed among remains the intravascular and interstitial spaces.
Blood products, non-blood products and combinations are used in fluid replacement, including colloid and crystalloid solutions. Colloids are increasingly used but they are more expensive than crystalloids. A systematic review
Systematic review
A systematic review is a literature review focused on a research question that tries to identify, appraise, select and synthesize all high quality research evidence relevant to that question. Systematic reviews of high-quality randomized controlled trials are crucial to evidence-based medicine...
found no evidence that resuscitation with colloids, instead of crystalloids, reduces the risk of death in patients with trauma, burns or following surgery.
Procedure
It is important to achieve a fluid status that is good enough to avoid oliguriaOliguria
Oliguria is the low output of urine, It is clinically classified as an output below 300-500ml/day. The decreased output of urine may be a sign of dehydration, renal failure, hypovolemic shock, HHNS Hyperosmolar Hyperglycemic Nonketotic Syndrome, multiple organ dysfunction syndrome, urinary...
(low urine production). Oliguria has various limits, but a urine output of 0.5mL/kg/hr in adults is usually considered adequate and suggests adequate organ perfusion. The parkland formula is not perfect and fluid therapy will need to be titrated to hemodynamic values and urine output.
The speed of fluid replacement may differ between procedures. The planning of fluid replacement for burn victims is based on the Parkland formula (4mL Lactated Ringers/kg/% TBSA burned). The parkland formula gives the minimum amount to be given in 24 hours. Half of the value is given over the first eight hours after the time of the burn (not from time of admission to ED) and the other half over the next 16 hours. In dehydration, 2/3 of the deficit may be given in 4 hours, and the rest during approx. 20 hours.
The initial volume expansion period is called the fluid challenge, and may be distinguished from succeeding maintenance administration of fluids. During the fluid challenge, large amounts of fluids may be administered over a short period of time under close monitoring to evaluate the patient’s response. Fluid challenge, as the procedure of giving large amounts of fluid in a short time, may be reserved for hemodynamically unstable patients, distinguished from conventional fluid administration for patients who are not acutely ill, who receive fluids as part of a diagnostic study, or for less acutely ill patients in whom fluid administration can be guided by fluid intake and output recordings.
See also
- HypodermoclysisHypodermoclysisHypodermoclysis, which can also be called interstitial infusion or subcutaneous infusion, is the subcutaneous administration of fluids to the body. This would often be in the form of a saline or glucose solution....
- Intravenous therapyIntravenous therapyIntravenous therapy or IV therapy is the infusion of liquid substances directly into a vein. The word intravenous simply means "within a vein". Therapies administered intravenously are often called specialty pharmaceuticals...
- HypovolemiaHypovolemiaIn physiology and medicine, hypovolemia is a state of decreased blood volume; more specifically, decrease in volume of blood plasma...
- Third Spacing
- PentastarchPentastarchPentastarch is a subgroup of hydroxyethyl starch, with five hydroxyethyl groups.It is sold under the name Pentaspan and used for fluid resuscitation. It is considered a plasma expander because it remains primarily intravascular after infusion....
- Passive leg raising testPassive leg raising testIn medicine, the passive leg raising test is a bedside test to evaluate the need for further fluid resuscitation in critically ill patients.The test involves raising the legs of a patient , which causes gravity to pull blood from the legs, thus increasing circulatory volume available to the heart ...