Intravascular volume status

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In medicine, intravascular volume status refers to the volume of blood in a patient's circulatory system, and is essentially the blood plasma component of the overall volume status of the body, which otherwise includes both intracellular fluid and extracellular fluid. Still, the intravascular component is usually of primary interest, and volume status is sometimes used synonymously with intravascular volume status.

Contents

It is related to the patient's state of hydration, but is not identical to it. For instance, intravascular volume depletion can exist in an adequately hydrated person if there is loss of water into interstitial tissue (e.g. due to hyponatremia or liver failure).

Clinical assessment

Intravascular Volume Depletion

Volume contraction of intravascular fluid (blood plasma) is termed hypovolemia, [1] [2] and its signs include, in order of severity:

Intravascular volume overload

Signs of intravascular volume overload (high blood volume) include:

Intravascular Blood Volume Correlation to a Patient's Ideal Height and Weight

For the clinical assessment of intravascular blood volume, the BVA-100, a semi-automated blood volume analyzer device that has FDA approval, determines the status of a patient’s blood volume based on the Ideal Height and Weight Method. [3] Using a patient’s ideal weight and actual weight, the percent deviation from the desirable weight is found using the following equation:

Using the deviation from desirable weight, the BV ratio (ml/kg), i.e. Ideal Blood Volume, can be determined. The machine was tested in clinical studies for the treatment of a broad range of medical conditions related to Intravascular Volume Status, such as anemia, [4] congestive heart failure, [5] sepsis, [6] CFS, [7] Hyponatremia, [8] Syncope [9] and more. This tool for measuring blood volume may foster improved patient care [10] as both a stand-alone and complementary diagnostic tool as there has been a statistically significant increase in patient survival. [6]

Pathophysiology

Intravascular volume depletion

The most common cause of hypovolemia is diarrhea or vomiting. The other causes are usually divided into renal and extrarenal causes. Renal causes include overuse of diuretics, or trauma or disease of the kidney. Extrarenal causes include bleeding, burns, and any causes of edema (e.g. congestive heart failure, liver failure).[ citation needed ]

Intravascular volume depletion is divided into three types based on the blood sodium level:

  1. Isonatremic (normal blood sodium levels) Example: a child with diarrhea, because both water and sodium are lost in diarrhea.
  2. Hyponatremic (abnormally low blood sodium levels). Example: a child with diarrhea who has been given tap water to replete diarrheal losses. Overall there is more water than sodium in the body. The intravascular volume is low because the water will move through a process called osmosis out of the vasculature into the cells (intracellularly). The danger is tissue swelling (edema) the most important being brain edema which in turn will cause more vomiting.
  3. Hypernatremic (abnormally high blood sodium levels). Example: a child with diarrhea who has been given salty soup to drink, or insufficiently diluted infant formula. Overall there is more sodium than water. The water will move out of the cell toward the intravascular compartment down the osmotic gradient. This can cause tissue breakage (in case of muscle breakage it is called rhabdomyolysis).

Intravascular volume overload

Intravascular volume overload can occur during surgery, if water rather than isotonic saline is used to wash the incision. It can also occur if there is inadequate urination, e.g. with certain kidney diseases.[ citation needed ]

See also

Related Research Articles

Orthostatic hypotension, also known as postural hypotension, is a medical condition wherein a person's blood pressure drops when standing up or sitting down. Primary orthostatic hypotension is also often referred to as neurogenic orthostatic hypotension. The drop in blood pressure may be sudden, within 3 minutes or gradual. It is defined as a fall in systolic blood pressure of at least 20 mmHg or diastolic blood pressure of at least 10 mmHg after 3 mins of standing. It occurs predominantly by delayed constriction of the lower body blood vessels, which is normally required to maintain adequate blood pressure when changing the position to standing. As a result, blood pools in the blood vessels of the legs for a longer period, and less is returned to the heart, thereby leading to a reduced cardiac output and inadequate blood flow to the brain.

<span class="mw-page-title-main">Bleeding</span> Loss of blood escaping from the circulatory system

Bleeding, hemorrhage, haemorrhage or blood loss is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vagina or anus, or through a puncture in the skin. Hypovolemia is a massive decrease in blood volume, and death by excessive loss of blood is referred to as exsanguination. Typically, a healthy person can endure a loss of 10–15% of the total blood volume without serious medical difficulties. The stopping or controlling of bleeding is called hemostasis and is an important part of both first aid and surgery.

<span class="mw-page-title-main">Dehydration</span> Deficit of total body water

In physiology, dehydration is a lack of total body water, with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mild dehydration can also be caused by immersion diuresis, which may increase risk of decompression sickness in divers.

Hyponatremia or hyponatraemia is a low concentration of sodium in the blood. It is generally defined as a sodium concentration of less than 135 mmol/L (135 mEq/L), with severe hyponatremia being below 120 mEq/L. Symptoms can be absent, mild or severe. Mild symptoms include a decreased ability to think, headaches, nausea, and poor balance. Severe symptoms include confusion, seizures, and coma; death can ensue.

<span class="mw-page-title-main">Hypotension</span> Abnormally low blood pressure

Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure and the diastolic blood pressure, which are the maximum and minimum blood pressures, respectively. A systolic blood pressure of less than 90 millimeters of mercury (mmHg) or diastolic of less than 60 mmHg is generally considered to be hypotension. Different numbers apply to children. However, in practice, blood pressure is considered too low only if noticeable symptoms are present.

<span class="mw-page-title-main">Hypovolemia</span> Low blood volume

Hypovolemia, also known as volume depletion or volume contraction, is a state of abnormally low extracellular fluid in the body. This may be due to either a loss of both salt and water or a decrease in blood volume. Hypovolemia refers to the loss of extracellular fluid and should not be confused with dehydration.

<span class="mw-page-title-main">Electrolyte imbalance</span> Medical condition

Electrolyte imbalance, or water-electrolyte imbalance, is an abnormality in the concentration of electrolytes in the body. Electrolytes play a vital role in maintaining homeostasis in the body. They help to regulate heart and neurological function, fluid balance, oxygen delivery, acid–base balance and much more. Electrolyte imbalances can develop by consuming too little or too much electrolyte as well as excreting too little or too much electrolyte. Examples of electrolytes include calcium, chloride, magnesium, phosphate, potassium, and sodium.

<span class="mw-page-title-main">Hypovolemic shock</span> Medical condition

Hypovolemic shock is a form of shock caused by severe hypovolemia. It could be the result of severe dehydration through a variety of mechanisms or blood loss. Hypovolemic shock is a medical emergency; if left untreated, the insufficient blood flow can cause damage to organs, leading to multiple organ failure.

Hypernatremia, also spelled hypernatraemia, is a high concentration of sodium in the blood. Early symptoms may include a strong feeling of thirst, weakness, nausea, and loss of appetite. Severe symptoms include confusion, muscle twitching, and bleeding in or around the brain. Normal serum sodium levels are 135–145 mmol/L. Hypernatremia is generally defined as a serum sodium level of more than 145 mmol/L. Severe symptoms typically only occur when levels are above 160 mmol/L.

The Syndrome of inappropriate antidiuretic hormone secretion (SIADH), also known as the syndrome of inappropriate antidiuresis (SIAD), is characterized by a physiologically inappropriate release of antidiuretic hormone (ADH) either from the posterior pituitary gland, or an abnormal non-pituitary source. Unsuppressed ADH causes a physiologically inappropriate increase in solute-free water being reabsorbed by the tubules of the kidney to the venous circulation leading to hypotonic hyponatremia.

<span class="mw-page-title-main">Chlortalidone</span> Thiazide-like diuretic drug

Chlortalidone, also known as chlorthalidone, is a thiazide-like diuretic drug used to treat high blood pressure, swelling, diabetes insipidus, and renal tubular acidosis. Because chlortalidone is effective in most patients with high blood pressure, it is considered a preferred initial treatment. It is also used to prevent calcium-based kidney stones. It is taken by mouth. Effects generally begin within three hours and last for up to three days. Long-term treatment with chlortalidone is more effective than hydrochlorothiazide for prevention of heart attack or stroke.

<span class="mw-page-title-main">Dextran</span> Chemical compound

Dextran is a complex branched glucan, originally derived from wine. IUPAC defines dextrans as "Branched poly-α-d-glucosides of microbial origin having glycosidic bonds predominantly C-1 → C-6". Dextran chains are of varying lengths.

Cerebral salt-wasting syndrome (CSWS), also written cerebral salt wasting syndrome, is a rare endocrine condition featuring a low blood sodium concentration and dehydration in response to injury (trauma) or the presence of tumors in or surrounding the brain. In this condition, the kidney is functioning normally but excreting excessive sodium. The condition was initially described in 1950. Its cause and management remain controversial. In the current literature across several fields, including neurology, neurosurgery, nephrology, and critical care medicine, there is controversy over whether CSWS is a distinct condition, or a special form of syndrome of inappropriate antidiuretic hormone secretion (SIADH).

<span class="mw-page-title-main">Saline (medicine)</span> Saline water for medical purposes

Saline is a mixture of sodium chloride (salt) and water. It has a number of uses in medicine including cleaning wounds, removal and storage of contact lenses, and help with dry eyes. By injection into a vein, it is used to treat dehydration such as that from gastroenteritis and diabetic ketoacidosis. Large amounts may result in fluid overload, swelling, acidosis, and high blood sodium. In those with long-standing low blood sodium, excessive use may result in osmotic demyelination syndrome.

<span class="mw-page-title-main">Hypervolemia</span> Medical condition

Hypervolemia, also known as fluid overload, is the medical condition where there is too much fluid in the blood. The opposite condition is hypovolemia, which is too little fluid volume in the blood. Fluid volume excess in the intravascular compartment occurs due to an increase in total body sodium content and a consequent increase in extracellular body water. The mechanism usually stems from compromised regulatory mechanisms for sodium handling as seen in congestive heart failure (CHF), kidney failure, and liver failure. It may also be caused by excessive intake of sodium from foods, intravenous (IV) solutions and blood transfusions, medications, or diagnostic contrast dyes. Treatment typically includes administration of diuretics and limit the intake of water, fluids, sodium, and salt.

<span class="mw-page-title-main">Osmotherapy</span> Medical treatment for cerebral edema

Osmotherapy is the use of osmotically active substances to reduce the volume of intracranial contents. Osmotherapy serves as the primary medical treatment for cerebral edema. The primary purpose of osmotherapy is to improve elasticity and decrease intracranial volume by removing free water, accumulated as a result of cerebral edema, from brain's extracellular and intracellular space into vascular compartment by creating an osmotic gradient between the blood and brain. Normal serum osmolality ranges from 280 to 290 mOsm/kg and serum osmolality to cause water removal from brain without much side effects ranges from 300 to 320 mOsm/kg. Usually, 90 mL of space is created in the intracranial vault by 1.6% reduction in brain water content. Osmotherapy has cerebral dehydrating effects. The main goal of osmotherapy is to decrease intracranial pressure (ICP) by shifting excess fluid from brain. This is accomplished by intravenous administration of osmotic agents which increase serum osmolality in order to shift excess fluid from intracellular or extracellular space of the brain to intravascular compartment. The resulting brain shrinkage effectively reduces intracranial volume and decreases ICP.

<span class="mw-page-title-main">Heat illness</span> Condition caused by the failure of the human body to dissipate heat in a hot environment

Heat illness is a spectrum of disorders due to increased body temperature. It can be caused by either environmental conditions or by exertion. It includes minor conditions such as heat cramps, heat syncope, and heat exhaustion as well as the more severe condition known as heat stroke. It can affect any or all anatomical systems. Heat illnesses include: Heat stroke, heat exhaustion, heat syncope, heat edema, heat cramps, heat rash, heat tetany.

<span class="mw-page-title-main">Adrenal crisis</span> Medical condition

Adrenal crisis is a potentially life-threatening medical condition requiring immediate emergency treatment. It is a constellation of symptoms that indicate severe adrenal insufficiency. This may be the result of either previously undiagnosed or untreated Addison's disease, a disease process that suddenly affects adrenal function, suddenly stopping intake of glucocorticoids or an intercurrent problem in someone known to have Addison's disease, congenital adrenal hyperplasia (CAH), or another form of primary adrenal insufficiency.

Hypoosmolar hyponatremia is a condition where hyponatremia is associated with a low plasma osmolality. The term "hypotonic hyponatremia" is also sometimes used.

Orthostatic syncope refers to syncope resulting from a postural decrease in blood pressure, termed orthostatic hypotension.

References

  1. MedicineNet > Definition of Hypovolemia Archived 2014-01-23 at the Wayback Machine Retrieved on July 2, 2009
  2. TheFreeDictionary.com --> hypovolemia Citing Saunders Comprehensive Veterinary Dictionary, 3 ed. Retrieved on July 2, 2009
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  4. Van, P.Y.; Cho, S.D.; Underwood, S.J.; Hamilton, G.J; Ham, L.B.; Schreiber, M.A. (1 March 2010). "Blood Volume Analysis Can Distinguish True Anemica From Hemodilution in Critically Ill Trauma Patients". Western Trauma Association.
  5. Androne, Ana Silvia; Hryniewicz, Katarzyna; Hudaihed, Alhakam; Mancini, Donna; Lamanca, John; Katz, Stuart D. (2004). "Relation of Unrecognized Hypervolemia in Chronic Heart Failure to Clinical Status, Hemodynamics, and Patient Outcomes". American Journal of Cardiology. 93 (10): 1254–1259. doi:10.1016/j.amjcard.2004.01.070. PMID   15135699.
  6. 1 2 Yu, Mihae; Pei, Kevin; Moran, Sharon; Edwards, Kurt D.; Domingo, Shirley; Steinemann, Susan; Ghows, Maimona; Takiguchi, Sharon; Tan, Andrew; Lurie, Fedor; Takanishi, Danny (2011). "A Prospective Randomized Trial Using Blood Volume Analysis in Addition to Pulmonary Artery Catheter, Compared With Pulmonary Artery Catheter Alone, to Guide Shock Resuscitation in Critically Ill Surgical Patients". Shock. 35 (3): 220–228. CiteSeerX   10.1.1.693.1316 . doi:10.1097/SHK.0b013e3181fc9178. ISSN   1073-2322. PMID   20926981. S2CID   21290772.
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