Hypovolemia
Encyclopedia
In physiology
and medicine
, hypovolemia (also hypovolaemia) is a state of decreased blood volume
; more specifically, decrease in volume of blood plasma
. It is thus the intravascular component of volume contraction
(or loss of blood volume due to things such as hemorrhaging or dehydration), but, as it also is the most essential one, hypovolemia and volume contraction are sometimes used synonymously.
Hypovolemia is characterized by salt (sodium) depletion and thus differs from dehydration
, which is defined as excessive loss of body water
.
, bleeding
, vomiting, severe burns
and drug vasodilators typically used to treat hypertensive
individuals. Rarely, it may occur as a result of a blood donation
, sweating, and alcohol consumption. It is also common during surgery due to the use of anesthetics, nil-by-mouth, and in-operation bleeding.
A ruptured ovarian cyst associated with (PCOS - polycystic ovarian syndrome) may cause severe internal bleeding, causing hypovolemic shock.
Hypovolemia can be recognized by tachycardia
, diminished blood pressure, and the absence of perfusion
as assessed by skin signs (skin turning pale) and/or capillary refill
on forehead
, lip
s and nail beds. The patient may feel dizzy, faint, nauseated, or very thirsty. These signs are also characteristic of most types of shock.
Note that in children, compensation can result in an artificially high blood pressure despite hypovolemia. Children will typically compensate (maintain blood pressure despite loss of blood volume) for a longer period than adults, but will deteriorate rapidly and severely once they do begin to decompensate. This is another reason (aside from initial lower blood volume) that even the possibility of internal bleeding in children should almost always be treated aggressively.
Also look for obvious signs of external bleeding while remembering that people can bleed to death internally without any external blood loss.
Also consider possible mechanisms of injury that may have caused internal bleeding such as ruptured or bruised internal organs. If trained to do so and the situation permits, conduct a secondary survey and check the chest and abdomen for pain, deformity, guarding, discoloration or swelling. Bleeding into the abdominal cavity can cause the classical bruising patterns of Grey Turner's sign or Cullen's sign
.
The 4 stages are sometimes known as the "Tennis" staging of hypovolemic shock, as the 4 stages of % volume of blood loss mimic the scores in a game of tennis: 15, 15-30, 30-40, 40. It is basically the same as used in classifying bleeding
by blood loss.
, although this is highly dependent on body weight. Larger people can tolerate slightly more blood loss than smaller people.
More serious hypovolemia should be assessed by a physician.
should be used in the case of hemorrhage that cannot be controlled by direct pressure. If left on for more than 8 hours, the use of a tourniquet can kill all the tissue below its application upon a limb, making amputation necessary.
The US Military now suggests applying a tourniquet to a bleeding extremity first, because direct pressure does not usually stop bleeding. Other techniques such as elevation and pressure points usually fail completely.
If a first-aid provider recognizes internal bleeding the life-saving measure to take is to immediately call for emergency assistance.
The use of intravenous fluids (IVs) may help compensate for lost fluid volume, but IV fluids cannot carry oxygen in the way that blood can, however blood substitutes
are being developed which can. Infusion of colloid or crystalloid IV fluids will also dilute clotting factors within the blood, increasing the risk of bleeding. It is current best practice to allow permissive hypotension
in patients suffering from hypovolemic shock both to ensure clotting factors are not overly diluted but also to stop blood pressure being artificially raised to a point where it "blows off" clots that have formed.
Fluid replacement
is beneficial in hypovolemia of stage 2, and is necessary in stage 3 and 4. Blood transfusion
s coupled with surgical repair are the definitive treatment for hypovolemia caused by trauma
. See also the discussion of shock and the importance of treating reversible shock while it can still be countered.
For a patient presenting with hypovolemic shock in hospital the following investigations would be carried out:
The following interventions would be carried out:
in traditional medicine practiced in the Greco-Roman civilization and in Europe during the Middle Ages. The word was possibly used to describe the lack of personality (by death or by weakness) that often occurred once a person suffered hemorrhage or massive blood loss.
In cases in which loss of blood volume is clearly attributable to bleeding (as opposed to, e.g., dehydration), most medical practitioners of today prefer the term exsanguination
for its greater specificity and descriptiveness, with the effect that the latter term is now more common in the relevant context.
episode "Blood Feud" (7F22: Season 2, Episode 22), C. Montgomery Burns suffers an attack of hypovolemia, described by Dr. Julius Hibbert as "hypohemia, meaning 'low blood'"; writers coined the latter term to satirize the proliferation of complex medical terms for conditions easily describable in plain English. The writers used the same roots occurring in the first and last elements of hypovolemia, with the added h being a transliteration of the breath mark
placed over the initial alpha
of the Greek root -[h]aim- when that element occurs at the start of a word or (in English words coined from Greek roots, but not in classical Greek) after an element that ends in a vowel.
In the horror film Saw V
, two victims are each forced to provide 5 USpt of blood, producing markedly noticeable symptoms of hypovolemia.
Physiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...
and medicine
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
, hypovolemia (also hypovolaemia) is a state of decreased blood volume
Blood volume
Blood volume is the volume of blood in the circulatory system of an individual.-Humans:A typical adult has a blood volume of approximately between 4.7 and 5 liters, with females generally having less blood volume than males....
; more specifically, decrease in volume of blood plasma
Blood plasma
Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...
. It is thus the intravascular component of volume contraction
Volume contraction
Volume contraction is a decrease in body fluid volume, also including any concomitant loss of osmolytes. The loss of the water component of body fluid is specifically termed dehydration.-By body fluid compartment:...
(or loss of blood volume due to things such as hemorrhaging or dehydration), but, as it also is the most essential one, hypovolemia and volume contraction are sometimes used synonymously.
Hypovolemia is characterized by salt (sodium) depletion and thus differs from dehydration
Dehydration
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...
, which is defined as excessive loss of body water
Body water
In medicine, body water is the water content of the human body. A significant fraction of the human body is water. Arthur Guyton 's Textbook of Medical Physiology states that "the total amount of water in a man of average weight is approximately 40 litres, averaging 57 percent of his total body...
.
Causes
Common causes of hypovolemia are 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...
, bleeding
Bleeding
Bleeding, technically known as hemorrhaging or haemorrhaging is the loss of blood or blood escape from the circulatory system...
, vomiting, severe burns
Burn (injury)
A burn is a type of injury to flesh caused by heat, electricity, chemicals, light, radiation or friction. Most burns affect only the skin . Rarely, deeper tissues, such as muscle, bone, and blood vessels can also be injured...
and drug vasodilators typically used to treat hypertensive
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
individuals. Rarely, it may occur as a result of a blood donation
Blood donation
A blood donation occurs when a person voluntarily has blood drawn and used for transfusions or made into medications by a process called fractionation....
, sweating, and alcohol consumption. It is also common during surgery due to the use of anesthetics, nil-by-mouth, and in-operation bleeding.
A ruptured ovarian cyst associated with (PCOS - polycystic ovarian syndrome) may cause severe internal bleeding, causing hypovolemic shock.
Diagnosis
Clinical symptoms may not be present until 10–20% of total whole-blood volume is lost.Hypovolemia can be recognized by tachycardia
Tachycardia
Tachycardia comes from the Greek words tachys and kardia . Tachycardia typically refers to a heart rate that exceeds the normal range for a resting heart rate...
, diminished blood pressure, and the absence of perfusion
Perfusion
In physiology, perfusion is the process of nutritive delivery of arterial blood to a capillary bed in the biological tissue. The word is derived from the French verb "perfuser" meaning to "pour over or through."...
as assessed by skin signs (skin turning pale) and/or capillary refill
Capillary refill
Capillary refill is the rate at which blood refills empty capillaries. It can be measured by holding a hand higher than heart-level , pressing the soft pad of a finger or toe until it turns white, and taking note of the time needed for the color to return once pressure is released. Normal refill...
on forehead
Forehead
For the Arsenal striker see GervinhoIn human anatomy, the forehead is the fore part of the head. It is, formally, an area of the head bounded by three features, two of the skull and one of the scalp. The top of the forehead is marked by the hairline, the edge of the area where hair on the scalp...
, lip
Lip
Lips are a visible body part at the mouth of humans and many animals. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech...
s and nail beds. The patient may feel dizzy, faint, nauseated, or very thirsty. These signs are also characteristic of most types of shock.
Note that in children, compensation can result in an artificially high blood pressure despite hypovolemia. Children will typically compensate (maintain blood pressure despite loss of blood volume) for a longer period than adults, but will deteriorate rapidly and severely once they do begin to decompensate. This is another reason (aside from initial lower blood volume) that even the possibility of internal bleeding in children should almost always be treated aggressively.
Also look for obvious signs of external bleeding while remembering that people can bleed to death internally without any external blood loss.
Also consider possible mechanisms of injury that may have caused internal bleeding such as ruptured or bruised internal organs. If trained to do so and the situation permits, conduct a secondary survey and check the chest and abdomen for pain, deformity, guarding, discoloration or swelling. Bleeding into the abdominal cavity can cause the classical bruising patterns of Grey Turner's sign or Cullen's sign
Cullen's sign
Cullen's sign is superficial edema and bruising in the subcutaneous fatty tissue around the umbilicus.It is named for Thomas S. Cullen , an obstetrician who first described the sign in ruptured ectopic pregnancy in 1916....
.
Stages of hypovolemic shock
Most sources state that there are 4 stages of hypovolemic shock, however a number of other systems exist with as many as 5 stages.The 4 stages are sometimes known as the "Tennis" staging of hypovolemic shock, as the 4 stages of % volume of blood loss mimic the scores in a game of tennis: 15, 15-30, 30-40, 40. It is basically the same as used in classifying bleeding
Bleeding
Bleeding, technically known as hemorrhaging or haemorrhaging is the loss of blood or blood escape from the circulatory system...
by blood loss.
Stage 1
- Up to 15% blood volume loss (750 mL)
- Compensated by constriction of vascular bed
- Blood pressure maintained
- Normal respiratory rate
- Pallor of the skin
- Normal mental status to slight anxiety
- Normal capillary refillCapillary refillCapillary refill is the rate at which blood refills empty capillaries. It can be measured by holding a hand higher than heart-level , pressing the soft pad of a finger or toe until it turns white, and taking note of the time needed for the color to return once pressure is released. Normal refill...
- Normal urine output
Stage 2
- 15–30% blood volume loss (750–1500 mL)
- Cardiac output cannot be maintained by arterial constriction
- Tachycardia >100bpm
- Increased respiratory rate
- Blood pressure maintained
- Increased diastolic pressure
- Narrow pulse pressure
- Sweating from sympathetic stimulation
- Mildly anxious/Restless
- Delayed capillary refill
- Urine output of 20-30 milliliters/hour
Stage 3
- 30–40% blood volume loss (1500–2000 mL)
- Systolic BP falls to 100mmHg or less
- Classic signs of hypovolemic shock
- Marked tachycardia >120 bpm
- Marked tachypnea >30 bpm
- Alteration in mental status (confusion, anxiety, agitation)
- Sweating with cool, pale skin
- Delayed capillary refill
- Urine output of approximately 20 milliliters/hour
Stage 4
- Loss greater than 40% (>2000 mL)
- Extreme tachycardia (>140) with weak pulse
- Pronounced tachypnea
- Significantly decreased systolic blood pressure of 70 mmHg or less
- Decreased level of consciousness, lethargy, coma
- Skin is sweaty, cool, and extremely pale (moribund)
- Absent capillary refill
- Negligible urine output
Treatment
Minor hypovolemia from a known cause that has been completely controlled (such as a blood donation from a healthy patient who is not anemic) may be countered with initial rest for up to half an hour. Oral fluids that include moderate sugars and electrolytes are needed to replenish depleted sodium ions. Furthermore the advice for the donor is to eat good solid meals with proteins for the next few days. Typically, this would involve a fluid volume of less than one literLitér
- External links :*...
, although this is highly dependent on body weight. Larger people can tolerate slightly more blood loss than smaller people.
More serious hypovolemia should be assessed by a physician.
First aid
External bleeding should be controlled by direct pressure. If direct pressure fails, a tourniquetTourniquet
An emergency tourniquet is a tightly tied band applied around a body part sometimes used in an attempt to stop severe traumatic bleeding. Tourniquets are also used during venipuncture and other medical procedures. Severe bleeding means the loss of more than 1,000 ml of blood. This flow of blood...
should be used in the case of hemorrhage that cannot be controlled by direct pressure. If left on for more than 8 hours, the use of a tourniquet can kill all the tissue below its application upon a limb, making amputation necessary.
The US Military now suggests applying a tourniquet to a bleeding extremity first, because direct pressure does not usually stop bleeding. Other techniques such as elevation and pressure points usually fail completely.
If a first-aid provider recognizes internal bleeding the life-saving measure to take is to immediately call for emergency assistance.
Field care
Emergency oxygen should be immediately employed to increase the efficiency of the patient's remaining blood supply. This intervention can be life-saving.The use of intravenous fluids (IVs) may help compensate for lost fluid volume, but IV fluids cannot carry oxygen in the way that blood can, however blood substitutes
Blood substitutes
A blood substitute is a substance used to mimic and fulfill some functions of biological blood, usually in the oxygen-carrying sense...
are being developed which can. Infusion of colloid or crystalloid IV fluids will also dilute clotting factors within the blood, increasing the risk of bleeding. It is current best practice to allow permissive hypotension
Permissive hypotension
Permissive hypotension or hypotensive resuscitation is a term used to describe the use of restrictive fluid therapy, specifically in the trauma patient, that increases systemic pressure without reaching normotension...
in patients suffering from hypovolemic shock both to ensure clotting factors are not overly diluted but also to stop blood pressure being artificially raised to a point where it "blows off" clots that have formed.
Hospital treatment
If the hypovolemia was caused by medication, the administration of antidotes may be appropriate but should be carefully monitored to avoid shock or the emergence of other pre-existing conditions.Fluid replacement
Fluid replacement
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 , intravenous administration, rectally, or hypodermoclysis, the direct injection...
is beneficial in hypovolemia of stage 2, and is necessary in stage 3 and 4. 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...
s coupled with surgical repair are the definitive treatment for hypovolemia caused by trauma
Physical trauma
Trauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death...
. See also the discussion of shock and the importance of treating reversible shock while it can still be countered.
For a patient presenting with hypovolemic shock in hospital the following investigations would be carried out:
- Blood tests: U+Es/Chem7, FBC, Glucose, Cross-match
- Central Venous Line/Blood Pressure
- Arterial Line/Arterial Blood Gases
- Urine output measurements (via urinary catheter)
- Blood pressure
- SpO2 Oxygen saturations
The following interventions would be carried out:
- IV access
- Oxygen as required
- Surgical repair at sites of hemorrhage
- Inotrope therapy (DopamineDopamineDopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...
, Noradrenaline) - Fresh frozen plasma/whole blood
History
Hypovolemia has historically been termed desanguination (from Latin sanguis, blood), meaning a massive loss of blood. The term was widely used by the HippocratesHippocrates
Hippocrates of Cos or Hippokrates of Kos was an ancient Greek physician of the Age of Pericles , and is considered one of the most outstanding figures in the history of medicine...
in traditional medicine practiced in the Greco-Roman civilization and in Europe during the Middle Ages. The word was possibly used to describe the lack of personality (by death or by weakness) that often occurred once a person suffered hemorrhage or massive blood loss.
In cases in which loss of blood volume is clearly attributable to bleeding (as opposed to, e.g., dehydration), most medical practitioners of today prefer the term exsanguination
Exsanguination
Exsanguination is the fatal process of hypovolemia , to a degree sufficient enough to cause death. One does not have to lose literally all of one's blood to cause death...
for its greater specificity and descriptiveness, with the effect that the latter term is now more common in the relevant context.
In popular culture
In The SimpsonsThe Simpsons
The Simpsons is an American animated sitcom created by Matt Groening for the Fox Broadcasting Company. The series is a satirical parody of a middle class American lifestyle epitomized by its family of the same name, which consists of Homer, Marge, Bart, Lisa and Maggie...
episode "Blood Feud" (7F22: Season 2, Episode 22), C. Montgomery Burns suffers an attack of hypovolemia, described by Dr. Julius Hibbert as "hypohemia, meaning 'low blood'"; writers coined the latter term to satirize the proliferation of complex medical terms for conditions easily describable in plain English. The writers used the same roots occurring in the first and last elements of hypovolemia, with the added h being a transliteration of the breath mark
Spiritus asper
In the polytonic orthography of Ancient Greek, the rough breathing , is a diacritical mark used to indicate the presence of an sound before a vowel, diphthong, or rho. It remained in the polytonic orthography even after the Hellenistic period, when the sound disappeared from the Greek language...
placed over the initial alpha
Alpha (letter)
Alpha is the first letter of the Greek alphabet. In the system of Greek numerals it has a value of 1. It was derived from the Phoenician letter Aleph...
of the Greek root -[h]aim- when that element occurs at the start of a word or (in English words coined from Greek roots, but not in classical Greek) after an element that ends in a vowel.
In the horror film Saw V
Saw V
Saw V is a 2008 Canadian-American horror film directed by David Hackl and written by Patrick Melton and Marcus Dunstan and stars Tobin Bell, Costas Mandylor and Scott Patterson...
, two victims are each forced to provide 5 USpt of blood, producing markedly noticeable symptoms of hypovolemia.