Examine individual changes

'{{short description|Low blood volume}} {{Infobox medical condition (new) | name = Hypovolemia | synonyms = Oligemia, hypovolaemia, oligaemia, hypovolæmia, volume depletion | image = Capillary microcirculation.svg | caption = A diagram showing the formation of [[interstitial fluid]] from the [[blood]]stream. | field = [[Emergency medicine]] | symptoms = headache, fatigue, nausea, profuse sweating, dizziness | complications = [[Hypovolemic shock]] | onset = | duration = | types = | causes = | risks = | diagnosis = | differential = [[Dehydration]] | prevention = | treatment = | medication = | prognosis = | frequency = | deaths = |alt=}} '''Hypovolemia''', also known as '''volume depletion''' or '''volume contraction''', is a state of abnormally low [[extracellular fluid]] in the body.<ref name="McGee 2018 p. ">{{Cite book |last=McGee |first=Steven |title=Evidence-based physical diagnosis |publisher=Elsevier |year=2018 |isbn=978-0-323-39276-1 |location=Philadelphia, PA |oclc=959371826 |quote=The term hypovolemia refers collectively to two distinct disorders: (1) volume depletion, which describes the loss of sodium from the extracellular space (i.e., intravascular and interstitial fluid) that occurs during gastrointestinal hemorrhage, vomiting, diarrhea, and diuresis; and (2) dehydration, which refers to the loss of intracellular water (and total body water) that ultimately causes cellular desiccation and elevates the plasma sodium concentration and osmolality. |name-list-style=vanc}}</ref> This may be due to either a loss of both salt and water or a decrease in [[blood volume]].<ref>{{cite web|url=http://www.medterms.com/script/main/art.asp?articlekey=3871 |title=Hypovolemia definition – MedicineNet |publisher=Medterms.com |date=2012-03-19 |access-date=2015-11-01}}</ref><ref>{{cite web|url=http://medical-dictionary.thefreedictionary.com/hypovolemia |title=Hypovolemia &#124; definition of hypovolemia by Medical dictionary |publisher=Medical-dictionary.thefreedictionary.com |access-date=2015-11-01}}</ref> Hypovolemia refers to the loss of extracellular fluid and should not be confused with [[dehydration]].<ref>{{Cite journal |vauthors=Bhave G, Neilson EG |date=August 2011 |title=Volume depletion versus dehydration: how understanding the difference can guide therapy |journal=American Journal of Kidney Diseases |volume=58 |issue=2 |pages=302–09 |doi=10.1053/j.ajkd.2011.02.395 |pmc=4096820 |pmid=21705120}}</ref> Hypovolemia is caused by a variety of events, but these can be simplified into two categories: those that are associated with [[Renal physiology|kidney function]] and those that are not.<ref name=":0">{{Cite book|title=Harrison's principles of internal medicine|editor-last1=Jameson|editor-first1=J. Larry|editor-last2=Kasper|editor-first2=Dennis L.|editor-last3=Longo|editor-first3=Dan L.|editor-last4=Fauci|editor-first4=Anthony S.|editor-last5=Hauser|editor-first5=Stephen L.|editor-last6=Loscalzo|editor-first6=Joseph|isbn=9781259644030|edition=20th|location=New York|publisher=[[McGraw-Hill Education]]|oclc=1029074059|date=2018}}</ref> The signs and symptoms of hypovolemia worsen as the amount of fluid lost increases.<ref>{{Cite web|url=https://medlineplus.gov/ency/article/000167.htm|title=Hypovolemic shock: MedlinePlus Medical Encyclopedia|website=medlineplus.gov|language=en|access-date=2019-09-02}}</ref> Immediately or shortly after mild fluid loss (from [[blood donation]], [[diarrhea]], [[vomiting]], bleeding from trauma, etc.), one may experience [[headache]], [[fatigue]], [[weakness]], [[dizziness]], or [[thirst]]. Untreated hypovolemia or excessive and rapid losses of volume may lead to [[hypovolemic shock]].<ref>{{Cite journal |last=Kolecki|first=Paul|name-list-style=vanc |date=October 13, 2016|title=Hypovolemic Shock|url=https://emedicine.medscape.com/article/760145-overview|journal=Medscape}}</ref> Signs and symptoms of hypovolemic shock include [[Tachycardia|increased heart rate]], [[Hypotension|low blood pressure]], [[Pallor|pale or cold skin]], and [[Altered level of consciousness|altered mental status]]. When these signs are seen, immediate action should be taken to [[Fluid replacement|restore the lost volume]]. ==Signs and symptoms== Signs and symptoms of hypovolemia progress with increased loss of fluid volume.<ref name=":0" /> Early symptoms of hypovolemia include headache, fatigue, weakness, thirst, and dizziness. The more severe signs and symptoms are often associated with hypovolemic shock. These include [[oliguria]], [[cyanosis]], abdominal and chest pain, [[hypotension]], [[tachycardia]], cold hands and feet, and progressively altering mental status.{{citation needed|date=November 2021}} ==Causes== The causes of hypovolemia can be characterized into two categories:<ref name=":0" /> ===Kidney=== * Loss of body [[sodium]] and consequent intravascular water (due to impaired reabsorption of salt and water in the [[tubule]]s of the kidneys) ** [[Osmotic diuresis]]: the increase in urine production due to an excess of osmotic (namely [[glucose]] and [[urea]]) load in the tubules of the kidneys ** Overuse of pharmacologic [[diuretic]]s ** Impaired response to hormones controlling salt and water balance (see [[mineralocorticoid]]s) ** [[Renal dysfunction|Impaired kidney function]] due to tubular injury or other diseases ===Other=== * Loss of bodily fluids due to:{{cn|date=June 2022}} ** Gastrointestinal losses; e.g. vomiting and diarrhea ** Skin losses; e.g. excessive sweating and burns ** Respiratory losses; e.g. hyperventilation (breathing fast) * Build up of fluid in empty spaces ([[third spaces]]) of the body due to:{{cn|date=June 2022}} ** [[Acute pancreatitis]] ** Intestinal obstruction ** Increase in [[vascular permeability]] ** [[Hypoalbuminemia]] * Loss of blood (external or internal [[bleeding]] or [[blood donation]]<ref>{{cite journal | vauthors = Danic B, Gouézec H, Bigant E, Thomas T | title = [Incidents of blood donation] | language = fr | journal = Transfusion Clinique et Biologique | volume = 12 | issue = 2 | pages = 153–59 | date = June 2005 | pmid = 15894504 | doi = 10.1016/j.tracli.2005.04.003 }}</ref>) == Pathophysiology == [[Image:170225 CVS Hypovolemic Shock Pathophysiology of Disease.png|thumb|upright=1.3|Pathophysiology of hypovolemia]] The signs and symptoms of hypovolemia are primarily due to the consequences of decreased circulating volume and a subsequent reduction in the amount of blood reaching the tissues of the body.<ref>{{Citation|last1=Taghavi|first1=Sharven|title=Hypovolemic Shock|date=2019|url=http://www.ncbi.nlm.nih.gov/books/NBK513297/|work=StatPearls|publisher=StatPearls Publishing|pmid=30020669|access-date=2019-09-02|last2=Askari|first2=Reza | name-list-style = vanc }}</ref> In order to properly perform their functions, tissues require the oxygen transported in the blood.<ref>{{Cite journal |vauthors=Carreau A, El Hafny-Rahbi B, Matejuk A, Grillon C, Kieda C |date=June 2011 |title=Why is the partial oxygen pressure of human tissues a crucial parameter? Small molecules and hypoxia |journal=Journal of Cellular and Molecular Medicine |volume=15 |issue=6 |pages=1239–53 |doi=10.1111/j.1582-4934.2011.01258.x |pmc=4373326 |pmid=21251211}}</ref> A decrease in circulating volume can lead to a decrease in bloodflow to the brain, resulting in headache and dizziness.{{citation needed|date=November 2021}} [[Baroreceptor]]s in the body (primarily those located in the [[carotid sinus]]es and [[aortic arch]]) sense the reduction of circulating fluid and send signals to the brain to increase sympathetic response (''see also: [[baroreflex]]'').<ref>{{Cite book |title=StatPearls |vauthors=Armstrong M, Moore RA |date=2019 |publisher=StatPearls Publishing |chapter=Physiology, Baroreceptors |pmid=30844199 |access-date=2019-09-02 |chapter-url=http://www.ncbi.nlm.nih.gov/books/NBK538172/}}</ref> This sympathetic response is to release [[Adrenaline|epinephrine]] and [[norepinephrine]], which results in peripheral [[vasoconstriction]] (reducing size of blood vessels) in order to conserve the circulating fluids for organs vital to survival (i.e. brain and heart). Peripheral vasoconstriction accounts for the cold extremities (hands and feet), increased heart rate, increased cardiac output (and associated chest pain). Eventually, there will be less [[perfusion]] to the kidneys, resulting in decreased urine output.{{citation needed|date=July 2020}} ==Diagnosis== {{see also|Shock index}} Hypovolemia can be recognized by a [[fast heart rate]], [[low blood pressure]],<ref>{{cite web|url=http://www.stagesofshock.com/stage3/index.html |title=Stage 3: Compensated Shock|archive-url=https://web.archive.org/web/20100611035541/http://www.stagesofshock.com/stage3/index.html |archive-date=2010-06-11}}</ref> 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 (circulatory)|shock]].<ref name="Alpert Ewy">{{Cite book |last=Alpert |first=Joseph S. |url=https://books.google.com/books?id=Qr9umARYOBYC&pg=PA101 |title=Manual of Cardiovascular Diagnosis and Therapy |last2=Ewy |first2=Gordon A. |publisher=Lippincott Williams & Wilkins |year=2002 |isbn=978-0-7817-2803-4 |page=101 |name-list-style=vanc}}</ref> In children, compensation can result in an artificially high blood pressure despite hypovolemia (a decrease in blood volume). Children typically are able to compensate (maintain blood pressure despite hypovolemia) for a longer period than adults, but deteriorate rapidly and severely once they are unable to compensate ([[Decompensation|decompensate]]).<ref name="Stapleton">{{Cite book |last=Henry |first=Mark C |url=https://books.google.com/books?id=LPoXkd4yN1AC&pg=PA471 |title=EMT Prehospital Care |last2=Stapleton |first2=Edward R |last3=Edgerly |first3=Dennis |publisher=Jones & Bartlett Publishers |year=2011 |isbn=978-0-323-08533-5 |pages=471– |name-list-style=vanc}}</ref> Consequently, any possibility of [[internal bleeding]] in children should be treated aggressively.<ref name="Beevi">{{cite book|author=Assuma Beevi|title=Pediatric Nursing Care Plans|url=https://books.google.com/books?id=2pQGoymRB9YC&pg=PT47|year=2012|publisher=JP Medical Ltd|isbn=978-93-5025-868-2|pages=47–}}</ref><ref name="Clement" /> Signs of external bleeding should be assessed, noting that individuals can bleed internally without external blood loss or otherwise apparent signs.<ref name="Clement">{{cite book| vauthors = Clement I |title=Textbook on First Aid and Emergency Nursing|url=https://books.google.com/books?id=AC__AwAAQBAJ&pg=PA113|year= 2013|publisher=Jaypee Brothers Publishers|isbn=978-93-5025-987-0|pages=113–}}</ref> There should be considered possible mechanisms of injury that may have caused internal bleeding, such as ruptured or bruised internal organs. If trained to do so and if the situation permits, there should be conducted a [[Advanced Trauma Life Support#Secondary survey|secondary survey]] and checked 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]] (bruising along the sides) or [[Cullen's sign]] (around the navel).<ref name="Amanda Graham">{{Cite book |last=Blaber |first=Amanda |url=https://books.google.com/books?id=jfPbQbvP1yAC&pg=PA83 |title=Assessment Skills For Paramedics |last2=Harris |first2=Graham |publisher=McGraw-Hill Education |year=2011 |isbn=978-0-335-24199-6 |pages=83– |name-list-style=vanc}}</ref> ===Investigation=== In a hospital, physicians respond to a case of hypovolemic shock by conducting these investigations:{{citation needed|date=November 2021}} * Blood tests: [[Basic metabolic panel|U+Es/Chem7]], full blood count, glucose, blood type and screen * [[Central venous catheter]] * [[Arterial line]] * Urine output measurements (via [[urinary catheterization|urinary catheter]]) * Blood pressure * SpO2 [[oxygen saturation]] monitoring ===Stages=== Untreated hypovolemia can lead to shock (see also: [[hypovolemic shock]]). Most sources state that there are 4 stages of hypovolemia and subsequent shock;<ref name="dynamicnursingeducation.com">{{cite web|author=Hudson, Kristi|url=http://dynamicnursingeducation.com/class.php?class_id=47&pid=18|title=Hypovolemic Shock – 1 Nursing CE|archive-url=https://web.archive.org/web/20090606044910/http://dynamicnursingeducation.com/class.php?class_id=47&pid=18 |archive-date=2009-06-06}}</ref> however, a number of other systems exist with as many as 6 stages.<ref>{{cite web|url=http://www.stagesofshock.com/stage1/index.html|title=Stage 1: Anticipation stage (a new paradigm)|archive-url=https://web.archive.org/web/20100116055045/http://www.stagesofshock.com/stage1/index.html|archive-date=2010-01-16}}</ref> The 4 stages are sometimes known as the "Tennis" staging of hypovolemic shock, as the stages of blood loss (under 15% of volume, 15–30% of volume, 30–40% of volume and above 40% of volume) mimic the scores in a game of tennis: 15, 15–30, 30–40 and 40.<ref name=emergencycare>{{cite book|editor1-last=Greaves|editor1-first=Ian|editor2-last=Porter|editor2-first=Keith|editor3-last=Hodgetts|editor3-first=Timothy|display-editors = 3 |editor4-last=Woollard|editor4-first=Malcolm| name-list-style = vanc |title=Emergency Care: A Textbook for Paramedics|date=2006|publisher=Elsevier Health Sciences|isbn=9780702025860|page=229}}</ref> It is basically the same as used in classifying [[bleeding]] by blood loss. The signs and symptoms of the major stages of hypovolemic shock include:<ref name="agabegi2nd">{{Cite book |last=Agabegi |first=Elizabeth D |url=https://archive.org/details/stepuptomedicine0000agab |title=Step-Up to Medicine (Step-Up Series) |last2=Steven S. |first2=Agabegi |publisher=Lippincott Williams & Wilkins |year=2008 |isbn=978-0-7817-7153-5 |location=Hagerstwon, MD |url-access=registration |name-list-style=vanc}}</ref><ref>{{Cite book|title=Robbins and Cotran pathologic basis of disease|editor-last1=Kumar|editor-first1=Vinay|editor-last2=Abbas|editor-first2=Abul K.|editor-last3=Aster|editor-first3=Jon C.|others=Illustrated by Perkins, James A.|date=2015|isbn=9781455726134|edition=9th|location=Philadelphia, PA|publisher=[[Saunders (imprint)|Saunders]]|oclc=879416939}}</ref> {| class="wikitable" style="margin: 1em auto 1em auto;" ! scope="col" | ! scope="col" | '''Stage 1''' ! scope="col" | '''Stage 2''' ! scope="col" | '''Stage 3''' ! scope="col" | '''Stage 4''' |- | '''Blood loss''' || Up to 15% (750 mL) || 15–30% (750–1500 mL) || 30–40% (1500–2000 mL) || Over 40% (over 2000 mL) |- || '''Blood pressure''' || Normal (Maintained<br />by [[vasoconstriction]]) || Increased [[diastolic blood pressure|diastolic BP]] || [[Systolic blood pressure|Systolic BP]] < 100 || Systolic BP < 70 |- || '''Heart rate''' || Normal || Slight [[tachycardia]] (> 100 bpm) || Tachycardia (> 120 bpm) || Extreme tachycardia (> 140 bpm) with weak pulse |- || '''Respiratory rate''' || Normal || Increased (> 20) || [[Tachypnea|Tachypneic]] (> 30) || Extreme [[tachypnea]] |- | '''Mental status''' || Normal || Slight anxiety, restless || [[Altered mental status|Altered]], confused || Decreased [[level of consciousness|LOC]], [[lethargy]], [[coma]] |- | '''Skin''' || [[Pallor|Pale]] || Pale, cool, clammy || Increased [[diaphoresis]] || Extreme [[diaphoresis]]; [[mottling]] possible |- | '''[[Capillary refill]]''' || Normal || Delayed || Delayed || Absent |- | '''Urine output''' || Normal || 20–30 mL/h || 20 mL/h || Negligible |} ==Treatment== ===Field care=== The most important step in treatment of hypovolemic shock is to identify and control the source of bleeding.<ref>{{cite journal |last1=Bulger |first1=E. M. |last2=Snyder |first2=D. |last3=Schoelles |first3=K. |last4=Gotschall |first4=C. |last5=Dawson |first5=D. |last6=Lang |first6=E. |last7=White |first7=L. |s2cid=15742568 |display-authors=1 |year=2014 |title=An evidence-based prehospital guideline for external hemorrhage control: American College of Surgeons Committee on Trauma |journal=Prehospital Emergency Care |volume=18 |issue=2 |pages=163–173 |doi=10.3109/10903127.2014.896962 |pmid=24641269 }}</ref> Medical personnel should immediately supply emergency oxygen to increase efficiency of the patient's remaining blood supply. This intervention can be life-saving.<ref>{{cite journal |last1=Takasu |first1=A. |last2=Prueckner |first2=S. |last3=Tisherman |first3=S. A. |last4=Stezoski |first4=S. W. |last5=Stezoski |first5=J. |last6=Safar |first6=P. |year=2000 |title=Effects of increased oxygen breathing in a volume controlled hemorrhagic shock outcome model in rats |journal=Resuscitation |volume=45 |issue=3 |pages=209–220 |pmid=10959021 |doi=10.1016/s0300-9572(00)00183-0 }}</ref> Also, the respiratory pump is especially important during hypovolemia as spontaneous breathing may help reduce the effect of this loss of blood pressure on stroke volume by increasing venous return. <ref>https://journals-physiology-org.proxy.library.vanderbilt.edu/doi/full/10.1152/japplphysiol.01009.2017</ref> The use of [[intravenous drip|intravenous fluids]] (IVs) may help compensate for lost fluid volume, but IV fluids cannot carry oxygen the way blood does—however, researchers are developing [[blood substitutes]] that can. Infusing [[colloid fluids|colloid]] or [[crystalloid fluid|crystalloid]] IV fluids also dilutes [[clotting factor]]s in the blood, increasing the risk of bleeding. Current best practice allow [[permissive hypotension]] in patients with hypovolemic shock,<ref>{{cite web |url=http://www.trauma.org/archive/resus/permissivehypotension.html |title=Permissive Hypotension |publisher=Trauma.Org |date=1997-08-31 |access-date=2015-11-01 |archive-url=https://web.archive.org/web/20131127011402/http://www.trauma.org/archive/resus/permissivehypotension.html |archive-date=2013-11-27 |url-status=dead }}</ref> both avoid overly diluting clotting factors and avoid artificially raising blood pressure to a point where it "blows off" clots that have formed.<ref name="AAOS">{{Cite book |last=Kennamer |first=Mike |url=https://books.google.com/books?id=YB2VAgAAQBAJ&pg=PA63 |title=Intravenous Therapy for Prehospital Providers |last2=American Academy of Orthopaedic Surgeons (AAOS) |publisher=Jones & Bartlett Publishers |year=2013 |isbn=978-1-4496-4204-4 |pages=63– |name-list-style=vanc}}</ref><ref name="Franchis Dell'Era">{{Cite book |last=de Franchis |first=Roberto |url=https://books.google.com/books?id=YrW9BAAAQBAJ&pg=PA113 |title=Variceal Hemorrhage |last2=Dell'Era |first2=Alessandra |publisher=Springer Science & Business Media |year=2014 |isbn=978-1-4939-0002-2 |pages=113– |name-list-style=vanc}}</ref> ===Hospital treatment=== [[Fluid replacement]] is beneficial in hypovolemia of stage 2, and is necessary in stage 3 and 4.<ref name="agabegi2nd" /> See also the discussion of [[Shock (circulatory)|shock]] and the importance of treating reversible shock while it can still be countered. The following interventions are carried out: * IV access * Oxygen as required * Fresh frozen [[Blood plasma|plasma]] or [[blood transfusion]] * Surgical repair at sites of bleeding [[Vasopressor]]s (such as [[dopamine (medicine)|dopamine]] and [[Norepinephrine (drug)|noradrenaline]]) should generally be avoided, as they may result in further tissue [[ischemia]] and don't correct the primary problem. Fluids are the preferred choice of therapy.<ref>{{cite journal|url=https://pubmed.ncbi.nlm.nih.gov/9001880/ |title=Failure of dobutamine to improve liver oxygenation during resuscitation with a crystalloid solution after experimental haemorrhagic shock|journal=The European Journal of Surgery = Acta Chirurgica|volume=162|issue=12|pages=973–979|publisher=Pubmed-NCBI |date=1996-08-31 |access-date=2017-11-21|last1=Nordin|first1=A. J.|last2=Mäkisalo|first2=H.|last3=Höckerstedt|first3=K. A.|pmid=9001880 }}</ref> ==History== In cases where loss of blood volume is clearly attributable to bleeding (as opposed to, e.g., dehydration), most medical practitioners 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.<ref>{{Cite journal |vauthors=Geeraedts LM, Kaasjager HA, van Vugt AB, Frölke JP |date=January 2009 |title=Exsanguination in trauma: A review of diagnostics and treatment options |journal=Injury |volume=40 |issue=1 |pages=11–20 |doi=10.1016/j.injury.2008.10.007 |pmid=19135193}}</ref> == See also == * [[Hypervolemia]] * [[Non-pneumatic anti-shock garment]] * [[Polycythemia]], an increase of the [[hematocrit]] level, with the "relative polycythemia" being a decrease in the volume of plasma * [[Volume status]] == References == {{Reflist|colwidth=30em}} {{Medical resources | DiseasesDB = 29217 | ICD10 = {{ICD10|E|86||e|70}}, {{ICD10|R|57|1|r|50}}, {{ICD10|T|81|1|t|80}} | ICD9 = {{ICD9|276.52}} | ICDO = | OMIM = | MedlinePlus = 000167 | eMedicineSubj = | eMedicineTopic = | MeshID = D020896 }} {{Electrolyte abnormalities}} {{shock types}} {{Disorders of volume state}} {{Cardiovascular system symptoms and signs}} [[Category:Blood disorders]] [[Category:Medical emergencies]]'