Editing Shock (circulatory) (section)

=== Low volume ===
{{main|Hypovolemia|Hypovolemic shock}}[[Hypovolemic shock]] is the most common type of shock and is caused by insufficient circulating [[blood volume|volume]].<ref name="Tint10" /> The most common cause of hypovolemic shock is [[haemorrhage|hemorrhage]] (internal or external); however, [[vomiting]] and [[diarrhea]] are more common causes in children.<ref name="EMB05" /> Other causes include burns, as well as excess urine loss due to [[diabetic ketoacidosis]] and [[diabetes insipidus]].<ref name="EMB05" />
{| class="wikitable" style = "float: right; margin-left:15px; text-align:center"
|+Hemorrhage classes<ref>{{Cite book |last=Tintinalli, Judith E. |title=Emergency Medicine: A Comprehensive Study Guide |publisher=McGraw-Hill Companies |year=2010 |isbn=978-0-07-148480-0 |location=New York}}</ref>
|-
! Class !! Blood loss (liters)!! Response !! Treatment
|-
| I || <15% (0.75&nbsp;L) || min. fast heart rate, normal blood pressure || minimal
|-
| II || 15–30% (0.75–1.5&nbsp;L) || fast heart rate, min. low blood pressure || intravenous fluids
|-
| III || 30–40% (1.5–2&nbsp;L) || very fast heart rate, low blood pressure, confusion || fluids and packed RBCs
|-
| IV || >40% (>2&nbsp;L)|| critical blood pressure and heart rate || aggressive interventions
|}

Signs and symptoms of hypovolemic shock include:
* A rapid, weak, thready pulse due to decreased blood flow combined with [[tachycardia]]{{cn|date=February 2025}}
* Cool skin due to [[vasoconstriction]] and stimulation of vasoconstriction{{cn|date=February 2025}}
* Rapid and [[shallow breathing]] due to [[sympathetic nervous system]] stimulation and [[acidosis]]{{cn|date=February 2025}}
* [[Hypothermia]] due to decreased [[perfusion]] and evaporation of sweat{{cn|date=February 2025}}
* Thirst and dry mouth, due to fluid depletion{{cn|date=February 2025}}
* Cold and mottled skin ([[livedo reticularis]]), especially extremities, due to insufficient perfusion of the skin<ref>{{Cite journal |last1=Hartig |first1=Frank |last2=Reider |first2=Norbert |last3=Sojer |first3=Martin |last4=Hammer |first4=Alexander |last5=Ploner |first5=Thomas |last6=Muth |first6=Claus-Martin |last7=Tilg |first7=Herbert |last8=Köhler |first8=Andrea |date=2020 |title=Livedo Racemosa - The Pathophysiology of Decompression-Associated Cutis Marmorata and Right/Left Shunt |journal=Frontiers in Physiology |volume=11 |pages=994 |doi=10.3389/fphys.2020.00994 |doi-access=free |issn=1664-042X |pmc=7497564 |pmid=33013436}}</ref>

The severity of hemorrhagic shock can be graded on a 1–4 scale on the physical signs. The [[shock index]] (heart rate divided by systolic blood pressure) is a stronger predictor of the impact of blood loss than heart rate and blood pressure alone.<ref name="Olaussen">{{Cite journal |vauthors=Olaussen A, Blackburn T, Mitra B, Fitzgerald M |date=June 2014 |title=Review article: shock index for prediction of critical bleeding post-trauma: a systematic review |journal=Emergency Medicine Australasia |volume=26 |issue=3 |pages=223–28 |doi=10.1111/1742-6723.12232 |pmid=24712642 |s2cid=19881753}}</ref> This relationship has not been well established in pregnancy-related bleeding.<ref>{{Cite journal |vauthors=Pacagnella RC, Souza JP, Durocher J, Perel P, Blum J, Winikoff B, Gülmezoglu AM |year=2013 |title=A systematic review of the relationship between blood loss and clinical signs |journal=PLOS ONE |volume=8 |issue=3 |pages=e57594 |bibcode=2013PLoSO...857594P |doi=10.1371/journal.pone.0057594 |pmc=3590203 |pmid=23483915 |doi-access=free}}</ref>