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The Info List - Hypovolemia


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Hypovolemia is a state of decreased blood volume; more specifically, decrease in volume of blood plasma.[1][2] It is thus the intravascular component of volume contraction (or loss of blood volume due to things such as bleeding or dehydration), but, as it also is the most essential one, hypovolemia and volume contraction are sometimes used synonymously. Hypovolemia is characterized by sodium depletion (salt depletion) and thus differs from dehydration, which is defined as excessive loss of body water.[3]

Contents

1 Causes 2 Diagnosis

2.1 Stages of hypovolemic shock

3 Treatment

3.1 Field care 3.2 Hospital treatment

4 History 5 See also 6 References 7 External links

Causes[edit] Common causes of hypovolemia are:[4]

Loss of blood (external or internal bleeding or blood donation[5]) Loss of plasma (severe burns[6][7] and lesions discharging fluid) Loss of body sodium and consequent intravascular water; e.g. diarrhea or vomiting

Excessive sweating is not a cause of hypovolemia, because the body eliminates significantly more water than sodium.[8] Diagnosis[edit] Clinical symptoms may not be present until 10–20% of total whole-blood volume is lost. Hypovolemia can be recognized by tachycardia, diminished blood pressure,[9] and the absence of perfusion as assessed by skin signs (skin turning pale) and/or capillary refill on forehead, lips 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. Obvious signs of external bleeding should be noted while remembering that people can bleed to death internally without any external blood loss. ("Blood on the floor, plus 4 more" = intrathoracic, intraperitoneal, retroperitoneal, pelvis/thigh) 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 secondary survey and checked the chest and abdomen for pain, deformity, guarding, discoloration or swelling. Bleeding
Bleeding
into the abdominal cavity can cause the classical bruising patterns of Grey Turner's sign or Cullen's sign. Stages of hypovolemic shock[edit] Usually referred to as a "class" of shock. Most sources state that there are 4 stages of hypovolemic shock;[10] however, a number of other systems exist with as many as 6 stages.[11] 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.[12] 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:[13]

Stage 1 Stage 2 Stage 3 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 by vasoconstriction) Increased diastolic BP Systolic BP < 100 Systolic BP < 70

Heart rate Normal Slight tachycardia (> 100 bpm) Tachycardia
Tachycardia
(> 120 bpm) Extreme tachycardia (> 140 bpm) with weak pulse

Respiratory rate Normal Increased (> 20) Tachypneic (> 30) Extreme tachypnea

Mental status Normal Slight anxiety, restless Altered, confused Decreased LOC, lethargy, coma

Skin Pallor 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[edit] Field care[edit] The single most important step in the treatment of hypovolemic shock is to identify and control the source of bleeding.[14] Emergency oxygen should be immediately employed to increase the efficiency of the patient's remaining blood supply. This intervention can be life-saving.[15] 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,[16] both to ensure clotting factors are not overly diluted and also to stop blood pressure being artificially raised to a point where it "blows off" clots that have formed. Hospital treatment[edit] Fluid replacement is beneficial in hypovolemia of stage 2, and is necessary in stage 3 and 4.[13] 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, full blood count, glucose, blood type and screen Central venous catheter
Central venous catheter
or blood pressure Arterial line
Arterial line
or 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 (Dopamine, Noradrenaline) which increase the contractility of the heart muscle Fresh frozen plasma or whole blood

Vasopressors (like Norepinephrine, Dobutamine) 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.[17] History[edit] 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.[18] See also[edit]

Exsanguination 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[edit]

^ " Hypovolemia definition - MedicineNet - Health and Medical Information Produced by Doctors". Medterms.com. 2012-03-19. Retrieved 2015-11-01.  ^ " Hypovolemia definition of hypovolemia by Medical dictionary". Medical-dictionary.thefreedictionary.com. Retrieved 2015-11-01.  ^ " Dehydration
Dehydration
definition - MedicineNet - Health and Medical Information Produced by Doctors". Medterms.com. 2013-10-30. Retrieved 2015-11-01.  ^ Sircar, S. Principles of Medical Physiology. Thieme Medical Pub. ISBN 9781588905727 ^ Danic B, Gouézec H, Bigant E, Thomas T (June 2005). "[Incidents of blood donation]". Transfus Clin Biol (in French). 12 (2): 153–9. doi:10.1016/j.tracli.2005.04.003. PMID 15894504.  ^ "Burn Shock / House Staff Manual". Total Burn Care. Retrieved 2015-11-01.  ^ "Resuscitation in Hypovolaemic Shock. Information page Patient". Patient.info. Retrieved 2015-11-01.  ^ "Saladin 5e Extended Outline : Chapter 24 : Water, Electrolyte, and Acid–Base Balance". Highered.mcgraw-hill.com. Retrieved 2015-11-01.  ^ "Stage 3: Compensated Shock". Archived from the original on 2010-06-11.  ^ Hudson, Kristi. "Hypovolemic Shock - 1 Nursing CE". Archived from the original on 2009-06-06.  ^ "Stage 1: Anticipation stage (a new paradigm)". Archived from the original on 2010-01-16.  ^ Greaves, Ian; Porter, Keith; Hodgetts, Timothy; et al., eds. (2006). Emergency Care: A Textbook for Paramedics. Elsevier Health Sciences. p. 229. ISBN 9780702025860.  ^ a b Elizabeth D Agabegi; Agabegi, Steven S. (2008). Step-Up to Medicine (Step-Up Series). Hagerstwon, MD: Lippincott Williams & Wilkins. ISBN 0-7817-7153-6.  ^ Bulger, E. M., Snyder, D., Schoelles, K., Gotschall, C., Dawson, D., Lang, E., ... & White, L. (2014). An evidence-based prehospital guideline for external hemorrhage control: American College of Surgeons Committee on Trauma. Prehospital Emergency Care, 18(2), 163-173. ^ Takasu A, Prueckner S, Tisherman SA, Stezoski SW, Stezoski J, Safar P. (2000), Effects of increased oxygen breathing in a volume controlled hemorrhagic shock outcome model in rats., PMID 10959021 ^ "Permissive Hypotension". Trauma.Org. 1997-08-31. Retrieved 2015-11-01.  ^ "Failure of dobutamine to improve liver oxygenation during resuscitation with a crystalloid solution after experimental haemorrhagic shock". Pubmed-NCBI. 1996-08-31. Retrieved 2017-11-21.  ^ L. Geeraedts Jr.; H. Kaasjager; A. van Vugt; J. Frölke. " Exsanguination in trauma: A review of diagnostics and treatment options". Injury. 40 (1): 11–20. doi:10.1016/j.injury.2008.10.007. 

External links[edit]

Classification

V · T · D

ICD-10: E86, R57.1, T81.1 ICD-9-CM: 276.52 MeSH: D020896

External resources

MedlinePlus: 000167

CRISP Thesaurus 00004050[dead link]

DDB 29217

v t e

Electrolyte imbalance and acid–base imbalance (E86–E87, 276)

Volume status

Volume contraction (dehydration/hypovolemia) Hypervolemia

Electrolyte

Sodium

High

Hypernatremia Salt poisoning

Low

Hypotonic Isotonic

Potassium

High Low

Chloride

High Low

Calcium

High Low

Acid–base

Acidosis

Metabolic: High anion gap

Ketoacidosis Diabetic ketoacidosis Alcoholic ketoacidosis Lactic

Normal anion gap

Hyperchloremic Renal tubular

Respiratory

Alkalosis

Metabolic

Contraction alkalosis

Respiratory

Both

Mixed disorder of acid-base balance

v t e

Symptoms and signs relating to the cardiovascular system (R00–R03, 785)

Chest pain

Referred pain Angina Aerophagia

Auscultation

Heart sounds

Split S2 S3 S4 Gallop rhythm

Heart murmur

Systolic Diastolic Continuous

Pericardial friction rub Heart click Bruit

carotid

Pulse

Tachycardia Bradycardia Pulsus tardus et parvus Pulsus paradoxus doubled

Pulsus bisferiens Dicrotic pulse Pulsus bigeminus

Pulsus alternans Pulse
Pulse
deficit

Vascular disease

Gangrene

Other

Palpitations

Apex beat

Cœur en sabot Jugular venous pressure

Cannon A waves

Hyperaemia

Shock

Cardiogenic Hypovolemic Distributive

.