Hypovolemia

What is Hypovolemia : Definition

Hypovolemia is a commonly present but less heard, condition which may turn life-threatening. This is a situation that can be corrected effectively, if timely care is given.

It is easier understood if we can break the term ‘Hypovolemia’ into different parts. Any words that contain ‘emia’ refer to something about blood. ‘Hypo’ and ‘Hyper’ are more commonly known prefix. ‘Hypo’ means which is ‘less’ and ‘Hyper’ means ‘more’. Hypovolemia thus refers to a decreased volume of blood in the body. (See info on : Hypervolemia)

Now since you know its meaning, it is sure to raise your interest in this obscure condition. You will find it easier here to know how hypovolemia occurs, how it can be understood, its treatment and what happens if it is not treated at the right time.

When the hypovolemia is not corrected, enough blood fails to reach the vital organs. These organs may start failing, and thus Hypovolemic shock occurs.

Concept

Blood Components:

• Liquid- Plasma
• Solid- Blood cells

To better understand this, you will have to know a few facts. The blood that flows in our arteries, veins and capillaries, by nature is liquid. In this liquid there are many cells and proteins that float.

If you remove the cellular components of blood (RBC, WBC and Platelets), what remains is called ‘plasma’. Hypovolemia in fact is the loss of this plasma.

Types

• Absolute Hypovolemia

• Relative Hypovolemia

If, hypovolemia occurred due to loss of blood/plasma from our blood vessels, to outside of our body, then it is called as ‘absolute hypovolemia’. If it occurred due to reasons other than the fluid loss, it is called as a ‘relative hypovolemia’.

For example, when the blood vessels become wider, the blood content does not increase. This can result in a relative decrease of blood that reaches the organs like brain, heart, liver etc.

A similar phenomenon occurs if fluid from blood leaks to the surrounding tissues as in case of ascites (Fluid collection in the peritoneum) or even when there is internal haemorrhage (Peptic ulcer disease)

Image 1: Causes, Symptoms & Signs of Hypovolemia
Picture Source: i.pinimg.com

Causes

Absolute Hypovolemia

• Loss of Blood- Haemorrhage ⁽¹⁾
• Loss of Plasma- Burns ⁽²⁾
• Loss of Water- Excessive loss (diarrhoea, vomiting, sweating, urination)⁽¹²⁾

Relative Hypovolemia

• Internal bleeding – Gastro intestinal tract, Aneurysms ⁽⁵⁾
• Heart failure – heart fails to pump enough blood into the circulation⁽¹²⁾
• Decreased protein in blood – leads to decreased osmotic pressure of the blood. This results in fluid leaking to the surrounding tissues.⁽¹²⁾
• Decreased sodium in blood – leads to decreased osmotic pressure of the blood. This results in fluid leaking to the surrounding tissues.⁽¹²⁾
• Increased width/diameter of the blood vessels – As seen in orthostatic hypotension, vasovagal syncope, septic shock, anaphylaxis etc.⁽¹²⁾

Signs and Symptoms

The symptoms of Hypovolemia depend on the severity of the blood or fluid loss. When the loss is more than 20%, hypovolemic shock ensues. At varying levels of hypovolemia the following symptoms can be seen. ⁽¹¹⁾

• Low Blood pressure- When the loss is less, body compensates the blood pressure to a certain degree. But if the loss is more, then blood pressure starts to fall. ^{(8, 11)}
• Increased Heart rate- Heart tries to beat faster to push the blood to reach the vital organs. ^{(8, 11)}
• Increased respiratory rate- The respiratory system tries to get more oxygen into our body to compensate the decreased amount of blood. ^{(8, 11)}
• Altered mental status- The mental status may range from normal and anxious to loss of consciousness and Coma, depending on the severity of the hypovolemia. ^{(8, 11)}
• Pale, cool, and clammy skin- Body tries to move blood to more important organs like brain, heart and lungs while reducing the circulation to skin and other less vital organs.^{(8, 11)}
• Reduced urine output- When blood is less, the urine formed also is decreased. In severe hypovolemia, the kidney may shut down and urine formation may even stop.^{(8, 11)}

First Aid

Hypovolemia is an emergency in most situations. But, if you can give appropriate care initially, before reaching hospital, that may help the person to survive through. ⁽⁴⁾

• Clear if anything is there in the mouth, so that the person can breathe better.
• Mouth to mouth breathing can be given until emergency care team arrives at the spot.
• Obvious bleeding can be stopped by applying pressure bandages or tying with clothes.⁽⁹⁾
• If there is injury and you suspect broken bones, make sure you do not move the person. Remember spinal injuries may become more serious on movement.⁽¹⁰⁾
• Elevate the foot end slightly.
• Shift the person immediately and rapidly to a hospital where proper care can be given.

What tests can be expected in Hospital?

The tests done in the hospitals are usually to diagnose the cause of hypovolemia and to know about its severity.

• Blood studies including Complete blood count, arterial blood gases, Electrolytes, coagulation studies, urine analysis, and urine pregnancy tests can be done. ⁽³⁾
• Imaging studies such as, Ultrasonography, X- Rays, CT scan, MRI, Echocardiography, endoscopy, right heart catheterization etc may be done for suspected injury confirmation or for ruling out other injuries.⁽⁷⁾

How is Hypovolemia treated?

The treatment of hypovolemia is targeted at increasing oxygen supply, limiting the blood loss and correction of the blood volume. The treatment may include the following.

• Supplemental Oxygen
• Wide bore needle cannulation⁽²⁾
• Arterial blood line placement⁽³⁾
• Intravenous fluid resuscitation ^{(1, 6)}
• Blood transfusion/ Plasma transfusion⁽¹⁾
• Surgical intervention to stop bleeding⁽³⁾
• Correction of fractures ⁽⁸⁾
• Medications ⁽⁸⁾

Complications

As we have already seen, hypovolemic shock can be dangerous enough to cause death. Other than death, it may cause failure of vital organs, especially Kidneys. Many a times it is seen to result in amputation of limbs, if it had led to gangrene.⁽⁸⁾

Generally, the outlook of recovery in Hypovolemia depends on the cause, the severity and the duration taken for the treatment to start. ⁽⁹⁾

References:

1. Zink KA, Sambasivan CN, Holcomb JB, Chisholm G, Schreiber MA. Am J Surg. 2009 May. 197(5):565-70; discussion 570. [Medline].
2. Burns B, Gentilello L, Elliot A, Shafi S. 2008 Dec. 65(6):1217-21. [Medline].
3. Dutton RP, Mackenzie CF, Scalea TM. J Trauma. 2002 Jun. 52(6):1141-6. [Medline].
4. Graham CA, Parke TR.  Emerg Med J. 2005 Jan. 22(1):17-21. [Medline].
5. Skagius E, Siegbahn A, Bergqvist D, Henriksson A.  Eur J Vasc Endovasc Surg. 2008 Jan. 35(1):37-40. [Medline].
6. Stern SA.. 2001 Dec. 7(6):422-30. [Medline].
7. http://reference.medscape.com/medline/abstract/17920310
8. http://emedicine.medscape.com/article/760145
9. https://www.doctorshealthpress.com/general-health-articles/hypovolemia/
10. https://www.healthline.com/health/hypovolemic-shock
11. https://en.wikipedia.org/wiki/Hypovolemia
12. http://www.ehealthstar.com/hypovolemia