Sunday, July 24, 2011

Hypovolemic Shock


Hypovolemic shock is a serious condition in which fluid loss prevents the heart from pumping enough blood to the body. This condition can lead to death if untreated. There are other types of shock, a few of which are cardiogenic shock and neurogenic shock. Cardiogenic shock occurs when a weakened heart loses its ability to pump to the body and neurogenic shock occurs when there is a decrease in neural tone, resulting in a heart that has difficulty pumping to the body. Shock as a condition occurs, then, when tissues don’t receive enough oxygen and nutrients which leads to cell death, organ failure, and eventually whole body death (Wedro, 2007, p.3).

Hypovolemic shock is preceded by untreated hypovolemia, which results from “internal fluid shifts or external fluid losses.” Diehl-Oplinger and Kaminski (2004) state that an internal fluid shift occurs when “fluid moves out of the intravascular compartment into another area of the body, such as the interstitial space” (p. 52). Third-spacing occurs when fluid gathers in the extracellular and intracellular compartments as well as another space that doesn’t support circulation. Lastly, an external fluid loss occurs when fluid is lost externally, through occurrences such as bleeding, vomiting, surgery or trauma. Some circumstances that can result in fluid loss, and therefore shock, are vomiting, diarrhea, external bleeding, internal bleeding and burns (Diehl-Oplinger & Kaminski, 2004, p. 52).

When fluid is lost, the heart has trouble pumping blood to the body, which leads to inadequate tissue perfusion (the delivery of nutrients to tissues). The body attempts to compensate for the low blood pressure by increasing the heart rate (Russell, 1994, p. 36). The skin gets pale and clammy due to the decreased perfusion and there is a decrease in urine output, which directly correlates to the decrease of cardiac output (Russell, 1994, p.38). Rapid breathing also shows that the body is trying to maintain the acid-base balance and oxygen supply (Mower-Wade, Bartley & Chiari-Allwein, 2001, p. 23). Furthermore, the confusion and/or unconsciousness is due to the fact that the brain is very sensitive to a decrease in oxygen levels, so these symptoms show that blood is not supplying enough oxygen (Russell, 1994, p. 36). Other symptoms of shock are weakness and a lowered temperature as a result of vasoconstriction. Vasoconstriction occurs when the baroreceptors in the aortic arch respond to the fluid pressure by sending signals to the autonomic regulatory centers in the central nervous system, such as the hypothalamus, causing the vessels to constrict or dilate (Russell, 1994, p. 38).

The stages of hypovolemic shock are classified by what symptoms are present. Stage one is mild and involves anxiety and cool extremities. Stage two is moderate and involves all the symptoms of mild shock, along with increased heart and respiratory rates and decreased urine output. Stage three is severe and includes all the symptoms of moderate shock, plus hypotension and altered mental functioning, from unconsciousness to coma (Diehl- Oplinger & Kaminski, 2004, p. 52).

Diagnosing hypovolemic shock can be done through blood chemistry tests, complete blood count and x-rays (Heller, 2010, p. 2). The most important part of treatment is restoring fluid volume. IVs are given to deliver the necessary nutrients as well as replace the lost fluid (Diehl-Oplinger & Kaminski, 2004, p. 52). Medicines such as dopamine and norepinephrine can be given to increase blood pressure and cardiac output (Heller, 2010, p. 2). Placing blankets on the person to keep them warm and avoid hypothermia is very important. Also, laying the person on their back and elevating their legs improves circulation by helping the blood to return to the heart. If the person is having trouble breathing, turn him on his side.

Shock can be prevented by treating the cause and can be helped with early first aid. The severity of this emergency depends on other pathologies, the stage of shock, and age. Elderly people generally have poorer outcomes. However, immediate medical attention is necessary to save lives.

References

Diehl-Oplinger, L. & Kaminski, M. F. (2004). Choosing the right fluid to counter hypovolemic shock. Nursing 2004, 34(3), 52-54.

Heller, J. L. (2010). Hypovolemic shock. Retrieved from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001220/.

Mower-Wade, D., Bartley, M. K. & Chiari-Allwein, J. L. (2001). How to respond to shock. Dimensions of Critical Care Nursing, 20(2), 22-27.

Russell, S. (1994). Hypovolemic shock. Nursing94, April, 34-39.

Wedro, B. C. (2007). Shock. Retrieved from http://www.emedicinehealth.com/shock/article_em.htm#Shock Overview.

Image: http://www.inmagine.com/paa289/paa289000015-photo

1 comment:

  1. cardivas 3.125 mg is an alpha and beta-blocker. It works by hindering the heart rate and loosening up blood vessels which makes the heart more productive at siphoning blood around the body.

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