Hypovolemic Shock

Question 1

How the renal system responds to shock

Answer 1

Stimulates an increase in renin secretions
Renin converts angiotensinogen to angiotensin I which converts in angiotensin II by the lungs and liver.
Angiotensin ii- helps reverse haemorrhagic shock by vasoconstriction of arteriolar smooth muscle and stimulation of aldosterone.
Aldosterone is responsible for active sodium reabsorption into the blood and water conservation.
Causing a drop in urine output and increased blood volume.

Question 2

How the neurone doctrine stream responds to shock

Answer 2

Causes an increase in circulation anti-diuretic hormone (ADH)
It is released from the posterior pituitary gland in response to the drop in BP.
ADH leads to an increased reabsorption of water and salt by the distal tubule, the collecting ducts and the loop of Henle.

Question 3

Causes of hypovolemic shock

Answer 3

External or internal haemorrhage (Blood)Haemorrhagic shock often occurs after trauma, gastro-intestinal bleeding, rupture of organs or aneurysms.g
Severe burns (Plasma)
Vomiting and Diarrhoea (Water & electrolytes)
Massive urine output ( Diabetic Ketoasidosis)
Sweating

Question 4

Symptoms of hypovolemic shock

Answer 4

Tachycardia 
Hypotension
Poor capillary refill
Oliguria 
Tachypnoea
Cool clammy skin
Abdominal pain
Dizziness
Changes in levels of consciousness

Question 5

Treatment of hypovolemic shock

Answer 5

Stop the blood- Manual pressure if external. Suspected internal haemorrhage;
Fluid Challenge- 500mls id fluid bolus to attempt to improve perfusion/ blood volume. (Crystalloid Solution (Salt solutions) tried first for adequate electrolyte and fluid balance), (Some use IV colloids (Solution containing dextran’s sugars and proteins) If BP doesn’t increase then surgery may be needed for haemorrhage repair.
Blood transfusion- To increase blood volume and red blood cells (Contain haemoglobin which permits the transportation of oxygen)
Venous action- Central venous line (A catheter tube that is passed through a vein to end up in the thoracic portion of the vena cava which is the large vein returning blood to the heart). Can prevent odeama over transfusions.
Or a Pulmonary artery catheter (allows direct, simultaneous measurement of pressures in the right atrium, right ventricle, pulmonary artery, and the filling pressure (“wedge” pressure) of the left atrium).
Burns- Use Clingfilm to keep moisture, allows cooling and warming as it is not an insulation barrier. Also avoids progression of full thickness.
Inotropes drugs- Dopamine- a neurotransmitter increases myocardial contractility & HR which enhances cardiac output and can cause vasoconstriction which causes BP to increase. Dobutamine- Increases cardiac output
ECG-Treat arrhythmias. ( Irregular heart rhythm)
02- Increase/ Improve perfusion.
Lactate levels- Show hypoperfusion
Pain Relief- Can increase metabolic rate and hypoperfusion
Vomiting & diarrhoea - Administer anti-emetics/ antidiarrheal

Question 6

Pathology of hypovolemic shock

Answer 6

Indequate perfusion of blood to the body’s cells/ tissues which results in multiple-organ failure-death.

Hypovolemic shock occurs from decreased intravascular fluid volume resulting from either internal fluid shifts or external fluid loss.

Loss of fluid due to interstitial fluid loss (fluid that surrounds the cells of the body) causes the fluid from the blood to replace the empty cellular space.

This fluid can be; while blood, plasma, water and electrolytes.

This results in a drop of blood volume, low venous return (The volume of blood flowing back to the heart) the body’s initial response is to increase the HR thus the hearts contractility and constrict peripheral vessels.

The baroreceptor (A receptor sensitive to changes in pressure) detects the low BP so is stimulated to improve cardiac output & maintain BP
The renal system is stimulated and angiotensin is created which causes constriction of arterial smooth muscle and stimulates alderstone which causes sodium reabsorption and fluid retention. Also in response to low BP ADH ( anti diuretic hormone is released)  causing the reabsorption of salt and water

Epinephrine (Adrenaline) is released , it causes vasoconstriction (Decreased blood vessels diameter) which increases peripheral vascular resistance (PVR) and decreases systemic vascular resistance (SVR) blood to the vital organs