What is hypovolaemic shock?
• When you lose about 20% of your circulating volume.
What three components determine oxygen delivery?
Blood flow x [Hb] x Oxygen saturation
By which mechanisms can fluid be lost from the body?
• GIT: Diarrhoea, vomitting
• Bleeding: Trauma, surgery
• GUT: High output renal failure, Diabetes
What are the four types of shock?
What is cardiogenic shock?
• Failure of the heart itself.
• Commonly caused by ischaemia, dysrythmias, vascular disease and inflammation of the heart.
What is maldistributive shock?
• This is caused by abnormal dilatation of small arteries, commonly due to sepsis or anaphylaxis.
- The leaking vessels can often lead to hypovolaemia.
What is obstructive shock?
This is when physical blockage of the heart or major vessels occur, the most common cause is a pulmonary embolis.
Shocked patients will have symptoms of organ failure and sympathetic activation, what are these?
• Alterations to conscious level
• Poor peripheral perfusion
• Low urine output
What will happen to blood lactate levels during shock?
• It will rise due to an increase in anaerobic respiration.
What investigations should be performed in order to seperate hypovolaemic shock from other types?
• FBC, U&Es, Glucose, Arterial Blood gases, Lactate, ECG, Chest X-Ray
What is the characteristic picture of Hypovolaemic shock?
Evidence of losses, dry, empty circulation.
What is the characteristic picture of cardiogenic shock?
Chest pain, ECG and rhythm changes, Rising upstream pressure, pulmonary and peripheral oedema.
What is the characteristic picture of maldistributive shock?
Source of sepsis, signs of infection, warm, dilated circulation.
What is the characteristic picture of obstructive shock?
The same as cardiogenic but without the symptoms of MI etc.
What is the treatment of shock?
A - Maintain airway
B - Give oxygen at 15L/min
C - Give 1.5L Hartmanns' or Saline rapidly. (20ml/kg, 10ml/kg in elderly)
D - Reassess conscious level, glucose.
E - Check thoroughly.
What are the 'tennis-score' rules for estimating acute blood loss?
• 0-15% - Thirst only
• 15-30% - Tachycardic
• 30-40% - Hypotension
• 40% - Game over.
What is the normal range for serum Sodium?
What is the normal range for serum levels of Potassium?
3.5 - 5.1 mmol/L
What is the normal serum levels of creatinine?
44 - 80 umol/L
What is the normal serum level of urea?
1.8 - 6.3 mmol/L
In a 70kg man how are the water compartments composed?
• 60% total bodyweight.
• 67% of that is intracellular
• 30% is extracellular
• 3% is vascular
Sympathetic stimulation, hypotension, and decreased sodium delivery cause the kidneys to release what?
Renin is a part of the Angiotensin system. Where is it released from? What does it do?
It is released from granular cells of the juxtaglomerular apparatus in the kidney, in response to hypotension, low sodium levels or sympathetic stimulation.
It converts angiotensinogen into angiotensin I.
Where is angiotensin I converted into angiontensin II and what is the enzyme responsible?
In the lungs, angiotensin converting enzyme ACE.
Angiotensin stimulates 6 mechanisms. What are they?
1) Cardiac and Vascular hypertrophy.
2) Systemic vasoconstriction.
3) Increased blood volume. (Through thirst)
4) Acts on the kidney to increase sodium and water retention.
5) Acts on the pituitary gland to stimulate the release of ADH.
6) Acts on the Adrenal cortex to release aldosterone.
When Urea and creatinine are raised, what does it indicate?
Dehydration or renal failure.