Week 107 - Hypovolaemia

Question 1

What is hypovolaemic shock?

Answer 1

• When you lose about 20% of your circulating volume.

Question 2

What three components determine oxygen delivery?

Answer 2

Blood flow x [Hb] x Oxygen saturation

Question 3

By which mechanisms can fluid be lost from the body?

Answer 3

• GIT: Diarrhoea, vomitting
• Bleeding: Trauma, surgery
• Burns
• GUT: High output renal failure, Diabetes

Question 4

What are the four types of shock?

Answer 4

1) Hyovolaemic
2) Cardiogenic
3) Maldistributive
4) Obstructive

Question 5

What is cardiogenic shock?

Answer 5

• Failure of the heart itself.
• Commonly caused by ischaemia, dysrythmias, vascular disease and inflammation of the heart.

Question 6

What is maldistributive shock?

Answer 6

• This is caused by abnormal dilatation of small arteries, commonly due to sepsis or anaphylaxis.
- The leaking vessels can often lead to hypovolaemia.

Question 7

What is obstructive shock?

Answer 7

This is when physical blockage of the heart or major vessels occur, the most common cause is a pulmonary embolis.

Question 8

Shocked patients will have symptoms of organ failure and sympathetic activation, what are these?

Answer 8

• Tachycardia
• Tachypnoea
• Hypotension
• Collapse
• Alterations to conscious level
• Poor peripheral perfusion
• Low urine output

Question 9

What will happen to blood lactate levels during shock?

Answer 9

• It will rise due to an increase in anaerobic respiration.

Question 10

What investigations should be performed in order to seperate hypovolaemic shock from other types?

Answer 10

• FBC, U&Es, Glucose, Arterial Blood gases, Lactate, ECG, Chest X-Ray

Question 11

What is the characteristic picture of Hypovolaemic shock?

Answer 11

Evidence of losses, dry, empty circulation.

Question 12

What is the characteristic picture of cardiogenic shock?

Answer 12

Chest pain, ECG and rhythm changes, Rising upstream pressure, pulmonary and peripheral oedema.

Question 13

What is the characteristic picture of maldistributive shock?

Answer 13

Source of sepsis, signs of infection, warm, dilated circulation.

Question 14

What is the characteristic picture of obstructive shock?

Answer 14

The same as cardiogenic but without the symptoms of MI etc.

Question 15

What is the treatment of shock?

Answer 15

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.

Question 16

What are the ‘tennis-score’ rules for estimating acute blood loss?

Answer 16

• 0-15% - Thirst only
• 15-30% - Tachycardic
• 30-40% - Hypotension
• 40% - Game over.

Question 17

What is the normal range for serum Sodium?

Answer 17

134-143mmol/L

Question 18

What is the normal range for serum levels of Potassium?

Answer 18

3.5 - 5.1 mmol/L

Question 19

What is the normal serum levels of creatinine?

Answer 19

44 - 80 umol/L

Question 20

What is the normal serum level of urea?

Answer 20

1.8 - 6.3 mmol/L

Question 21

In a 70kg man how are the water compartments composed?

Answer 21

• 60% total bodyweight.

• 67% of that is intracellular
• 30% is extracellular
• 3% is vascular

Question 22

Sympathetic stimulation, hypotension, and decreased sodium delivery cause the kidneys to release what?

Answer 22

Renin.

Question 23

Renin is a part of the Angiotensin system. Where is it released from? What does it do?

Answer 23

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.

Question 24

Where is angiotensin I converted into angiontensin II and what is the enzyme responsible?

Answer 24

In the lungs, angiotensin converting enzyme ACE.

Question 25

Angiotensin stimulates 6 mechanisms. What are they?

Answer 25

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.

Question 26

When Urea and creatinine are raised, what does it indicate?

Answer 26

Dehydration or renal failure.