Week 6

Question 1

What is shock?

Answer 1

The situation where there is insufficient blood supply to the tissues, to meet their demands

Question 2

Adequate perfusion of tissues depends on… (4 requirements)

Answer 2

1. The pumping ability of the heart to maintain tissue perfusion
2. Sufficient blood to fill the circulation
3. A vascular system that moves blood around the body and back to the heart
4. Tissues that are able to extract and use nutrients

Question 3

What are the 4 main classes of shock?

Answer 3

Cardiogenic
Hypovolaemic
Obstructive
Distributive

Question 4

What is cardiogenic shock?

Caused by?

Answer 4

The heart is unable to maintain an adequate blood pressure.
Due to:
1. Failure of the heart as a pump (myocardial damage or deterioration)
2. Severe alterations in rhythm
3. Mechanical defect (i.e. valve damage)

Question 5

What is hypovolaemic shock?

Caused by?

Answer 5

Decrease in circulatory volume
Due to:
1. Diminished blood volume
2. Loss of whole blood
3. Loss of plasma
4. Loss of extracellular fluid

Question 6

What is obstructive shock?

Caused by?

Answer 6

Inability of the heart to fill adequately or obstruction to outflow from the heart
Due to:
-Valve damage
-Aortic stenosis

Question 7

What is distributive shock?

Answer 7

Loss of sympathetic vasomotor tone. Cause = damage to the CVS centre in the medulla or damage to the sympathetic outflow
Present of vasodilator substances in the blood e.g. histamine
Shunting of vascular fluid to interstitial spaces
Arterio-venous shunting
Failure of the cells to use oxygen (e.g. poison)

Question 8

What is CK (CPK)?
What is LDH?
What are they markers for?

Answer 8

CK: A creatine kinase (CK) test may be used to detect inflammation of muscles (myositis) or muscle damage due to muscle disorders (myopathies)
LDH: Lactate dehydrogenase detects tissue/cellular damage

Question 9

What does the decreased elasticity of her skin signify?

Answer 9

Hypovolaemic shock due to decreased blood volume

Question 10

Clearly differentiate the terms hypoxia and hypoxaemia?

Answer 10

Hypoxaemia: Condition where arterial oxygen tension or PaO2 is low
Hypoxia: Reduction of oxygen supply at the tissue level

Question 11

Which is the most sensitive organ to the effects of hypoxia? How might this present?

Answer 11

The brain is the most sensitive organ to the adverse effects of hypoxia. First symptom is brain malfunction with brain injury being the main long term complication. Presents as altered consciousness

Question 12

What are the “five vital signs?”

Answer 12

1. Oxygen saturation
2. Pulse
3. Blood pressure
4. Temperature
5. Respiratory rate

Question 13

Which two clinical conditions does the Guideline suggest oxygen therapy is indicated
for despite the absence of low oxygen saturation? Explain why.

Answer 13

1. Carbon monoxide poisoning: CO binds more avidly than oxygen to the haemoglobin molecule so doesn’t present as low oxygen saturation
2. All patients with shock, major trauma, sepsis:

Question 14

In addition to the patient’s identity, date and signature of the clinician what 3 other
details should be clearly outlined in all prescriptions for oxygen?

Answer 14

Starting dose, initial mode of delivery, continuous/as required