applied science of sedation

Question 1

What is used in quiet breathing?

Answer 1

The diaphragm

Question 2

What is used for more forceful breathing?

Answer 2

Intercostal and accessory muscles

Question 3

What is tidal volume?

Answer 3

The amount of air that moves in or out of the lungs with each breath
450ml for an average person

Question 4

What is alveolar ventilation?

Answer 4

The amount of fresh air entering the alveoli in each breath
300ml in the average person

Question 5

How does gas move across alveolar walls and what determines the rate at which this happens?

Answer 5

Diffusion
Determined by partial pressure gradients

Question 6

What are the different ways in which oxygen is transported?

Answer 6

Attached to haemoglobin (97%)
Dissolved in plasma (3%)
With increased inspired PO2

Question 7

How is carbon dioxide transported?

Answer 7

Through erythrocytes
Through plasma

Question 8

What is carbon dioxide transported as?

Answer 8

Dissolved carbon dioxide (10%)
Combined to carbohydrates (20%)
Bicarbonate ions (70%)

Question 9

What different receptors control breathing?

Answer 9

Cerebral cortex
Central chemoreceptors
Joint and muscle receptors
Lung stretch receptors
Peripheral arterial chemoreceptors

Question 10

What is hypoxia?

Answer 10

A reduced supply of oxygen

Question 11

What are the different types of hypoxia?

Answer 11

Anaemia hypoxia
Stagnant (ischaemic) hypoxia
Cytotoxic hypoxia

Question 12

What is anaemia hypoxia?

Answer 12

When the oxygen carrying ability of the blood decreases

Question 13

What is stagnant (ischaemic) hypoxia?

Answer 13

Abnormally low blood flow to the lung

Question 14

What is cytotoxic hypoxia?

Answer 14

When the cells can’t use their oxygen properly

Question 15

What is cyanosis?

Answer 15

Blue colouration of the skin and mucous membranes due to a high level of de-oxygenated haemoglobin
2 forms - central and peripheral

Question 16

Describe central cyanosis

Answer 16

Affects the whole body and is evident in oral tissues
Generally due to decreased oxygen delivery to blood

Question 17

Describe peripheral cyanosis

Answer 17

Due to decreased oxygen delivery to a localised and peripheral part. Of the body
Often due to reduced blood flow to tissues (stagnant hypoxia)

Question 18

What do the P, QRS and T waves each stand for in an ECG?

Answer 18

P - atrial depolarisation
QRS - ventricular depolarisation
T - ventricular repolarisation

Question 19

When is coronary blood flow the greatest?

Answer 19

During ventricular diastole

Question 20

How is blood pressure (BP) calculated?

Answer 20

Cardiac output x total peripheral resistance
COxTPR

Question 21

How is cardiac output calculated?

Answer 21

Heart rate x stroke volume
HRxSV

Question 22

Name 2 arterial pulses

Answer 22

Any from:
- external carotid artery
- facial artery
- superficial temporal artery
- radial artery

Question 23

Name a venous pulse

Answer 23

Jugular venous pulse

Question 24

What is total peripheral resistance?

Answer 24

The combined resistance of all the systemic blood vessels

Question 25

Give 4 advantages of the dorsum of the hand for a cannulation site

Answer 25

Access
No nearby arteries
No nearby nerves
No joints

Question 26

Give 4 disadvantages of the dorsum of the hand as a cannulation site

Answer 26

Small veins
Susceptibility to cold/anxiety
Mobile veins
More painful

Question 27

Give 3 advantages of the antecubital fossa as a cannulation site

Answer 27

Big, well tethered veins
Less painful
Less venoconstriction

Question 28

Give 4 disadvantages of the antecubital fossa as a cannulation site

Answer 28

Access
Potential nerve damage
Potential intra-arterial injection
Joint immobilisation