Physiology of anaesthesia

Question 1

what is the definition of anaesthesia?

Answer 1

the state of controlled, temporary loss of sensation or awareness that is induced for medical purposes

Question 2

what is sedation?

Answer 2

the act of calming by administration of a sedative

Question 3

what could trigger cardiac arrhythmias?

Answer 3

catecholamines
- adrenaline and noradrengaline

Question 4

how is general anaesthesia achieved?

Answer 4

• injectable
• gaseous and injectable combo

Question 5

what are the levels of anaesthesia?

Answer 5

• stage 1 - voluntary excitement
• stage 2 - involuntary excitement
• stage 3 - surgical anaesthesia
• stage 4 - excessively deep - intervention required

Question 6

what are the three planes of stage 3?

Answer 6

• plane 1 - light - minor examinations
• plane 2 - medium - suitable for most surgery
• plane 3 - deep - usually unneccessary

Question 7

what is the triad of anaesthesia?

Answer 7

• narcosis - sleep
• analgesia - pain relief
• relaxation of muscles

Question 8

what is dead space?

Answer 8

any part of the respiratory tract in which no gaseous exchange takes place

Question 9

what is anatomical dead space?

Answer 9

parts of the airways where no gaseous exchange takes place

Question 10

what is physiological dead space?

Answer 10

parts of the airways that normally would contribute to gaseous exchanges but are unable to due to pathology
- pulmonary oedema
- blood in airways
- intra-bronchial intubation

Question 11

what is equipment/mechanical dead space?

Answer 11

the contribution of the anaesthetic equipment to the dead space

Question 12

what does anatomical dead space include?

Answer 12

• nasal passages
• pharynx
• larynx
• trachea
• bronchi
• bronchioles
• may include alveolar

Question 13

what is tidal volume?

Answer 13

the volume of air that goes in and out with each breath

Question 14

what is the tidal volume of a patient less than 10kg?

Answer 14

15ml/kg

Question 15

what is the tidal volume of a patient more than 10kg?

Answer 15

10ml/kg

Question 16

what is minute volume?

Answer 16

the volume of air exchanged each minute

Question 17

what is anoxia?

Answer 17

absence of oxygen in the tissues

Question 18

what is hypoxia?

Answer 18

reduced levels of oxygen in the tissues

Question 19

what is hypoxaemia?

Answer 19

deficient oxygenation of the blood

Question 20

what is apnoea?

Answer 20

cessation of breathing

Question 21

what is hypercapnia?

Answer 21

high co2

Question 22

what is hypoventilation?

Answer 22

decrease in rate/depth of ventilation

Question 23

what is the trachea held open by?

Answer 23

rings of cartilage

Question 24

what is acidosis?

Answer 24

when the body fluids contain too much acid

Question 25

what are the pHs for acidic, neutral and alkaline?

Answer 25

under 7 - acidic 7 - neutral over 7 - alkaline

Question 26

what pH should the body be?

Answer 26

7.35-7.45

Question 27

what does more hydrogen ions mean?

Answer 27

lower pH = acidic

Question 28

what does less hydrogen ions mean?

Answer 28

higher pH = alkaline

Question 29

how does the body maintain acid-base balance?

Answer 29

- respiration

Question 30

what controls respiration?

Answer 30

medulla oblongata

Question 31

what does the medulla oblongata control?

Answer 31

- blood pressure - heart rate - body temperature - respiration

Question 32

Rate and depth will increase because of :

Answer 32

- fall in blood oxygen - increase in demand for oxygen - decrease in blood carbon dioxide - increase in blood pH

Question 33

effects of anaesthesia on the respiratory system:

Answer 33

- reduced bodies response to co2 - effects tidal volume - effects RR

Question 34

what is heart rate controlled by?

Answer 34

the autonomic nervous system

Question 35

what is part of the parasympathetic nervous system and decreases hr?

Answer 35

vagus nerve

Question 36

what is blood pressure?

Answer 36

the product of cardiac output and peripheral resistance

Question 37

what does cardiac output depend on?

Answer 37

- heart rate - stroke volume (amount of blood heart pumps out on each beat)

Question 38

what is systolic blood pressure?

Answer 38

maximum pressure in the artery as the heart contracts

Question 39

what is a diastolic blood pressure?

Answer 39

lowest pressure in the artery when the heart is between contractions

Question 40

what is blood pressure monitored by?

Answer 40

baroreceptors

Question 41

what is the blood brain barrier?

Answer 41

a network of blood vessels and tissue that is made up of closely spaced cells and helps keep harmful substances from reaching the brain

Question 42

true or false: all inhalant gases reduce total liver blood flow

Answer 42

true

Question 43

what parts of the renal system does inhalant anaesthetics affect?

Answer 43

- renal blood flow - glomerular filtration rate