Anaesthesia And Pain

Question 1

Pain receptors are

Answer 1

Nociceptors

Question 2

Pain is

Answer 2

Subjective, unpleasant sensory and emotional experience and is a protective mechanism. Memory of pain can help avoid future harmful events

Question 3

Chronic pain

Answer 3

Lasts more than 6 months, exaggerated afferent pain impulses or permanent sensitised dorsal horn or a poor descending pathway

Question 4

Pain reaches the brain by

Answer 4

Stimulus providing detecting by nociceptors, generation of an action potential and receptors reach the spinal cord via the dorsal root which synapses with the dorsal horn and ascends to the brain via thalamus and somatosensory cortex

Question 5

4 phases of GA

Answer 5

Induction - inducing unconsciousness
Maintenance - homeostasis and anaesthesia
Emergence - unconscious - concious
Recovery

Question 6

Analgesia is

Answer 6

Suppression of physiological responses to painful stimuli

Question 7

Anaesthesia is

Answer 7

Administration of meds that block feeling of pain / deep state of unconsciousness. Relieve pain and support physiological functions during a procedure

Question 8

Local anaesthetic

Answer 8

Induces absence of pain locally by injecting around a nerve / trunk to provide anaesthesia in the peripheral nervous system, inhibits excitation conduction process

Question 9

GA strives to achieve 4 A’s

Answer 9

Lack of awareness,
Amnesia,
Analgesia and
Akinesia

Question 10

Pre meds

Answer 10

Benzodiazepines - hypnotics /sedatives to relieve anxiety
Analgesics - morphine/panadol/NSAIDS
Anticholinergics - reduce saliva control/bradycardia/ antiemetic to reduce pop nausea
Antis - reduce wound infection

Question 11

GABA is

Answer 11

An inhibitory neurotransmitter widely distributed in the CNS.
Neuronal activation - GABA released to synapse and acts on post synaptic GABA receptors
Thiopentone - mimics GABA - depresses excitatory neurotransmission

Question 12

Propofol

Answer 12

Acts on specific GABAa receptor to shorten channel opening times at nicotine’s ACh receptors - rapid induction

Question 13

Ketamine

Answer 13

Glutamate receptor antagonist, interacts with Nictotinic ACh receptors and voltage gated CA channels

Question 14

Inhalation agents

Answer 14

Face mask - alveolar capillary membrane- circulation.

Binds to lipid layer of cell membranes to cause small expansion/swelling to distort ion channels - inhibiting excitatory brain and spinal cord activity

Question 15

Volatile agent examples

Answer 15

Desflurane
Isoflurane
Sevoflurane
N20

All are triggers of malignant hyperthermia

Question 16

There is no antidote to

Answer 16

Inhaled agents

Question 17

Pain impulses at nociceptors are transmitted to the CNS via

Answer 17

myelinated delta fibres in response to mechanical and thermal pain
unmyelinated C fibres (slow pathway) in response to chemical, slow burning

Question 18

Neurotransmitters involved with pain are

Answer 18

Substance P - activates ascending pathway to brain
and
Glutamate - neurotransmitter on dorsal horn, causes permeability changes to allow ca entry to dorsal horn = increased excitability.

Opioids receptor inhibits at the afferent pain fibre synapse

Question 19

Descending analgesic pathway

Answer 19

inhibits pain transmission, endogneous opioids are released which inhibit substance p release and block the pain impulses to the brain

Question 20

Opioids found throughout the CNS and perpiheral tissues

Answer 20

inhibit afferent pathway,
activate descending pathway and
inhibit excitation of sensory nerve terminals.

Question 21

Gate control theory of pain

Answer 21

proposes how pain is reduced by activating a nonpainful sensation by the alpha delta smaller sensory nerve, decreasing pain in the dorsal horn. E.g rubbing a painful area

Question 21

Gate control theory of pain

Answer 21

proposes how pain is reduced by activating a nonpainful sensation by the alpha delta smaller sensory nerve, decreasing pain in the dorsal horn. E.g rubbing a painful area

Question 22

Pain management by multimodal approach

Answer 22

Mild pain - Non opioid, paracetomol, NSAID
Mod Pain - Weak opioid & non-opioid
Severe pain - strong opioid

Question 23

Inhalation (volatile) agents used for induction are…

Answer 23

Desflurane, Isoflurane, Sevoflurane,
- act on alveolar-capillary membrane to enter systemic, crosses BBB (lipophillic) to distort ion channels and inhibit excitatory activity in CNS