Anaesthetics

Question 1

Difference of Local and General anaesthesia

Answer 1

General: agents used are designed to make pt unaware and unresponsive to painful stimuli during surgical procedures. Acts on CNS

Local: agents used are designed to block communication in the PNS preventing transmission of pain impulses to the CNS. Acts on PNS

Question 2

Inhaled anaesthetics

Answer 2

Nitrous oxide

Fluorinated hydrocarbons

Question 3

Pharmacodynamics of Nitrous oxide on low and high doses

Answer 3

Low doses:
Opioid and GABA agonist causing analgesic, sedation and euphoria

High doses:
NMDA antagonist by preventing glutamate release

Question 4

Fluorinated hydrocarbons

Answer 4

desflurane
isoflurane
sevoflurane

• generalised muscle relaxants

Question 5

Adverse effects of fluorinated hydrocarbons

Answer 5

Malignant hyperthermia
hyperkalemia
rhabdomyolysis

Question 6

General anaesthesia causes:

Answer 6

Analgesia
Unconsciousness
Amnesia
Paralysis and areflexia (loss of autonomic and somatic reflexes)

Question 7

Most used IV anaesthetics

Answer 7

Propofol

Question 8

Adverse effects of Propofol

Answer 8

Hypotension
Tachycardia
Euphoria

Question 9

Pharmacodynamics of Ketamine

Answer 9

IV route

NMDA - receptor antagonists preventing glutamate release
causes amnesia, psychosensory and analgesia

Question 10

Adverse effects of Ketamine

Answer 10

Psychotic effects: hallucinations
HTN
tachycardia
nausea
sedation

Question 11

Pharmacodynamics of local anaesthetics

Answer 11

inhibits sodium ions movement

Question 12

Local anaesthetics adverse effects

Answer 12

Affects hear conduction (risk of asystole) 
Vasodilation
restlessness
Hypersensitivity (monitor)
Acidic pH

Question 13

Local anaesthetics

Answer 13

Lidocaine

Mepivacaine

Benzocaine

Prilocaine

Bupivacaine

Question 14

Pharmacodynamics of Lidocaine

Answer 14

attach to voltage-gated sodium channels preventing influx of sodium ions and hold membrane in depolarised state thereby, inhibits action potentials thus, no pain signals are relayed to the brain

Question 15

Why use adrenaline with local anaesthetics?

Answer 15

Generally: delay absorption of local anaesthetic agents by constricting blood vessels and prolong and enhance the anaesthetic effects

Non-selective agonist of adrenergic receptors causing vasoconstriction
Increase peripheral resistance and reduce peripheral circulation
- less likely to distribute anaesthetic to heart
-bloodless field
-increases duration of efficacy

Question 16

Nursing considerations of using local anaesthetics such as lidocaine with adrenaline

Answer 16

DO NOT use it for pt with severe HTN and poor peripheral circulation conditions such as diabetes and frost bite
USE in low concentration - total adrenaline dose should not exceed 500 mcg