Anaesthetic Agents

Question 1

Nitrous oxide
MAC 1.02 - analgesia + amnesic properties

Answer 1

C/I
- Pregnancy
- Gastric insufflation: bowel obstruction, Pneumothorax, gastric distension
- Severe COPD
- Reduced GCS/ Intoxicated

Side fx:
- Dysphoria
- Vomitting
- Apnoea

Question 2

Local Anaesthetic Agents

Answer 2

Lignocaine
- dose: 5mg/kg (plain), 7mg/kg (adrenaline)
- 1% = 1g/100mls (10mg/ml)
- DOA - 40mins

Bupivacaine
- dose: 2mg/kg (plain), 3mg/kg (adrenaline)

Prilocaine
- dose: 6mg/kg (plain), 8mg/kg (adrenaline), 3mg/kg (Biers block)

Ropivacaine
- dose: 3mg/kg

Question 3

Local Anaesthetic Toxicity
C/F

Answer 3

Generalised (early) - perioral tingling, muscle twitching, tinnitus, nystagmus, dizziness
CNS - Seizures, Coma
CVS - Arrythmias (Prolong PR, QRS, VT), Hypotension

Question 4

Local Anaesthetic Toxicity - Rx

Answer 4

Cease infusion
A - ETT
B - Hyperventilate, FiO2 1.0 - avoid acidosis
C - CPR,IV fluids, Inotropes, Defibrillate
D - Benzo - seizures
Rx: Intralipid 20%: 1.5mg/kg IV Q5minly max 12ml/kg. IVI 0.25ml/kg/min
IV NaHCO3 8.4% 1-2mmol/kg
Others: Methylene blue 1mg/kg IV over 10mins

Question 5

Paeds Acute Pain Management

Answer 5

< 8 y.o = Barker faces
> 8 y.o = 1-10 score
Sucrose = up to 4-6 m.o peak effect 2 mins, DOA 5-10mins
Morphine = 0.1mg/kg IV
Fentanyl = 1.5mcg/kg IN, 0.5-2mcg/kg IV

Question 6

Ketamine
- NMDA receptor antagonist
- mu, kappa, delta receptors

Answer 6

Dose:
IM 4mg/kg
IV - analgesic: 0.1 -0.3mg/kg
- sedation: 1mg/kg
- induction: 2mg/kg
Onset
IM: 2-4 mins
IV: 60-90s
Duration
IM: 15-30 mins
IV: 10-15mins

Question 7

Ketamine: Indications, C/I

Answer 7

Indications:
- Induction
- asthma (severe)
- hypotension
- procedural sedation
- analgesia
- refractory status epilepticus

C/I:
< 3m.o
True allergy

Relative C/I
- Current resp illness
- known difficult airway
- Raised IOP - glaucoma
- CVS disease - elevated HR & CO c/i

Question 8

Ketamine
- Adv fx

Answer 8

Emergence phenomenon
Laryngospasm
Vomitting
Bronchorrhoea/salivation

Question 9

Propofol

Answer 9

Dose: 1-2mg/kg IBW (Induction)
0.5-1mg/kg IBW (sedation)
Onset: 15-45s, Duration: 5-10mins
Pro’s: Rapid onset + offset, antiemmetic
Cons: Hypotension, Resp depression, no analgesic effect

Question 10

Fentanyl

Answer 10

Dose: 2-10mcg/kg (TBW) IV
Onset: <60s
Pros: HD unstable patient - cardiogenic shock, HF
Cons: Resp depression, apnoea

Question 11

Midazolam

Answer 11

Dose: 0.3mg/kg IV (TBW)
Onset: 60-90s
Duration: 15-30mins
Pro: anxiolytic, amnesic, antiepileptic, minimal hemodynamic fx
Cons: Resp depression, apnoea, hypotension

Question 12

Paeds Induction Agents & Antiepileptic

Answer 12

Newborn:
Sux: 2-3mg/kg
Fentanyl: 10-20mcg/kg
Morphine: 0.1mg/kg
Atropine: 10-20mcg/kg
Midazolam: 0.1mg/kg
Levetiracetam: 40mg/kg
Phenobarbitone: 20mg/kg

Question 13

Suxamethonium
- Depolarising NMB

Answer 13

Dose: 1-2mg (TBW)
Rapid onset 45s
DoA: 5-10 mins
C/I: Hyperkalaemia, burns, Muscular dystrophy, crush injuries, GBS, Rhabdo
Adv fx:
Cardiac: arrythmia
Hyperkalaemia
Raised IOP, Raised ICP
Post op myalgia

Question 14

Rocuronium
- NON Depolarising NMB

Answer 14

Dose: 1-2mg/kg
Onset: 45-60s
DoA: 60mins
C/I: Hypersensitivity
Reversal : Sugammadex 16mg/kg IV