General anaesthesia

Premedication

Sedation and anxiolysis

Use one of the following:

Diazepam (IV)

• 0.05–0.1 mg/kg.

OR

Diazepam (PO)

• 0.5–0.75 mg/kg.

OR

Lorazepam

• IM: 0.05 mg/kg.

• IV: 0.04 mg/kg.

OR

Midazolam (IV)

• 0.05–0.1 mg/kg.

Benzodiazepine overdose

Antidote

Flumazenil (IV)

• Initial dose: 0.2 mg over 30 seconds.

• Repeat 0.2 mg every 1 minute until the desired level of consciousness is achieved.

• Do not exceed 4 doses (total 1 mg).

Management of muscarinic side effects

For bradycardia, excessive salivation, or other muscarinic adverse effects, administer one of the following:

Atropine (IV)

• 0.01 mg/kg.

OR

Glycopyrrolate (IV)

• 0.2–0.4 mg (0.2 mg for every 1 mg of neostigmine).

Alternative dosing

• 10–15 micrograms/kg (0.01–0.015 mg/kg) IV together with neostigmine 50 micrograms/kg (0.05 mg/kg) or an equivalent dose of pyridostigmine.

Prevention of postoperative nausea and vomiting (PONV)

Administer one of the following:

Dexamethasone sodium phosphate (IV)

• 4–5 mg.

OR

Metoclopramide (IV)

• 10 mg.

OR

Ondansetron (IV)

• 4 mg administered over 2–5 minutes.

Aspiration prophylaxis

Antacids are recommended for patients at increased risk of aspiration, such as pregnant women undergoing Caesarean section.

Use one of the following:

Sodium citrate (PO)

• 0.3 mol/L, 30 mL.

• Administer no more than 30 minutes before induction of anaesthesia.

OR

Pantoprazole (IV)

• 40 mg.

• Administer as soon as the need for emergency surgery is recognized.

General anaesthetic agents

General anaesthetic agents may be used for induction as bolus doses or for maintenance as continuous infusions during total intravenous anaesthesia (TIVA).

Ketamine

Ketamine (IV)

• 1–2 mg/kg.

Used for induction and may also be used for maintenance during TIVA.

Contraindication: Avoid in patients in whom a significant increase in blood pressure (BP), intraocular pressure (IOP), or intracranial pressure (ICP) would constitute a serious hazard.

Thiopental

Thiopental (IV)

• 3–5 mg/kg.

Used for induction and may also be used for maintenance during TIVA.

Propofol

Propofol (IV)

• Induction: 1.5–2.5 mg/kg.

• Maintenance during TIVA: 6–12 mg/kg/hour infusion.

Contraindication: Avoid in patients at risk of hypotension. Use a volatile anaesthetic agent for maintenance instead.

Etomidate

Etomidate (IV)

• 0.3 mg/kg (range 0.2–0.6 mg/kg).

Suitable for induction because of cardiovascular stability.

Note: Etomidate suppresses cortisol production.

Inhalational anaesthetic agents

Halothane

• Induction: 2–4% in air, oxygen, or oxygen/nitrous oxide.

• Maintenance: 0.5–1.5%.

Nitrous oxide is delivered in a 70:30 ratio with oxygen to reduce the requirement for more potent anaesthetic agents.

Isoflurane

• 1.2–2.5%.

Titrate according to the desired clinical effect.

Sevoflurane

• Induction: 5–7%.

• Maintenance: 0.5–3%, with or without concomitant nitrous oxide.

Muscle relaxants

Suxamethonium

Suxamethonium (IV)

• 1–1.5 mg/kg for induction.

Pancuronium

Pancuronium (IV)

• 0.04–0.1 mg/kg for maintenance.

Atracurium

Atracurium (IV)

• Initial dose: 0.4–0.5 mg/kg administered over 60 seconds.

• Maintenance: 0.08–0.1 mg/kg administered 20–45 minutes after the initial dose.

Alternative

• Continuous infusion: 0.05–0.1 mg/kg/minute.

Preferred in patients with renal impairment.

Rocuronium

Rocuronium (IV)

• 0.6–1 mg/kg.

May be used for induction when sugammadex is available for reversal.

Advantages:

• Minimal adverse effects.

• Suitable when suxamethonium is contraindicated.

Contraindications to suxamethonium

Do not use suxamethonium in patients at risk of hyperkalaemia, including those with:

• Upper motor neuron lesions

• Lower motor neuron lesions

• Prolonged chemical denervation

• Direct muscle trauma

• Muscle tumour or inflammation

• Thermal injury (burns)

• Disuse atrophy

• Severe infection

Reversal of neuromuscular blockade

Use one of the following:

Neostigmine

Neostigmine (IV)

• 50 micrograms/kg.

Administer together with:

Atropine (IV)

• 20 micrograms/kg.

• Maximum dose: 1.2 mg.

Glycopyrrolate

Glycopyrrolate (IV)

• 10 micrograms/kg.

Sugammadex

Sugammadex (IV)

• 2–4 mg/kg.

Perioperative pain management

Non-opioid analgesic

Paracetamol (IV)

• 15 mg/kg every 8 hours.

Opioid analgesics

Use one of the following:

Tramadol

Tramadol (IM or IV)

• 50 mg every 6 hours.

Morphine

Morphine (IV or IM)

• Initial dose: 3–5 mg.

• Additional boluses: 1–2 mg/minute as required.

Maximum total dose:

• 0.1–0.2 mg/kg.

Monitor vital signs closely.

Pethidine

Pethidine (IV or IM)

• 1–2 mg/kg.

May be used for analgesia during anaesthesia and during labour.

Fentanyl

Fentanyl (IV)

• 1–2 micrograms/kg.

Opioid antagonist

Opioid overdose

Naloxone (IV)

• 0.4–2 mg.

Alternatively, naloxone may be administered:

• Intramuscularly (IM)

• Subcutaneously (SC)

Reversal of opioid-induced sedation

Naloxone (IV)

• Initial dose: 0.1–0.2 mg.

• Repeat every 2–3 minutes until the desired degree of reversal is achieved.