Anaesthesiology - Crisis Management

Question 1

LA toxicity

• S/S

Answer 1

Neurological symptoms and signs
- Light headedness, dizziness, drowsiness.
- Tingling around lips/ fingers,
- Metallic taste, tinnitus, blurred vision.
- Confusion, restlessness, incoherent speech
- Tremors, convulsions
- Loss of consciousness
- Coma

Cardiovascular symptoms and signs
- Bradycardia, hypotension, cardiovascular collapse, and respiratory arrest.
- ECG changes (prolongation of QRS and PR interval, AV block, and/or changes in T wave amplitude).

Question 2

LA toxicity management

Answer 2

• Discontinue LA injection
• Call for help, activate medical emergency team
• Airway, Breathing – 100% O2, Intubate and ventilate if required
• Circulation: Vasopressor for hypotension - ephedrine, phenylephrine, noradrenaline, or adrenaline
• Disability: BDZ for convulsions -IV midazolam (3-10mg), diazepam (5-15mg), lorazepam (0.1mg/kg) or thiopental (50-150mg)
• Lipid emulsion therapy/ Intralipid therapy
• Hyperventilation (increasing pH in the presence of metabolic acidosis)

Question 3

LA toxicity

Risk factors

Answer 3

• Large volumes / high concentrations of local anaesthetics.
• Location of local anaesthetic injection (e.g. lumbar plexus / intercostal block higher risk.)
• Failure to aspirate before and during injection
• Use of agent with narrow therapeutic window, e.g. bupivacaine vs.
  levobupivicaine.

Question 3

Ddx LA toxicity

Answer 3

Fainting/ vasovagal syncope
Anaphylaxis/ Allergic reaction to any injected agent
Epilepsy
Anxiety disorder/ attack
Cardiogenic/ Neurocardiogenic syncope

Question 4

LA toxicity

Maximum doses for LA drugs

Answer 4

Question 5

Anaphylaxis

S/S

Answer 5

Most common presentation:
-Cardiovascular collapse (88%)
-erythema (48%), bronchospasm (40%)
-angioedema (24%)
-cutaneous rash (13%)
-urticaria (8%).

Question 6

Anaphylaxis management

Answer 6

General:
- Stop any likely trigger agents eg IV colloids, latex, and chlorhexidine.
- Call for help and note time

Airway, Breathing: 100% O2, Ventilate and intubate (RSI)
Circulation: Elevate legs, lower head position, fluid resuscitation

Drug therapy:
- Inject adrenaline: 50 μg IV, 0.5mg IM
- Antihistamines: chlorphenamine 10-20mg slowly IV or IM
- Steroids: hydrocortisone 200mg slowly IV or IM
- Bronchodilators: salbutamol 2.5-5.0mg nebulized or 0.25mg IV
- Vasopressors

Ix:
Serum tryptase to test for mast cell degranulation: ASAP, repeat 1-2h and 24h after reaction

Question 7

Respiratory failure

definition
management
management for persistent hypoxia
Ix

Answer 7

Definition:
* Type1 (hypoxaemic): PaO2 <8 kPa. Normal or decreased PaO2.
* Type2 (hypercapnic): PaO2<8 kPa. PaO2>6.7 kPa.

Management:
- Clear airway, basic airway maneuvers, simple airway adjuncts, advanced airway options
- Ventilation: BVM, 100% O2

Persistent hypoxia:
- Re-expand by recruitment manoeuvres,
suction, and PEEP.
- Check intraoperative drug administration (muscle relaxant, opioid, sedative, volatile use).
- Opioid overdose: consider naloxone (400 µg) IV
- benzodiazepine overdose: flumazenil 0.2-1mg IV
- muscle relaxants: reversal agent (neostigmine/atropine, sugammadex)

Ix:
- pulse oximeter, non-invasive BP, ECG
- ABG
- CXR
- Lung POCUS
- Peripheral nerve stimulation