Anaesthesia + peri-op care

Airway manoeuvres

• head tilt/chin lift

• Jaw thrust → c spine injury concern

Can be used in addition to adjuncts

Types of airway devices

• Oropharyngeal airway: easy + most often used, ideal for short procedures

• Laryngeal mask:

• Tracheostomy:

• Endotracheal tube

American Society of Anaesthesiologists (ASA) classification

• ASA I: Normal, healthy pt (non-smoking + alcohol)

• II: mild systemic disease (eg smoker, diabetes , BMI 30-40)

• III: severe systemic disease (poorly controlled DM/HTN, dialysis, hx MI/CVA >3m)

• IV: severe disease that is constant threat to life

• V: moribund pt not expected to live w/o op (AAA, massive trauma, ischaemic bowel)

• VI: brain dead pt → organ donor

Surgeries w/ unlikely chance of blood transfusion + action

Group + Save

• simple hysterectomy

• Appendicectomy

• Thyroidectomy

• Elective C-section (lower segment)

• Laparoscopic procedures eg cholecystectomy

Surgeries w/ likely chance of blood transfusion + action

Crossmatch 2 units

• ruptured ectopic pregnancy → salpingectomy

• THR

Surgeries w/ definite chance of blood transfusion + action

Crossmatch 4-6 units

• total gastrectomy

• Oophorectomy

• Oesophagectomy

• Elective AAA repair

• Cystectomy

• Hepatectomy

Local anaesthetic agents

Used to numb specific area where procedure is being performed

Inhibit AP conduction across nerve fibres by blocking Na+ channels

Rapidly absorbed into blood stream = decreased effect

• lidocaine (intermediate action)

• Cocaine (ester - topical only)

• Bupivacaine (long action)

• Prilocaine

Topical, injection or nerve block

What can be given w/ local anaesthetics to increase effectiveness

Adrenaline can be added

• Vasoconstrictor so decreased blood flow to area → prolongs duration of action

• Permits higher dose usage (except bupivacaine = cardiotoxic)

Local anaesthetics side effects

• vasodilation = hypotension

• Decreased activity of inhibitory neurones → restlessness, anxiety, seizures

• CNS depression

• Respiratory depression

• CVS → bradycardia + decreased CO

Malignant hyperthermia

Serious anaesthetic complication → hypermetabolic state

Unregulated calcium release in muscle cells → intracellular overload = sustained muscle contraction + breakdown

Risk w/: volatile anaesthetics (isoflurane, sevoflurane and desflurane) + Suxamethonium

Genetic mutations increase risk → autosomal dominant

Malignant hyperthermia investigations + management

• Hyperkalaemia

• raised CK

• ABG → Respiratory + metabolic acidosis

• Coagulation screen → DIC

• Myoglobinuria

IV dantrolene + stop agent/switch anaesthetic

Hyperventilate to blowoff excess CO2