When and why it is used

Core idea: matching technique to patient + surgery

• Anaesthesia choices are about balancing: patient factors (risk), surgical needs (access, duration, pain), and environment (staffing, location, equipment).
• Always ask: What problem am I trying to solve? (e.g., pain, immobility, airway protection, ventilation, haemodynamic control).
• Aim for the simplest option that meets the surgical requirement safely, with a clear backup plan.
• Reassess continuously: what was appropriate at induction may need changing during surgery or recovery.

When to use General Anaesthesia (GA) — and why

• Use GA when surgery needs unconsciousness, immobility, or controlled ventilation (e.g., laparotomy, laparoscopy, long/complex cases).
• Use GA when regional/local techniques are unsuitable or declined, or when patient cannot cooperate (e.g., severe anxiety, confusion).
• Why: provides reliable hypnosis (unconsciousness), analgesia (pain control), and muscle relaxation when needed.
• Key safety aim: maintain oxygenation, ventilation, circulation, and temperature while preventing awareness and aspiration.

When to use Sedation — and why

• Use sedation for short procedures where the patient can maintain their own airway and respond to verbal/tactile stimulus (e.g., endoscopy, minor procedures, some regional blocks).
• Why: reduces anxiety and discomfort while avoiding full GA in selected patients.
• Sedation is a continuum: patients can unintentionally drift into deep sedation/GA—be ready to manage airway and ventilation.
• Always define the target depth, monitor closely, and have oxygen, suction, airway equipment, and help immediately available.

When to use Regional Anaesthesia (spinal/epidural/peripheral nerve blocks) — and why

• Use regional techniques when surgery is suitable and benefits outweigh risks (e.g., lower limb surgery, C-section spinal, upper limb blocks).
• Why: excellent analgesia, reduced opioid needs, can avoid airway instrumentation in some patients, and may aid early mobilisation.
• Common reasons to avoid/stop: patient refusal, infection at site, significant bleeding risk/anticoagulation issues, severe hypovolaemia/shock, raised intracranial pressure (for neuraxial), inability to position/cooperate safely.
• Plan for failure: blocks can be incomplete—agree in advance whether you will top up, convert to GA, or postpone.

When to use Local Anaesthesia (LA) infiltration/topical — and why

• Use LA for minor procedures or as part of multimodal analgesia (e.g., wound infiltration, line insertion, topical airway anaesthesia for awake techniques).
• Why: reduces pain and opioid requirement; can improve recovery and reduce nausea/sedation.
• Know your maximum safe doses (especially with adrenaline/epinephrine vs without) and document total dose given.
• Watch for local anaesthetic systemic toxicity (LAST): early symptoms can be subtle—tinnitus, metallic taste, agitation—progressing to seizures/cardiac collapse.

When to use a supraglottic airway (SGA) — and why

• Use an SGA for many short-to-moderate elective cases with low aspiration risk (e.g., day-case limb surgery, some gynaecology).
• Why: usually easier insertion, less haemodynamic response than intubation, and often smoother emergence.
• Avoid/think carefully if aspiration risk is high (full stomach, bowel obstruction, severe reflux, pregnancy beyond early gestation), if high airway pressures are expected, or if surgical position/access makes rescue difficult.
• Always confirm ventilation (chest rise, capnography) and have a plan if ventilation is inadequate.

When to use tracheal intubation — and why

• Use intubation when airway protection is needed (aspiration risk), when controlled ventilation/high pressures are expected (e.g., laparoscopy, obesity with reduced compliance), or for long/complex surgery.
• Use intubation for shared airway surgery (ENT, maxillofacial) and when patient positioning limits access to the airway (prone, steep Trendelenburg).
• Why: most secure airway for ventilation and aspiration protection (though not absolute).
• Always consider difficulty: assess airway, plan A/B/C, and ensure you can oxygenate throughout (pre-oxygenate well; use capnography).

When to use rapid sequence induction (RSI) — and why

• Use RSI when aspiration risk is high and you need to secure the airway quickly (e.g., emergency laparotomy, bowel obstruction, trauma with full stomach, late pregnancy).
• Why: minimise time between loss of airway reflexes and cuff inflation.
• RSI still prioritises oxygenation: if intubation fails, follow the difficult airway plan and ventilate as needed rather than persisting without oxygen.
• Ensure suction is working, drugs are drawn up, and the team knows the plan (including failed intubation actions).

When to use invasive monitoring (arterial line/CVC) — and why

• Arterial line: use when beat-to-beat blood pressure is needed, frequent blood sampling is likely (e.g., major surgery, vasoactive infusions, severe cardiovascular disease, unstable patient).
• Why: improves detection and treatment of rapid haemodynamic changes; enables ABGs and labs.
• Central venous catheter (CVC): consider for reliable access for vasopressors, poor peripheral access, or specific indications (e.g., certain major surgeries/ICU pathways).
• Balance benefits vs risks (infection, bleeding, pneumothorax, arterial puncture). Use ultrasound guidance where appropriate and document line details.

When to use vasopressors/fluids — and why (common early scenarios)

• Hypotension after induction is common: causes include vasodilation from anaesthetic drugs, relative hypovolaemia, or reduced cardiac output.
• Fluids: use when there is likely volume deficit or fluid responsiveness; avoid reflex fluid boluses in heart failure/renal failure without reassessment.
• Vasopressors (e.g., metaraminol/phenylephrine) are often needed for anaesthetic-induced vasodilation; treat the cause and reassess frequently.
• Escalate early if hypotension is persistent, severe, or associated with ECG changes, bleeding, bronchospasm, or suspected anaphylaxis.

How to decide quickly (a simple framework)

• Patient: aspiration risk, airway difficulty, cardiorespiratory reserve, anticoagulation, sepsis/bleeding, fasting status, pregnancy.
• Procedure: site, duration, expected pain, need for paralysis, position (prone/steep head-down), shared airway.
• Place: theatre vs remote site, available help, monitoring, recovery capability.
• Plan: primary technique + analgesia plan + antiemetic plan + clear backup (including conversion to GA and difficult airway plan).