Indications

What does “indication” mean in anaesthesia?

• An indication is a clear clinical reason to do something (e.g., give an anaesthetic, secure an airway, insert an arterial line).
• Good indications link to a goal: safety, oxygenation/ventilation, analgesia, immobility, surgical access, or monitoring.
• Always balance benefit vs risk, and consider alternatives (including doing nothing or delaying).
• Indications are patient-specific: the same procedure may need different anaesthetic plans depending on comorbidity and urgency.

Common indications for general anaesthesia (GA)

• Need for unconsciousness: patient cannot tolerate the procedure awake (painful, distressing, long, or requires immobility).
• Airway/ventilation control required: shared airway surgery, aspiration risk, severe respiratory compromise, or need for controlled ventilation.
• Surgical requirements: muscle relaxation, prone position, laparoscopic surgery, or procedures where movement is dangerous.
• Failure or unsuitability of regional/local techniques: block contraindicated, inadequate block, or time-critical situation.
• Patient factors: inability to cooperate (confusion, severe anxiety, learning disability) where safe sedation is unlikely.

Common indications for regional anaesthesia (spinal/epidural/peripheral nerve blocks)

• Surgery confined to a region where a block can provide surgical anaesthesia (e.g., lower limb, lower abdomen, upper limb).
• Reduce opioid requirements and improve postoperative analgesia (especially in major orthopaedic, thoracic, abdominal surgery).
• High risk with GA: severe respiratory disease, difficult airway concerns (case-by-case; ensure a backup plan).
• Facilitate early mobilisation and physiotherapy (e.g., joint replacement pathways).
• Labour analgesia: epidural for pain relief; can be extended for operative delivery if needed.

Indications for procedural sedation (and when to avoid it)

• Short, painful or anxiety-provoking procedures where GA is not required (e.g., fracture reduction, cardioversion, endoscopy).
• Patient can maintain their own airway and ventilation with minimal support (aim for the lightest effective level).
• Avoid/seek senior help if: high aspiration risk, predicted difficult airway, severe OSA/obesity with airway concerns, haemodynamic instability, or very limited physiological reserve.
• Sedation is not a substitute for poor local anaesthesia—optimise local/nerve block first where appropriate.
• Have a clear plan for escalation to GA and airway management before starting.

Indications for securing the airway (supraglottic airway or tracheal intubation)

• Protect airway from aspiration: full stomach, bowel obstruction, active reflux/vomiting, pregnancy (especially >20 weeks), major trauma.
• Need for controlled ventilation: respiratory failure, laparoscopic surgery, long procedures, or where CO2 control is important.
• Shared airway or airway access needed: ENT/maxillofacial surgery, prone positioning, head/neck surgery.
• Anticipated airway obstruction or loss of airway tone: deep sedation, severe OSA, airway pathology.
• Tracheal intubation is usually preferred when aspiration risk is significant or ventilation must be guaranteed.

Indications for invasive monitoring and access (new starter essentials)

• Arterial line: need beat-to-beat BP (major haemodynamic swings), frequent blood gases, major surgery, vasoactive infusions, severe cardiovascular disease.
• Central venous access: poor peripheral access with urgent need, multiple infusions/vasopressors, long-term access, some complex cases (not routine).
• Large-bore IV access: major haemorrhage risk (trauma, obstetrics, major vascular, liver surgery).
• Urinary catheter: major surgery, expected long duration, need accurate urine output (shock, sepsis, major fluid shifts).
• Temperature monitoring: most GAs >30 minutes, major surgery, high-risk patients (prevent hypothermia).

Indications for rapid sequence induction (RSI) – practical framing

• Used when aspiration risk is high and you need to secure the airway quickly with minimal time unprotected.
• Typical scenarios: emergency laparotomy, bowel obstruction, trauma with unknown fasting status, pregnancy with urgent surgery, active vomiting/bleeding.
• RSI is a technique choice, not a badge—tailor to physiology (e.g., shocked patient) and airway difficulty.
• If predicted difficult airway + aspiration risk: involve senior early; consider awake intubation or modified approaches with a clear failed airway plan.

Indications to delay or optimise before anaesthesia (often overlooked)

• Unstable physiology: uncontrolled sepsis, severe hypoxia, shock—resuscitate and involve seniors unless surgery is life-saving.
• Uncontrolled medical issues: severe asthma exacerbation, decompensated heart failure, uncontrolled arrhythmia.
• Correctable problems: severe anaemia, electrolyte derangements (especially potassium), hypoglycaemia, significant dehydration.
• Inadequate consent/capacity assessment or missing critical information (allergies, anticoagulants, last oral intake) where delay is safe.
• Escalate early if the urgency of surgery conflicts with optimisation needs.

How to communicate an indication (SBAR-style in theatre)

• State the procedure and urgency (elective/urgent/emergency).
• Name the key patient risks driving your plan (e.g., aspiration risk, severe COPD, severe aortic stenosis).
• Say what you propose and why (e.g., “ETT and controlled ventilation due to laparoscopy and reflux”).
• Confirm backup plans (difficult airway plan, blood availability, postoperative destination).