Airway vs breathing vs equipment

Why split problems into Airway, Breathing, Equipment?

• When oxygen levels fall or ventilation is difficult, you need a simple structure to troubleshoot fast.
• Airway = getting gas to the lungs (patency + seal).
• Breathing = lungs and chest mechanics + gas exchange (what happens after gas reaches the lungs).
• Equipment = everything delivering/monitoring gas (machine, circuit, filters, valves, oxygen supply, monitors).
• In real life, more than one category may be contributing—start with what kills first: oxygenation and ventilation.

Core definitions (new-starter level)

• Oxygenation problem: low SpO2 (pulse oximeter) and/or low PaO2—often needs more oxygen and recruitment of lung units.
• Ventilation problem: rising end-tidal CO2 (ETCO2) and/or high PaCO2—often due to low minute ventilation or obstruction.
• Upper airway obstruction: tongue/soft tissues, laryngospasm, foreign body, biting tube, kinked supraglottic airway.
• Lower airway problem: bronchospasm, mucus plug, endobronchial intubation, pneumothorax, pulmonary oedema.
• Equipment fault: disconnection, empty oxygen supply, wrong gas flow, blocked filter, faulty valve, mis-set APL, ventilator/circuit leak.

First response to desaturation or difficult ventilation (safe sequence)

• Call for help early; ask someone to bring the difficult airway trolley and suction.
• Increase FiO2 to 1.0 (100% oxygen).
• Look at the patient first: chest movement, colour, airway device position, work of breathing (if spontaneous).
• Switch to manual ventilation (bag) if on ventilator—this separates patient from ventilator problems quickly.
• Check the trace: ETCO2 waveform, airway pressure, SpO2 trend; confirm pulse oximeter signal quality.
• Use a structured check: Airway → Breathing → Equipment (or Equipment → Airway → Breathing if you suspect disconnection/empty oxygen).
• If you cannot ventilate: follow local difficult airway guidance; prioritise oxygenation and consider waking the patient if appropriate.

AIRWAY: common causes and quick fixes

• Mask ventilation difficulty: poor seal, wrong mask size, beard/edentulous face, head/neck position, airway obstruction.
• Immediate actions: head tilt–chin lift or jaw thrust; two-person technique; use oropharyngeal/nasopharyngeal airway; ensure good mask seal.
• Supraglottic airway (SGA) issues: malposition, inadequate depth of anaesthesia, laryngospasm, leak at cuff, biting.
• SGA fixes: deepen anaesthesia, reposition (lift jaw, adjust depth), check cuff volume/pressure, consider changing size/device, use bite block if appropriate.
• Tracheal tube issues: oesophageal intubation, endobronchial intubation, cuff leak, kinking, biting, tube obstruction (secretions/blood).
• Tube checks: capnography present and sustained; equal chest rise; auscultation; check depth at teeth; pass suction catheter; check cuff pressure; consider reintubation if uncertain.

BREATHING: common causes and what to look for

• Bronchospasm: wheeze, prolonged expiration, rising airway pressures, “shark-fin” capnography; treat with deepen anaesthesia, bronchodilator, consider adrenaline if severe, check triggers (e.g., light anaesthesia, airway irritation).
• Laryngospasm (often at induction/emergence): no/poor air entry, high inspiratory effort, stridor; treat with jaw thrust, CPAP with 100% O2, deepen anaesthesia; consider small dose of muscle relaxant if persistent and trained to do so.
• Atelectasis: common after induction; reduced compliance, desaturation; treat with adequate FiO2, recruitment manoeuvre if appropriate, PEEP, optimise positioning.
• Pneumothorax (especially with positive pressure ventilation/trauma/central line): sudden high pressures, reduced breath sounds one side, hypotension; call for help, stop nitrous oxide if used, treat urgently per local protocol.
• Pulmonary oedema/aspiration: crackles, pink froth, poor oxygenation; suction, 100% O2, PEEP, call for senior help, treat cause.
• Endobronchial intubation is often “Breathing-looking” but is an Airway placement issue: unilateral chest movement and desaturation—withdraw tube slightly and reassess.

EQUIPMENT: the quick check that saves time

• Oxygen supply: confirm pipeline connected and/or cylinder on with adequate pressure; check flowmeters and FiO2 setting.
• Circuit: look for disconnection, loose connections, hole/tear, water in circuit, blocked HME filter, kinked tubing.
• APL valve (bagging): if fully open you may not build pressure; if fully closed you may generate high pressures—set appropriately and watch the manometer.
• Ventilator: wrong mode/settings, ventilator not engaged, scavenging issues, fresh gas flow too low (especially in some circuits), alarms silenced/ignored.
• Capnography: absent ETCO2 may be apnoea, disconnection, oesophageal intubation, or cardiac arrest—interpret with the clinical picture.
• Suction: ensure it is working before induction and available during airway events.

A simple troubleshooting approach (what to do in the moment)

• If SpO2 falling: 100% O2, manual ventilation, check airway patency and seal, then assess breathing causes and equipment.
• If ETCO2 rising: increase minute ventilation (rate/tidal volume if appropriate), check for obstruction/bronchospasm, check circuit/valves and CO2 absorber (if relevant).
• If high airway pressure: think obstruction (kink/biting/secretions), bronchospasm, pneumothorax, endobronchial tube, or closed APL; check stepwise.
• If low airway pressure/low delivered volume: think leak/disconnection/cuff leak/SGA leak; check connections and cuff.
• Always reassess after each intervention: SpO2 trend, chest movement, ETCO2 waveform, airway pressure.

Common “first time” scenarios and what helps

• First time bag-mask ventilation: use two hands for seal if needed; ask for two-person technique early; insert an oropharyngeal airway sooner than you think.
• First time using an SGA: choose correct size, lubricate, insert gently, confirm with chest rise + capnography, secure well, check leak pressure.
• First time with a tracheal tube: confirm with sustained capnography; secure tube; document depth; check cuff pressure; ensure bite protection on emergence.
• First time troubleshooting desaturation: switch to manual ventilation, look at the patient, then do Airway/Breathing/Equipment checks—avoid random adjustments.
• First time hearing “capno is flat”: check patient (apnoea/cardiac arrest), check airway placement, then check circuit connection and sampling line.