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Airway and respiratory · Core05 / 12

Brittle asthma for ankle fixation, with bronchospasm at induction26-year-old woman, 64 kg, for urgent fixation of a displaced ankle fracture from a twisting fall yesterday

Reactive airway: asthma optimisation, anaphylaxis and severe bronchospasm with gas trapping

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Know this first

  • A past ICU admission or ventilation for asthma marks near-fatal asthma.
  • PEF under 60% of personal best is a severe exacerbation.
  • If her surgery can't wait out an exacerbation: 3 days of prednisone, 40–60 mg each day.
  • Severe asthma ventilation: low rate, small tidal volume, long expiratory time.
  • Tryptase sample within 30–120 minutes of a suspected allergic reaction.

The patient

26-year-old woman, 64 kg, for urgent fixation of a displaced ankle fracture from a twisting fall yesterday; no other injuries. Brittle asthma: intubated in ICU 2 years ago. A cold this week; now using salbutamol 6 times a day. Wheezes after ibuprofen. Drugs: budesonide–formoterol inhaler, salbutamol. Vitals: BP 118/72, HR 104, SpO2 95% on air, RR 22. Peak flow 260 L/min; personal best 420.

The examiner asks

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  1. Consider

    What are the key issues?

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    • A 26-year-old with brittle asthma, in an exacerbation, for urgent ankle fixation. Patient
    • An isolated twisting injury; no other injuries on her survey.
    • Her past ICU intubation classes her as near-fatal asthma, my highest risk group. Disease
    • A recent cold and heavy reliever use mean her airways are irritable now. Stem trigger
    • She wheezes after ibuprofen, so all NSAIDs are out.

  2. Prepare

    Is she fit to proceed today, and how do you get her ready?

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    • Peak flow 260 against her best of 420 is 62%; below 60% would be severe. Disease
    • I listen, check SpO2 and ask about night waking; I treat her chest before her ankle.
    • Her fracture is urgent, not an emergency: a short steroid course first, prednisone 40–60 mg daily for 3 days. Stem trigger
    • Her inhalers continue; salbutamol 2–4 puffs 20–30 minutes before theatre. Disease
    • Anaphylaxis drugs drawn up, since antibiotic and relaxant reactions present as bronchospasm. Crisis

  3. Plan

    What anaesthetic do you plan?

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    • Regional first: popliteal sciatic and saphenous blocks avoid her airway entirely. Surgery
    • If GA is needed, a supraglottic airway rather than a tube; it causes less bronchospasm. Airway
    • Deep before any airway touch: propofol, or ketamine 1–2 mg/kg for its bronchodilation.
    • Lidocaine 1–1.5 mg/kg IV 1–3 minutes before the airway goes in.
    • Analgesia from the blocks and paracetamol 1 g IV; no NSAIDs. After surgery

  4. Crisis

    She declines the block. Two minutes after cefazolin and propofol, intubated, she is flushed. Peak pressure 40 cmH2O, wheeze, SpO2 88%, BP 68/35, HR 132. What do you do?

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    • Anaphylaxis algorithm: hypotension, bronchospasm and flushing minutes after cefazolin. Crisis
    • Trigger stopped, help, 100% oxygen; vapour off while hypotensive, kept asleep with small propofol doses.
    • Adrenaline 0.5 mg IM in the thigh now, repeat at 5 minutes; IV 0.05–0.1 mg only if no response.
    • Crystalloid 1 L fast; capillary leak drains her circulation quickly.
    • Bronchospasm left after adrenaline: salbutamol 4–8 puffs down the tube.
    • Still hypotensive: adrenaline infusion 0.05–0.1 mcg/kg/min, then vasopressin 2–10 units; no beta-blocker, so no glucagon.
    • Tryptase within 30–120 minutes; allergy clinic referral and cefazolin flagged. After surgery

  5. Crisis

    BP recovers, but her chest goes silent. The capnograph trace flattens and falls, peak pressure 50 cmH2O, SpO2 85%. What do you do?

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    • Silent chest: near-total bronchospasm with trapped gas; I pass a suction catheter to exclude a blocked tube. Crisis
    • Brief disconnection from the ventilator with chest compression to let trapped gas out.
    • Then a low rate, small tidal volumes and a long expiratory time.
    • Adrenaline 1 mcg/kg IV bolus for this refractory bronchospasm.
    • Magnesium 2 g IV over 20 minutes; methylprednisolone 1–2 mg/kg.
    • A sudden pressure rise or one silent side: tension pneumothorax, decompress.
    • Surgery postponed; ICU, with volatile agents or ECLS if still refractory. After surgery

Fatal mistakes

  • Instrumenting her airway under light anaesthesia.
  • Fast ventilation that stacks breaths and traps gas.
  • Delaying adrenaline in anaphylaxis.
  • Missing a tension pneumothorax.

Checked against: Global Strategy for Asthma Management and Prevention (2024 update) · Miller 10e · Stoelting 8e · AHA guidelines: special circumstances of resuscitation (2025) · Faust

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Another patient · Intra-operative crises. Severe bronchospasm and gas trapping in brittle asthma. Same brittle asthma: gas trapping progressing to pulseless arrest

Know this first

  • Prior intubation for asthma and emergency care in the past year mark high risk of asthma death.
  • Bronchospasm under anaesthesia: 4–8 salbutamol puffs into the tracheal tube, repeating 2 puffs each 10 min.
  • Magnesium 2 g IV over 20 min; refractory: adrenaline 1 mcg/kg IV.
  • Low rate, low tidal volume and long expiry limit gas trapping.
  • Breath stacking arrest: brief disconnection and chest compression; consider tension pneumothorax.

The patient

26-year-old man, 72 kg, brittle asthma; ventilated in ICU once; emergency visit and oral prednisolone 3 weeks ago. Drugs: budesonide-formoterol inhaler. Urgent incision and drainage of a perianal abscess. Wheezy today, peak flow 60% of his best. Vitals: BP 132/80, HR 102, SpO2 95% on air, RR 20.

The examiner asks

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  1. Consider

    What are your concerns?

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    • A 26-year-old with brittle asthma, once ventilated, for urgent drainage of a perianal abscess. Patient
    • Past intubation and a recent emergency visit mark high risk of asthma death. Disease
    • Recent exacerbation and prior intubation also raise his perioperative lung complications.
    • Wheezy at 60% of his best: this is urgent, not an emergency, so I can improve him first.
    • Perianal surgery suits a spinal, so his airway need not be touched. Surgery

  2. Plan

    What is your anaesthetic plan?

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    • Salbutamol before theatre: 2–4 puffs, or a 2.5 mg nebuliser, 20–30 minutes ahead. Disease
    • First choice: spinal, with no airway manipulation at all. Airway
    • If general: supraglottic airway rather than a tube where possible.
    • Deep before any airway: ketamine 1–2 mg/kg or propofol, both lower airway resistance.
    • If he needs a tube: lidocaine 1–2 mg/kg IV, 1–3 minutes before.
    • Ventilator set for long expiry: low rate and small tidal volumes.

  3. Crisis

    The spinal fails and he is intubated. Peak pressure rises to 48 cmH2O, the capnograph is shark-fin shaped, SpO2 90%, BP 104/60. What do you do?

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    • High airway pressure: 100% oxygen, hand-ventilate, call for help. (Crisis)
    • Tube first: pass a suction catheter, check its position and listen to both sides.
    • Shark-fin trace and wheeze: bronchospasm; unequal sounds would mean pneumothorax.
    • Deepen with volatile; salbutamol 4–8 puffs into the tracheal tube, repeating 2 puffs each 10 minutes.
    • Not settling: magnesium 2 g IV over 20 minutes.
    • Severe and persistent: adrenaline 1 mcg/kg IV bolus.
    • Low rate, small breaths, long expiry to stop his gas stacking.

  4. Crisis

    Ten minutes later BP falls to 50/30, then no pulse; the monitor shows sinus rhythm at 120. What now?

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    • Adult arrest algorithm: PEA in a ventilated asthmatic, so gas trapping first. Crisis
    • Disconnect him from the ventilator and press on his chest to empty trapped gas.
    • Start CPR; adrenaline 1 mg IV every 3–5 minutes.
    • His other reversible cause: tension pneumothorax; decompress if signs point to it.
    • Reconnect slowly: low rate and small breaths.
    • Refractory: ECMO, which has supported life-threatening asthma.
    • After ROSC: ICU, with volatile if bronchospasm persists. After surgery

Fatal mistakes

  • Bronchodilators for a blocked or kinked tube.
  • Fast ventilator rates with gas trapping.
  • Missing a tension pneumothorax.
  • Intubating him in a light plane.

Checked against: Global Strategy for Asthma Management and Prevention (2024 update) · Faust · AHA guidelines: special circumstances of resuscitation (2025) · Miller 10e

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