Intraoperative bronchospasm
Stem
A 38-year-old woman, 72 kg, with poorly controlled asthma and a cold two weeks ago, is having a laparoscopic cholecystectomy. Minutes after intubation and before incision, the peak airway pressure rises from 18 to 40 cmH2O, delivered tidal volume falls, and the capnograph shows a slanted, upsloping trace. You hear expiratory wheeze on both sides. SpO2 is 93% and blood pressure 118/72.
Question
What is your differential, and how will you manage her?
Ideal answer
HeadlineBronchospasm, treated while I exclude the mechanical mimics: 100% oxygen, and I hand-ventilate to feel the compliance.
- Suction catheter down the tube, listen both sides, to rule out a kinked or bitten tube, secretions, mainstem intubation and the circuit.
- Deepen with propofol or a volatile agent, because light anesthesia is the commonest trigger, and her tube went in minutes ago in a reactive airway.
- Albuterol through the circuit, 8–12 puffs or more, timed with inspiration, because deposition through a tube is poor.1
- Epinephrine in small IV doses if not improving or hypotensive,2 because it treats both bronchospasm and anaphylaxis.
- Low rate, long expiration, hypercapnia accepted, watching for auto-PEEP, with steroids for their later effect.
Watch for: skin, pressure and every drug's timing; bronchospasm that does not behave like asthma is often anaphylaxis, aspiration, pulmonary edema or pneumothorax.
Breaking down the answer
- Exclude the mimics — kinked tube, mainstem or esophageal intubation, secretions, cuff herniation and the circuit cause high pressure without bronchoconstriction;2 a suction catheter that will not pass means the tube is obstructed, not the bronchi. Running the differential while treating shows organization.
- Deepen first — airway stimulation under light anesthesia causes most bronchospasm; propofol 0.5–1 mg/kg acts in seconds, and sevoflurane works if I can still ventilate.
- Albuterol first, epinephrine early — albuterol is the first-line drug, repeated;2 epinephrine 10–100 mcg slow IV and escalating, or 0.5 mg IM,2 is the most effective bronchodilator and the drug for anaphylaxis, so it comes early when pressure falls.
- Peak versus plateau — I accept high peak pressure if plateau is acceptable;2 trapping causes hypotension. High peak, normal plateau: airway resistance (bronchospasm or obstructed tube). High plateau: reduced compliance (pneumothorax, edema, mainstem intubation or abdominal pressure).
- Adjuncts — ketamine in small boluses (about 20 mg in an adult) or 1–3 mg/kg/h, magnesium 50 mg/kg to 2 g IV over 20 minutes, IV salbutamol 250 mcg slowly, and hydrocortisone 200 mg, knowing steroids take hours.2
- Prevention — recent URI, active wheeze, poorly controlled asthma, heavy smoking and instrumentation under light anesthesia raise risk: albuterol pretreatment, propofol or ketamine induction, a supraglottic airway when surgery allows. At extubation: deep or with lidocaine, only after the wheeze has resolved.
Follow-up question
The wheeze settles, and the surgeon asks for the antibiotic. Five minutes after it goes in, the peak pressure is 45 cmH2O, the SpO2 88%, the blood pressure 65/30, and her chest is red.
What is happening, and what do you do now?
Follow-up answer
HeadlineAnaphylaxis with bronchospasm, not simple reactive airway disease. I call for help, stop the suspected drug and tell the surgeon to finish quickly.
I go to 100% oxygen, give epinephrine 50 mcg IV and repeat it, starting an infusion after about three boluses,3 and give fluid rapidly. Antihistamines and steroids are no longer acute treatment, only for refractory or ongoing symptoms.3 If epinephrine fails, vasopressin 1–2 units, and glucagon 1–2 mg IV every 5 minutes if she takes a beta-blocker.1 I reassess pressure, airway pressure and saturation after each dose. Tryptase once she is stable, again at 1–2 hours and after 24 hours, then allergy testing.3
Pitfalls that cost points
- Giving only two puffs of albuterol through the tube.
- Hyperventilating and causing auto-PEEP.
- Withholding epinephrine in a hypotensive bronchospastic patient.
Rapid-fire
Q: Why does the capnograph look like a shark fin? A: Uneven emptying of obstructed alveoli prolongs the expiratory upstroke; the plateau slopes and does not flatten.
Q: Why is desflurane avoided? A: It is pungent and irritant to the airway, increasing resistance, especially in smokers and at high concentrations; isoflurane is also best avoided.2
Q: Why does a beta-blocked patient need glucagon? A: Glucagon raises cyclic AMP independent of beta receptors, so it works when epinephrine is blunted.
Q: When do you use heliox or ECMO? A: Heliox lowers turbulent resistance in refractory cases but limits FiO2; ECMO is the rescue for life-threatening, refractory bronchospasm.
Numbers to know
| Item | Value |
|---|---|
| Albuterol via circuit | 8–12 puffs, repeat1 |
| Epinephrine IV, bronchospasm | 10–100 mcg, escalate2 |
| Epinephrine IV, anaphylaxis | 50 mcg bolus, repeat; infusion after ~3 boluses3 |
| Epinephrine infusion | 0.05–0.1 mcg/kg/min |
| Magnesium | 50 mg/kg, adult 2 g IV over 20 min2 |
| Hydrocortisone | 200 mg IV2 |
| Ketamine | ~20 mg bolus; infusion 1–3 mg/kg/h2 |
Links
- COPD and reactive airway disease, anaphylaxis, aspiration, Pneumothorax and tension pneumothorax, laryngospasm
- Atlas: Capnography: waveforms and sudden loss of ETCO2; Monitor atlas: perioperative respiratory events
- GINA Global Strategy for Asthma Management and Prevention
Sources
- 1.Perioperative Anaphylaxis Management Guidelines, Card 3: Adult Refractory Management (v14) · ANZAAG / ANZCA, 2022 · anzca.edu.au
- 2.Quick Reference Handbook 3-4 Bronchospasm (v.2) · Association of Anaesthetists, 2019 · wuth.nhs.uk
- 3.Quick Reference Handbook 3-1 Anaphylaxis (v.5) · Association of Anaesthetists, 2022 · rightdecisions.scot.nhs.uk
Facts on this page were checked against these sources on Oct 14, 2026. Guidelines change; confirm doses against current institutional protocols.