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Airway and respiratory · Core07 / 12
Subglottic stenosis for laser and dilation with jet ventilation46-year-old woman, 98 kg, BMI 38, for elective suspension laryngoscopy
Shared airway: laser safety, jet ventilation and airway fire drill
From memory: the diagnosis and the notes are hidden. Answer each question aloud, then press Show.
Know this first
An adult trachea narrowed below 5 mm causes symptoms at rest.
Supraglottic jet: 20–50 psi pulses, often 1 second on, 3 off; needs TIVA; no ETCO2.
Laser: lowest oxygen that keeps saturation, no nitrous oxide, saline-filled cuff tinted blue.
Airway fire: tube out, gases off, saline in, ventilate, then bronchoscope.
Cricothyroidotomy is contraindicated with subglottic stenosis.
The patient
46-year-old woman, 98 kg, BMI 38, for elective suspension laryngoscopy, CO2 laser and balloon dilation of subglottic stenosis.
Stenosis after 3 weeks of ICU intubation last year; stridor climbing stairs, none at rest. CT: 6 mm lumen, 2 cm below the cords.
Drugs: omeprazole.
Vitals: BP 136/84, HR 88, SpO2 97% on air, RR 18.
The examiner asks
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Consider
What are the issues in this case?
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A 46-year-old obese woman with post-intubation subglottic stenosis, for laser and balloon dilation. Patient
Her 6 mm lumen is just above the 5 mm where stridor appears at rest. Disease
A fixed scar stenosis rarely collapses at induction, unlike a mass in the trachea.
Shared airway with a laser: fuel, oxygen and ignition all meet in her trachea. Surgery
Her obesity makes supraglottic jet ventilation less effective. Airway
Prepare
How do you prepare, with the surgeon?
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I review her CT for level, length and lumen; her flow-volume loop should be flat both ways. Disease
One shared plan: how we ventilate, who controls oxygen, and what happens if we lose the airway. Airway
Surgeon and rigid bronchoscope in theatre at induction; the rigid scope can ventilate past the narrowing.
Cricothyroidotomy won't work over her stenosis; surgical tracheostomy is my front-of-neck plan.
Dexamethasone 4–8 mg IV for airway oedema. After surgery
Plan
What is your ventilation strategy while the laser is in use?
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TIVA, since jet ventilation leaves no closed circuit for vapour. Stem trigger
Supraglottic jet through the laryngoscope at 20–50 psi, 1 second on, 3 off. Airway
Gas must leave between pulses; I watch her chest fall each cycle.
If a tube is used: laser-resistant, cuff filled with saline tinted with methylene blue.
Lowest oxygen that holds her SpO2, aiming at 30% or less, and no nitrous oxide. Stem trigger
The surgeon warns me before firing, and waits a few minutes after I lower the oxygen. Surgery
No ETCO2 with jet, so I follow SpO2, chest movement and gas samples. Airway
Crisis
During laser work through a laser tube there is a flash, then flame inside the tube. SpO2 95%, BP 150/90, HR 110. What do you do?
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Airway fire: tube out at once and all airway gases stopped. Crisis
Sponges out, and saline poured into her airway.
Fire out: ventilate by mask, avoiding oxygen-rich gas if she tolerates it.
The removed tube is inspected for missing pieces; bronchoscopy for debris and burns.
Reintubate with a smaller tube before her raw airway swells shut.
Dexamethasone, ICU, then open disclosure and an incident report. After surgery
Crisis
Later, during jet ventilation, SpO2 falls to 80%. Her chest stays high between pulses; BP 80/50, HR 125. What do you do?
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Gas is going in and not coming out: stop jetting now. (Crisis)
Surgeon clears the outflow: laryngoscope adjusted, debris and blood removed.
Jet ventilation can cause pneumothorax and pneumomediastinum; I examine and decompress if tension.
Secure the airway past the stenosis with a small tube via the rigid bronchoscope.
Restart conventional ventilation with a long expiratory time; chest film after.
Fatal mistakes
High inspired oxygen while the laser fires.
Jet ventilation with no path for gas to escape.
Leaving a burning tube in the airway.
No surgical airway backup planned.
Checked against: Stoelting 8e · Miller 10e · Practice Advisory for the Prevention and Management of Operating Room Fires: An Updated Report by the American Society of Anesthesiologists Task Force on Operating Room Fires (2013)
Mark Got it only if you said every point. Again brings the case back tomorrow; Got it brings it back in 3, then 7, 14 and 30 days.
Same topic, another patient
Run these after the main case when you have time. Same skills, a different patient or setting.
Another patient · Thoracic and vascular. Tracheal stenosis for rigid bronchoscopy and stenting. Same post-intubation stenosis lower down: rigid bronchoscopy and stenting
Know this first
CT gives the level, length and degree of the stenosis.
Acquired stenosis seldom collapses at induction; intratracheal masses can.
Ventilation options: he breathes himself, apnoea with oxygen, a ventilating scope, or jet.
Jet ventilation needs an open path for passive exhalation, or barotrauma follows.
The patient
54-year-old man, 96 kg, for urgent rigid bronchoscopy, dilation and silicone stent this week.
Tracheostomy for ICU ventilation a year ago; now stridor at rest. CT: 1.5 cm stenosis, 6 mm lumen, 3 cm below the cords.
Moderate COPD on tiotropium; ex-smoker.
Vitals: BP 148/88, HR 102, SpO2 93% on air, RR 24.
The examiner asks
Answer aloud, then press Show.
Consider
What are the issues?
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A 54-year-old with post-tracheostomy stenosis and stridor at rest, for rigid dilation and stenting. Patient
CT sets the plan: 3 cm below the cords, 1.5 cm long, lumen 6 mm. Airway
We share his airway, so the bronchoscopist and I talk throughout. Surgery
His COPD makes expiration slow, so trapping is likely if exhalation is blocked. Disease
A scarred stenosis rarely collapses at induction, unlike a soft intratracheal mass. Airway
Prepare
How do you prepare?
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Settle the stridor first: dexamethasone 4–8 mg IV and nebulised racemic adrenaline 0.5–0.75 mL of 2.25%. Airway
Done in theatre with the bronchoscopist scrubbed and rigid scopes of several sizes ready.
Glycopyrrolate 0.2 mg IV beforehand to dry his secretions.
Arterial line; ETCO2 is unreliable with an open airway, so I'll use gases. Disease
His stenosis is high, near the subglottis, where cricothyrotomy is contraindicated; the rigid scope is my rescue. Airway
Plan
Describe your anaesthetic.
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TIVA, since the airway is open: remifentanil 0.1–1.0 mcg/kg/min with propofol 100–200 mcg/kg/min. Airway
Preoxygenate, induce, and confirm I can ventilate by mask first.
Only then rocuronium 0.6 mg/kg; sugammadex ready for full reversal at the end.
Jet ventilation through the scope with its proximal end open, so gas can escape.
Short apnoeic spells allowed; when SpO2 drops, the bronchoscopist stops and I ventilate.
Suction and blood ready; bleeding and perforation are known complications. Surgery
Extubated to a monitored bed, with steroid and humidified oxygen continued. After surgery
Crisis
During jet ventilation SpO2 falls to 84%, the chest barely moves and his neck is swelling. What do you do?
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Stop jetting now: gas isn't escaping, so this is barotrauma. Crisis
Bronchoscopist pulls back above the stenosis and opens the scope end.
Hand ventilation through the side arm, with throat packs to seal the leak.
Look for pneumothorax: decompress it, then a chest drain.
Still failing: rigid scope through the stenosis and ventilate beyond it.
Chest X-ray afterwards for pneumothorax and mediastinal air. After surgery
Crisis
An hour later in recovery he develops sudden stridor and can barely speak; SpO2 85%. What do you do?
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A migrated stent is blocking his trachea until proven otherwise: call the bronchoscopist and help. Crisis
Sit him up, 100% oxygen, and prepare to return to theatre now.
Silicone stents need rigid bronchoscopy, so retrieval or repositioning happens in theatre.
If he obstructs completely first, rigid scope past the block; cricothyrotomy is no rescue here.
Afterwards he is monitored overnight; unmonitored recovery after stenting is the error. After surgery
Fatal mistakes
Jet ventilation with no path for gas to escape.
Paralysing him before ventilation is proven.
Unmonitored recovery after stenting.
Relying on front-of-neck access above the stenosis.