DOPS: left double-lumen tube and desaturation on one lungDOPS: a 62-year-old man, 176 cm, 80 kg, for elective thoracoscopic right upper lobectomy
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Know this first
- Size: men over 170 cm 41 Fr; under 170 cm 39 Fr; women 37 or 35 Fr.
- Left DLT depth at the teeth: about 12 + height/10 cm.
- Auscultation alone missed malposition in 48% on fibreoptic check.
- One-lung ventilation: tidal volume 4–6 mL/kg IBW, PEEP, recruitment; FiO2 1.0 if desaturating.
- Most desaturation comes early, in the first 10 minutes on one lung.
The patient
The examiner asks
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Prepare
How do you prepare?
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- Right lobectomy, so a left-sided tube; it avoids blocking the right upper lobe bronchus. (Procedure step)
- He's a man over 170 cm, so a 41 Fr tube.
- Depth at the teeth about 12 plus height over 10: roughly 29 to 30 cm.
- Test both cuffs, lubricate, and have the fibreoptic scope, connector and clamps ready.
Perform
Talk me through insertion and confirmation.
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- Bronchial tip through the cords, turn 90 degrees anticlockwise, advance gently without force. (Procedure step)
- Tracheal cuff up, ventilate, check both sides move and sound equal.
- Clamp each limb in turn: the clamped side stops moving, the other side keeps ventilating.
- Scope down the tracheal lumen: blue bronchial cuff just below the carina.
- Scope down the bronchial lumen: the left upper lobe opening is clear.
- After turning him lateral, I recheck with the scope, as tubes often move.
Perform
How do you set up one-lung ventilation?
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- Two lungs for as long as possible; isolate the right lung when the surgeon needs it. (Procedure step)
- Tidal volume 4–6 mL/kg of his ideal weight, with PEEP and recruitment breaths.
- Keep plateau pressure under 25 cmH2O and adjust the rate for carbon dioxide.
- Watch saturation closely; most falls come within the first 10 minutes.
Crisis
Five minutes into one-lung ventilation, SpO2 falls from 97% to 86%. BP 125/75, HR 80. What do you do?
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- Desaturation on one lung: FiO2 to 1.0 and tell the surgeon. (Crisis)
- Scope the tube: has it moved, or is a lobe of the left lung blocked?
- Check blood pressure and cardiac output; keep volatile below 1 MAC.
- Recruit the ventilated left lung, then increase its PEEP.
- Give the right lung CPAP of 1–2 cmH2O after a recruitment breath, if surgery allows.
- If it falls fast or keeps falling, return to two-lung ventilation.
Scan · Bronchoscopy: the carina
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Looking down the trachea onto the main carina; scope rotation not stated
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, open the image full sizeThis image carries no labels of its own; the structures are named below.
Labels The main carina (from the source caption)
- Cartilage rings are in front; the smooth flat wall is at the back.
- This ridge ahead is the main carina.
- The wider, straighter opening is the right main bronchus.
- Just inside it, on the side wall, this hole with three openings is the right upper lobe.
- The other side, longer before it divides, is the left main bronchus.
- Tracheal rings and posterior wall Rings in front, flat membranous wall behind: sets orientation
- Main carina Sharp ridge where the trachea splits
- Right main bronchus Wider, straighter, short before it branches
- Right upper lobe take-off On the right lateral wall, three openings: proves it is right
- Left main bronchus Longer, about 5 cm, before its first split
Checked against: Barash 9e · Miller 10e
Image: Knight SE et al., Pigtail catheter found in the Lingula of a pediatric patient on VV-ECMO while performing flexible bronchoscopy: a case report on an unexpected finding (Front Med (Lausanne) 2026; doi:10.3389/fmed.2026.1912185), Figure 2 (image 1, cropped), CC BY 4.0. Changes: Trimmed the frame edge. Question image: panel number '1' covered
Scan · Bronchoscopy: left double-lumen tube
Here is your image. Point to and name each structure, then say why it matters.
Fibreoptic bronchoscope down the tracheal lumen first, then the bronchial lumen; repeat after repositioning.
Down the tracheal lumen of a left DLT onto the carina; scope rotation not stated
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, open the image full sizeLabels Arrow: bronchial cuff of the left double-lumen tube in the left main bronchus
- Down the tracheal lumen I see the carina straight ahead.
- The blue cuff edge sits just inside the left bronchus, below the carina.
- It does not bulge over the carina or push it right.
- On the right I find the upper lobe with its three openings.
- Down the bronchial lumen, both left lobar openings are clear.
- I recheck with the scope after every position change.
- Tracheal carina Seen straight ahead down the tracheal lumen
- Blue bronchial cuff edge In left bronchus, about 5–10 mm below carina
- No cuff herniation Bulging cuff can block the right main bronchus
- Right upper lobe take-off Confirms which side you are looking at
- Left upper and lower lobe orifices Down bronchial lumen: both open, none blocked or impacted
Checked against: Miller 10e · Faust · Barash 9e
Image: Tan DJA et al., Difficult Lung Isolation in a Heavy Smoker With a History of Left Lower Lobectomy: A Case Report (Cureus 2024; doi:10.7759/cureus.69388), Figure 2, CC BY 4.0. Changes: Cropped to panel A. Question image: red arrow and panel letter A covered with boxes
Fatal mistakes
- No fibreoptic confirmation.
- Persisting with one-lung ventilation while hypoxia worsens.
Checked against: Miller 10e · Barash 9e
Report a problem with this case
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.