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Anaesthesia for thoracic surgery and one-lung ventilation
In one-lung ventilation all blood passing through the collapsed lung is shunt; it is reduced by HPV, an accurately placed tube and, if needed, CPAP to the operated lung and PEEP to the ventilated lung.
Why it matters in the exam
The exam asks about the indications for lung separation (isolating an infected or bleeding lung, bronchopleural fistula, single-lung lavage, surgical exposure), why a left double-lumen tube is preferred, what to do when saturation falls during one-lung ventilation, and how a patient is assessed before lung resection by ppoFEV1 and ppoDLCO. Questions also cover an anterior mediastinal mass and pulmonary oedema after pneumonectomy.
In the lateral position the lower lung is ventilated and receives most of the blood, and the upper lung is collapsed. Hypoxic pulmonary vasoconstriction (HPV) diverts blood away from the collapsed lung and reduces the shunt; halogenated agents below 1 MAC impair it a little, whereas vasodilators impair it more. The right main bronchus is short, and the right upper lobe takes off close to the carina — so a right double-lumen tube may block it, and the left side is preferred. Position is confirmed with a flexible bronchoscope after every change of position.
Before lung resection the expected postoperative value is calculated: preoperative FEV1 times the fraction of segments that will remain (out of 19). When ppoFEV1 and ppoDLCO are above 60% the risk is low; between 30% and 60% a simple exercise test is added; below 30% — full cardiopulmonary exercise testing, and a maximal oxygen uptake below 10 mL/kg/min indicates very high risk. With a large anterior mediastinal mass spontaneous breathing is kept and paralysis is avoided until the airway is secure.
Key points
- In one-lung ventilation the collapsed lung is shunt; HPV reduces it.
- A left double-lumen tube is the default; confirm with a bronchoscope.
- Hypoxaemia: FiO2 1.0, check the tube, PEEP to the ventilated lung, CPAP to the operated one.
- Before resection: ppoFEV1 and ppoDLCO; above 60% — low risk.
- Anterior mediastinal mass — keep spontaneous breathing.
Summary table
| Situation | What is done | Exam point |
|---|---|---|
| Tube choice | Left double-lumen tube in most cases; bronchial blocker when intubation is difficult | A right tube may block the right upper lobe |
| Ventilation | 4–6 mL/kg of predicted weight to the ventilated lung, PEEP 5, FiO2 as needed | Limit the plateau pressure |
| Hypoxaemia | FiO2 1.0, check position with a bronchoscope, recruitment and PEEP to the ventilated lung, CPAP to the operated lung | Then — temporary two-lung ventilation |
| Assessment before resection | ppoFEV1 and ppoDLCO above 60% — low risk; 30%–60% — exercise test; below 30% — cardiopulmonary test | VO2max below 10 mL/kg/min — very high risk |
| Anterior mediastinal mass | Spontaneous breathing, awake intubation, no early paralysis | Collapse when supine and at induction |
A free exam question
מטופל נמצא בניתוח Lobectomy בהרדמה כללית עם One Lung Ventilation . חצי שעה לאחר תחילת הניתוח המטופל מוריד סטורציה מ- 97% ל- 85% ., ללא שינוי המודינמי מה יש לעשות? (the question as examined, in Hebrew)
- א. להוסיף O CPAP 10 cm H2 לריאה התחתונה) Dependent
- ב. לתת בולוס של 500 מ"ל ringer lactate
- ג. להעלות את ה- tidal volume של המטופל ל- 10 mL/kg
- ד. לבדוק את מיקום ה– double lumen tube
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Sources
- Miller's Anesthesia, 9th edition (2020) — Anesthesia for Thoracic Surgery
- BTS guidelines on the radical management of patients with lung cancer, 2010 — Assessment of fitness for surgery
- Morgan & Mikhail's Clinical Anesthesiology, 7th edition (2022) — Anesthesia for Thoracic Surgery
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.