Hypoxaemia during one lung ventilation

 

Risk factors:

Patient

·           Old age

·           Lung disease

Surgery

·           Right lung operation

·           Supine position

Surrogates

·           ↓PaO2 pre-op

·           ↓PaO2 pre-isolation

 

Causes:

Low PiO2

·           Unlikely

Hypoventilation

·           Pressure-limitation

V/Q inequality

·           HPV impaired by general anaesthesia

Shunt

·           Upper lung perfused but not ventilated

·           HPV impaired by general anaesthesia

 

Troubleshooting:

First things

·           FiO2 100%

·           Announce problem

·           Ask surgeon to stop

Check airway

·           Confirm capnography

·           Fibreoptic down tracheal lumen

·           Look for carina + trachealis + enlocated bronchial cuff

Lower lung

·           ↑PEEP

·           ↑PIP

·           ↑i-time

Upper lung

·           Ask permission from surgeon to ventilate upper lung

·           Gentle hand-bagging – long i-time

·           CPAP circuit

Drugs

·           Reduce volatile to <1 MAC

·           Switch to propofol TIVA

Last ditch

·           Ask surgeon to clamp the upper lung pulmonary artery

 

Feedback welcome at ketaminenightmares@gmail.com