Techniques for single lung ventilation (SLV) include a hollow main tube with outer diameter sized to fit inside a bronchus of a patient. The length of the main tube is sufficient for a distal end of the main tube to reach a first side bronchus from a proximal end configured to be located in a vicinity of a mouth of the patient. The hollow main tube has a ventilating orifice separated from the distal end at a location that corresponds to a different second side bronchus. A hollow tubular sleeve is moveably disposed inside and longitudinally aligned with the main tube. The sleeve is configured to be positioned in at least two positions: a first position that does not block the ventilating orifice and, a second position that does block the ventilating orifice.