A single lumen endobronchial tube comprising: a medical tube comprising a single lumen extending between a proximal end and a distal end of the medical tube, the medical tube having a tracheal portion and a bronchial portion distal to the tracheal portion such that the single lumen extends through the tracheal and bronchial portions, wherein the single lumen includes a first opening at a proximal end of the tracheal portion adapted for connection of the single lumen to an external mechanical ventilation device to supply a medical gas to the single lumen, and a second opening at a distal end of the bronchial portion adapted for delivery of the medical gas from the single lumen to a left lung of a patient; a first tracheal inflatable cuff positioned around an external surface of the tracheal portion and adapted to expand radially outward for sealing against a trachea of the patient; a second tracheal inflatable cuff positioned around an external surface of the tracheal portion and located at a position distal to the first tracheal inflatable cuff, the second tracheal inflatable cuff adapted to expand radially outward for sealing against the trachea of the patient; a bronchial inflatable cuff positioned around an external surface of the bronchial portion and adapted to expand radially outward against the left main stem bronchi of the patient; an aperture positioned between the first tracheal inflatable cuff and the second tracheal inflatable cuff and adapted to deliver an amount of the medical gas to a right lung of the patient; and characterised in that it further comprises a distal intraluminal balloon blocker positioned in the single lumen of the bronchial portion and adapted to expand radially outward for sealing the single lumen in the bronchial portion. a medical tube comprising a single lumen extending between a proximal end and a distal end of the medical tube, the medical tube having a tracheal portion and a bronchial portion distal to the tracheal portion such that the single lumen extends through the tracheal and bronchial portions, wherein the single lumen includes a first opening at a proximal end of the tracheal portion adapted for connection of the single lumen to an external mechanical ventilation device to supply a medical gas to the single lumen, and a second opening at a distal end of the bronchial portion adapted for delivery of the medical gas from the single lumen to a left lung of a patient; a first tracheal inflatable cuff positioned around an external surface of the tracheal portion and adapted to expand radially outward for sealing against a trachea of the patient; a second tracheal inflatable cuff positioned around an external surface of the tracheal portion and located at a position distal to the first tracheal inflatable cuff, the second tracheal inflatable cuff adapted to expand radially outward for sealing against the trachea of the patient; a bronchial inflatable cuff positioned around an external surface of the bronchial portion and adapted to expand radially outward against the left main stem bronchi of the patient; an aperture positioned between the first tracheal inflatable cuff and the second tracheal inflatable cuff and adapted to deliver an amount of the medical gas to a right lung of the patient; and characterised in that it further comprises a distal intraluminal balloon blocker positioned in the single lumen of the bronchial portion and adapted to expand radially outward for sealing the single lumen in the bronchial portion. <EOS>