Arguably the simplest way to achieve one-lung ventilation is through deliberate bronchial intubation with a standard endotracheal tube. If this is used as a blind technique, the tube is most likely to go down the right main bronchus, as the course of the right main bronchus is more in line with the trachea than the course of the left, which comes off at the carina at a bigger angle.
This technique has several drawbacks: When a standard ETT is used to intubate the right main bronchus, the tube cuff is very likely to occlude the right upper lobe bronchus. So in addition to isolating the left lung this technique can inadvertently also isolate a significant part of the right lung. A second disadvantage is that left main bronchus intubation is not reliably achieved when this technique is used blindly. A fiberoptic scope is therefore frequently necessary to place a tube into the left main bronchus.