The SBT is meant to accurately predict the tolerance
of unassisted breathing after extubation. However, itdoes not predict well the consequences of the tube
removal in terms of upper airway patency and lower
airway protection, removal of secretions and,
ultimately, the ability to sustain spontaneous
breathing. Interestingly, it has been suggested that
extubation success may be well correlated to the
patient’s subjective perception of his ability to
breathe without the ventilator