You are caring for a patient with a tracheostomy tube in place.

You are caring for a patient with a tracheostomy tube in place.  You determine that the patient needs to be suctioned.  Which of the following pieces of information is the most important in helping you determine the level of suction you should set on the suction dial?
a.   The viscosity of the secretions that need to be suctioned.
b.   The providers order will indicate what the level of suction should be.
c.   The level of suction that has been used on the shift before you (e.g. suction head is already set to a suction level)
d.   How often the shift before you had to suction the patient