ABSTRACT
Ely et al. (6) used the following five criteria for their screen for readiness to proceed with an SBT: (1) f/Vt < 105; (2) PaO
> 200; (3) PEEP < 5 cm H 2 O; (4) adequate cough during suc-
tioning; (5) no infusions of vasopressors or sedatives (low rate of dopamine was acceptable). Yang and Tobin (7) described f/Vt as a test to be used to prior to an SBT. f/Vt should be measured after removing the patient from assisted ventilation (no PS, no PEEP), and it can be measured within the first few minutes of unassisted ventilation. The threshold value is typically < 100.
