Deciding when to remove an endotracheal (i.e., breathing tube) from a patient in the ICU is in part governed by the patient’s weaning parameters. Although there are many protocols used, most intensive care physicians focus on three factors to evaluate the patient’s ability to tolerate removal of the ET tube. These are:
1. Rapid shallow breathing index (RSBI or Tobin score) of less than 105 and optimally less than 85 on no ventilator support. This value is usually calculated by the ventilator is the frequency of breaths divided by the tidal volume in liters.
2. Negative inspiratory force (NIF) of > than -30 mmHG. This is a physiological measure of the patient’s ability to cough and clear secretions.
3. A vital capacity of > 10cc/kg on miminal ventilator support.
Generally, the “foot of the bed” test should not be used to decide on intubation without consideration of the above parameters.