Table 1.

Classification of patients according to the weaning process

Group/category	Definition
Simple weaning	Patients who proceed from the initiation of weaning to successful extubation on the first attempt without difficulty
Difficult weaning	Patients who fail initial weaning and require up to three spontaneous breathing trials or as long as 7 days from the first spontaneous breathing trial to achieve successful weaning
Prolonged weaning	Patients who fail at least three weaning attempts or require > 7 days of weaning after the first spontaneous breathing trial