Simple, difficult, or prolonged weaning: the most important factor is the success or failure of the first weaning trial.

A recent international consensus conference1 published in 2007 proposed to categorize ventilated patients into 3 groups, based on the difficulty and duration of the weaning process: “simple weaning” (group 1) includes patients who succeed the first weaning trial and are extubated without difficulty, “difficult weaning” (group 2) includes patients who fail the first weaning trial and require up to 3 spontaneous breathing trials or 7 days to achieve successful weaning, and “prolonged weaning” (group 3) includes patients who require more than 7 days of weaning after the first weaning trial. According to the literature,2-4 the proportion of patients in each group was estimated at 70% for simple weaning, 15% for difficult weaning, and 15% for prolonged weaning. The conference emphasized that the first weaning trial must be performed as soon as the patient meets the following criteria: resolution of disease for which the patient was intubated; cardiovascular stability with no or minimal vasopressors; no continuous sedation; and adequate oxygenation, defined as PaO2/FIO2 150 mm Hg and PEEP 8 cm H2O.