Weaning from mechanical ventilation

Practice guidelines on weaning should be based on the results of several we ll-designed randomized studies performed over the last decade. One of those studies demonstrated that immediate extubation after successful trials of spontaneous breathing expedites weaning and reduces the duration of mechani cal ventilation as compared with a more gradual discontinuation of ventilat ory support. Two other studies showed that the ability to breathe spontaneo usly can be adequately tested by performing a trial with either T-tube or p ressure support of 7 cmH(2)O lasting either 30 or 120 min. In patients with unsuccessful weaning trials, a gradual withdrawal for mechanical ventilati on can be attempted while factors responsible for the ventilatory dependenc e are corrected. Two randomized studies found that, in difficult-to-wean pa tients, synchronized intermittent mandatory Ventilation (SIMV) is the most effective method of weaning.