Weaning refers to the process in which the intensive care team try to get a patient to breathe without the help of the mechanical ventilator. When patients have recovered enough, they often can breathe by themselves or with only a little help from the ventilator. This ability is checked during a short testing period called a weaning "trial." If the patient remains comfortable during a trial, an arterial blood gas if taken. If a patient becomes very short of breath or anxious during the weaning trial or if the levels of oxygen or carbon dioxide are not at an acceptable level, the patient has "failed" the trial. Further attempts at weaning may be made later that day or on another day.
In some cases, the intensive care staff chooses to reduce, in steps, the amount of help a patient gets from the ventilator. This reduction can occur rapidly (over minutes or hours) in patients who are doing well, or it can occur gradually (over days) in patients who are still moderately ill. At each step, the comfort of the patient is assessed. Computer-driven protocols for weaning have been developed as described below.
i. Review: Weaning from mechanical ventilation. Critical Care 2000, 4:72-80
ii. A Multicenter Randomized Trial of Computer-driven Protocolized Weaning from Mechanical Ventilation
iii. SmartCare®/PS-The automated weaning protocol