ESTER: an expert system for management of respiratory weaning therapy

The withdrawal of mechanical ventilation generally presents no problems if carried out when the values of certain predictive physiological variables suggest that the patient will be able to breathe for him or herself. In certain cases, however, a more gradual weaning procedure is necessary, in which the amount of mechanical assistance provided is in some way reduced little by little. One of the usual means of achieving this gradual reduction is by intermittent mandatory ventilation (IMV), in which short bursts of mechanical ventilation are separated by progressively longer periods of "ventilator silence" which stimulate the patient's endogenous respiration. ESTER is an expert system in which the most widely accepted criteria are systematically called upon to supply advice to the clinician who has to prescribe a respiratory therapy regime suited to the needs of the patient. After effecting a preliminary prognosis of the patient's condition, ESTER asks for certain physiological parameters to be keyed in. Analysis of these parameters reveals the patient's condition and allows a recommended respiratory therapy to be designed.