In mechanically ventilated patients, assisted
mechanical ventilation (MV) is employed early, following the acute phase of
critical illness, in order to eliminate the detrimental effects of controlled MV, most notably the development of
ventilator-induced diaphragmatic dysfunction. Nevertheless, the benefits of assisted MV are often counteracted by the development of
patient-ventilator dyssynchrony.
Patient-ventilator dyssynchrony occurs when either the initiation and/or termination of mechanical breath is not in time agreement with the initiation and termination of neural inspiration, respectively, or if the magnitude of mechanical assist does not respond to the patient's respiratory demand. As
patient-ventilator dyssynchrony has been associated with several adverse effects and can adversely influence patient outcome, every effort should be made to recognize and correct this occurrence at bedside. To detect
patient-ventilator dyssynchronies, the physician should assess patient comfort and carefully inspect the pressure- and flow-time waveforms, available on the
ventilator screen of all modern
ventilators. Modern
ventilators offer several modifiable settings to improve patient-
ventilator interaction. New proportional modes of ventilation are also very helpful in improving patient-
ventilator interaction.