Patient-Ventilator Asynchronies: Clinical Implications and Practical Solutions

Mechanical ventilation is a supportive treatment commonly applied in critically ill patients. Whenever the patient is spontaneously breathing, the pressure applied to the respiratory system depends on the sum of the pressure generated by the respiratory muscles and the pressure generated by the ventilator. Patient-ventilator interaction is of utmost importance in spontaneously breathing patients, and thus the ventilator should be able to adapt to patient's changes in ventilatory demand and respiratory mechanics. Nevertheless, a lack of coordination between patient and ventilator due to a mismatch between neural and ventilator timing throughout the respiratory cycle may make weaning difficult and lead to prolonged mechanical ventilation. Therefore, appropriate monitoring of asynchronies is mandatory to improve the applied strategies and thus improve patient-ventilator interaction. We conducted a literature review regarding patient-ventilator interaction with a focus on the different kinds of inspiratory and expiratory asynchronies, their monitoring, clinical implications, possible prevention, and treatment. We believe that monitoring patient-ventilator interaction is mandatory in spontaneously breathing patients to understand, by using the available technologies, the type of asynchrony and consequently improve the adaptation of the ventilator to the patient's needs. Asynchronies are relatively frequent during mechanical ventilation in critically ill patients, and they are associated with poor outcomes. This review summarizes the different types of asynchronies and their mechanisms, consequences, and potential management. The development and understanding of monitoring tools are necessary to allow a better appraisal of this area, which may lead to better outcomes for patients.