Optimizing patient-ventilator synchrony

Mechanical ventilation assumes the work of breathing, improves gas exchange , and unloads the respiratory muscles, all of which require good synchroniz ation between the patient and the ventilator. Causes for patient-ventilator dyssynchrony include both patient factors (abnormalities of respiratory dr ive and abnormal respiratory mechanics) and ventilator factors (triggering, flow delivery breath termination criteria, the level and mode of ventilato r support, and imposed work of breathing). Although patient-ventilator dyss ynchrony can often be detected on physical exam, careful analysis of ventil ator waveforms (pressure-time, flow-time) allows for more precise definitio n of the underlying cause. Patient-ventilator interaction can be improved b y reversing patient factors that alter respiratory drive or elevate patient ventilatory requirements and by correcting factors that contribute to dyna mic hyperinflation. Proper setting of the ventilator using sensitive trigge ring mechanisms, satisfactory flow rates, adequate delivered minute ventila tion, matching machine TI to neural T,, and applying modes that overcome th e imposed work of breathing, further optimize patient-ventilator synchrony.