Failure to ventilate in critical illness

Mechanical ventilation is an efficacious therapy to respiratory failure because it improves gas exchange and rests respiratory muscles. During controlled mechanical ventilation, a patient’s inspiratory muscles are resting and the ventilator delivers a preset tidal volume through the generation of inspiratory flow, overcoming resistive and elastic thresholds of the respiratory system. During assisted ventilation, the same goal is reached through an interplay between the patient’s inspiratory muscles and ventilator. Every perturbation of this interaction causes patient ventilator asynchrony and exposes to the risk of failure to ventilate. Patient–ventilator asynchrony may occur at each stage of assisted breath Signs of patient’s discomfort, the use of accessory muscles, tachycardia, hypertension, and assessment of flow and airway pressure traces displayed on modern ventilators, helps to detect asynchronies. Prompt recognition and intervention to improve patient–ventilator interaction may expedite liberation from mechanical ventilation, and reduce intensive care unit and length of hospital stay.