Henry Ford Health System (HFHS) Critical Care Practice Exam

Pressure Support Ventilation (PSV) is a mode of mechanical ventilation where the ventilator assists the patient's spontaneous breathing efforts by providing a set pressure during inspiration. One of the key characteristics of PSV is that the tidal volume delivered can vary based on several factors, particularly the patient's respiratory mechanics, including airway resistance and lung compliance.

When airway resistance is significant, the pressure support may not yield consistent tidal volumes. If the patient's airway resistance increases, for example due to bronchospasm or secretions, the tidal volume can decrease even if the pressure support level is unchanged. This variability may also reflect differences in the patient's effort and overall lung mechanics, leading to inconsistent ventilation and potentially impacting overall gas exchange.

Understanding this variability is crucial for clinicians managing patients on PSV, as it can affect the adequacy of ventilation and oxygenation. By recognizing the role of airway resistance in influencing tidal volume, healthcare providers can make more informed decisions about adjusting ventilator settings or addressing underlying issues.