VQ mismatch
Impaired matching of ventilation and blood flow in the lungs, leading to inefficient gas exchange.
Full Definition
Ventilation-perfusion (VQ) mismatch occurs when there is inadequate matching between airflow (ventilation) and blood flow (perfusion) in different regions of the lung. In healthy lungs, ventilation and perfusion are closely matched to optimize gas exchange. When this relationship is disrupted—such as in pneumonia, pulmonary embolism, or ARDS—some areas may be well-ventilated but poorly perfused (dead space) or well-perfused but poorly ventilated (shunt). Respiratory therapists must understand VQ relationships to optimize ventilator settings, positioning, and other interventions that can improve gas exchange efficiency.
Usage
Usage note: May be written as V/Q mismatch, VQ mismatch, or ventilation-perfusion mismatch.
In Context
- "The patient's refractory hypoxemia suggests significant VQ mismatch rather than simple hypoventilation." — Pulmonary consultation note
- "Prone positioning may help reduce VQ mismatch in ARDS patients." — Respiratory therapy protocol