Breathlessness is the most common symptom in individuals with pleural effusion and
is often disabling. The pathophysiology of breathlessness associated with pleural
effusion is complex. The severity of breathlessness correlates weakly with the size
of the effusion. Improvements in ventilatory capacity following pleural drainage are
small and correlate poorly with the volume of fluid drained and improvements in breathlessness.
Impaired hemidiaphragm function and a compensatory increase in respiratory drive to
maintain ventilation appear to be an important mechanism of breathlessness associated
with pleural effusion. Thoracocentesis reduces diaphragm distortion and improves its
movement; these changes appear to reduce respiratory drive and associated breathlessness
by improving the neuromechanical efficiency of the diaphragm.
Keywords
dyspnea - breathlessness - pleural effusion - ultrasonography - VAS - diaphragm
