Scintigraphic Assessment of Lung Perfusion and Ventilation in Patients After Pneumonectomy

Background/Objectives: The physiological ventilation-perfusion ratio (V/Q) in the upper pulmonary field is >3 and in the lower pulmonary field it is <1 due to the effect of gravity when the body is in an upright position. Pneumonectomy leads to significant changes in ventilation and perfusion conditions. The aim of this study was to evaluate perfusion and ventilation after pneumonectomy complicated by pleural empyema, including the relationship between surgical outcomes, sex, and time from pneumonectomy. Methods: The study group included 30 patients (25 men, 5 women) who underwent pneumonectomy complicated by pleural empyema. Lung function was assessed using ventilation-perfusion scintigraphy. Twenty-one patients were assessed within 5 years after pneumonectomy and nine patients >5 years after pneumonectomy. Results: Average flow was 21.1% in the upper field, 47.8% in the middle field, and 30.35% in the lower field. The mean perfusion value was significantly higher in the lower field of the right lung than in the lower field of the left lung (33.35 vs. 28.05, p = 0.001). Average ventilation was 17.21% in the upper field, 46.73% in the middle field, and 34.28% in the lower field. The mean V/Q in the upper field was in the range of 0.81-0.87, but it reached approximately 1 (0.96-1) in the middle field and exceeded 1 (1.05-1.25) in the lower field. Conclusions: Pneumonectomy led to increased perfusion in the upper pulmonary field and increased ventilation in the lower pulmonary field compared to the literature for patients with the two lungs (the two-lung system), with a reversal of the V/Q between the upper and lower field.