The effect of thoracentesis on lung function and transthoracic electrical bioimpedance

This study aimed to determine the relationship between improvement in lung function and changes in transthoracic electrical bioimpedance (TEB) after t horacentesis in patients with pleural effusions. Fifteen patients with pleural effusions due to either malignant (n=8) or ca rdiac (n=7) diseases were included. Pulmonary function was assessed before and after thoracentesis. During thoracentesis the patients were monitored w ith TEE. Using linear correlation analysis, the increases for each litre of aspirate d thoracic fluid wen: forced expiratory volume in 1 s (FEV,) 0.261; forced vital capacity (FVC)0.33 1; total lung capacity (TLC)0.58; and the lung dif fusing capacity (DLCO)I 2.4 mi min(-1) mmHg(-1) . Baseline impedance increa sed by 2.3 Ohm l(-1) ' aspirated thoracic fluid. The relative increase in b aseline impedance was twice: as high for patients with cancer as for patien ts with heart failure (P<0.05). We found only minor changes in systolic blo od pressure and mean arterial pressure. The improvements in diffusing capacity, airflow, and lung volumes after tho racentesis are correlated to an increase in baseline impedance, but changes are dependent on the primary disease.