PURPOSE: Pleural effusion leads a decrease of mechanical advantage and lung expansion ability of diaphragm muscle causing dyspnea. Thoracentesis usually relieves the symptoms improving the performance of diaphragm by working on more advantageous position. The maximal inspiratory pressure (Pimax) and the maximal expiratory pressure (Pemax) are useful to evaluate the respiratory muscle strength. The aim of this study was verify if after therapeutic thoracentesis there are improvement in Pimax and Pemax.
METHODS: Fourteen patients with large pleural effusion were submitted to therapeutic thoracentesis and had Pimax and Pemax evaluated before and 48 h after the procedure. Paired test-t was used to compare results.
RESULTS: Results are expressed in mean and standard deviation as shown in the table and figure. The mean of drained pleural effusion was 1646 ± 619 ml. The mean of Pimax was -71 ± 16 cmH2O before and -89 ± 9 cmH2O after (p < 0.001). The mean of Pemax was 79 ± 22 cmH2O before and 92 ± 20 cmH2O after thoracentesis (p = 0.002).
CONCLUSION: Thoracentesis improves the maximal inspiratory and expiratory pressures. We suggest that the improvement on respiratory muscle strength after thoracentesis occurs because the diaphragm is able to work on more advantageous position on the chest wall.
CLINICAL IMPLICATIONS: The evaluation of Pimax and Pemax, an easy test to be performed, may help to understand the diaphragm dynamic in patients with pleural diseases.
DISCLOSURE: Lisete Teixeira, No Financial Disclosure Information; No Product/Research Disclosure Information