Therapeutic thoracentesis will be performed in a sitting position. wide bore catheter as a pleural catheter will be inserted into the pleural cavity. simple water manometer will be connected to the pleural catheter via 3-way adapter.connected to the infusion lines with one draining into the drainage collection bottle and the other pre-flushed with normal saline hanging down till 40 cm below the puncture site and then rising up (forming a "U") with the ascending arm taped to the IV stand. baseline pleural pressure will be registered before the beginning of pleural fluid withdrawal. Pleural pressure curve will subsequently be registered after the withdrawal of each 200 ml of pleural fluid up to a total volume of 1000 ml.

Therapeutic thoracentesis will be performed in a sitting position. The skin will be cleaned with betadine antiseptic solution. Pleural aspiration should take place in a clean area using full aseptic techniques. 5-10 cc Lidocaine 2% will be given as local anesthetic in the site of puncture. the IV cannula is advanced till fluid is aspirated. Then, the needle is withdrawn and the catheter is fixed to two 3-way adapters fixed in series placed in between. connected to the infusion lines with one draining into the drainage collection bottle.

Recording pleural pressure during therapeutic thoracocentesis using a simple water manometer.

To measure the pleural pressure(mmHg) during thoracocentesis in patients with pleural effusion using a simple water pleural manometer