Cannulation of a large central vein is the standard clinical method for mornitoring CVP and is also performed for a number of additional therapeutic interventions, such as providing secure vascular access for administration of vasoactive drugs or to initiate rapid fluid resuscitation in operation or for aspiration of air emboli. But there are many complications such as vessel injury, pneumothorax, nerve injury, arrhythmias, arteriovenus thrombus, pulmonary emboli, infection at insertion site, because there are major vessels, nerve and organs around of central veins. We report a case of Rt. Hydrothorax after internal jugular vein cannulation and a contralateral reexpansion pulmonary edema and pleural effusion after Rt. chest tube insertion for hydrothorax.