Plankton Sign on POCUS Complex pleural effusion after CABG - plankton sign Plankton sign + , swirling internal echoes in anechoic collection with multiple septae and echogenic areas of ? clots - highly suggestive of hemothorax and rules out transudate. History is important. Dr. Marcio Siqueira Jr @masiqueirajr #Plankton #Sign #POCUS #clinical #pulmonary #effusion #pleural