<unk>  is a medical procedure used for a number of reasons:
to relieve abdominal pressure from ascites
to diagnose spontaneous bacterial peritonitis and other infections (e.g. abdominal TB)
to diagnose metastatic cancer
to diagnose blood in peritoneal space in trauma
to puncture tympanic membrane for eg. to take bacterial swab from middle ear
Paracentesis
Thoracentesis
Peritoneovenous shunt
Ascites CT
Ascites surgery
Lithotomy
Percutaneous hepatic perfusion
Cholecystectomy