While Paracentesis is a common enough procedure in the emergency department (for either diagnostic or therapeutic purposes), we must remember that LOW RISK does NOT = NO RISK. In the literature ~ 1 % of paracentesis result in severe hemorrhage requiring transfusion or even operative intervention. There is even risk of death.
While it has become standard of care to utilize static US-guidance to "find the best pocket," remember that you can also consider utilizing real-time US guidance to guide your needle. Dr. Hollingsworth reviews a case where he utilized US-guidance to successfully perform a paracentesis. Resulting in an important diagnosis of first-time spontaneous bacterial peritonitis!
And remember, next time you are on shift to always CONSIDER THE PROBE!