Crazy mixup #2

A little old lady turned up at the Emergency Department not long ago with a grossly distended and tense abdomen.  We were pretty sure that her underlying problem was severe right heart failure but the fly in the ointment was that she did have hereditary angioedema.  I was halfway through working her up when my registrar walked into the cubicle to find me doing a beautiful soft-shoe shuffle in front of a bemused patient.

"What are you doing?" shrieked my registrar, "I asked you do do an ascitic tap!"

"Oh!" said I, "I thought you said an asthetic tap."