What does it mean if the md does "central line placement procedure"?

Into the large vesse: Central line placement is a procedure that places a catheter into the large vessels near the heart generally for the purpose of providing fluids. The catheter is usually placed under the collar bone or neck. This is different from a IV placed in your forearm or hand. It allows one to give larger volumes of fluids or fluids in concentrations that might severely irritate smaller peripheral vessels.

Also: These lines are placed in seriously ill patients in the intensive care units to monitor the pressure within a vessel to help guide therapy.