Final answer:
The third lumen in a Foley catheter is used for medication administration, providing a direct pathway for medicine to the bladder, which is different from other functions related to temperature regulation or hemostasis control. Option 2 is correct.
Step-by-step explanation:
The additional function of the third lumen in a Foley catheter, aside from inflation and drainage, is Option 2: Medication administration.
A Foley catheter typically has two lumens or channels; one is used to drain urine from the bladder to a collection bag, while the other is used to inflate a balloon at the tip of the catheter that prevents the tube from sliding out of the bladder.
The third lumen can be used to provide medications directly into the bladder. This could be useful in the treatment of bladder infections or instilling medication that needs to be in contact with the bladder lining. It is not designed for temperature regulation, hemostasis control, or contrast injection, which are functions more related to vascular or other medical equipment.