I had a pt last night that had a total knee replacement done on the 21st, well this pt last night was tachycardic, irregular HR and running a temp of 102.4. Previous shift medicated him with tylenol and got the temp down to normal. At 0400 lab comes to draw blood and I just happen to see her in the hallway and she states that the pt told her he had ran a fever and she was going to do blood cultures (as she was filling the bottles with blood to do the blood culture.) I thought oh ok couldn't hurt whatever and didn't think anything of it other than I didnt know lab could just decide what labs they thought were neccessary but whatever. At 0730 the nurse relieving me got a phone call from lab saying they had blood culture samples but no orders and that they needed orders to run them. I stated what had happenned and that they were no orders, the nurse getting report said well just write the order. I wrote the order and thought nothing more of it and came home. I was just called at 1400 by the charge nurse and informed that the Dr for this pt was upset and wanted to know why we ordered Blood cultures I told her what happenned and she was very understanding but said not to ever do it again and that she would let it go and not write anyone up. My question is ok I know I should have questioned this more but I was tired and ready to go and thougt it couldn't hurt to figure out why this guy was running a temp after surgery what would you have done?