Hamsiao

Hey guys I have an oddly specific scenario and I'd really appreciate some advice! Basically we had a patient with hypokalemia and they ordered IV potassium chloride. Initiating the IV potassium kept burning the patient's arm despite running it at a slower rate so I tried to dilute it with some normal saline KVO. What I did specifically was Run the potassium on a pump so that the 100cc bag would finish in a lil over an hour (forgot the exact rate). Then I connected that tubing to the higher port on a small bag of NS 100cc in total which was connected to the patient. Later on I checked on the patient and found the potassium bag empty but the bag of saline seemed bigger than it initially was. The saline also seemed to start burning her, so I am worried that the potassium backed up into the saline and she never got the full dose. I did end up filling an incident report and wrote myself up. The doctor did not seem concerned at all, the patient is not harmed, and all my coworkers now think I'm a crazy worrywort because they stated it was impossible for the potassium to back up into the saline since they were both on pumps. But I want to know for the future in case this scenario happens again. Do you think the potassium backed up into the saline? What would you have done?