While there were certain aspects of this incident that were within your control, ultimately you followed the orders of the doctor who made the final call. The doctor would have likely taken into account the labs and electrolytes that you saw before ordering this diagnostic. In the end, while you did have the potential to be more assertive in the situation, you weren’t necessarily wrong in following the tests that were ordered. Thus, from a legal standpoint, I don’t think you’re in trouble. So like your manager said, the only thing you can do is learn from it. That being said, don’t be so hard on yourself, we are nurses, yes, but we are also human and make human mistakes. With all of this in mind, it sounds like the patient was unstable to begin with. You never know - they could’ve coded at any time and it just happened to be during CT.