When suspecting grade 3 phlebitis, what is the first nursing action?

Stopping the intravenous fluid infusion is the first nursing action when grade 3 phlebitis is suspected. This level of phlebitis indicates significant inflammation of the vein, which could lead to more severe complications, such as infection or thrombosis, if the infusion were to continue. By halting the infusion, the nurse minimizes the risk of further irritation and damage to the vein.

In this situation, the priority is to ensure patient safety and prevent any exacerbation of the existing condition. Other actions, such as applying a cool compress, notifying the physician, or reassessing the site, should follow but are secondary to stopping the infusion. These subsequent actions could be taken to manage symptoms or alert healthcare providers, but addressing the immediate risk to the vein is crucial.