A client is admitted to the hospital with deep vein thrombosis (DVT). An infusion of heparin is established. What nursing action best protects the client's safety if the antidote is needed?

A. Ensure that the client's cellphone is easily accessible: While it is important for clients to have access to communication in case of an emergency, this action does not directly relate to the safety measures for managing heparin therapy or reversing its effects. B. Have two nurses independently monitor the client's heparin infusion: While independent double-checking is a good practice for ensuring correct medication administration, it is not the most critical action in preparing for the potential need for an antidote. C. Ensure that protamine sulfate is readily available: Protamine sulfate is the antidote for heparin overdose or excessive anticoagulation. In the event of a bleeding complication, it is crucial that this antidote is readily available to reverse the effects of heparin quickly and safely. D. Keep a preloaded syringe of vitamin K in the room: Vitamin K is the antidote for warfarin, not heparin. Therefore, keeping vitamin K available would not be effective in reversing the effects of heparin therapy. The correct antidote for heparin is protamine sulfate.