What action should a nurse take to prevent compartment syndrome in a client with a newly applied plaster leg cast?

To prevent compartment syndrome in a client with a newly applied plaster leg cast, it is important to maintain adequate circulation and ensure that swelling does not occur to a degree that would compromise blood flow within the muscle compartments. Elevating the limb slightly is the most appropriate action as it can help reduce swelling by facilitating venous return without risking further complications.

Keeping the leg elevated above heart level may restrict arterial blood flow and could lead to further complications. It is essential to find a balanced position where the limb is elevated enough to assist in reducing swelling but not so high that it adversely affects circulation.

Applying ice to the cast can also be beneficial in reducing swelling; however, this is typically done intermittently and with care, so as not to cause skin damage. It does not directly address how to position the limb for optimal circulation.

Performing range of motion exercises would not be advisable in the context of a newly applied cast, as movement could jeopardize the immobilization necessary for healing and could further increase the risk of developing compartment syndrome.

In summary, slightly elevating the limb promotes circulation and can prevent excessive swelling, thus being the most effective approach to mitigate the risk of compartment syndrome in this situation.