Final answer:
Cold therapy following an arm contusion causes vasoconstriction, reduces the formation of edema and inflammation, and lessens muscle spasms. It reduces, rather than increases, blood flow to the affected area and helps with pain relief by inhibiting the release of pain-inducing substances.
Step-by-step explanation:
A nurse applying cold therapy to a client with a contusion of the arm can anticipate several physiological effects. Cold therapy typically causes vasoconstriction, which is the narrowing or constricting of blood vessels, leading to reduced blood flow in the immediate area. This action can help reduce swelling and bruising by minimizing the flow of fluid into the tissues, which helps to reduce the formation of edema and inflammation.
In addition, by decreasing the blood flow, cold therapy can also reduce muscle spasms that are often associated with injury or inflammation. The cold can interfere with the pain transmission, thus providing pain relief.
It is important to note that cold therapy does not increase blood flow to tissues or cause vasodilation; rather, it has the opposite effect. Likewise, cold therapy does not increase the local release of pain-producing substances but rather helps to reduce them.