Which nursing observation related to a client with a fractured humerus is critical for immediate intervention?

The most critical nursing observation for immediate intervention in a client with a fractured humerus is when the client reports severe pain. Severe pain can indicate complications such as inadequate pain management, potential irritation of surrounding tissues, or even the possibility of fracture displacement that may require urgent assessment and treatment.

While the other observations, such as ambulating in socks or the refusal to wear a sling, are notable, they do not immediately impact the client’s safety or well-being as significantly as severe pain would. Similarly, swelling is a common response to fractures; while it requires monitoring, it usually does not necessitate immediate intervention unless accompanied by other concerning symptoms. Prompt assessment and intervention in response to reported severe pain is essential to ensure the client’s comfort and to prevent further complications.