Final answer:
A client's report that "the dressing over my incision feels like it is too tight" after a subtotal thyroidectomy warrants immediate investigation due to the risk of a hematoma that could lead to tracheal compression.
Step-by-step explanation:
The statement by a client who is 24 hours post-subtotal thyroidectomy that requires an immediate investigation by the nurse is: "the dressing over my incision feels like it is too tight". This could be indicative of postoperative bleeding or swelling, and the tightness described by the client could suggest the development of a hematoma under the incision site, which could lead to complications such as tracheal compression. Immediate assessment and potential intervention are crucial to prevent more severe outcomes.