What symptom may indicate a complication from a supraclavicular block in a patient after surgery?

Unequal pupil diameter can indicate a complication from a supraclavicular block due to the potential involvement of the sympathetic nervous system during the procedure. A supraclavicular block targets the brachial plexus, which is located near the neck and can affect nearby structures, including the sympathetic chain. If the sympathetic fibers are inadvertently affected during the block, it can lead to Horner's syndrome, characterized by ptosis (drooping of the eyelid), miosis (constricted pupil), and sometimes anhidrosis (absence of sweating) on the affected side of the face. The resultant presence of unequal pupil diameter is a clear sign of such a complication.

Gastrointestinal upset, increased heart rate, and elevated blood pressure may occur for a variety of reasons unrelated to a supraclavicular block. Gastrointestinal upset is often linked to the patient's response to anesthesia or medications rather than the block itself. Increased heart rate and elevated blood pressure can be responses to pain, anxiety, or other systemic factors during the postoperative period, but they do not specifically indicate a complication from the supraclavicular block. Therefore, these symptoms do not provide the same level of diagnostic clue as unequal pupil diameter does in relation to a supraclavicular block complication