Final answer:
A nurse must closely observe and further evaluate if a patient with a newly applied cast shows a capillary refill of less than 6 seconds, as it could indicate poor circulation.
Step-by-step explanation:
When a nurse performs a neurovascular assessment on a client with a newly applied cast, close observation and further evaluation would be required if the nurse notes capillary refill less than 6 seconds.
A normal capillary refill time is usually less than 2 seconds; a refill time longer than this could indicate poor blood circulation or arterial blockage, potentially resulting in tissue hypoxia and necrosis.
Other signs that are normal and would not typically require additional evaluation include palpable pulses distal to the cast, blanching of the nail bed when it is depressed which should return to pink promptly when pressure is released which indicates adequate blood flow, and intact sensation when the area distal to the cast is pinched which indicates that nerve function is preserved.