Final answer:
The nurse would document the loud murmur with no thrill as Grade IV.
Step-by-step explanation:
According to the given information, the murmur is loud, but there is no thrill associated with it. Murmurs are graded on a scale of 1 to 6, with 1 being the least serious. Based on this grading system, the nurse would document the loud murmur with no thrill as Grade IV.
It's important to note that the absence of a thrill indicates that the murmur is not associated with a strong vibration or palpable sensation.