A 58-year-old male is admitted with a history of kidney stones. Over the past three hours, the nurse monitors the following: Parameter 7:30 9:00 1:15 Temperature 99.4 99.6F 100.1°F Heart Rate 60 68 70 Right Flank Pain 4/10 6/10 9/10 Urinary output 94ml 95 ml 75 ml Based on this trend, which finding requires the nurse's immediate attention?