The patient, age 30, has a history of renal calculi and is admitted to the hospital with gross hematuria and severe colicky left flank pain that radiates to his left testicle. an intravenous pyelogram confirms the presence of a 4-mm renal calculus in the proximal left ureter. physician orders include meperidine (demerol) 100 mg 1m q4h prn, strain all urine, and encourage fluids to 4,000 mL/day. in planning care for this client, the nurse gives the highest priority to which nursing diagnosis?