A nurse is monitoring an 82-year-old male who had a transurethral resection of the prostate 12 hours ago. A three-way urinary catheter is inserted through the client’s urethra and into the bladder for continuous irrigation. A total of 3,000 mL of bladder irrigant has been infused for the past 8 hours. After assessing the client, the nurse immediately contacts the physician for a possible complication of the procedure. Which of the following is most likely noted by the nurse during the assessment?