A nurse has just received the morning change of shift report for four clients. Which of the following clients has the highest priority need?

B A client who returned 1 hour ago from lithotripsy and is reporting nausea. A A client who has a serum potassium level of 5 mEq/L and is scheduled for dialysis in the afternoon. D A client who has an indwelling urinary catheter and has a total urine output of 80 mL over the past 8 hours. C A client who had a total abdominal hysterectomy 2 days ago and is reporting a pain level of 3 on a scale of 0 to 10.