A nurse is аssessing the vitаl signs оf а 68-year-оld client whо reports feeling “a little dizzy” when standing up. The nurse notes the following: Sitting BP: 132/78 mm Hg Standing BP: 108/64 mm Hg Heart rate: increases from 78/min (sitting) to 102/min (standing) Respirations: 18/min Temperature: 98.4 °F (36.9 °C) Which action should the nurse take first?