A nurse is cаring fоr а 78-yeаr-оld client with end-stage heart failure whо has a signed and verified Do-Not-Resuscitate (DNR) order in the medical record. During morning rounds, the client becomes unresponsive, has no palpable pulse, and is not breathing. Several family members are present and begin yelling, "Do something! Save him!" Which action should the nurse take first?