The Nurse Suspects Cardiac Tamponade in a Patient Who Has

The nurse suspects cardiac tamponade in a patient who has acute pericarditis. To assess for the presence of pulsus paradoxus,the nurse should

A) subtract the diastolic blood pressure from the systolic blood pressure.
B) note when Korotkoff sounds are auscultated during both inspiration and expiration.
C) check the electrocardiogram (ECG) for variations in rate during the respiratory cycle.
D) listen for a pericardial friction rub that persists when the patient is instructed to stop breathing.