Carotid sinus massage is indicated in the elderly patient who has a history of unexplained falls, loss of consciousness and presyncope, and in whom results of the cardiac and neurologic work-up have been inconclusive. Because syncopal episodes account for a large number of emergency department visits in the elderly, physicians should know how to perform this maneuver. O'Shea and Parry describe the protocol used in their clinic, which has about 3,000 new patients each year.
Absolute contraindications to carotid sinus massage include myocardial infarction, transient ischemic attack or stroke within the preceding three months. A history of ventricular fibrillation or tachycardia, or a previous adverse reaction to carotid sinus massage are also absolute contraindications. A relative contraindication is the presence of carotid bruits, which should be evaluated by Doppler ultrasonography before proceeding with massage. If the ultrasound shows stenosis or atheroma, the patient should understand the risks and benefits of the procedure.
Electrocardiography (ECG) and continuous blood pressure monitoring should occur with the patient supine for at least five minutes before the carotid sinus massage. Baseline systolic and diastolic blood pressure measurements and heart rate should be recorded. By convention, carotid sinus massage is first done on the right carotid sinus with the patient supine. The carotid sinus is between the angle of the mandible and the superior border of the thyroid cartilage. The carotid sinus should be massaged firmly (editor's note: It has been described as the amount of pressure needed to indent a tennis ball) and should last five seconds. This five-second period should be marked on the ECG, and the ECG should continue until the baseline heart rate has returned. The lowest systolic and diastolic blood pressure measurements usually occur within 15 seconds of the end of the carotid sinus massage and should be recorded.
Carotid sinus massage should be discontinued immediately if the ECG shows asystole for more than three seconds. If asystole is prolonged, a chest blow should be administered. If neurologic complications occur, the procedure should be stopped, aspirin should be given if not contraindicated, and the patient should be closely observed. Symptoms of pre-syncope or syncope should be recorded and compared with the original symptoms for which the patient is being evaluated. The procedure is then repeated on the left side with the patient in the supine position, and then on both sides with the patient in the erect position. The diagnostic rate increases when the carotid sinus massage is repeated in the upright position. The baseline values should return before the next step of the procedure is begun. After the procedure, the patient should be observed in the supine position for at least 10 minutes before discharge.