It’s important that the patient be lying down, in case they experience any lightheadedness or loss of consciousness from the CSM.

Even if you’re performing a CSM to reduce a patient’s excessively rapid heartbeat (supraventricular tachycardia, or SVT), you should still monitor the heart’s electrical activity via ECG. Use an ECG every time a CSM is performed. [6] X Research source

Once the patient has lain down, and you have applied the ECG and began monitoring blood pressure, wait five minutes before beginning the procedure. This will allow the patient’s heart to slow to a resting rate so you can get an accurate baseline measurement of blood pressure and heart rate.

The angle of the jaw should be the location at which their jawbone bends, about 4 inches (10 centimeters) back from the tip of their chin. The second carotid sinus will be located in the identical position on the other side of the patient’s neck.

Avoid pressing too hard, or you may risk reducing the flow of oxygen to the patient’s brain. As a rule of thumb, use the amount of pressure that you would need to indent the surface of a tennis ball.

If the patient’s cardiac arrest continues once you’ve stopped administering the CSM, you may need to begin performing live-saving measures, such as a precordial thump (chest blow). [12] X Research source Do not defibrillate unless the ECG shows a shockable rhythm such as ventricular fibrillation or ventricular tachycardia. Asystole is not a shockable rhythm.

If you’re performing the CSM for diagnostic purposes, ask the patient if the lightheadedness or fainting that they just experienced is similar to other symptoms they commonly experience.

Ask your patient if a physician has diagnosed them with CSH, or if they have ever had a negative reaction to—or lost consciousness during—a carotid sinus massage.

Myocardial Infarction Transient Ischemic Attack within the past 3 months Cerebrovascular Accident within the past 3 months History of Ventricular Fibrillation History of Ventricular Tachycardia Carotid Artery Occlusion Previous adverse reaction to CSM If a patient has a carotid bruit, a carotid ultrasound should be done first to check for stenosis. [17] X Research source