Carotid Sinus Massage
Technique:
- Place the patient in a supine position with their neck extended and rotated to the opposite side of the carotid sinus that the provider intends to massage. The carotid sinus is at the arterial impulse just inferior to the angle of the mandible, anterior to the sternocleidomastoid, and the upper level of the thyroid cartilage. The provider uses the fingertips of their index and middle finger to apply pressure in the posteromedial direction for 5 to 10 seconds. If unsuccessful, the procedure is repeatable after 1 minute. If still unsuccessful, the clinician may attempt the maneuver on the opposite side. Adjunct to the CSM includes placing the patient in Trendelenburg, leg raise, concomitant VM, or simultaneously applying pressure to the patient’s upper abdomen. Possible responses to the CSM include slowing of the patient’s heart rate, termination of arrhythmia, or no response.
Contraindications:
- Avoid carotid sinus massage (CSM) in patients with carotid bruits and patients with a history of transient ischemic attack (TIA) or stroke. Also, avoid it in patients who have experienced ventricular tachycardia, ventricular fibrillation, or myocardial infarction in the past three months. Older age is a relative contraindication because this population has a higher risk for carotid artery disease. Rarely, performing CSM in patients with carotid artery disease may induce transient or permanent neurological symptoms. Simultaneous bilateral CSM is contraindicated, given the risk of compromising cerebral circulation. CSM has not been studied in pediatric patients and is not recommended in children less than ten years old.
Valsalva
Technique:
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Standard VM - the patient is placed in the supine position and asked to take a deep breath and blow out against a closed glottis for 10 to 15 seconds. Variations include asking the patient to blow a 10 mL syringe until the plunger moves for 10 to 15 seconds. In children, the VM may be tried by using an obstructed straw or asking them to blow on their thumb.
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Modified Valsalva Maneuver – The modified VM has been found to be more efficacious than the standard VM. In at least one study, success rate (conversion to sinus rhythm) for the modified VM was upwards of 40%, more than double the success rate of the standard VM. In contrast to the standard VM, the patient begins in an upright sitting position in the modified VM. The patient then blows against a closed glottis or syringe and is immediately dropped into a supine position. Simultaneously to the head of the bed being lowered, the patient’s legs are brought into either a knees-to-chest position or in an extended 45 to 90-degree angle to the torso. The patient continues to blow outwards for 10 to 15 seconds, and the legs are held in position for 45 seconds to one minute. The maneuver is repeatable if needed.
Contraindications:
- See linked note. No absolute contraindications. The patient must be capable of following commands. Tachypnea and dyspnea are relative contraindications due to the unlikeliness of success.
Diving Reflex
Technique:
- The adult patient should be in a comfortable seated position for 1 to 3 minutes. They should take multiple deep breaths, then hold their breath in inspiration. Immediately, the patient immerses their face into the basin of water. The physician should speak to them throughout this time in a calming voice, informing them about the progress of the procedure. The patient may stay immersed as long as tolerated but should resurface if they become air hungry. For the infant or young pediatric patient, place the patient in a supine position, and cover the forehead and nose with the bag of ice water for up to 30 seconds. Observe for resolution of the SVT.
Contraindications:
- The adult or adolescent patient must be able to submerge their face in a basin of ice water without risk of aspiration. The safest and most commonly used alternative employs filling a plastic bag with ice water, which prevents aspiration and airway obstruction in the higher risk pediatric and elderly populations.