###### Created: 2024-06-11 16:37 ###### Areas & Topics: #medicine #physiology #cardiovascular ###### Note Type: #permanent ###### Connected to: [[Peri-Arrest Rhythms]] [[Baroreceptor Reflex]] - Vagal Manoeuvres are techniques used to increase vagal parasympathetic tone, in order to try and treat various arrythmias. - The main vagal manoeuvres include the Valsalva Manoeuvre (VM), Carotid Sinus Massage (CSM) and the Diving Reflex - Other less used vagal manoeuvres include ocular pressure, stimulation of the gag reflex, applied abdominal pressure and headstands. - Vagal Manoeuvres should be attempted 2 or 3 times before moving on to appropriate antiarrhythmic medication. ### Anatomy and Physiology **Valsalva and Carotid Sinus Massage** - The VM and CSM work by increasing arterial pressure in the carotid sinuses and aortic arch. - This action triggers the [[Baroreceptor Reflex]], which increases parasympathetic output to the heart via the vagus nerve. - The right vagus nerve mainly innervates the sinoatrial (SA) node and the left vagus nerve mainly innervates the atrioventricular (AV) node. - Increased parasympathetic outflow to these nodes will reduce the speed and frequency of electrical impulses in the heart, potentially terminating tachydysrhythmias. **Diving Reflex** - The Diving Reflex (also known as the mammalian dive reflex) is an autonomic response seen in various mammals, including humans. - It is triggered by breath-holding and cold water stimulus on the face. - It is theorised that cold water exposure to the face and nostrils stimulates afferent fibres of the trigeminal nerve (CN V), which then send impulses to go on to stimulate vagal nuclei in the brain, leading to slowing of AV node conduction and eventual bradycardia. ### Valsalva Manoeuvre (VM) - The VM, at its core, involves the voluntary increasing of intrathoracic pressure. - The simplest way to do this is by asking the patient to take a deep breath, pinching their nose and closing their mouth, and then blowing out against their closed glottis for 10 to 15 seconds. - In the standard VM, the patient does this while supine. - You can also give the patient a 10 to 15 ml syringe and ask them to blow into it and get the plunger to move for 10 to 15 seconds. - The Modified VM is a form of the VM that has been shown to be twice as effective (around 40% success rate) for converting patients to sinus rhythm. Modified Valsalva Manoeuvre (VM) Technique 1. Start with the patient upright and ask them to take a large breath in. 2. Then, get them to pinch their nose and close their mouth and begin to blow out against their closed glottis. 3. As the patient is doing this, immediately make the patient supine. 4. As the patient is being made supine, tuck their knees into their chest (whilst the patient continues to blow) 5. Get the patient to continue blowing for 10 to 15 seconds and keep their knees tucked to their chest for 45 seconds to 1 minute. 6. Repeat if needed ### Carotid Sinus Massage (CSM) The technique to perform a CSM is as follows: 1. Lay the patient supine. 2. Ask them to extend their neck and rotate it to one side (the opposite side of the carotid sinus you will be massaging) 3. The carotid sinus will be found inferior to the angle of the mandible, anterior to sternocleidomastoid and the upper level of the thyroid cartilage. 4. Place the fingertips of your index and middle finger on the sinus, and apply pressure in the posteromedial direction for 5 to 10 seconds. 5. If unsuccessful, this can be repeated after 1 minute. 6. If unsuccessful after 2 to 3 attempts, attempt on the opposite side. N.B. You can also put the patient in a Trendelenburg position, raise their legs or apply pressure to their upper abdomen (these can further help increase arterial pressure in the sinus and stimulate the [[Baroreceptor Reflex]]) ![[DOBpI5oWsAEhkbX.jpg]] ### Diving Reflex 1. Ask the patient to sit in a comfortable seated position for 1 to 3 minutes 2. Ask them to take multiple deep breaths and then hold their breath after inspiration. 3. Immediately after, get the patient to immerse their face in a basin of ice water as long as they can comfortably tolerate. 4. Observe to see if the supraventricular tachyarrhythmia resolves. N.B. For frail or paediatric patients, ask them to lay supine and put a sealed bag of ice water on their forehead for up to 30 seconds. ### Other Uncommon Manoeuvres Ocular Pressure - Pressure on the eye or traction on the extraocular muscles stimulates the ophthalmic branch of the trigeminal nerve and eventually the vagal nuclei. - This eventually can induce bradycardia. Stimulation of Gag Reflex - The gag reflex is controlled by the glossopharyngeal nerve (CN IX) and the vagus nerve (CN X). - Stimulation of the gag reflex will therefore also stimulate the vagus nerve, increasing parasympathetic outflow to the heart and thereby potentially reducing electrical activity and tachydysrhythmia. Applied Abdominal Pressure - Applying upper abdominal pressure during patient inspiration can increase heart rate, through activating the baroreceptor reflex. - However, as the patient goes through multiple respiratory cycles, the vagus nerve will be stimulated during exhalation which can help reduce tachydysrhythmia. - This can be used as an adjunct to the CSM, if unsuccessful alone. Headstands - It is theorised that doing a headstand increases intrathoracic pressure, thereby acting as a vagal manoeuvre in the same way as the VM. ### Resources Niehues LJ, Klovenski V. Vagal Maneuver. [Updated 2023 Jul 3]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK551575/ Godek D, Freeman AM. Physiology, Diving Reflex. [Updated 2022 Sep 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538245/ Diving Reflex - Wikipedia https://en.wikipedia.org/wiki/Diving_reflex Oculocardiac Reflex - EyeWiki https://eyewiki.aao.org/Oculocardiac_Reflex Patient education: Vagal maneuvers and their responses (The Basics) UptoDate https://pro.uptodatefree.ir/Show/83898