Sono Pro Tips and Tricks for Evaluation of Elevated Intracranial Pressure

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Written by: Emma Greever (NUEM ’25) Edited by: Maurice Hajjar, MD (NUEM ’22)
Expert Commentary by: John Bailitz, MD

Welcome to the NUEM SonoPro Tips and Tricks Series where Local and National Sono Experts team up to take you scanning from good to great for a particular diagnosis or procedure.

For those new to the probe, we recommend first reviewing the basics in the incredible FOAMed Introduction to Bedside Ultrasound Book, 5 Minute Sono, and POCUS Atlas. Once you’ve got the basics beat, then read on to learn how to start scanning like a Pro!

Did You Know?

Ocular ultrasound is a quick procedure which can be done at the bedside to help differentiate between various ophthalmologic emergencies including retinal detachment, vitreous detachment, vitreous hemorrhage, lens detachment, and presence of foreign bodies. Indications for ocular ultrasound include eye pain, acute changes in vision, eye trauma, and suspicion of elevated intracranial pressure, or if there is swelling of periorbital tissue that inhibits direct visualization of the eye. The one absolute contraindication for ocular ultrasound is any suspicion for globe rupture, as placing any pressure on the globe can worsen extrusion of intraocular contents.

Ocular ultrasound can also be used to evaluate for elevated intracranial pressure (ICP). The optic nerve sheath communicates directly with the subarachnoid space. Cerebrospinal fluid flows between the intracranial space and orbit within the subarachnoid space; therefore, increased intracranial pressure is transmitted to the optic nerve sheath. Elevation of ICP is reflected by dilation of the optic nerve sheath. This can be quantified by measuring optic nerve sheath diameter (ONSD).  Dilation of the optic nerve sheath often occurs with anterior bulging of the optic disc, seen as optic disc elevation (ODE) on ultrasound. Bulging of the optic disc is seen as papilledema on fundoscopic exam. Both ONSD and ODE measurements are ways to assess for elevated ICP. 

If there is concern for elevated ICP, it is not always possible to do a dilated fundoscopic exam, invasive monitoring, or other imaging such as a CT. Point of care ultrasound (POCUS) allows for quick evaluation. Furthermore, POCUS allows for monitoring dynamic changes in ICP as doing serial fundoscopic exams and CTs is not feasible. It is also less invasive than other intra-cranial monitoring. When comparing ONSD (with a cut-off value of >5 mm) with findings of increased ICP on CT, sensitivity and specificity are 95.6% and 92.3%, respectively.

Beyond the emergency department, where else can a SonoPro scan for increased ICP?:

Aside from patients in the emergency department, POCUS for elevated ICP can be used in critically ill children in the PICU, adults in the Neurocritical ICU, and on the battlefield with handheld ultrasounds in combat medicine. ONSD changes within minutes of ICP changing. Studies have demonstrated that the change in ONSD or ODE is strongly correlated with changes in ICP, implying that POCUS could be used to dynamically detect real-time changes in ICP. In neuro-critically ill children, POCUS cannot replace invasive ICP monitoring but can be used as a screening tool in the ICU for intermittent monitoring of ICP when invasive methods are unavailable. It can allow for accurate dynamic evaluation of ICP, which is important in children with traumatic brain injury as fluctuations are common. Additionally, POCUS can be used in many different environments in which imaging is not readily available, such as on the battlefield or in-flight.

How to scan like a Pro:

• Place the head of the bed at 45 degrees.

• Apply a large, waterproof transparent film dressing (such as a Tegaderm) over the eye you are going to ultrasound, making sure the eye is closed. Make sure to get as much air out from under the Tegaderm as you can. 

• Apply a large amount of water-soluble ultrasound gel on top of the dressing.

• Using a high-frequency linear probe set to ocular mode, place the probe over the eye with the indicator to the patient’s right. It is important to use very minimal pressure on the eye. To have control over the probe and to be able to make small movements with minimal pressure on the eye, rest the side of your hand on the patient’s cheek or bridge of the nose to stabilize your hand. 

• Ensure the probe is oriented in the transverse plane.

• Tell the patient to look straight forward, to the left or right, up, or down as needed to obtain the best view.

• Be sure to scan both eyes when concerned for elevated ICP.

What to Look For:

• Identify the following structures: anterior chamber, lens, vitreous, retina, and optic nerve.

• Use the rule of 3x5 to measure optic nerve sheath diameter:

1. Find the posterior aspect of the globe overlying the optic nerve 

2. From that point measure 3 mm posteriorly (point A)

3. Maximal sheath distension occurs at 3 mm behind the papilla

• Measure the diameter of the optic nerve from the second point (point B, 3 mm deep)

  • Measure from outer wall to outer wall

  • < 5mm is normal, 5-6 mm is indeterminate, >6 mm is elevated

• Assess for papilledema – measure optic disc elevation (ODE)

  • Measure area between the fundus and dome of the papilla

• ODE >0.6 mm predicts presence of fundoscopic optic disc edema (sensitivity 82%, specificity 76%); if using the threshold of 1.00 mm then sensitivity is 73% and specificity 100%

• This sign can take a couple days to develop and may not appear at the same time as elevated ocular disc diameter

How to interpret:

• Determine if ICP is elevated:

  • < 5 mm = Likely normal ICP

  • >6 mm = Indicates elevated ICP 

  • Many causes of this, next steps are to identify what is causing the elevation in ICP 

  • 5-6 mm = Indeterminate range 

• If elevated, further evaluation for etiology of elevated ICP and treatment of cause.

• If indeterminate, assessing for papilledema by measuring the ODE can help in the indeterminate range, although absence of papilledema does not indicate normal ICP. 

• It is important to note that there is significant variation from person to person regarding ONSD. In other words, >6 mm does not necessarily indicate increased diameter and <5mm does not necessarily mean normal. The SonoPro must use clinical judgement while assessing the ONSD.

Where to Learn More (References)

Where to Learn More (Hyperlinked References):

https://coreem.net/core/ocular-ultrasound/

https://www.coreultrasound.com/onsd/

https://emcrit.org/pulmcrit/pulmcrit-algorithm-diagnosing-icp-elevation-ocular-sonography/

https://www.thepocusatlas.com

1. Lin JJ, Chen AE, Lin EE, Hsia SH, Chiang MC, Lin KL. Point-of-care ultrasound of optic nerve sheath diameter to detect intracranial pressure in neurocritically ill children - A narrative review. Biomed J. 2020;43(3):231-239. doi:10.1016/j.bj.2020.04.006

2. Richards E, Mathew D. Optic Nerve Sheath Ultrasound. [Updated 2021 Jul 31]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan. Available from: https://www.ncbi.nlm.nih.gov/books/NBK554479/

3. Teismann N, Lenaghan P, Nolan R, Stein J, Green A. Point-of-care ocular ultrasound to detect optic disc swelling. Acad Emerg Med. 2013 Sep;20(9):920-5. doi: 10.1111/acem.12206. PMID: 24050798.

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Expert Commentary

Thank you for providing this outstanding NUEM Blog Post! Ocular ultrasound for ICP has been a hot topic for over a decade in the EM, PEM, and ICU POCUS literature. 

For a full review of my approach to ocular ultrasound, please refer to our 2018 Post - Ocular Ultrasound: From Floaters to Fogginess! 

Since that post ,additional literature has been posted questioning the need for Tegaderms over the eye for the reasons we discussed in 2018. Bottomline, if the patient is reliable and can keep their eyes closed for five minutes, then you can skip the Tegaderm. But when the patient is less reliable, then the extra step may still make sense. When locating and measuring the Optic Nerve Sheath (ONS), be absolutely sure to stabilize your hand on the patient's face or forehead particularly when you are over-caffeinated or tired. Then be careful to rock the probe about 15 degrees laterally (illustrated here) to visualize the ONS parallel to the probe’s center US beams, and thereby avoid any edge artifact from visualizing at an angle. Even with the best technique, our local teaching, clinical use, and pilot research has consistently confirmed the need for obtaining multiple measurements of the small optic nerve sheath. Then averaging the best three to obtain the most accurate measurement. 

Thank You Dr. Greever (NUEM ’25) and Dr. Hajjar, MD (NUEM ’22) for helping to improve patient care and MedEd through POCUS! Happy scanning everyone.

John Bailitz, MD

Vice Chair for Academics, Department of Emergency Medicine

Professor of Emergency Medicine, Feinberg School of Medicine

Northwestern Memorial Hospital

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Greever, E. Hajjar, M. (2024, Sep 11). Sono Pro Tips and Tricks for Evaluation of Elevated Intracranial Pressure. [NUEM Blog. Expert Commentary by Bailitz, J]. Retrieved from http://www.nuemblog.com/blog/sonopro-tips-and-tricks-for-evaluation-of-elevated-intracranial-pressure

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Becoming a New Mom and New Resident

Written by: Courtney Premer-Barragan, MD, PhD (NUEM ‘25) Edited by: Saabir Kaskar, MD (NUEM ‘23)
Expert Commentary by: Ivonne H. Schulman, MD

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As I am sitting here, pondering how to adequately share my experiences of becoming a brand-new mom and intern, what better time than when I’m recovering from family “Sienna-itis” as we like to call it ("Sienna-itis” being the many fevers, coughs, and colds she has brought our way). The adage goes, get lots of sleep, rest, and hydration to fight sickness, and wow, does that sound great! However, when you have a child crying inconsolably because they have a 104.5* fever, and simultaneously you have fever, body aches, and feel miserable, your child comes first. You suppress all your aches and ignore your need to recover deferring to motherly instincts that demand your baby feel safe and loved. This is a slightly harsh metaphor of what it’s like to be an intern with a new baby. There is no such thing as rest and recovery. I am responsible for another human. Finally, a day off the MICU. Want to lounge around all day? Watch TV and relax? Nope! Just got off a night shift. Want to sleep all day to recover? Nope. Hey, I don’t work until 2pm, let me sleep in. Nope. It’s a constant rollercoaster that none of my co-interns can relate to, and that makes it even more challenging. But would I do it all over again? Look at this face. Yes! She makes everything worth it. So how did I get here and what have I learned along the way?

Let’s start where it all started, medical school… 

I decided during medical school that I was ready to start a family. Previous lengthy graduate school years enhanced the sense of growing older and moving past my prime reproductive years. Looking at the literature, a career in medicine and motherhood seemed daunting. “Pregnant trainees and those contemplating pregnancy often report stress related to faculty and coworker attitudes, rigid and intense educational requirements, long work hours, unpredictable work demands, altered schedules, guilt over colleagues’ increased workloads, and concern for maternal–fetal well-being.” 2 I scoured the internet to find support groups or at least supportive views showing that you can equally be an attentive mom and thrive in your medical residency, albeit this view was scant. Literally every article mentioned medical trainees felt sentiments of guilt, vulnerability, overworked, judged, and feelings of inadequacy1-6. I ultimately decided that I wanted a family, and medicine and family shouldn’t be mutually exclusive. So, I was pregnant at the end of my 3rd year. I did the all-important EM rotation in my 2nd trimester of pregnancy, took Step 2 in my 3rd trimester, did all my residency interviews feeling like I was about to pop (7-8 months pregnant), and matched at my dream program. 

 On to residency…. 

The transition to residency, while embracing my new reality as a mom, was tough. You’re stepping into a new role in your life, learning to be a new doctor, and then compounding that with trying to figure out how to take care of another human. Sleep deprivation. Guilt. FOMO. Sadness. Happiness. Isolation. Joy. Every day seemed like a new feeling. As I watched my co-residents all go out together, enjoying fun times when off shift, forging close bonds, I was increasingly feeling sad and isolated, as it was often impossible for me to join. This was heightened by having no family in Chicago as a support network. But then, full stop! There’s the utter feeling of fulfillment. Coming home to Sienna with her blazing smile and her unconditional love is sheer bliss. Lying next to her as she crawls, stands, and slobbers all over me is pure joy. Hearing her laugh permeate the room. Watching her dance with no care in the world. Her self-clap when she takes a new step. So many priceless moments. Again, it’s a rollercoaster of emotions, lots of highs and lots of lows, lots of feeling like the most loved person in the world while also feeling completely isolated. I’m sharing my experiences with all its vulnerabilities to add another perspective to the scant literature and lack of advice to hopefully help fill in the void. 

Some lessons I learned along the journey… 

1. There’s never going to be a perfect time. 

I was so thankful to have a mentor who ingrained in my brain, “never wait for the right time to have kids, because you always find an excuse.” But I’m about to do residency interviews. I can’t show the program I’m pregnant. But I’m just starting my intern year. It’s a huge challenge and draining, and it’s crazy to add a child into the mix. But I’m a senior resident running the department. Let me wait a couple more years until my career is established. Although I’m a new Attending, I need to start my career strong. I’m applying for a promotion. Now is not the right time. But here’s the thing: you name the time, and there will ALWAYS be an excuse. Understanding that there will NEVER be a right time and learning how to make your time the right time, is fundamental. 

2. This goes against the common convention but talk about family life/being pregnant/wanting to get pregnant in interviews, during residency, or whatever stage of your career you are at. 

I received very mixed advice regarding this point while going through residency interviews. Some attendings were shocked that I wanted to be so open about my pregnancy. Some were like, “heck yes!” Is there still bias against women in medicine having children? 100%! With this in mind, I wanted to find a program that I knew would support an arduous journey I was about to embark upon. I was appalled by a couple of residency interviews and how they responded to me being pregnant. And boy, was I thankful they transparently showed their colors. I can’t imagine if I would have kept my pregnancy a secret and then have been stuck in an unsupportive environment. Thankfully, most of my interactions were very positive and gave me hope that medicine and babies can mix. When I matched at Northwestern and they sent Sienna a little snow hat, I instantly knew my family would be supported.  All my fear and anxiety surrounding being the intern with the baby dissipated. 

3. Support is everything (family, co-residents, friends). 

Lean on EVERYONE for help, because man, do you need it! My mother moved here for the first month of residency, and that support was everything. Don’t be shy to ask for help. Unless you also have a baby, you can’t imagine how incredibly difficult it is to be an intern and a mom. Let yourself be vulnerable and relish in all the support. If someone offers to help watch the baby, heck yes! If someone offers to bring you groceries because they know you’re struggling with every task, let them bring you the groceries.  

4. It’s okay to take mini breaks to survive long rounds. 

As women, we put a lot of pressure on ourselves to not show any weakness. That pressure is only heightened when pregnant, trying to show that we are just as strong as everyone else. But guess what? It’s not a sign of weakness to take that little break on 4 hours of grueling rounds because your back is breaking. Grab that hospital orange juice if you’re feeling light-headed or weak. Run to the bathroom multiple times if that’s what’s calling. I was so thankful that I did my internal medicine rotation with my best friend who consistently reminded me that I needed to take care of myself, and I’ll still look like a rockstar medical student, even if I silently disappear for a minute here or a couple minutes there. At the end of the day, while we think the attending and co-medical students/co-residents are judging us for doing those little things, get over it! They’re not! So, take care of you and you’ll still shine. 

5. Advocate for your breastfeeding journey. 

Let me reinforce this vital tenant: advocate for yourself and your baby. I cannot stress that statement enough. If you are breastfeeding and therefore pumping at work, don’t be embarrassed/shy to take those pumping breaks. And, for the love of everything, don’t feel like a burden for taking those 20-minute breaks while your co-residents are working. You are balancing being a mother and a physician. No one else can possibly fathom the overtime amount of work you are doing both at work and at home. (Pro tip: if pumping multiple times per shift, put all the parts in the fridge so you don’t have to clean everything between each pump session. It saves sooo much time!) 

6. Embrace the emotions. 

You’re going to have the happiest of days. You’re going to have the darkest of days. AND THAT’S OKAY! Talk about when you’re feeling sad. But also share those glorious happy moments. Celebrate all the wins that make it so incredibly worth it. It’s really important to normalize all your feelings. 

7. Most importantly…. Take care of you! 

In case all the above did not sufficiently convey that balancing residency and parenthood can be quite exhausting, and make it so easy to forget about yourself, it’s vital to remember you need time to decompress and recharge. Go on that hour run by yourself. Get your nails done. Go on a date. Take a long bath. When you have a list of things that need to get done on your day off, look at that list, and think, “is this really the priority? Will life fall apart if I clear my mind at the gym instead of doing 20 Rosh Review questions and cleaning the bathroom?” To be a good mother, an engaged resident, and a good wife, you need to also take care of you. Period. 

References

1. Attieh, E., Maalouf, S., Chalfoun, C., Abdayem, P., Nemr, E., & Kesrouani, A. (2018). Impact of female gender and perspectives of pregnancy on admission in residency programs. Reproductive Health, 15(1), 1-5. 

2. Blair, J. E., Mayer, A. P., Caubet, S. L., Norby, S. M., O’Connor, M. I., & Hayes, S. N. (2016). Pregnancy and parental leave during graduate medical education. Academic Medicine, 91(7), 972-978. 

3. Finch, S. J. (2003). Pregnancy during residency: a literature review. Academic Medicine, 78(4), 418-428. 

4. Peters, G. W., Kuczmarska-Haas, A., Holliday, E. B., & Puckett, L. (2020). Lactation challenges of resident physicians-results of a national survey. BMC pregnancy and childbirth, 20(1), 1-8. 

5. Sandler, B. J., Tackett, J. J., Longo, W. E., & Yoo, P. S. (2016). Pregnancy and parenthood among surgery residents: results of the first nationwide survey of general surgery residency program directors. Journal of the American College of Surgeons, 222(6), 1090-1096. 

6. Walsh, A., Gold, M., Jensen, P., & Jedrzkiewicz, M. (2005). Motherhood during residency training: challenges and strategies. Canadian Family Physician, 51(7), 990-991. 

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Expert Commentary

The decision to begin having children during medical school or residency is one that preoccupies many women, even before they decide to pursue a career in medicine. This is in sharp contrast to men, who although now consider work/life balance and parental responsibilities more than before, still benefit from societal gender roles that place the bulk of the parenting and domestic responsibilities on women.

The number of female physicians has continuously increased over the past few decades, with women now comprising just over half of the medical students in the United States (1). Despite increasingly egalitarian societal attitudes toward gender roles, female physicians still struggle to balance a medical career and a family. Female physicians, particularly young ones, are much more likely to reduce their work hours than males, a gap that emerges immediately following medical training.

Moreover, significant gender differences in the time spent on parenting and domestic responsibilities among physicians are still evident (2). There is evidence that traditional gender roles impact female physicians’ medical specialty choices, representation in academic and professional societies, original and invited authorships, leadership positions, compensation, full time vs. part time work status, and promotion and retention in academic medicine. These findings highlight the importance of increasing awareness and expanding social and institutional support for work-family balance for female and male physicians. Until policies and a culture allowing women and men to be both parents and physicians are created, women are less likely to be retained and to advance in medicine. Proposals for solutions include availability and affordability of childcare services, maternity and paternity leave, and advocating, through mentorship, leadership courses, and support groups, for changes in social norms, such as sharing of household and child care responsibilities and creating an environment conducive to work-life

balance for all genders (3).

References

1. AAMC. The Majority of U.S. Medical Students Are Women, New Data Show. Association of American Medical Colleges; www.aamc.org; 2019.

2. Frank E, Zhao Z, Sen S, Guille C. Gender Disparities in Work and Parental Status Among Early Career Physicians. JAMA Netw Open. 2019;2(8):e198340.

3. Dandar VM, Lautenberger DM, Garrison GE. Promising Practices for Understanding and Addressing Salary Equity at U.S. Medical Schools. Association of American Medical Colleges; 2019. Disclosure: The opinions expressed in this paper are those of the author and do not necessarily reflect those of the National Institute of Diabetes, Digestive and Kidney Diseases, the National Institutes of Health, the Department of Health and Human Services, and the government of the United States.

Ivonne H. Schulman, MD

Senior Scientific Advisor for Acute Renal Failure and Renal Pathophysiology

Program Director, Translational and Clinical Studies of Acute Kidney Injury

Division of Kidney, Urologic &amp; Hematologic Diseases (DKUH)

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

National Institutes of Health (NIH)

University of Miami Miller School of Medicine

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Premer-Barragan, C. Kaskar, S. (2024, Jul 29). Becoming a New Mom and New Resident. [NUEM Blog. Expert Commentary by Schulman, I]. Retrieved from http://www.nuemblog.com/blog/new-mom-and-new-resident

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Vagal Maneuvers Simplified

Written by: Keara Kilbane, MD (NUEM ‘25) Edited by: Maren Leibowitz, MD (NEUM ‘23)
Expert Commentary by: Danielle M McCarthy, MD

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Vagal Maneuvers Simplified

 https://acls-algorithms.com/rhythms/supraventricular-tachycardia/

Introduction to Vagal Maneuvers:

• Vagal maneuvers are considered the first line treatment for hemodynamically stable supraventricular tachycardia (SVT). 

• Studies demonstrate up to a ~40% success rate in converting patients back into normal sinus rhythm. 

• Benefits of vagal maneuvers: 

• Safe for most patients*

• Avoids use of adenosine, a medication that is associated with side effects like lightheadedness, chest discomfort, vomiting, and severe anxiety, all of which can be very concerning to patients.

*see contraindications to specific vagal maneuvers below

Brief Physiology of Vagal Maneuvers:

https://www.hopkinsmedicine.org/health/conditions-and-diseases/anatomy-and-function-of-the-hearts-electrical-system

Normal sinus rhythm starts with an electrical impulse at the sinoatrial (SA) node → atrial tissue → atrial contraction → AV node → His-Purkinje system → ventricular myocardium → ventricular contraction

https://www.cprseattle.com/blog/slow-down-youre-going-too-fast-svt-and-the-modified-valsalva-maneuver

• SVT (specifically AVRT/AVNRT) is most commonly caused by a re-entry conduction pattern involving a retrograde accessory pathway from the ventricles to the atrium, bypassing the SA node.

• Vagal maneuvers work by stimulating the vagus nerve, which slows the impulse at the sinus node, conduction at the AV node, and lengthens the AV node refractory period.

• Initially, pressure against a closed glottis results in increased intrathoracic pressure → increase in blood pressure → increased aortic pressure →  baroreceptor activation → increased parasympathetic output to the heart via the vagus nerve →  decreased heart rate. 

Ghazal, S.N. Valsalva maneuver in echocardiography. J Echocardiogr 15, 1–5 (2017).

• During the straining period of the vagal maneuver, there is a prolonged period of increased intrathoracic pressure → decreased venous return → decreased cardiac output → reflexive increase in HR to maintain stroke volume.

• When the maneuver is stopped, there is sudden decrease in intrathoracic pressure → increased venous return and right atrial pressure → increased blood pressure and aortic pressure → reflexive decrease in heart rate and termination of SVT

Types of Vagal Maneuvers:

http://healthcaresciencesocw.wayne.edu/cnm/8_2.htm

• The Valsalva Maneuver 

  • Main take away: creating pressure against a closed glottis

  • Success rate:  5 – 20%

  • Contraindications: 

  • Unstable SVT 

  • SVT due to acute MI

  • Aortic Stenosis 

  • Carotid artery stenosis 

  • Glaucoma or retinopathy

https://www.medicalnewstoday.com/articles/322661

• Methods:

  • Gag

  • Cough 

  • Have patient plug nose, close mouth, and try to blow air out for 15 seconds

  • Blow on a 10mL syringe for 15 seconds

  • Bear down and strain by trying to push the air out of the lungs while closing nose and mouth. Attempt for 15 seconds

with 45 seconds of passive leg raise

https://www.ecgmedicaltraining.com/wp-content/uploads/2016/06/REVERT-Trial-SVT.jpg

• The Modified Valsalva Maneuver (REVERT Trial)

• Main take away: Valsalva using 10mL syringe + passive leg raise to improve venous return

• Success Rate: In the RCT REVERT, the modified valsalva maneuver demonstrated 43% success rate, significantly more than valsalva maneuver alone (only 17%).

• Contraindications: same as the valsalva maneuver 

• Methodology: 

  • Place patient in a sitting position

  • Have patient blow into a 10mL empty syringe for 15 seconds (~40mmHg)

  • After 15 seconds, immediately recline patient into supine position with 45 seconds of passive leg raise

https://www.grepmed.com/images/10366/algorithm-tachycardia-treatment-management-peds

• Ice Water on the Face

• Main take away: In pediatric patients who cannot follow directions, placing a bag of ice water over their forehead and eyes is the first line vagal maneuver. This stimulates the vagus nerve via activating a “diving reflex”, causing the child to valsalva.

• Success rate: 33-63%

• Contraindications: 

  • Unstable SVT

• Methodology: Place a bag of iced water over an infant's eyes and forehead and hold for 15-30 seconds. Do not cover the infant's nose or mouth

 https://coreem.net/core/avnrt/

• Carotid Massage

• Main take away: Stimulates the carotid sinus, which stimulates vagus nerve, activating parasympathetic response and slows impulse at SA node. Generally, it has fallen out of favor given the risk of precipitating stroke in patients with carotid stenosis.

• Contraindications:

  • Unstable SVT

  • Carotid bruit

  • Prior TIA or CVA in past 3 months

  • Pediatric patients

• Methodology: Patient in a supine position with the neck extended, and applying pressure to one carotid sinus for approximately 10 seconds

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References:

1. Appelboam A, et al. Postural modification to the standard Valsalva manoeuvre for emergency treatment of supraventricular tachycardias (REVERT): a randomized controlled trial. The Lancet 2015; 386 (10005): 1747-1753.

2. Ghazal, S.N. Valsalva maneuver in echocardiography. J Echocardiogr 15, 1–5 (2017). https://doi-org.turing.library.northwestern.edu/10.1007/s12574-016-0310-8

3. Manole MD, Saladino RA. Emergency department management of the pediatric patient with supraventricular tachycardia. Pediatr Emerg Care. 2007 Mar;23(3):176-85; quiz 186-9. doi: 10.1097/PEC.0b013e318032904c. PMID: 17413437.

4. Niehues LJ, Klovenski V. Vagal Maneuver. [Updated 2021 Jul 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK551575/

5. Patti L, Ashurst JV. Supraventricular Tachycardia. [Updated 2021 Aug 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK441972/

6. Salim Rezaie, "The REVERT Trial: A Modified Valsalva Maneuver to Convert SVT", REBEL EM blog, September 14, 2015. Available at: https://rebelem.com/the-revert-trial-a-modified-valsalva-maneuver-to-convert-svt/.

Expert Commentary

Thank you for this excellent review of the non-pharmacologic options for managing SVT in the ED.  At one point or another in my career, I have tried them all…. and I think one of the most important things to remember about these options is: there are very few harms that can result from giving them a try.   

Although the individual success rate of each maneuver is not high, there is not a lot to be lost in attempting one (or more) of these techniques while other activities are in-motion to start pharmacologic therapy should the non-pharmacologic maneuvers fail.  I typically do not delay having nursing establish an IV and pulling medications in preparation for pharmacologic management given that the maximal reported success rate is 43%; however, assuming no contra-indications, it doesn’t hurt try.  Even in the most highly functioning EDs, it takes a few minutes to get a patient on a monitor, get continuous EKG set up and get pharmacy / nursing colleagues to bedside for administration of adenosine (or other meds) with real-time EKG tracing.  It is during those minutes that I make use of these maneuvers to see if the pharmacologic therapy can be avoided. 

Pre-2015, I could count on one hand the number of times I’d been successful with a vagal maneuver; however, since publication of the REVERT Trial, I have personally found using Modified Valsalva Maneuver to be more successful than Valsalva alone and have been able to avoid adenosine for numerous patients.  Consider reviewing the prior NUEM blog post that discusses the REVERT Trial results in detail.   

Since starting to personally use this Modified Valsalva technique in ~2016, I have adopted a few practices that may be helpful.  First, I explain to the patient that we are going to ask them to do some stuff that may seem silly, but it might help them to avoid medications and I caution them that it only works ~40% of the time.  Second, I’ve taken to holding up my phone with the digital timer facing the patient so they can see the seconds counting down. I’ve subjectively found that it helps them to “hang in there” and maintain the breath hold longer than without looking at a timer. Without a timer, we (doctors/nurses) tend to unintentionally “speed-up” our pace of counting as we see the patient fatiguing and therefore don’t achieve a full 15 second count.  Similarly, I advocate for using your phone or a wall-clock to maintain the leg raise for a full 45 seconds.  This adherence to the time intervals ensures that you’re sticking to the true technique of the maneuver rather than approximating the technique and potentially diminishing its effect. Third, if it works, I review the steps with them again and send them home with an empty syringe (and they think you’re a magician). If it fails, you already counseled them that it would likely fail; you’ve lost neither time nor trust.   

Finally, I have noticed that successful or not, having a few doctors and nurses cheer a patient on to maintain the breath hold builds a spirit of trust and camaraderie. This trust is hopefully helpful to the patient…particularly when we start to explain how we are going to give a medicine that will temporarily stop their heart and make them feel transiently terrible. 

In conclusion, give it a try. If these maneuvers fail, then move on. In the stable patient, consider adenosine or calcium channel blockers (see NUEM blog post on CCB as an alternative to adenosine in SVT here). 

Danielle M McCarthy, MD

Vice Chair for Research, Department of Emergency Medicine

Associate Professor, Emergency Medicine

Northwestern Memorial Hospital

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Kilbane, K, Leibowitz, M (2024, Jul 14). Vagal Maneuvers Simplified. [NUEM Blog. Expert Commentary by McCarthy, M]. Retrieved from http://www.nuemblog.com/blog/vagal-maneuvers-simplified

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Symptomatic Bradycardia: Considering the Differential Diagnosis

Written by: Keara Kilbane (NUEM ‘25) Edited by: Eric Power (NUEM ‘24)
Expert Commentary by: Seth Trueger, MD, MPH, FACEP

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THE HEART CONDUCTION SYSTEM

"Normal” adult heart rates range from 60-100 beats per minute (BPM), with bradycardia defined as a heart rate of less than 60 BPM. Electrical impulses for each heartbeat begin at the sinoatrial (SA) node, then propagate through the atrium to the atrioventricular (AV) node, continuing down the Bundle of His, and lastly to each bundle branch, causing the ventricles to contract. Bradycardia can be physiologic, such as in individuals who have high levels of cardiovascular training. However, pathologic and/or symptomatic bradycardia results from a disruption in this electrical circuit [1].

What is symptomatic bradycardia [1-2]?

Defined as the presence of bradycardia, resulting in debilitating symptoms with lack of alternate explanation. 

The most common symptoms include: 

• Lightheadedness

• Syncope 

• Chest pain

• Exercise intolerance 

• Fatigue

**Important note: The heart rate at which patients experience symptoms may vary based on their ability to increase stroke volume. 

CARDIAC OUTPUT = STROKE VOLUME X HEART RATE

Treatment Algorithm for Symptomatic Bradycardia [2-4]:

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What are common causes of symptomatic bradycardia [2]?

1. Myocardial Infarction

2. Medication

3. Sinus node dysfunction

4. Infectious Disease

5. Hypothermia

6. Metabolic Abnormalities (hypothyroidism, hyperkalemia, ect.)

7. Elevated intracranial pressure (ICP)

8. Genetic Conditions

Myocardial Infarction

Bradyarrhythmias occur in up to 25% of patients with an acute myocardial infarction, especially those involving the right coronary artery (RCA) which supplies the SA node in up to 60% of patients. 

Treatment for bradycardia secondary to myocardial infarction is standard care for an occlusive MI, including emergent cardiology consult and cath lab activation, and loading the patient with anti-platelet medications [5-7]. 

Common Medications and Mechanisms of Causing Bradyarrhythmias

• Beta Blockers and Non-Dihydropyridine Calcium Channel Blockers (Diltiazem and Verapamil)

• Inhibit the automaticity of the SA node 

• Antiarrhythmics (Amiodarone, Adenosine, Flecainide) 

• Inhibits the SA and AV node 

• Acetylcholinesterase inhibitors  (Donepezil, Neostigmine, Pyrodostigmine, Physostigmine)

• Activates the parasympathetic nervous system which leads to inhibition of the automaticity of the SA node 

• Clonidine

• Stimulation of central alpha-2-receptors, reducing the norepinephrine

• Antidepressants (Citalopram, Escitalopram, Fluoxetine)

• Sodium and calcium channel inhibition

• Digoxin

• Increases vagal tone 

• Anesthetics (Bupivacaine, Propofol) 

• Reduces sympathetic activity 

Treatment depends on the medication involved. If high suspicion or known overdose, involve and consult your local Poison Center [8]. 

Sinus Node Dysfunction (Sick Sinus Syndrome) [9-10]: 

Sick sinus syndrome is most commonly due to aging of the sinus node and surrounding atrial myocytes. It is often associated with severe bradycardia (HR<50 bpm. It is also associated with sinus pauses, arrests, and SA node block, and or a junctional escape rhythm. Treatment includes  permanent pacemaker placement [9].

Hypothermia

Moderate to severe hypothermia can cause significant bradycardia leading to hypotension. Treatment includes removing all wet clothing, externally rewarming with bair huggers and warm blankets, administering warm IV fluids, active core rewarming including bladder and thoracic irrigation with warmed fluids). It is also important to remember that the differential to hypothermia itself is broad itself and not just limited to environmental exposure. For example, hypothyroidism, adrenal insufficiency, sepsis, neuromuscular disease, malnutrition, thiamine deficiency, hypoglycemia can all lead to hypothermia [11-13]. 

 Decompensated Hypothyroidism (Myxedema Coma)        

Classic symptoms of myxedema coma include: 

• Decreased mentation or delirium

• Hypothermia 

• Bradycardia 

• Hyponatremia 

• Hypoglycemia 

• Hypoventilation

• Hypotension

Common triggering events:  

• Infection 

• Medication non-adherence 

• Surgery or trauma

• Myocardial infarction

• CHF exacerbation 

• Cerebral Vascular Accident 

• GI bleed 

Treatment includes IV atropine if unstable while treating the underlying condition (IV steroids, IV levothyroxine) [14]. 

Increased Intracranial Pressure

Classic triad of bradycardia, respiratory depression, and hypertension (Cushing reflex), concerning for brainstem compression and/or herniation [15]. 

 Treatment includes treating the underlying condition, and stabilization through maneuvers including [15]:

• Hyperventilation 

• Head of the bed elevation to maximize venous outflow

• Ensure neck braces (c-collar) is appropriately placed (not too tight)

• Hypertonic solutions like mannitol or hypertonic saline 

• Emergent craniotomy

Other Etiologies of Symptomatic Bradycardia [15-16]

• Prolonged hypoxia

• Severe electrolyte derangements (hyperkalemia)

• Vagal response 

• Severe obstructive sleep apnea

• Genetic channelopathies 

References: 

1. Spodick, D. H., Raju, P., Bishop, R. L., & Rifkin, R. D. (1992). Operational definition of normal sinus heart rate. The American Journal of Cardiology, 69(14), 1245–1246. https://doi.org/10.1016/0002-9149(92)90947-w

2. UpToDate. (n.d.). Www.uptodate.com. https://www.uptodate.com/contents/sinus-bradycardia?search=Bradycardia&source=search_result&selectedTitle=1~150&usage_type=default&disp

3. Spodick, D. H. (1992). Normal sinus heart rate: Sinus tachycardia and sinus bradycardia redefined. American Heart Journal, 124(4), 1119–1121. https://doi.org/10.1016/0002-8703(92)91012-p

4. ACLS Bradycardia Algorithm. (n.d.). ACLS Medical Training. https://www.aclsmedicaltraining.com/adult-bradycardia-algorithm/

5. A. A. J. Adgey, Geddes, J. S., Mulholland, H., Keegan, D., & Pantridge, J. F. (1968). INCIDENCE, SIGNIFICANCE, AND MANAGEMENT OF EARLY BRADYARRHYTHMIA COMPLICATING ACUTE MYOCARDIAL INFARCTION. The Lancet, 292(7578), 1097–1101. https://doi.org/10.1016/s0140-6736(68)91577-8

6. UpToDate. (n.d.). Www.uptodate.com. Retrieved June 11, 2024, from https://www.uptodate.com/contents/sinus-node-dysfunction-clinical-manifestations-diagnosis-and-evaluation?search=bradycardia&source=

7. ROTMAN, M., WAGNER, G. S., & WALLACE, A. G. (1972). Bradyarrhythmias in Acute Myocardial Infarction. Circulation, 45(3), 703–722. https://doi.org/10.1161/01.cir.45.3.703

8. Tisdale, J. E., Chung, M. K., Campbell, K. B., Hammadah, M., Joglar, J. A., Leclerc, J., & Rajagopalan, B. (2020). Drug-Induced arrhythmias: A scientific statement from the american heart association. Circulation, 142(15). https://doi.org/10.1161/cir.0000000000000905

9. Kusumoto, F. M., Schoenfeld, M. H., Barrett, C., Edgerton, J. R., Ellenbogen, K. A., Gold, M. R., Goldschlager, N. F., Hamilton, R. M., Joglar, J. A., Kim, R. J., Lee, R., Marine, J. E., McLeod, C. J., Oken, K. R., Patton, K. K., Pellegrini, C. N., Selzman, K. A., Thompson, A., & Varosy, P. D. (2019). 2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and

10. Cardiac Conduction Delay. Journal of the American College of Cardiology, 74(7), e51–e156. https://doi.org/10.1016/j.jacc.2018.10.044

11. Farkas, J. (2021, October 1). Hypothermia. EMCrit Project. https://emcrit.org/ibcc/hypothermia/

12. UpToDate. (n.d.). Www.uptodate.com. Retrieved June 11, 2024, from https://www.uptodate.com/contents/accidental-hypothermia-in-adults?search=hypothermia&source=search_result&selectedTitle=1~150&usage_type=default&display_r

13. Näyhä, S. (2005). Environmental temperature and mortality. International Journal of Circumpolar Health, 64(5), 451–458. https://doi.org/10.3402/ijch.v64i5.18026

14. Decompensated Hypothyroidism (“Myxedema Coma”). (n.d.). EMCrit Project. https://emcrit.org/ibcc/myxedema/#treatment_of_cause

15. UpToDate. (n.d.). Www.uptodate.com. Retrieved June 11, 2024, from https://www.uptodate.com/contents/evaluation-and-management-of-elevated-intracranial-pressure-in-adults?search=increased%20intracranial%20pressure&source=search_result&selectedTitle=2~150&usage

16. UpToDate. (n.d.). Www.uptodate.com. https://www.uptodate.com/contents/sinus-bradycardia?search=Bradycardia&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=

Expert Commentary

Thank you for this nice review of the differential diagnosis of bradycardia. As emergency physicians, it’s easy to slip into the default of “symptomatic/unstable” vs “asymptomatic/stable” and slip past the underlying causes, and with bradycardia (as with many things), patients are often not divided quite so neatly.

Similarly, the context matters considerably: what resources are available? Is a cardiologist who can place a permanent pacer upstairs and ready with a staffed lab? Or is “definitive care” hours away (eg, requires transfer, or the cardiology team needs to come in from home). A patient with bradycardia from an acute MI will need the cath lab regardless, but in settings that require a transfer that may require transvenous pacemaker prior to transfer. On the other hand, a patient being whisked upstairs to a cath lab requires a different conversation with the cardiology team, eg preparing for transcutaneous pacing while getting the patient from the door to the balloon in a handful of minutes.

The differential can also be helpful when considering other logistics. For example, while I am happy to place a transvenous pacemaker for a patient who needs it for, say, a high degree AV block from Lyme disease, I may consider if the patient is stable enough to have a transvenous pacer placed more elegantly by the cardiology team as the patient may keep the TVP for 2 weeks but not need a permanent pacemaker.

Of course there are also secondary causes of bradycardia that need other, non-cardiac, definitive treatments, eg, overdose, hypothermia, Cushing’s response, and of course, hyperkalemia; keeping the differential in mind is part of the reason why we have not yet been replaced by robots.

Seth Trueger, MD, MPH, FACEP

Associate Professor of Emergency Medicine

Northwestern Memorial Hospital

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How To Cite This Post:

[Peer-Reviewed, Web Publication] Kilbane, K. Power, E. (2024, Jun 17). Symptomatic Bradycardia: Considering the Differential Diagnosis. [NUEM Blog. Expert Commentary by Trueger, S]. Retrieved from http://www.nuemblog.com/blog/symptomatic-bradycardia

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