Bruit and Thrill | How to Identify & Nursing Overview

The word Bruit (pronounced ‘broo-ee’) means noise in French. In medical speak, it is a whooshing or swishing sound caused by turbulent blood flow through an artery. Healthcare professionals can auscultate a bruit with a stethoscope over an artery such as the carotid or abdominal aorta. Nurses General Nursing Knowledge

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Bruit and Thrill | How to Identify & Nursing Overview

Do you know what causes Bruit and Thrill and how to identify them? This article reviews the underlying pathology of bruit and thrill as well as assessment techniques and implications to nursing care. 

Table of Contents

What are Bruit and Thrill?

The word Bruit (pronounced 'broo-ee’) means noise in French. In medical speak, it is a whooshing or swishing sound caused by turbulent blood flow through an artery. Healthcare professionals can auscultate a bruit with a stethoscope over an artery such as the carotid or abdominal aorta. Although it often indicates an abnormal finding, hearing a bruit over an arteriovenous fistula (AVF) used for hemodialysis is normal. 

A thrill is a palpable vibration on the skin over the area of turbulent blood flow. Thrills can occur in the chest directly over the heart or an artery. It is normal to palpate a thrill over an AVF. Since bruits and thrills are signs of turbulent blood flow, they often go hand in hand. The phrase "hear the bruit, feel the thrill" can help nurses remember the difference between bruit and thrill. 

What is the Significance of Bruit and Thrill?

It is crucial for the nurse to report any bruits and thrills, as they can be indicators of vascular disease. 

The most common reason for a bruit is stenosis (a narrowed artery) caused by atherosclerosis. Blood flow through a narrowed vessel will meet resistance and create the bruit sound during systole. Research suggests patients with a carotid bruit are at higher risk for cerebrovascular disease (1).

Other abnormal causes of bruit are aneurysms or arterial vascular malformations. An aneurysm is a weakened and ballooned vessel, and an arterial vascular malformation is an abnormal connection between an artery and vein (2). In both cases, the abnormality in the vessel diverts the normal flow of blood, but the bruit may be constant. The nurse should be aware that these conditions are not as common but can be life-threatening (3).

In the case of an AVF, a surgeon attaches an artery to a vein to allow venous access for hemodialysis. The pressure from the artery creates a rapid flow of blood into the vein, making a continuous, gentle, rhythmic bruit and thrill. Both bruit and thrill indicate that the AVF is functioning properly. 

Regular monitoring is vital because changes in bruit and thrill indicate stenosis or thrombosis (blood clot) in or near the fistula. The common signs of stenosis or thrombosis include a weak or absent thrill or bruit or a bruit that is higher pitched and heard only during systole (4). The nurse should monitor any changes as well as educate the patient on how to self-monitor. Early detection of changes in bruit and thrill is key to maintaining the AVF (5). 

How to Assess Bruit and Thrill  

To prepare to assess bruit and thrill, perform hand hygiene and disinfect your stethoscope. 
The most common place the nurse will encounter vascular bruit and thrill is over the carotids. Ensure the patient is sitting or supine. Palpate the carotid pulse to locate the artery and note any thrill. Place the bell of the stethoscope over the artery. Ask the patient to inspire and hold their breath for several seconds. This action will eliminate breath sounds so you can hear any bruits. Depending on the amount of atherosclerosis present, a bruit can be soft and only heard during systole or higher pitched and heard during both systole and diastole (6).

To assess for abdominal bruits,

  1. Ask the patient to assume the supine position.
  2. Use the stethoscope bell to auscultate over the abdominal aorta and renal and iliac arteries (see illustration for locations of arteries). You can perform this step while assessing bowel sounds.
  3. Note the character and location of any bruit sounds.  

To assess an AVF, ask the patient to remove any constrictive sleeves. Locate the patient's AVF on the inner side of the wrist, elbow crease, or upper arm. To palpate for a thrill, lightly place two fingers on the part of the fistula that has the strongest vibration. This location is where the artery and vein are anastomosed. A healthy AVF will feel soft and have a continuous thrill. It is usual for the motion of the blood flowing to move your fingers slightly. A weak or absent thrill or a bounding, forceful pulse that moves your fingers up and down are signs of stenosis or thrombosis (7). 

To auscultate the bruit, place the bell of the stethoscope directly on the AVF. Remember, a normal-sounding AVF has a continuous bruit you can hear in systole and diastole. Changes in pitch, a whistling sound, or sound present in systole only are signs of stenosis. Keep in mind stenosis can occur anywhere in or near the fistula. A diminished or absent bruit is a sign of thrombosis. 

In summary, knowing the significance of bruit and thrill and how to assess them enables the nurse to recognize various vascular problems. This knowledge is especially valuable in caring for dialysis patients. Both new and experienced nurses can apply this information to provide excellent preventative care and improve patient outcomes.

STAFF NOTE: Original Community Post 

This article was created in response to a community post. The comments and responses have been left intact as they may be helpful. Here's the original post:

Quote

I am new to this web site I have only been a nurse for about 6 months and would like to know how to check the thrill and bruit on a patient. Thank you

References

  1. Lucerna, A., & Espinosa, J. (2022, August 28). Carotid bruit. StatPearls. https://www.ncbi.nlm.nih.gov/books/NBK536913/
  2. National Institute of Neurological Disorders and Stroke. (n.d.). Arteriovenous malformations (AVMs). https://www.ninds.nih.gov/health-information/disorders/arteriovenous-malformations-avms
  3. Centers for Disease Control and Prevention. (2021, September 27). Aortic aneurysm. https://www.CDC.gov/heartdisease/aortic_aneurysm.htm
  4. National Kidney Foundation. (n.d.). Detection and management of clinically significant AV access lesion (stenosis/thrombosis). https://www.kidney.org/sites/default/files/vait-15_detection_management_clinically_significant_av_access_lesion-stenosis_thrombosis.pdf
  5. Abreo, K., Amin, B.M., & Abreo, A. P. (2018). Physical examination of the hemodialysis arteriovenous fistula to detect early dysfunction. The Journal of Vascular Access, 20(1).  DOI: 10.1177/1129729818768183 
  6. Lucerna, A., & Espinosa, J. (2022, August 28). Carotid bruit. StatPearls. https://www.ncbi.nlm.nih.gov/books/NBK536913/
  7. End Stage Renal Disease National Coordinating Center. (n.d.). "Ready, set, go" the steps to catheter freedom. https://www.kidney.org/sites/default/files/ready_set_go_avg-patient_week_4.pdf
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kgrieco53

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Specializes in Med Surg, Hospice, Home Health.

You can feel the thrill and hear a bruit (buzzing sound)...

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Bruits, particularly those in the carotids, can be auscultated with a stethoscope at either side of the neck. Have the patient hold their breath for a moment so that you can listen effectively. A thrill, typically caused by an av fistula, can be felt at the fistula site, and a good one cannot be missed. You'll never forget it when you feel it - and wear gloves. Perhaps you can go back to your assessment book from nursing school to get more info.

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Specializes in Cath Lab, OR, CPHN/SN, ER.

Agreed.

Thrills feel kinda like what a cats neck feels like when it's purring really loud.

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You can feel a thrill (feels like water running through a thin hose), or hear a bruit (swishing swooshing sound) right on an AV Fistula. *Av fistula: dialysis access device where they fuse a artery and vein.

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If your pt. is a dialysis pt with a fistula you "feel the thrill" which is a buzzing sensation, the bruit is a whooshing sound that you can hear with a stethoscope. Hope this helps!

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