Fine crackles, also called rales, are abnormal lung sounds that present like a popping or crackling noise towards the end of inspiration.
However, before we jump right into identifying fine crackles, let’s go over the basics in helping you understand how to identify adventitious lung sounds.
What questions should you be asking yourself while auscultating adventitious lung sounds?
When you’re auscultating lungs sounds you want to tune your ears to take notice of the following things that will help you determine what type of abnormal sound you are hearing:
- Timing: are you hearing it mainly on inspiration or expiration or even both?
- Pitch: low or high pitch?
- Discontinuous or continuous? meaning are you able to distinguish the individual sounds that come in a series and are intermittent (discontinuous)? Or are they a continuous sound?
- Location? large airways (upper respiratory, trachea, large bronchi) vs. small airways (lower parts of the respiratory like the bronchioles or alveoli)
- Does it have defining auditory characteristics that are hard to ignore? for example, harsh-grating, squeaky musical whistling, snoring, or squawking etc.
Fine Crackles Description
Timing: Occurs toward the end of inspiration and is brief (short)
Pitch: High-pitched
Discontinuous
Location: Small airways
Defining characteristics: the light crackling or popping of a fire and it doesn’t go away with coughing
Listen to Fine Crackles
Causes of Fine Crackles?
This sound is usually occurring because when the patient inhales air into the small airways (like the bronchioles and alveoli, which are deflated or collapsed) it leads these structures to all of a sudden “crackle” or “explode” open, which creates this high-pitched crackling noise that is brief.
It can occur with cases of congestive heart failure, atelectasis, pulmonary fibrosis, and pneumonia.
Now test your knowledge with this free fine crackles quiz.
Nurse Sarah’s Notes and Merch
Just released is “ABG Interpretation Notes, Mnemonics, and Workbook by Nurse Sarah“. These notes contain 64 pages of Nurse Sarah’s illustrated, fun notes with mnemonics, and worksheets that include over 90 ABG practice problems and 60 test review questions covering ABG concepts.
You can get an eBook version here or a physical copy of the book here.
References:
Kataoka H, Matsuno O. Age-related pulmonary crackles (rales) in asymptomatic cardiovascular patients. Ann Fam Med. 2008 May-Jun;6(3):239-45. doi: 10.1370/afm.834. PMID: 18474887; PMCID: PMC2384982.
Zimmerman B, Williams D. Lung Sounds. [Updated 2022 Aug 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537253/