About

The Respiratory Sounds Atlas is a teaching resource, first written in Turkish, that brings together the theory, clinical use and clinical scenarios of respiratory sounds in one place. It was designed for every health professional, from medical students to specialist physicians.

How to use it

• To learn: Course outline. Seven modules of short lessons. Each lesson ends with a "Check yourself" section.
• For reference: Sound atlas, Disease guide and Pocket card.
• For practice: Clinical cases, Test yourself and Flashcards.

Every page follows the same layout. At the top you find a one-sentence summary and three key points. The middle gives a plain explanation. At the bottom, a collapsible "Going deeper" box holds the numbers and sources.

Sources

The content is based on the respiratory sounds literature and on international standards (CORSA, the 2016 ERS terminology). The diagrams were drawn for this site. Selected key sources are listed in the reference list.

Author

Dr İhsan Topaloğlu is a faculty member in the Department of Pulmonary Medicine at Kafkas University Faculty of Medicine. His clinical and research work focuses on respiratory acoustics, that is, the quantitative analysis of digital lung sounds, and its applications in COPD, asthma, sleep-disordered breathing and pulmonary thromboembolism.

How were the sounds made?

All sounds on this site are synthesised in real time in your browser. The background breath sound is noise that is shaped by respiratory phase and passed through filters that imitate the filtering effect of the thorax. Crackles are built so that their initial deflection width and two-cycle duration give the CORSA reference values exactly (fine crackle 0.7 ms / 5 ms, coarse crackle 1.5 ms / 10 ms). Wheezes, rhonchi and stridor are continuous musical sounds. Wheezes are generated anew in every breath: their number, duration, pitch, pitch course and intensity are drawn from distributions measured in open-licence recordings from 41 adult patients (KAUH). These sounds are passed through an electronic stethoscope filter, so they are slightly muffled. A rhonchus fills most of expiration and stridor fills inspiration; in a rhonchus the pitch falls through expiration and the harmonics grow stronger. Each breath differs a little from the one before in duration and intensity, and the width of each crackle varies slightly. Their pitch and intensity jitter, harmonic structure and prominence over the background sound were tuned to measurements of more than 400 real events annotated by experts in the open-licence SPRSound database (recordings from children). The chest sounds also include a faint recording floor between breaths and the filtering effect of the chest wall and stethoscope. The pleural friction rub is built from clusters of stick-slip pulses. Spectrograms are drawn with 16 kHz sampling, a Hann window and the same fixed dB reference for every sound. Differences in brightness therefore reflect differences in intensity between sounds.

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