Breath Sounds: From Basic Science to Clinical Practice

Abstract

The book Breath Sounds:From Basic Science to Clinical Practice is a literary accomplishment of epic dimensions. Yet, what is the need for a hardcover on lung sounds in the year 2018? The answer, given by the editors Priftis, Hadjileontiadis, and Everard, is that “the stethoscope will remain the first medical device a medical student will invest in (other than their smartphone).” The book takes the reader on a 319-page journey in 4 parts and 19 chapters through the past, present, and future of respiratory sound analysis. An impressive number of 36 international authors have contributed to this state-of-the-art overview of thoracic auscultation and technological advances in breath sound analysis. The book begins with the historical origins of the art of auscultation, which we owe to the invention of the stethoscope—recently celebrating its bicentennial anniversary—by René-Théophile-Hyacinthe Laënnec (1781–1826). This first part underlines the importance of clinical skills to examine and interpret the manifold variations in respiratory sounds. Chapter 3 includes instructive cases from the emergency room. “Let’s get physical,” in the second part, provides insights into the basic principles of sound recording and analysis. Chapter 6, introducing home-based sleep studies to screen for obstructive sleep apnea, is convincing and well written. Due to the development of new tracheal sound sensors and amplification of signals with subsequent inline filtering, we not only detect but also characterize respiratory events in sleep disorders. Extending the transmission through a modified medium brings back the percussion technique (first described by Leopold Auenbrugger in 1761) and may have some value in acute lung injury. Experimental studies to adapt ventilation with positive end-expiratory pressure are presented. Chapters 8 and 9 on breath sound recording and analysis address current techniques for multichannel recording of respiratory sounds followed by analog processing and digitization. Advanced approaches with fractality/lacunarity, swarm decomposition–swarm transform, and deep learning are shown to explain how big data will enhance the diagnostic value of breath sounds. The third part of the book sheds light on pulmonary pathophysiology and exposes the acoustic correlate of various respiratory conditions. Normal and adventitious lung sounds such as wheezing, crackles, rhonchi, and cough sounds are described in detail. Anesthesiologists will appreciate chapter 13 on the anatomy of the upper airway and stridor due to laryngeal obstruction or vocal cord dysfunction. The next chapter describes the fascinating biomedical engineering behind sleep disorder assessment and apnea detection. Deriving the sleep architecture from breath sounds recorded by freestanding microphones can be a medical application of the Internet of Things and refine the monitoring of patients in the intensive care unit. Part 4 of the book gives a short outlook on future prospects for respiratory sound research and the pursuit of a unified nomenclature. The book is complemented by 3 short audio files, accessible via a link in chapter 5. Overall, the online extras are scarce for a book of this scale. Additional samples of breath sounds are welcomed as a clinical guide for the reader or teaching purposes. Modern medicine has definitely entered the digital age. High-tech additions to conventional auscultation such as ultrasonography are now well-established routine investigations. However, the breath sound as a biosignal should not disappear from clinical practice, but be further integrated into innovative diagnostic tools and enriched by a computerized analysis of sound. Training of auscultatory skills remains relevant for junior doctors. The stethoscope will always offer a quick first impression of the patient’s respiratory condition. Moreover, the caring and gestural communication aspect of traditional auscultation plays a meaningful role in the patient–physician relationship. Because this book deals with a particular aspect of clinical diagnostics, its value is certainly highest in respiratory medicine, while critical care, infectious diseases, and pediatrics are marginally touched. In that, the book occupies a niche for a distinctive readership. Whether or not to own a copy of this book as an anesthesiologist comes down to a simple question: do you regularly wear a stethoscope in the operating room or intensive care unit? If yes, this book is for you, and it will precisely inform about the acoustic features of respiratory conditions encountered in clinical practice. If not, the volume’s worst fate is to take a lonely spot in an antiquary collection of books for the nostalgic. Nicolai Goettel, MD, DESA, EDICDepartment of AnesthesiaSurgical Intensive CarePrehospital Emergency Medicine and Pain TherapyUniversity Hospital Basel, University of BaselBasel, Switzerland[email protected] Matthias J. Herrmann, MDClinic of Pulmonary Medicine and Respiratory Cell ResearchUniversity Hospital Basel, University of BaselBasel, Switzerland