Cervical Versus Thoracic Auscultation

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Answer

Today cervical auscultation (CA) is experiencing a renaissance as an adjunct to the clinical swallowing assessment. It is a controversial technique with a small evidence base, as opposed to thoracic auscultation (TA) which has a long and illustrious history. Below your question is addressed with some definitions to help in explanation.

First, there is a difference between CA, what the SLP would do, and TA, what the nurse would do. In CA a listening device, stethoscope or microphone, is placed on the lateral neck overt he thyroid cartilage. In TA the device is placed on the chest's anterior, lateral or posterior surfaces in a number of sites. Each provides information of a different sort. Cervical swallowing sounds, click (initial discreet sound, J Bosma, Intro. CA Workshop, Dept. Pedi., Univ. Maryland, Baltimore, 22.APR.92) associated with the opening of the eustachian tube, and clunk (final discreet sound, Bosma, 92), is associated with the opening of the upper esophageal sphincter. These sounds may be diminished, absent, or out of order in dysphagia. The application of any understanding of the sounds generated during swallowing needs further research before reliable and broad clinical application. However, CA is helpful in identifying inhalatory and exhalatory phases, the moment of the pharyngeal swallow, whether secretions are in the airway before or after the swallow, changes in secretion levels, and to reveal the result of motor activity necessary for swallowing. With CA one is listening for the sequence of sounds to discern proper function, but little about actual aspiration. With TA, one is discerning whether there are changes in normal respiratory sounds, like fluid in the lungs. Thoracic sounds, tidal turbulent air, and crackles and rales in pathologic states, reveal the result of respiration. In most cases, the amount of fluid need be no larger than a level teaspoon to produce pathologic sounds.

Second, Zenner PM, et al., (Dysphagia, 1995, 10(1):27-31) found that the use of CA in clinical dysphagia, when compared with videofluoroscopy, revealed significant agreement for both. Their results support the use of CA as a highly sensitive and specific method. P. Leslie, et al, (Dysphagia, 2003, Vol. 19(4):231-240) speculated that swallow sound contains audible cues that should in principle permit reliable classification, in addition to other information clinicians bring into the assessment. But they reported reliability of individual judges varied widely. Meaning the agreement between judges was poor. This information applies to your question. Interestingly, neither article offered information on what exactly 'aspiration sounds' are. However, that nursing and you are working together on patient management is good. For nursing to be most helpful, listening should be done over the right lung, to the right of the lower sternum if the patient is upright, and in the same location on the posterior surface of the thorax if the patient is recumbent. This has to do with the nature of tracheobronchial tree anatomy.

Mr. Charpied is the Director of the Department of Speech Pathology, in the Department of Otolaryngology - Head and Neck Surgery, with the University Rochester's School of Medicine and Strong Memorial Hospital. A clinically certified Speech Pathologist who specializes in voice and swallowing, Mr. Charpied has developed techniques and manuals on the diagnosis, treatment and management of voice and swallowing disorders. He teaches at Nazareth College, as well in the ENT resident program. His research interests include anatomy of the larynx, quantification of laryngeal function through image analysis, and the use of computers as a clinical tool. Besides publications and numerous abstracts, Mr. Charpied's introductory text for Speech Pathology students will be published Spring of 2006.