What are beta blockers and how do they work? Beta blockers, also known as beta-adrenergic blocking agents, are a class of drugs that works by blocking the neurotransmitters norepinephrine and epinephrine from binding to receptors. There are three known types of beta receptors, known as beta1 (Î²1), beta2 (Î²2) and beta3 (Î²3).
Although many newer imaging techniques for the evaluation of lung pathology have been developed, auscultation of the chest remains an invaluable clinical tool and is still probably the most common method of evaluating the lung. Evaluation of lung sounds is a routine part of a clinical examination. Breath sounds can be classified into 2 broad categories: normal breath sounds and adventitious (or abnormal) sounds. Adventitious breath sounds include wheezes, coarse crackles, fine crackles, and rhonchi. See the video of breath sound assessment, below.
Abnormal Breath Sounds. There are several abnormal sounds that can be heard over the lung fields. Click on the stethoscope to hear the abnormal lung sound. Click on the name of the abnormal lung sound to learn more about the sound. Wheezes (Sibilant)-a high-pitched, musical sound similar to a squeak. It is heard most commonly during expiration, but also can be heard during inspiration. It is heard in narrowed airway diseases such as asthma and chronic emphysema.