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.
This breath sound is abnormal if heard over the peripheral lung fields. Bronchial Breath Sound-a harsh, high pitch, low intensity breath sound with expiration longer than inspiration (I<E) (1:2). This sound is normal over the trachea but always considered abnormal if heard over the peripheral lung fields.