Without oxygen, there is no life – on average, humans breathe in and out almost 20,000 liters of air every day. In the process, oxygen is supplied to the body and toxic carbon dioxide is removed. To do this, the lungs are constantly in use. Various diseases can impair its function. Correct diagnosis is important for prevention and adequate therapy. Complaints often lead the patient to the doctor. However, the examination of the lungs is also of great importance in the context of preventive medical checkups or fitness tests for work and sports. Like every examination, the lung examination begins with a discussion between the doctor and the patient. The patient is asked not only about current symptoms such as breathing difficulties, cough, sputum, chest pain and fever, but also about previous illnesses and allergies, illnesses in the family and the use of medication.
Smoking habits and occupation are also important, since certain substances, for example, can cause chronic changes in lung tissue. In addition, there are the findings that the physician obtains by looking at the patient and during the physical examination. Special tests are then used to refine the diagnosis and set up the therapy concept or to monitor treatment. In some cases, they can be coupled directly with therapeutic measures. Which apparative tests are used depends on the suspected diagnosis and question.
Basic diagnostics
Physical examination is usually performed on a sitting or supine patient with the upper body undressed. Externally visible signs (inspection) of lung disease include blue lips and fingers, changes in fingernails, deformities of the chest, changes in breathing, and coughing.
During palpation, the physician checks for symmetry in the breathing of the chest, changes in the thyroid, trachea, and lymph nodes, or painfulness of the bones when pressure is applied or when tapped.
The voice fremitus can be used to roughly check the conduction of sound in the lungs, which is altered in pathological processes. To do this, the examiner places his hands flat on the patient’s back while he speaks the number “99”.
By tapping (percussion) the chest, initial statements can be made about the size and air content of the lungs, as well as checking the lung displacement during inhalation and exhalation. Side-by-side percussion is supplemented by listening with a stethoscope (auscultation). This is used to perceive the sounds caused by the airflow in the airways. In the case of lung diseases, these are often altered or secondary sounds are present. Depending on the type, one speaks, for example, of rales, stridor (a whistling), crackling or leather creaking. For the trained examiner, the findings on percussion and auscultation provide important clues to diseases of the lungs and pleura.
Depending on the question, various laboratory values are determined in the blood, which, however, usually only provide indications of causes or risk factors. In the case of lung diseases in particular, oxygen saturation can be measured via the skin on the ear or finger (pulse oximetry) or determined by taking blood from an artery, e.g. on the wrist (blood gas analysis). In addition, the examination of any sputum (sputum diagnostics) for pathogens and cells is also important.
