The term dyspnea is often used in a broader sense, and they are combined: shortness of breath, both rapid and slow and unusually deep breathing, both difficult and easy.
With real shortness of breath or shortness of breath, there is almost always an increase in breathing. It does not differ at all from the well-known phenomenon when a healthy subject “suffocates” after a hard run or any other effort. Breathing is not only frequent, but also difficult. It also involves muscles not normally involved in breathing and can be seen tense over the collarbones and elsewhere in the chest. The face usually shows more or less suffering and often has bluish lip coloration and dark facial coloration. The most common causes of dyspnea are various types of heart disease, pneumonia, large pleuritic effusion, asthma, and consumption. Two types of dyspnea can be distinguished – mechanical and chemical dyspnea.
Mechanical dyspnea is associated with a decrease in O2 and an increase in CO2 in the blood, therefore, it has cyanosis of the corresponding degree. It rarely reaches a significant size in patients kept in bed and does not increase at night, unless the patient slides down from his semi-sitting position. It increases with pressure on the abdomen, in which blood rushes to the heart.
With chemical shortness of breath, there is no excess CO2 in the blood and there is no significant cyanosis. It is usually seen in bedridden patients, worse at night, even when there is no forced sitting position and the patient has not slipped down. It does not increase with pressure on the abdominal cavity. Finally, it is associated with the presence or increase in the blood of some unknown non-volatile acid, in other words, with acidosis. Therefore, it can be compared with acidosis in case of shortness of breath after prolonged heavy exercise (from lactic acid formed during muscle contraction) and with acidosis in the “big” breathing of diabetics. The presence of acidosis has also been proven with increased breathing in normal people at high altitudes, with diabetes, uremia, laboratory pneumonia, thyrotoxicosis, pneumothorax, and eclampsia.
The mechanical and chemical causes of dyspnea often act at the same time. With shortness of breath, inhalation may be especially difficult, as happens, for example, when there is a foreign body in the larynx or with an ordinary “croup.” in persons with a barrel chest. In the latter state, air during breathing easily enters the chest, but there is difficulty in returning it. The exhalation is significantly lengthened and often wheezing.
A combination of both types of shortness of breath is more common, in which both parts of the respiratory act are difficult.
Whenever, for whatever reason, the lungs are unable to expand properly during inhalation, dyspnea can be observed to draw in the intercostal spaces in the lower axillary spaces or under the collarbones. Such retraction of the intercostal space can be observed in the presence of an obstacle in the glottis.
Dyspnea should be distinguished from simple rapid breathing. The most common causes that can lead to increased breathing are:
- Muscular effort.
Diseases of the heart and lungs and the accumulation of fluid or dense masses from top to bottom from the abdominal obstruction, pushing this muscle upward and causing it to abnormally penetrate into the chest cavity.
Most infectious febrile diseases are also often accompanied by rapid breathing, especially when the fever is associated with diseases of the heart, lungs, pleura, or pericardial sac. Further chemical study of blood will no doubt help to more accurately subdivide and classify the types of dyspnea. A purely mechanical type of dyspnea occurs in bed patients, probably only occasionally.
The ratio of dyspnea to cyanosis.
In the chemical, acidosis-induced type of dyspnea, cyanosis is absent or disproportionately mild. On the other hand, with erythremia, some people with a pronounced barrel chest and congenital heart defects may have a sharp cyanosis with little or no shortness of breath. Here there is an overflow of peripheral capillaries with red blood cells, which is mainly the reason for the color of the patient’s integument. In many of these cases, there is a true increase in bone marrow activity, and the number of red blood cells is increased not only in the periphery, but also in larger blood vessels and in internal organs.