Breathing Abnormalities Flashcards
What is Orthopnea?
It is standing up or sitting up breathing to relive dyspnea
Paroxysmal nocturnal dyspnea?
It is a dyspneic experience of the patient that wakes the patient from sleep often after an hour or two
Trepopnea ?
It is a dyspneic experience that occurs only in one lateral decubitus position over the other
Platypnea ?
It is a dyspneic experience that occurs in standing or sitting and is relieved by laying down
Dyspnea is not experienced until ventilation is_____.
Tripled
Pathophysiology of dyspnea?
When there is a mismatch between pressure generated by the respiratory muscles and tidal volume, the intercostal muscles transmit signals that bring the act of breathing to the conscious level. While at the same time juxta capillary receptors of the alveolar interstitium stimulates vagal afferents to the inspiratory area in the medullary respiratory center and apneustic center of the pons leading to the activation of Herring Breaur inflation reflex resulting in rapid shallow breathing known as dyspnea.
In pulmonary edema what causes dyspnea?
It is the activation of Herring Breaur inflation reflex by the exclusive inhibition of medullary inspiratory centre and pontine apneustic center by the inhibitory signals transmitted by the Juxta capillary alveolar interstitial receptors.
What is vital capacity?
It is the total amount of air expired after maximal inhalation. The normal value= 4800 L. It is the sum of TV + IRV+ ERV
Tidal volume?
It is the amount of air that moves in and out of the lungs during a respiratory cycle.
In man = 500 mL
In women= 400 mL
Total lung capacity?
It is the maximum volume of air in the lungs after a maximal inspiration. It is usually 6 litters in most people
Mechanism of Orthopnea?
In the recumbent position there is a redistribution of blood from the lower extremities and splanchnic beds to the lungs. In CCF patients the additional volume can’t be pumped out by the left ventricle which causes significant reduction in vital capacity and pulmonary compliance leading to dyspnea.
Mechanism of exertional dyspnea?
It is a sign of early left ventricular failure. The cardiac output doesn’t increase sufficiently in response to moderate exertion leading cerebral and tissue acidosis and the patient experiences dyspnea on exertion. The SoB maybe accompanied by fatigue, smothering or sensation of strenal compression.
Respiratory complaints of later stage left ventricular failure?
Exertional dyspnea on mild exercise, Orthopnea, paroxysmal nocturnal dyspnea
