Dyspnea(呼吸困难)

Toxic dyspnea
The overdose of morphine and pentobarbital can depress respiratory center causing slow respiration or Cheyne-Stokess respiration.
Neuro-Psychogenic dyspnea
Inspiratory dyspnea



Clinical characteristics: visible indrawing over the sternal notch, the supraclavicular spaces, the intercostal spaces and the epigastrium in the inspiration(三凹症). Accompanied by a coarse, low pitched inspiratory wheezing and dry cough. Stenosis and obstruction of larynx, trachea, and bronchi
Left heart failure
Basal diseases: Coronary heart disease Hypertensive heart disease Rheumatic heart disease Congenital heart disease
Left heart failure
How to describe these sensations

Cannot get enough air Air does not go all the way down Smothering feeling in the chest Tightness in the chest Fatigue in the chest
Functional classification



Class Ⅰ– no limitation: Ordinary physical activity does Class Ⅱ– slight limitation of physical activity Class Ⅲ– Marked limitation of physical activity Class Ⅳ– inability to carry or any physical activity without discomfort
Biventricular failure
Left heart failure plus right heart failure may cause severe dyspnea?
Toxic dyspnea
In the metabolic acidosis (uremia尿毒症 and diabetic acidosis糖尿病性酸中毒), the acid metabolites stimulate the respiratory center, causing deep and regular respiration (Kussmanul) with snoring.
Normal
person may experience the physiologic dyspnea during heavy exercise Environment short of oxygen
Respiratory dyspnea



Respiratory dyspnea is caused by abnormal ventilation and gas exchange. Reduction in ventilatory capacity, hypercapnia(二氧化碳潴留) and hypoxemia(低氧血症) resulting from respiratory disease. Three clinical types: inspiratory dyspnea, expiratory dyspnea, mixed dyspnea.
The respiratory center loses the blood supply or is compressed while patient suffering from cerebro vascular disease. The respiration becomes deep, slow and irregular.
Definition


Dilatation of nares(鼻翼扇动), cyanosis(紫绀), use of accessory muscles of respiration Abnormalities of respiratory rate,depth or rhythm
Etiology
Mechanism: Lung congestion decrease gas dispersion Alveoli are stiff and more work is needed to overcome elastic recoil The high alveolar pressure stimulate stretch receptor High pulmonary circulation pressure stimulate respiratory nerve center
Right heart failure
Basal diseases: Acute cor pulmonale(肺心病) which caused by pulmonary embolism(肺栓塞) Chronic cor pulmonale which caused by chronic obstructive pulmonary disease(慢阻 肺)
Right heart failure
Mechanism: The pressure of right atria and superior vena cava is the natural stimulus of respiratory center. Hypoxemia and the accumulation of the acid metabolites stimulate respiratory center. The restriction of the respiratory movement caused by enlargement of liver,ascites and pleural effusion.
Left heart failure
Clinical representation: Exhausted dyspnea(劳力性呼吸困难) Orthopnea(端坐呼吸) Paroxysmal nocturnal dyspnea( 夜间阵发性呼 吸困难)
Exhausted dyspnea
Dyspnea
Definition


Dyspnea is defined as an awareness of difficulty in breathing. Most patients suffer from actual difficulty, some patients just taste an awareness of hyperventilation(换气过度).

Cardiac dyspnea


Cardiac dyspnea is usually attributable to pulmonary vascular congestion resulting from the left and/or right heart failure. Dyspnea is the primary symptom of left heart failure.
Expiratory dyspnea



Clinical characteristics: expiration is prolonged and laboured with wheezing. Cause: the decrease of lung elasticity and spasm narrowing of the bronchioles and smaller bronchi. Familiar diseases: emphysema(肺气肿), bronchial asthma(支气管哮喘) and chronic asthmatic bronchitis(喘慢支).

Respiratory disease Cardic disease Toxic Nero-Psychogenic Haematological disease Increase of abdominal pressure (massive ascites(腹水), pregnancy(怀孕) etc)
Paroxysmal nocturnal dyspnea


The patient awakes short of breath at night, but often obtain relief by sitting up for a period of time. Physical examination: moist rales at the both lung bases, tachycardia, wheezing and bronchospasm (cardiac asthma心源性哮喘).
Paroxysmal nocturnal dyspnea
Reason: Supine posture for sleep impel more blood into pulmonary circulation, and decrease vital capacity. Vagus excitement cause coronary artery constriction and bronchioles spasm.
Orthopnea
Difficulty in breathing in the supine position relived by sitting up Reduce the degree of pulmonary congestion by pooling blood in the lower extremities Improve the diaphragmatic movement Increase vital capacity
Mixed dyspnea



Clinical characteristics: breathing is difficult during both inspiration and expiration. Respiratory frequency increase and respiration superficial. Cause: decrease of ventilators and gas exchange capacity Familiar diseases: severe pneumonia(肺炎), pulmonary fibrosis(肺纤维化), massive atelectasis(大片肺不张) etc
Difficulty
in breathing when the patient is in activity relived when he relax. Doing exercise impel more blood into pulmonary circulation. More oxygen is needed for body demand, especially the heart.