PATHOPHYSIOLOGY OF RESPIRATORY SYSTEM

Respiratory insufficiency

• Is a pathologic process, which develops as a result of external respiration disorder, when the gas content of the blood does not correspond to organism requirements at rest and under physical load

Pathogenetic Classification

• Ventilative
• Diffusive
• Perfusive
• Combined

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Ventilative Respiratory insufficiency�

• Obstructive (emphysema, asthma, bronchiectasis, and chronic bronchitis)
• Restrictive
• Extrapulmonary(pneumothorax,myositis)
• Pulmonary( atelectasis, tuberculosis, pneumosclerosis)
• Disregulative( hyperventilation, hypoventilation, bradypnea, apnea, periodic breathing)

Disregulation ventilative insufficiency

• Respiratory Center Dysfunction (changes of respiration depth and rate lead to alveolar ventilation decrease- hypoventilation, increase – hyperventilation.

Bradypnea – infrequent breathing

Tachypnea – frequent shallow breathing

Hyperpnea – deep frequent breathing

Periodic breathing:

• Cheyne- Stokes breathing
• Biot’s breathing

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An unconscious young man in the state of morphine intoxication has been delivered into an admission room. The patient’s respiration is slow and shallow due to suppression of the respiratory center. What kind of respiratory failure occurred in this case?

• Ventilatory disregulation
• -Ventilatory obstruction
• -Ventilatory restriction
• -Perfusion
• -Diffusion

Obstructive ventilative insufficiency�

Connected with pathology of the respiratory tract

• Compressive ventilative insufficiency in cases if the respiratory ways or lungs are pressed from outside by a tumor, inflammatory swelling, enlarged thyroid gland.
• Occlusive ventilative insufficiency occurs as a result of narrowing of the respiratory ways from inside and increased resistence to air.
• Entrance of foreing bodies into the respiratory ways
• Occlusion by vomit mass, water, blood
• Thickening of the respiratory tract walls
• Hypertrophy and hyperplasia of mucous cells

Obstructive ventilative insufficiency

• Spasmodic is a widespread and significant mechanism of bronchial obstraction

Bronchial spasm

Nervous causes

• Increased activity of the cholinergic neurons of the vagus nerve and acetylcholine release.
• Increased activity of the peptidergic neurons of the vagus nerve, which release the P substance
• Deficiency of VIPergic neuron activity.

Humoral causes ( histamine, leukotrienes, kinins, prostaglandins)

A patient, who has been suffering from bronchial asthma for a long time, developed acute respiratory failure. What is the main mechanism of pathology development in this case?

• Obstructive disorders of pulmonary ventilation
• Restrictive disorders of pulmonary ventilation
• Pulmonary blood supply disturbance
• Pulmonary enzyme system disturbance
• Decreased elasticity of the pulmonary tissue

When studying the signs of pulmonary ventilation, reduction of forced expiratory volume has been detected. What is the likely cause of this phenomenon?

• Obstructive pulmonary disease
• Increase of respiratory volume
• Increase of inspiratory reserve volume
• Increase of pulmonary residual volume
• Increase of functional residual lung capacity

Restrictive ventilative insufficiency�

Pulmonary reasons

• Disorders of the Surfactant System of the Lungs
• Synthesis impairment
• Acceleration removal from the sueface of the alveoli
• Destruction
• Atelectasis is collapse of the lungs
• Pneumosclerosis

A patient with marked pneumofibrosis that developed after infiltrating pulmonary tuberculosis has been diagnosed with respiratory failure. What is its pathogenetic type?

• Restrictive
• -Obstructive
• -Dysregulatory
• -Reflex
• -Apneistic

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Examination of a miner revealed pulmonary fibrosis accompanied by disturbance of alveolar ventilation. What is the main mechanism of this disturbance?

• Limitation of respiratory surface of lungs
• Constriction of superior respiratory tracts
• Disturbance of neural respiration control
• Limitation of breast mobility
• Bronchi spasm

Restrictive ventilative insufficiency

Extrapulmonary reasons

• Impaired structure and function of the respiratory muscles
• Hampered mobility of the thorax and diaphragm
• Increased pressure in the pleural cavity, accumulation of exudate or transudate.

A 30-year-old man has sustained an injury to his thorax in a traffic incident, which caused disruption of his external respiration. What type of ventilatory difficulty can be observed in the given case?

• Restrictive extrapulmonary ventilatory impairment
• Restrictive pulmonary ventilatory impairment
• Obstructive ventilatory impairment
• Impaired ventilation regulation dysfunction
• Cardiovascular collapse

Diffusive respiratory insufficiency

• Decrease of the area of the alveolar capillary membrane
• Thickening of the capillary membrane
• Decrease of the transmembrane gradient of partial pressure of gases in the alveoli-blood system
• Decrease of the volume of the capillary blood in the lung
• Decrease of the speed of reaction between O2 and Hb and oxygen capacity of the blood.
• Decrease of alveolar ventilation
• Decrease of the exposition and contact of erythrocytes with the alveolar air.

Diffusive respiratory insufficiency

• Damage of membranes ( membranogenic poisoning)
• Inflammation and accumulation of inflammatory exudate
• Sclerosis
• Fibrosis
• Edema
• Anemia and Hb inactivation
• Emphysema
• Cardiac insufficiency.

Perfusive respiratory insufficiency

• Systemic disorders of blood circulation ( shock, Collapse)
• Disorders of right ventricle contractility ( infarction, myocarditis,cardiosclerosis)
• Disorders of left ventricle contractility
• Disorders congestion in the lungs
• Some congenital and acquired cardiac disorders, heart disease
• Embolism of the pulmonary artery.

Disorders of the Ventilation-Perfusion ratio in Lung Disease

• When ventilation prevails over blood flow, a larger amount of CO2 is released from the blood than usually ( hypocapnia)
• If ventilation is slower than the blood stream, pCO2 concentration in the alveolar air increases and pO2 concentration in the blood decreases with hypoxemia and hypercapnia.

High Ventilation-Perfusion ratio only slightly increases blood oxygenation while a low one determines its significant decrease and results in substantially decreased content of oxygen in the blood.

Periodic breathing

Cheyne- Stokes

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• A 62-year-old patient was admitted to the neurological department due to cerebral haemorrage. His condition is grave. There is evident progression of deep and frequent breath that turnes into reduction to apnoea and the cycle repeates. What respiration type has developed in the patient?
• Cheyne-Stockes respiration
• Kussmaul respiration
• Biot’s respiration
• Gasping respiration
• Apneustic respiration

A 23-year-old patient has been admitted to a hospital with a cranio-cerebral injury. The patient is in a grave condition. Respiration is characterized by prolonged convulsive inspiration followed by a short expiration. What kind of respiration is it typical for?

• Apneustic
• Gasping breath
• Kussmaul’s
• Cheyne-Stokes
• Biot’s

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