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Chronic respiratory insufficiency

Table of contents
Chronic respiratory insufficiency
Pathogeny of respiratory insufficiency
Clinical signs and symptoms
Diagnosis
Therapy of patients

Respiratory insufficiency  – inability of system of breath to provide normal gas structure of an arterial blood.
Another, more practical, the following definition is: respiratory insufficiency – a pathological syndrome at which the partial tension of oxygen in an arterial blood (Rao2) is less than 60 mm hg and/or the partial tension of carbon dioxide (RASO2) of more than 45 mm hg.
  Epidemiology
 By approximate estimates, in industrialized countries the number of the patients of chronic respiratory insufficiency (chronic respiratory insufficiency) demanding carrying out an oxygen therapy or respiratory support in house conditions makes about 8-10 people on 10 thousand population. Generally it is sick HOBL, is more rare – with pulmonary fibroses, diseases of a thorax, respiratory muscles, etc.

Etiology

Normal functioning of respiratory system depends on work of its many components (a respiratory center, neuromuscular system, a thorax, respiratory tracts and alveoluses). Disturbance of work any of these links can lead to development of chronic respiratory insufficiency (table 1).
Table 1. The most frequent reasons of chronic respiratory insufficiency


Defeat of a link + breath device

Example of chronic respiratory insufficiency

Central nervous system and respiratory center

Primary alveolar hypoventilation, central apnoea, hypothyroidism.

Neuromuscular system

Dyushenn's illness, hereditary and metabolic myopathies, effects of an injury of a spinal cord (CI-CIV), phrenoplegia, poliomyelitis effects.

Thorax

Kyphoscoliosis, obesity, state after a thoracoplasty, a fibrothorax.

Respiratory tracts

Upper: obstructive night apnoea, tracheomalacia.
Lower: HOBL, the mucoviscidosis obliterating a bronchiolitis, a bronchoectatic disease.

Alveoluses

Alveolites, pulmonary fibroses, sarcoidosis, asbestosis.

Classification.
   I. On the speed of development distinguish acute respiratory insufficiency and chronic respiratory insufficiency.
The Acute Respiratory Insufficiency (ARI) develops within several days, hours or even minutes and demands carrying out an intensive care as it can pose direct threat for the patient's life. At fast development of respiratory insufficiency compensatory mechanisms from systems of breath, blood circulation, the acid-base state (ABS) of blood do not manage to turn on. A characteristic sign of ODN is disturbance of BRAIDS of blood – respiratory acidosis at ventilating respiratory insufficiency (pH <7,35) and a respiratory alkalosis at parenchymatous respiratory insufficiency (pH> 7,45).
Chronic respiratory insufficiency develops within months and years. The beginning of chronic respiratory insufficiency can be imperceptible, gradual, gradually, or it can develop at incomplete recovery after ODN. Long existence of chronic respiratory insufficiency allows to join to compensatory mechanisms – a polycythemia, to increase of cordial emission, a delay kidneys of bicarbonates (leading to correction of respiratory acidosis).
   II. Pathogenetic classification of respiratory insufficiency.
Distinguish two big categories of respiratory insufficiency: hypoxemic – parenchymatous, pulmonary, or type DN I, and giperkapnichesky – ventilating, "pumping", or type DN II.
   Hypoxemic respiratory insufficiency it is characterized by an anoxemia and normo-or a hypocapny. Usually this form of respiratory insufficiency arises against parenchymatous diseases of lungs, such as alveolites, pulmonary fibroses, a sarcoidosis.
   Cardinal sign of ventilating respiratory insufficiency is the hypercapnia, the anoxemia is also present, but it usually well gives in to therapy by oxygen. Ventilating respiratory insufficiency can develop owing to defeat of a respiratory center. HOBL and dysfunction of respiratory muscles – the most frequent reasons of ventilating respiratory insufficiency, follow them the obesity, a kyphoscoliosis, diseases which are followed by decrease of the activity of a respiratory center, etc.
   There is one more widespread pathogenetic classification of respiratory insufficiency (more often it is used at chronic respiratory insufficiency) – as disturbance of mechanics of breath – obstructive respiratory insufficiency and restrictive respiratory insufficiency. At decrease in the general vital capacity of easy (VC) less than 80% of due values, proportional reduction of all pulmonary volumes and a normal ratio of the relation of Tiffno of FEV1/VC (> 80%) speak about a restrictive syndrome. Decrease in the relation of FEV1/VC, decrease in stream indicators, increase of bronchial resistance and increase in pulmonary volumes is characteristic of an obstructive syndrome. Existence of a combination of restrictive and obstructive disturbances is possible.
   III. Classification of respiratory insufficiency by severity is based on gas-metric indicators (table 2).
Table 2. Classification of respiratory insufficiency by severity


Degree

RASO2

Rao2

Norm

36-44

80-96

I

<50

> 70

II

50-70

70-50

III

> 70

<50

Giperkapnichesky coma

90-130

 

Gipokapnichesky coma

 

39-30

In clinical practice allocate 4 stages of acute respiratory insufficiency.
/ the stage (initial) — as a rule, has no bright clinical manifestations, proceeds is hidden against a basic disease. Its main signs — breath increase, emergence of an asthma and feeling of shortage of air at a small exercise stress.
//the stage (subcompensated) - is characterized by an asthma in a rest sostoyoyaniya, constant feeling of shortage of air, participation in breath of auxiliary respiratory muscles, cyanosis of lips, podnoggevy spaces, tachycardia, tendency to a povyyosheniye of arterial pressure, feeling of alarm, concern.

  • the stage (dekompensirovanny) — is shown by the sharp strengthening of an asthma forced by the position of patients expressed uchasyotiy in breath of auxiliary muscles, feeling uduyoshya, by psychomotor excitement, tachycardia, widespread cyanosis, sharp falling of arterial pressure.
  • the stage (terminal) — has the following symptomatology:

- sharp oppression of consciousness, up to a coma, often develops gi-
poksemichesky hypostasis of a brain;
-    diffuse cyanosis; skin is covered with clammy cold sweat;
-  the breath which is speeded up, superficial, arrhythmic, appears Cheyn-Stokes's dyyokhaniye or the Biota; at development of acidosis — Kussmaul's breath;
-     pulse is threadlike, a frequent ekstrasistoliya against bradycardia;
-    deep arterial hypotension;
-   significant increase in tracheobronchial secretion, hypostasis of a sliyozisty cover of bronchial tubes, development of a syndrome expiratory zakyorytiya of respiratory tracts
-   oligoanuriya.
The final of an end-stage is the hypoxemic giperkapnichesky coma.



 
"Fibroziruyushchy alveolitis   Chronic obstructive pulmonary disease"