COR
PULMONALE
Definition
The
W.H.O definition of pulmonary heart disease is Hypertrophy of
the right ventricle resulting from diseases affecting the function and/or
the structure of the lung, except when these pulmonary alterations are the
result of diseases that primarily affect the left side of heart or of congenital
heart disease.
1.
Chronic bronchitis with or with out emphysema.
2.
Generalized obstructive lung disease (without mention of emphysema) or
asthma.
3.
Emphysema without mention of bronchitis.
4.
Pneumoconiosis and other occupational diseases of the lung.
5.
Other diseases of the lung or pleura.
6.
Parasitic diseases affecting the lung.
7.
Chest deformities. Congenital or acquired.
8.
Thrombo-embolic diseases.
9.
Other diseases of blood or blood vessels.
10.
Unspecified causes.
The normal palmary artery systolic/Diastolic and mean
pressures average 16/7 10m.m of mercury, and the normal pulmonary venous
pressure is 2 or 3 m.m of Hg. So that the driving pressure or gradient across
the pulmonary vascular bed averages 7 to 8 m.m of mercury.
The resistance to flow through the vascular bed is
called the pulmonary vascular residence (PVR) and may be calculated from the
mean pulmonary artrial and venous pressures and the cardial output, since the
easily obtained by cardiac catherusation. Assuming a normal cardiac output of 5
litres per minute. The normal pulmonary vascular resistance is less than 2 m.m
of mercury per litre per minute.
Pressure
Resistance
In the above case.
Mean pulm art press- Mean left =Pam Pvm.(mm: Hg.)
Artrial Pr:
(PVR) cardiac output (L/m)
10-2
or
= 1.6 m.m Hg. /L/Min
pulmonary hypertension is arbitransily defined as an
elevation of pulmonary artery pressure exceeding 30/ 15. 20 m.m of mercury
resistance is expressed as Units in m.m Hg./litre/min Narrowing of the
pulmonary vascular bed by vasoconstriction or disease elevates the resistance
and dilatation decreases it.
Normally pulmonary vessels contain 500 to 600 ml of
blood about 90ml of which is in the pulmonary capillaries and approximately Two-
Third of the entire amount is in the veins. The pulmonary vascular system has a
relatively low compliance and thus total volume changes with little pressure
changes.