1. Pulmonary Circulation and Pulmonary Edema
DR KAMRAN AFZAL

2. OBJECTIVES
Describe regional differences in pulmonary blood flow in an upright person
Define zones I, II, and III in the lung, with respect to pulmonary vascular pressure and alveolar pressure
Describe the major functions of the bronchial circulation
Discuss pulmonary edema
Identify Clinical Correlations

3. Distribution of blood circulation
280 billion capillaries, supplying 300 million alveoli
Total volume of blood in all vessels
man: 5.4 l (70-80 ml / kg)
woman: 4.5 l (65-70 ml / kg)
Distribution:
Heart 7%
Pulmonary circulation 9-10%
Systemic circulation 84%
from that veins 75%
large arteries 15%
small arteries 3%
capilaries: 7%

4. DOUBLE CIRCULATION
Double circulation is made possible because of heart
advantage
all body organs with oxygenated blood at high pressure
at low pressure to the lungs as they are spongy tissue

5. Pulmonary Blood Pressures
Gravity and Distance:
Distance above or below the heart (arterial ,venous)
Distance between Apex and Base 5

6. Pulmonary Capillary dynamics
Starling forces (ultra filtration)
Capillary hydrostatic P = 7 mmHg.
Interstitial hydrostatic P = -8 mmHg.
Plasma colloid osmotic P = 28 mmHg.
Interstitial colloid osmotic P = 14 mm
Filtration forces = 15 mmHg.
Reabsorption forces = 14 mmHg.
Net forces favoring filtration = 1 mmHg.
Excess fluid removed by lymphatics

7. 3 Zones 23 mm Hg pressure difference between top and bottom.
23 mm Hg pressure difference between top and bottom
At top, 15 mm Hg < than the PAP at the level of the heart
At the bottom, 8 mm Hg greater than the PAP at the level of the heart.

8. Gravity and Blood Flow

9. Regional Pulmonary Blood Flow Depends Upon Position Relative to the Heart
Main PA
15 mmHg
Apex
2 mmHg
Base
25 mmHg

10. Gravity, Alveolar Pressure, and Blood Flow
1. Typically no zone 1 in normal healthy person
zone 2 (intermittent flow) at the apices.
zone 3 (continuous flow) in all the lower areas.
2. Large zone 1 in positive pressure ventilation
3. In normal lungs, Zone 2 begins 10 cm above the mid-level of the heart to the top of the lungs.

11. Effect of hydrostatic P on regional pulmonary flow From apex to base capillary P  (gravity)
Zone 1:
no flow
alveolar air pressure (PALV) is higher than arterial pressure during any part of cardiac cycle.
Zone 2:
intermittent flow
systolic arterial pressure higher than alveolar air pressure, but diastolic arterial pressure below alveolar air pressure.
Zone 3:
continuous flow
pulmonary arterial pressure (Ppc) remain higher than alveolar air pressure at all times.

12. Lung Ventilation/Perfusion Ratios
The ratio of V/Q in lung at rest 0.8 (4.2 L/min ventilation divided by 5.5 L/min blood flow).
When the ventilation (Va) is zero, yet there is still perfusion (Q) of the alveolus, the Va/Q is zero.
at the other extreme, when there is adequate ventilation, but zero perfusion, the ratio Va/Q is infinity.
At a ratio of either zero or infinity, there is no exchange of gases through the respiratory membrane of the affected alveoli

13. Lung blood flow rises towards bases and also during Exercise
1.- at rest, the blood flow is very low at the top of the lungs; most of the flow is through the bottom of the lung.
2.-During exercise, flow ↑(4-7) fold.
- Top of lung ↑ by 700 to 800%, the - =bottom by 200 to 300%.
reason for these differences is PAP ↑ during exercise to convert the lung apices from a zone 2 to a zone 3 pattern .

14. Double circulation in the respiratory system 1. Bronchial Circulation 2. Pulmonary Circulation
Arises from L Ventricle.(systemic - oxygenated).
1-2% of left ventricular output.
Supplies the supporting tissues of the lungs, including the connective tissue, septa, and bronchi.
Venous return from the bronchial by 2 routes.
bronchial drainage is into azygous (1/2)
2.pulmonary veins (1/2) (short circuit
Pulmonary Circulation Arises from
Right Ventricle.
Receives 100% of blood flow.

15. Special features of bronchial circulation
LV output > (1=2%) than RV output & some deO2 blood into O2ated pulmonary venous blood + L atria
Does not supply beyond terminal respiratory units (respiratory bronchioles, alveolar ducts, and alveoli)
Bronchial arterial pressure is =same as Aortic pressure, and bronchial vascular resistance is > than resistance in the
pulmonary circulation
4.Only capable of undergoing angiogenesis,(new vessels).

16. Definition:
Pulmonary edema is a condition characterized by fluid accumulation in the lungs caused by back pressure in the lung veins. This results from malfunctioning of the heart.

17. Causes:
Pulmonary edema is a complication of a myocardial infarction (heart attack), mitral or aortic valve disease, cardiomyopathy, or other disorders characterized by cardiac dysfunction.

18. Pathophysiology:
Fluid backs up into the veins of the lungs. Increased pressure in these veins forces fluid out of the vein and into the air spaces (alveoli). This interferes with the exchange of oxygen and carbon dioxide in the alveoli.

19. Symptoms: Extreme shortness of breath, severe difficult breathing
Feeling of "air hunger" or "drowning"
"Grunting" sounds with breathing
Inability to lie down
Rales
Wheezing
Anxiety

20. Symptoms: Restlessness Cough Excessive sweating Pale skin
Nasal flaring
Coughing up blood
Breathing, absent temporarily

21. Signs:
Listening to the chest with a stethoscope (auscultation) may show crackles in the lungs or abnormal heart sounds.
A chest x-ray may show fluid in the lung space.
An echocardiogram may be performed in addition to (or instead of) a chest x-ray.

22. Tests: Blood oxygen levels (low)
A chest X-ray may reveal the following:
Fluid in or around the lung space
Enlarged heart

23. Tests:
An ultrasound of the heart (echocardiogram) may reveal the following:
Weak heart muscle
Leaking or narrow heart valves
Fluid surrounding the heart

24. Treatment:
This is a medical emergency! Do not delay treatment. Hospitalization and immediate treatment are required.
Oxygen is given, by a mask or through endotracheal tube using mechanical ventilation.

25. Expectations (Prognosis):
Pulmonary edema is a life-threatening condition. It is often curable with urgent treatment and subsequent control of the underlying disorder.

26. Complications:   
Long-term dependence on a breathing machine (ventilator)