Dasgupta - Pulmonary Circulation Flashcards
Bronchial circulation is part of _________ circulation
Systemic
About _ of the bronchial capillary venous blood from this circulation drains into the pulmonary veins, adding desaturated, venous blood to the arterial blood.
This counts as a shunt
2/3
Pulmonary vessels offer ______ resistance to blood flow than do the systemic arterial vessels
Much less
What factors lead to the much lower intravascular pressure of the pulmonary vessels compared to that of the systemic vessels ?
Lower resistance
More distensible
More compressible
Lung anastamoses
Connections between bronchial and pulmonary capillary
Systolic mean pulmonary arterial pressure =
25mmHg
Zone 2 is only perfused intermittently at ________
Systolic pressure
Zone 1 is defines as the region of the lung that is _________
Not perfused
Because PA > Pa > PV
Zone 3 is the region of the lung which is ______
Always perfused
Pa > PV > PA
In hemorrhage or general anesthesia, you have high amounts of zone _____ because of low pulmonary systolic pressure
1
In exercise, high cardiac output, you have increases in zones ____ and ____
2 and 3
Zone 1 recruited to zone 2, zone 2 recruited to zone 3
Patients on positive pressure ventilators will have high amounts of zone
1
Cor pulmonale
Right heart failure
Passive influences on pulmonary vascular resistance
Recruitment of un-perfused capillaries
Distention of existing pulmonary capillaries
At high lung volumes, the resistance to blood flow offered by the alveolar vessels ________
Increases greatly
At low lung volumes, the resistance to blood flow offered by the alveolar vessels ____
Decrease
As lung volume increases, the resistance to blood flow offered by extraalveolar vessels _______
Decreases
Due to their exposure to intrapleural pressure
Radiopaque substance is injected into pulmonary artery and its movement is monitored by x-rays
Pulmonary angiography
Principally related to an increase in capillary pressure
No change in Kf or sigma
This type of edema is common w/ left heart failure due to left ventricular infarction or mitral stenosis
Hydrostatic (cardiogenic) edema
Increase in permeability of the capillary walls of the lungs to either fluid or protein, causing edema.
Principle disorder in ARDS
Change in Kf or sigma
Permeability edema
S/s: breathlessness, rapid, shallow breathing, dry cough, chest pain
diffuse alveolar damage and pulmonary edema
Usually observed after some form of insult to the lung like inhalation of toxins or infections
X ray shows diffuse airspaces and bilateral alveolar infiltrates
ARDS
