Resp 2 Flashcards
What is the delta PaO2 between PaO2 in the lungs?
110mmHg (high delta)
What is the PaO2 in the blood that is driving gas exchange?
40mmHg
What must hgb go through to before binding to Hgb in RBCs?
Several fluids and epithelial layers
That is why it is important to maintain a high PaO2 in the alveoli to ensure it dissolves.
What are some diseases that causes changes in the PaO2 in the alveoli or in Delta PaO2 and therefore cause a drop in the Diffusion Limit of O2?
Fibrosis
COPD
Emphysema
How does Fibrosis drop the diffusion limit?
Increases the thickness of the membrane
How does COPD drop the diffusion limit?
Reduces the SA to volume ratio
How does Emphysema drop the diffusion limit?
Decrease the surface area
Excess fluid, excess thickness will affect diffusion of O2 and therefore O2 and therefore O2 ___________ in the blood.
Tension
How is the diffusion of O2 and O2 tension measured in the blood?
DLCO (Carbon Monoxide tracer)
T/F: Changes in overall morphology in lungs causes a reduced DIFFUSION capacity of O2.
True
What is being measured in the oxyhemoglobin dissociation curve?
PO2:Partial pressure of oxygen
VO2: Volume of O2
SaO2: Oxygen saturation
How well we exchange gases
What causes a R shift?
Acidosis
Inc temp
Inc 2,3 DPG
What happens during a Right shift?
Oxygen will readily RELEASE from hgb
What causes a L shift?
Alklalosis
Dec temp
Dec 2,3 DPG
What happens during a L shift?
Oxygen will LATCH to hgb
What happens to the alveolar capillaries as the lungs expands?
Stretch of the alveolar wall compresses the alveolar capillaries and elevates PVR.
What happens to the extra alveolar vessels as the lungs expands?
They are pulled open due to recoil forces. The opposite is true at low lung volumes.
The net result is that perfusion of the pulmonary vasculature is ____________ at or near _____________.
Optimal; FRC
The compression of alveolar capillaries causes increased pulmonary pressures with ___________ & _________. This will create a back up causing Pulm HTN.
Emphysema;COPD
What is perfusion of the lungs dependent upon?
The driving pressure (pulmonary artery pressure-pulmonary vein pressure) and the resistance of the regional vascular bed.
What lung zone will you have big alveoli (high ventilation) and low resistance?
Zone 1.
D/t being above the heart, more gravity->less perfusion
What lung zone are alveoli well ventilated and will also have good perfusion?
Zone 2
“Normal” working parameters of the lungs
What happens in zone 3 of the lungs?
Alveoli are poorly ventilated, d/t gravity, good perfusion.
Low V/Q ratio
Gets a mixture of deoxygenated blood with oxygenated blood (Shunt)
What happens during during zone 1 mismatch?
To prevent dead space, the body will bronchoconstrict areas that are being ventilated and not perfused->shunting away from there.
Dependent on Bronchodynamics: Ince or Dec air resistance or bronchiolar resistance.
What happens during Zone 3 mismatch?
A shunt normally means low O2 in the venous blood
Hypoxia: regulator for vasoconstriction
What is considered a shunt in Zone 3?
Shunt=hypoxic vasoconstriction, which reduces perfusion to areas not well ventilated.
Improvement: Control of blood flow and PVR
During PNA, edema, etc, what causes vasodilation?
Inflammatory cytokines
Reduced PVR>don’t get hypoxic
Describe what happens during Obstructive DO.
Increased compliance
Decrease in resistance
Drop in FEV1/FVC ratio
Dif getting air out
Where does Obstructive DO occur?
Alveolar Space
Name examples of Obstructive DO
COPD
Asthma
Chronic bronchitis
Emphysema
Bronchiectasis
Where do Restrictive DO occur?
Interstitial space
Name examples of Restrictive DO?
“Osis” diseases
Interstitial pneumonias
Granuloma diseases
Carcinomas
TB
Where do Vascular DO take place?
Capillaries/blood vessels of the lungs
Name examples of Vascular DO
Pulm edema
Pulm HTN
Pulm emboli
Name examples of Combo DO
ALI/Resp Distress
Bacterial PNA
What happens during Combo DO?
Infection in lungs->fluid shifts (interstitial edemas, pulm edema)->leads to obstruction and restrictive patterns
Are Combo DO acute or chonic?
Most of the time they are Acute
Not doing PFTs on them
Rely on physical exam, labs, and CXR
What do you see in infective disorders?
Fever, WBCs
What do you see in PNA?
Opacifications
What is an example of an inspiratory disorder in children?
Extrathoracic Obstructions (child aspirated something)
What curve does most process diseases processes occur?
Expiratory Curve
Measures peak flow
What happens to the FEV1/FVC ratio in Restrictive D/O?
It is above normal, usually high
What occurs during Restrictive DO?
Hard time getting air IN
Total volume change is lower, but flow rate is really high
They can get air out in the first second
What happens to the diaphragm in COPD?
It flattens
What is the Meniscus sign?
Fluid in the pleural space
