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Cardiogenic APO is defined as Acute Pulmonary Oedema secondary to heart failure, where ineffective cardiac contraction leads to back up of fluid into the atria and lungs.
Increased pressure/pooling--> Increased pulmonary venous pressure--> Increased pulmonary capillary pressure--> fluid in interstitial spaces--> Increased pressure in Interstitial spaces--> fluid in alveoli (pulmonary edema).

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2. Is it obstructive or restrictive? Why?

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2. Is it obstructive or restrictive? Why?

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Restrictive. as in APO there is an accumulation of fluids that will affect the surfactant of the lungs leading to decreased compliance the lungs.

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pH: High (hyperventilation)
Reduced PaO2
Normal-reduced PaCO2
Low SpO2

Respiratory Alkalosis

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4. Explain the role of V/Q mismatch in this condition.

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4. Explain the role of V/Q mismatch in this condition.

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Lower V/Q ratio: despite full perfusion, ventilation is reduced due to impaired gas exchange.

Accumulated blood in the pulmonary circulation causes increased hydrostatic pressure that forces fluid into the alveoli of the lungs. The fluid filled alveoli are unable to effectively undertake gas exchange creating a V/Q mismatch (low V/Q ratio).

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5. How is oxygenation and ventilation affected? 

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5. How is oxygenation and ventilation affected? 

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Hypoventilation
Fluid build-up in alveolar spaces reduces ventilation. Increased shunting results in greater hypoxemia than hypercapnia (because carbon dioxide can more easily dissolve into the fluid to reach the alveolar membrane for exchange). The oedema prevents air from reaching pulmonary capillaries, resulting in perfusion without ventilation and shunting.

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6. What type of respiratory failure would this condition lead to?

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6. What type of respiratory failure would this condition lead to?

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Type 1 (Low PaO2 but normal PaCO2).
Acute hypoxemia.

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On examination, the positive findings include:

General appearance

Confusion, agitation, and irritability may be present, associated with excessive sweating, cold extremities, and upright posture (sitting upright), cyanosis of the lips.

JVP/JVD      Usually raised.

Blood Pressure

Hypertension is more often present, but if hypotension prevails, it is an indicator of severe left ventricular systolic dysfunction, and cardiogenic shock. Cold extremities are a feature of low perfusion and shock.
-increased BP d/t increased Cardiac output secondary to fluid retention

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Respiratory Rate

-Tachypnea, gasping for breath.
-Orthopnea
-Paroxysmal nocturnal dyspnoea

As alveolar oedema increases, diffusion of O2 into the pulm capillaries is impaired, & manifests as dyspnoea;

Pulse

Tachycardia and associated finding of the cause in the pulse.

Pedal Edema

Usually co-exists with pulmonary edema in CHF

Respiratory Findings

Dyspnea and tachypnea are usually present,  use of accessory muscles. Fine crackles heard at the bases of lungs bilaterally, and progress apically as the edema worsens. Ronchi and wheeze may also be presenting signs.

Cardiovascular Findings

Additional heart sounds and murmurs due to mitral valve stenosis/regurgitation, or aortic stenosis/regurgitation

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Gastrointestinal System

Tender hepatomegaly may be a feature in cases of right-sided cardiac failure, which may worsen to hepatic fibrosis and hepatic cirrhosis in chronic congestion. Ascites may sometimes be present.

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3. How does the condition effect lung compliance and/or airway resistance?

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3. How does the condition effect lung compliance and/or airway resistance?

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Reduced compliance. Reduced stroke volume > increased fluid in the lungs > impairs production of surfactant > can cause atelectasis > shunting.
Increased resistance. Fluid build-up > narrows airway.

note:  In pulmonary edema, liquid-filled alveoli induce mechanical stress on air-filled alveoli, reducing the compliance of air-filled alveoli, and hence overall lung compliance.