Respiratory Failure -Goya

Question 1

What is hypoxemic respiratory failure? Hypercapnic respiratory failure?

Answer 1

Hypoxemic respiratory failure:
PaO2 < 60 mm Hg when breathing room air

Hypercapnic respiratory failure:
PaCO2 > 50 mm Hg

Question 2

What determines how you get CO2 out?

Answer 2

Respiratory rate

Tidal volume

Ventilation-perfusion matching

Question 3

What are the primary causes for Type 2 respiratory failure?

Answer 3

those that affect the brainstem or the respiratory mm or chest wall

(ventilation/hypercarbic failure)

Question 4

What is the most common cause of hypoxemia?

Answer 4

Ventilation/Perfusion Mismatch

others: Alveolar hypoventilation, shunt, diffusion abnormalities

Question 5

What happens with V/Q mismatch? How can you correct this?

Answer 5

A-a O2 gradient is widened

inc ventilation will not correct the hypoxemia (CO2 often normal or low)

**only way to correct=give O2

Question 6

What is a shunt? Can oxygenation improve a shunt ?

Answer 6

an extreme V/Q mismatch

(venous blood directly bypass arterial circulation without participation in gas exchange)

oxygenation will not improve

Question 7

When could you see a systemic shunt? a pulmonary parenchymal shunt?

Answer 7

Systemic shunt seen in sepsis

Pulm parenchymal shunt in PE

Question 8

How can you differentiate between hypercapnic and hypoxemic respiratory failure?

Answer 8

PAO2 = (PIO2) -(PaCO2/R)

PIO2 =normal =150 mmHg
R=0.8

A-a gradient = difference between alveolar and arterial PO2

normal A-a gradient =15-20 depending on pt

anything affects the lung ==> widened A-a gradient (Hypoxemia resp failure )

if lung not affected (hypercapnic resp failure) ==> A-a normal