Pulmonary Hypertension + Respiratory Failure

Question 1

What causes pulmonary venous hypertension?

Answer 1

Left heart disease

• ischaemia (systolic dysfunction)
• mitral regurgitation/stenosis
• cardiomyopathy

Question 2

What are the causes of primary pulmonary hypertension?

Answer 2

Hypoxia: COPD, pulmonary fibrosis, OSA
Multiple PEs
Vasculitis e.g. SLE
Drugs e.g. appetite suppressants - fenfluramine
HIV
Cardiac left to right shunt (ASD, VSD)

Question 3

What is cor pulmonale?

Answer 3

Right heart disease secondary to lung disease

- fluid retention due to hypoxia +/- RHF

Question 4

Which murmur is most commonly caused secondary to pulmonary hypertension/RHF?

Answer 4

Tricuspid regurgitation

Question 5

What are the clinical signs of pulmonary hypertension/RHF?

Answer 5

Central cyanosis (if hypoxic)
Oedema
Raised JVP with V waves (due to tricuspid regurgitation)
Right ventricular heave felt at left parasternal edge
Loud P2
Enlarged pulsatile liver

Question 6

How is respiratory failure defined?

Answer 6

Hypoxia with a PaO2 < 8

Divided into type 1 and 2 dependent on PaCO2 level

Question 7

What is the definition of type 1 respiratory failure?

Answer 7

Hypoxia (PaO2 < 8) with a normal or low PaCO2

Question 8

What causes type 1 respiratory failure?

Answer 8

V/Q mismatch:
pneumonia 
pulmonary oedema
PE
asthma
emphysema
pulmonary fibrosis
ARDS

Question 9

What is the definition of type 2 respiratory failure?

Answer 9

Hypoxia (PaO2 < 8) + hypercapnia (PaCO2 > 6)

Question 10

What causes type 2 respiratory failure?

Answer 10

Alveolar hypoventilation +/- V/Q mismatch:

• pulmonary disease
• reduced respiratory drive e.g. sedative drugs, CNS tumour or trauma
• neuromuscular disease

Question 11

What are the symptoms of hypoxia?

Answer 11

SOB
restlessness/agitation
confusion
central cyanosis
if longstanding --> pulmonary hypertension/cor pulmonale

Question 12

What are the symptoms of hypercapnia?

Answer 12

headache
peripheral vasodilation
tachycardia
bounding pulse
tremor/flap
papilloedema
confusion/drowsiness/coma

Question 13

Describe the use of oxygen therapy in type 1 respiratory failure:

Answer 13

Give oxygen 35-60% to correct hypoxia

Consider assisted ventilation if PaO2 < 8 despite 60% oxygen

Question 14

Describe the use of oxygen therapy in type 2 respiratory failure:

Answer 14

Give controlled oxygen therapy starting at 24%
Recheck ABG after 20 minutes
- if PaCO2 steady or decreased, increase oxygen to 28%
- if PaCO2 has risen > 1.5 and patient still hypoxic, consider assisted ventilation