Applied Pulmonary Circulation and Therapeutics

Question 1

what ways can we measure pulmonary pressure?

Answer 1

• direct with right heart catheterizaiton

or

• indirectly using doppler ultrasound

Question 2

in a healthy person is pulmonary pressure greater or lesser than systemic pressure?

Answer 2

in health it’s much lower than systemic pressure

Question 3

does the pulmonary circulation have greater or lesser resistance than systemic circulation?

Answer 3

it has lower resistance (1/10th of the systemic cirulatory resistance)

Question 4

Do you have to generate the same amount of pressure in the right side of the right as in the left side?

Answer 4

no - the right side of the heart pumps to the lungs which are at the same level and have little resistance compared to systemic circulation. t

Therefore the left side requires far more pressure

Question 5

pulmonary hypertension implies hypertrophy of what side of the heart?

Answer 5

hypertrophy of the right side of the heart

Question 6

What is the cardiac output of the left side of the heart?

Answer 6

5L/min

Question 7

murmers upon inspiration/expiration are indicative of what?

Answer 7

breath in = right sided murmers are louder

breath out = left sided murmers are louder

Question 8

what drives our need for respiration?

Answer 8

buildup of CO2

Question 9

how does pulmonary circulation differ from systemic circulation in the event of hypoxia?

Answer 9

pulmonary circulation constricts to shunt blood away from hypoxic areas of the lung - unlike the systemic ccirculation which increases in the setting of hypoxia

• this, theoretically, favors better perfusion to areas which are better ventilated

Question 10

where does gas exchange occur in the lungs?

Answer 10

ONLY at the alveolar pulmonary capillary interface

which is a single cell/thin wall

Question 11

what amount of gas exchange occurs in the lungs?

Answer 11

250 ml/min oxygen diffusion from alveoli to blood

200 ml/min CO2 diffusion from blood to alveoli

Question 12

if capillary filtration exceeds lymphatic absorption, what develops?

Answer 12

pulmonary oedema

Question 13

what are the different causes of pulmonary oedema?

Answer 13

• Hydrostatic
  
  • increased pulmonary capillary venous pressure due to pulmonary venous stenosis or pulmonary venous hypertension due to raised left atrial pressure
• alveolar membrane permeability increase
  
  • adult respiratory distress syndrome due to permeability problem in the alveoli
• Low oncotic pressure - more often get ascites, lower limb oedema
• Lymph obstruction

Question 14

what is the normal pulmonary arterial pressure?

Answer 14

25/8 mmHg

Question 15

What is the difference between primary and secondary pulmonary arterial hypertension?

Answer 15

primary = just hypertension of the pulmonary artery - give vasodilators/phosphodiesterase inhibitors for treatment

secondary = could be pulmonary venous hypertension, pulmonary embolis, pulmonary artery vasoconstriction secondary to hypoxaemia etc- treatment is to cure the underlying condition, thus curing the hypertension as well

Question 16

Why do people with an uncorrected hole in their heart often experience pulmonary hypertension?

Answer 16

b/c volume overload causes constriction -

people with an uncorrected hole in their heart will have vasoconstrictino and therefore pulmonary hypertension