Pulmonary Assessment and Physiology

Question 1

What is the clinical indicator of ventilation?

Answer 1

PaCO2

Question 2

What is the formula for minute ventilation?

Answer 2

Tidal Volume x Respiratory Rate

Question 3

What is normal ventilation?

Answer 3

4L/min

Question 4

An increase in minute ventilation indicates that there is a ___ in ____.

Answer 4

increase in work of breathing

Question 5

List examples of conditions that affect the health of the diaphragm

Answer 5

deconditioning, hypoxemia, acidosis, hypophospatemia

Question 6

What is dead space ventilation?

Answer 6

volume of air that does not participate in gas exchange

Question 7

what is the normal anatomic dead space?

Answer 7

2mL/kg of Tidal volume

Question 8

What is the formula for physiologic dead space?

Answer 8

anatomic dead space + alveolar dead space

Question 9

Increased alveolar dead space can come from ____.

Answer 9

a pulmonay embolus

Question 10

A pulmonary embolus results in ___ in that area of pulmonary circulation

Answer 10

no blood past alveoli

Question 11

What is alveolar dead space?

Answer 11

pathologic, non-perfused alveoli, PE

Question 12

Why do chronic PaCO2 retainers rely on mild hypoxemia?

Answer 12

It can decrease their drive to breathe. If PaO2 is corrected to normal, it may result in decreased drive to breathe

Question 13

What is pulmonary perfusion?

Answer 13

movement of blood through the pulmonary capillaries

Question 14

What will a decrease in blood flow past alveoli affect?

Answer 14

ventilation/perfusion ratio and gas exchange

Question 15

What is the normal ventilation/perfusion ratio?

Answer 15

4L V / min / 5 L Q / min

Question 16

What is the ideal lung unit?

Answer 16

0.8 ratio; normal V/Q ratio

Question 17

Do you want the “good” lung or the “bad” lung down?

Answer 17

good lung down so that blood can be oxygenation better with gravity

bad lung down can result in hypoxemia

Question 18

Explain what PEEP is

Answer 18

• Positive end-expiratory pressure
• increases alveolar recruitment
• prevents alveolar collapse by decreasing surface tension of alveoli
• increases driving pressure, extends time of gas transfer, allows decrease in FiO2

Question 19

What is a shunt?

Answer 19

movement of blood from the right side of the heart into the left side of the heart without getting oxygenated; venous blood to the arterial side

Question 20

How do you treat a shunt?

Answer 20

Give oxygen (FiO2) and PEEP

Question 21

What happens in a normal physiologic shunt?

Answer 21

thebesian veins of the heart empty into the left atrium

Question 22

Give an examples of anatomic shunts

Answer 22

ventricular or atrial septal defect

Question 23

What happens in a pathologic shunt?

Answer 23

blood goes through the lungs but does not get oxygenated resulting in refractory hypoxemia

Question 24

At the cellular level, sufficient O2 is needed for the production of ___.

Answer 24

adenosine triphosphate (ATP) which is needed for cell energy and life

Question 25

Without sufficient oxygen, ___ is produced

Answer 25

lactic acid

Question 26

What does lactic acidosis suggest?

Answer 26

anaerobic metabolism, organ failure, eventual cell death

Question 27

What conditions cause a left shift of the oxyhemoglobin dissociation curve?

Answer 27

- alkalosis (low H+) - low PaCO2 - hypothermia - Low 2,3-DPG - high SaO2 ; low O2 to tissues - hemoglobin "holds on" to oxygen molecules

Question 28

What conditions cause a right shift of the oxyhemoglobin dissociation curve?

Answer 28

- acidosis (high H+) - high PaCO2 - fever - high 2,3-DPG - hemoglobin "release" oxygen easily to tissue - Low SaO2, higher O2 to tissue

Question 29

What is 2,3-DPG?

Answer 29

- an organic phosphate found in RBCs that has the ability to alter the affinity of hemoglobin for oxygen - low 2,3-DPG = hemoglobin hold on to oxygen - high 2,3-DPG = hemoglobin release oxygen

Question 30

how does carbon monoxide affect oxygenation?

Answer 30

- carbon monoxide has a greater affinity for hemoglobin than oxygen - in the presence of CO, oxygen cannot be carried --> tissue hypoxia

Question 31

why wouldn't you use a pulse oximeter for oxygenation monitoring in a patient with CO poisoning

Answer 31

- pulse oximeter cannot differentiate between CO and O2

Question 32

How is CO poisoning treated?

Answer 32

- 100% FiO2 until sx resolve and carboxyhemoglobin level is < 10% - Hyperaric oxygen chamber if available, generally within 30 mins

Question 33

What is static compliance?

Answer 33

measurement of the elastic properties of the lung

Question 34

What is dynamic compliance?

Answer 34

measurement of the elastic properties of the airways

Question 35

What is normal compliance?

Answer 35

45-50 mL/ cm H2O