Week 8 Pulmonary

Question 1

Define Hypoxemia vs hypoxia

Answer 1

Hypoxemia is in arterial blood, Hypoxia is in tissues

Question 2

Definine two types of Respiratory Failure (Type I (Hypoxemic Respiratory Failure) VS.
Type II (Hypercapnic Respiratory Failure))

Answer 2

Type I (Hypoxemic Respiratory Failure)
PaO2 < 60 mmHg
normal/ or low PaCO2

Type II (Hypercapnic Respiratory Failure)
PaCO2 > 50 mmHg

Question 3

Describe the path of Sars Cov-2 infection

Answer 3

Viral ‘S’ protein spike binds to ACE2 receptors in human cell
ACE2 receptors are present in lungs, heart, kidney, liver, intestine, blood vessels

TMPRSS2 (transmembrane serine protease 2) is an endothelial cell surface protein that cleaves the ‘S’ spike
Enables virus to enter host cell, release RNA & replicate

Infects bronchial epithelial and capillary endothelial cells
Resulting inflammatory response
Influx monocytes & neutrophils

Question 4

Definition of chronic bronchitis

Answer 4

hypersecretion of thick tenacious mucous, chronic cough > 3 months for at least 2 consecutive years

involves Mucous gland hyperplasia
Bronchial wall thickening
Inflammation

Question 5

hat would you expect to find on a patient’s PFT’s?

Answer 5

Decreased FVC, FEV1
Increased FRC, RV

Question 6

Different function of Type I Alveolar Cells
Vs
Type II Alveolar Cells

Answer 6

Type I Alveolar Cells:
squamous epithelium cells
main sites of gas exchange
most predominant cells (make up 97% of surface)

Type II Alveolar Cells:
cuboidal, interspersed among Type I cells
secretory cells – pulmonary surfactant

Question 8

PaO2:

Answer 8

PaO2: partial pressure of oxygen dissolved in arterial blood (Normal range: 80-100 mmHg)

Question 9

SaO2

Answer 9

SaO2: % of the amount of hemoglobin saturated with oxygen (Normal range >95%; pulse oximetry is a non-invasive estimate of SaO2)

Question 10

PaCO2:

Answer 10

PaCO2: partial pressure of carbon dioxide in arterial blood (Normal range 35-45 mmHg)

Question 11

What causes a L/R shift in the oxygehemoglobin dissociation curve

Answer 11

right shift: reduced affinity of hemoglobin for oxygen at any given PaO2 (in other words more oxygen is released to the tissues)
Causes of a right-shift include: fever, acidosis (low pH), increased PaCO2
left shift: there is an increased affinity of hemoglobin for oxygen at any given PaO2 (i.e. less oxygen is released to the tissues which can cause hypoxia)
Causes of a left-shift include: hypothermia, alkalosis, decreased PaCO2