Respiratory Pt. 1

Question 1

What is the primary function of the respiratory system?

Answer 1

gas exchange between atmospheric air in alveoli and blood in pulmonary circulation

Question 2

What is ventilation?

Answer 2

movement of air into and out of the lungs via inspiration and expiration

Question 3

What is diffusion?

Answer 3

O₂ moves from the alveoli to the blood, and CO₂ moves from the blood to the alveoli, from high to low concentration.

Question 4

What is perfusion?

Answer 4

flow of blood through the lungs to exchange gases

deliver O2 and remove CO2

Question 5

What is oxygenation?

Answer 5

process of adding O₂ to the blood for delivery to tissues

Question 6

What is the partial pressure of O2 in arterial blood (PaO2)?

Answer 6

• the amount O₂ dissolved in the arterial blood
• 80-100 mmHg

how well oxygen moves from lungs to blood

Question 7

What is the arterial O2 saturation (SaO2)?

Answer 7

• percentage of hemoglobin in arterial blood that is saturated with oxygen
• 95-100%

Question 8

What is anatomic dead space?

Answer 8

parts of the respiratory system (nose, trachea, and bronchi) where no gas exchange occurs

Question 9

How do we test for hypoxemia and hypoxia?

Answer 9

• Hypoxemia (Low Blood O₂):
  
  • arterial blood gases (ABG)
  • PaO2 < 60 mmHg or SpO2 < 90%
• Hypoxia (Low Tissue O₂):
  
  • clinical signs (cyanosis, confusion)
  • confirmed by ABG or pulse oximetry showing low oxygen levels

Question 10

What is the difference between hypoxemia and hypoxia?

Answer 10

• Hypoxemia = Low oxygen in the blood
• Hypoxia = Low oxygen in the tissues

Hypoxemia can lead to hypoxia, but hypoxia can occur without hypoxemia!

-“emia” = blood
-“oxia” = tissue

Question 11

What happens to ABG levels in hypoventilation? How does this affect pH and PaCO₂?

Answer 11

• PaCO₂ increases due to poor exhalation of CO₂ (hypercapnia)
• respiratory acidosis, lowering pH (becomes more acidic)

Hypoventilation → ↑ CO₂ → ↓ pH (Respiratory Acidosis)

Question 12

What conditions correspond with specific ABG results?

Answer 12

• Respiratory Acidosis (↓ pH, ↑ PaCO₂)
• Respiratory Alkalosis (↑ pH, ↓ PaCO₂)
• Metabolic Acidosis (↓ pH, ↓ HCO₃⁻)
• Metabolic Alkalosis (↑ pH, ↑ HCO₃⁻)

ROME: Respiratory = Opposite (pH & CO₂), Metabolic = Equal (pH & HCO₃⁻)

normal pH: 7.35-7.45
normal PaCO₂: 35-45
normal HCO₃: 22-26

Question 13

How does hyperventilation affect ABG results and oxygenation?

Answer 13

• increased exhalation lowers PaCO₂ (hypocapnia)
• respiratory alkalosis, increasing pH (more alkaline)

Hyperventilation → ↓ CO₂ → ↑ pH (Respiratory Alkalosis)

Question 14

What are the differences between respiratory and metabolic causes of acidosis and alkalosis?

Answer 14

• Respiratory: Involves CO₂ levels.
  
  • Respiratory acidosis: High CO₂ (hypoventilation).
  • Respiratory alkalosis: Low CO₂ (hyperventilation).
• Metabolic: Involves bicarbonate (HCO₃) levels.
  
  • Metabolic acidosis: Low HCO₃ (kidney failure, diarrhea).
  • Metabolic alkalosis: High HCO₃ (diuretics, vomiting).

Question 15

How do ABGs affect patient diagnosis?

Answer 15

• help identify respiratory or metabolic imbalances (acidosis or alkalosis)
• reveal oxygenation status
• guide treatment
• track disease progression or response to therapy

shows how well O₂ is being distributed and how well CO₂ is removed

Question 16

How to name your ABGs!

Answer 16

• FIRST NAME
  
  • Compensated (pH = 7.35-7.45)
  • Partially/Uncompensated (pH < 7.35, > 7.45)
• MIDDLE NAME
  
  • Respiratory (PaCO2) or Metabolic (HCO3)
• LAST NAME
  
  • Acidosis (pH < 7.40) or Alkalosis (pH > 7.40)

partially: has 2 abnormal buffers (same direction) instead of 1

Question 17

What is restrictive lung disease?

Answer 17

difficult to expand the lungs fully, leading to SOB and less air in the lungs

↓ compliance → stiff lungs → limit expansion → harder to inhale

Question 18

What is obstructive lung disease?

Answer 18

difficult to exhale air (blockages or narrowing of airways), leading to SOB and trapped air

↑ compliance from alveolar damage → air trapping → harder to exhale

Question 19

What does a low V/Q mean?

What does this lead to?

Answer 19

Shunt – perfusion without ventilation, leads to hypoxemia

blood flows through the lungs but doesn’t get oxygenated (no air flow)

Question 20

What does a high V/Q mean?

What does this lead to?

Answer 20

Dead space – ventilation without perfusion, leads to wasted ventilation and poor gas exchange

air goes through the lungs but not oxygenating the blood (no blood flow)

Question 21

What conditions cause a low V/Q?

Answer 21

• fluid or consolidation within the alveoli
• collapse of the alveoli
• reduced air reaching the alveoli
• blood flow bypassing the alveoli

Conditions that reduces the amount of air moving into the alveoli

poor ventilation with normal perfusion

Question 22

What conditions cause a high V/Q?

Answer 22

• pulmonary embolism
• microvascular clotting
• cardiogenic shock

Conditions that cause blockage of blood vessels in lungs

poor perfusion with normal or excessive ventilation

Question 23

What is a normal V/Q mismatch?

Answer 23

when ventilation and perfusion are not perfectly matched, but the body can still compensate, typically with small variations

natural occurrence in the lungs

Question 24

What is the ideal V/Q?

Answer 24

1:1