Pneumothorax, Respiratory Failure Type 1 and 2

Question 1

What anatomical structures does pneumothorax affect?

Answer 1

Anatomical space between lungs and chest wall (pleural cavity). Boundaries are visceral (lung) and parietal (chest wall) pleura

Question 2

What is purpose of serous fluid in pleural cavity?

Answer 2

Allows lubrication of lung against chest wall, preventing friction

Question 3

Why does pleural cavity contain a vacuum?

Answer 3

Negative pressure to assist process of inspiration / lung expansion

Question 4

What is pneumothorax?

Answer 4

Collection of air in the pleural cavity (between lungs and chest wall). Causes collapse of lung.

Question 5

What are effects of pneumothorax?

Answer 5

Impaired mechanics of ventilation / movement of air in and out of lungs

Reduction of O2 if severe

Question 6

What is primary/secondary pneumothorax?

Answer 6

1ary –> without prior known lung disease

2ary –> COPD or physical trauma to chest (including iatrogenic e.g. surgery)

Question 7

What are severity of symptoms of pneumothorax determined by?

Answer 7

Size of air leak and speed by which it occurs

Question 8

What are symptoms/clinical sings of pneumothorax?

Answer 8

• Chest pain
• Shortness of breath
• Deviated trachea (away from side of tension pneumothorax)
• Stethoscope reduced breath sounds (same side)
• Hypoxia
• Hypotension

Question 9

What is tension pneumothorax?

Answer 9

Air is trapped in the pleural cavity under positive pressure, displacing mediastinal structures and compromising cardiopulmonary function

i.e. tension pneumothorax begins to affect other nearby organs

Question 10

What would chest x-ray show in pneumothorax?

Answer 10

Air between lung and chest wall at apex of lung

Question 11

How can small pneumothoraces be treated?

Answer 11

Often resolve by themselves and require no treatment

Question 12

How can larger pneumothoraces be resolved?

Answer 12

The air may be aspirated with a syringe, or a one-way chest tube / drain is inserted to allow the air to escape

Question 13

What is 1ary/2ary treatment of pneumothorax?

Answer 13

• Pleurodesis (sticking the lung to the chest wall), may be used if there is a significant risk of repeated episodes of pneumothorax
• Avoid significant changes in atmospheric pressure (e.g. aeroplanes)

Question 14

What is type 1 respiratory failure?

Answer 14

Low level of O2 in the blood (hypoxemia) with either a normal (normocapnia) or low (hypocapnia) level of CO2 but not an increased level (hypercapnia)

Question 15

What are the normal partial pressure reference values for CO2 and O2?

Answer 15

PaO2: 10.0 - 13.3 kPa
PaCO2: 4.7 - 6.0 kPa

Question 16

What structural abnormalities indicate type 1 respiratory failure?

Answer 16

• Significant obstruction of upper airway/trachea/bronchial tree/alveoli
• Fluid, blood or air in pleural space
• Weakness or damage to chest wall / diaphragm
• Damage to brain and central respiratory control by trauma or sedation by drugs

Question 17

What physical abnormalities are present in type 1 respiratory failure?

Answer 17

• Absence of hypercapnia (high PaCO2)
• Inadequate gas exchange by respiratory system
• Arterial O2 levels cannot be maintained within normal range
• Drop in blood oxygenation (hypoxaemia)

Question 18

What is type 1 respiratory failure typically caused by?

Answer 18

Ventilation/perfusion (V/Q) mismatch –> volume of air flowing in and out of lungs not matched with flow of blood to lungs

Question 19

What can cause (V/Q) mismatch causing type 1 respiratory failure?

Answer 19

• Pulmonary embolus blocking pulmonary artery

- Pneumonia resulting in poor gas transfer to and from blood

Question 20

Symptoms of type 1 respiratory failure?

Answer 20

• Dyspnoea (short of breath)

Question 21

Clinical signs of respiratory failure?

Answer 21

• Hypoxia (low O2 saturation)

- Tachypnoea (fast respiration)

Question 22

What are test results in respiratory failure?

Answer 22

• PaO2 markedly decreased (< 8.0 kPa)
• PaCO2 normal or low (< 6.0 kPa)
• pH normal or increased

Question 23

Treatment for respiratory failure?

Answer 23

• Oxygen

- Treat underlying cause

Question 24

1ary / 2ary prevention for respiratory failure?

Answer 24

Prevent causes:

• Pulmonary oedema (avoid excess intravenous fluids, use of diuretic therapy)
• Pulmonary embolus (preventative use anticoagulants if a patient is restricted to bed in hospital)

Question 25

What is type 2 respiratory failure?

Answer 25

Inadequate alveolar ventilation (both O2 and CO2 are affected). Buildup of carbon dioxide levels (PaCO2) that has been generated by the body but cannot be eliminated

Question 26

What are structural abnormalities of type 2 respiratory failure?

Answer 26

• Any significant obstruction of the upper airway / trachea / bronchial tree / alveoli
• Fluid, blood or air in the pleural space
• Weakness of damage to the chest wall / diaphragm
• Damage to brain and central respiratory control by trauma or sedation by drugs

Question 27

Physiological abnormalities in type 2 respiratory failure?

Answer 27

Inadequate ventilation of respiratory system so arterial oxygen and/or carbon dioxide levels cannot be maintained within their normal ranges

• Hypercapnia (high PaCO2)
• Hypoxaemia (drop in blood oxygenation)

Question 28

Causes of type 2 respiratory failure?

Answer 28

• Reduced breathing effort (in fatigued patient)

- A decrease in area of lung available for gas exchange (e.g. in COPD with emphysema)

Question 29

Symptoms of type 2 respiratory failure?

Answer 29

• Dyspnoea (short of breath)

Question 30

Clinical signs of type 2 respiratory failure?

Answer 30

• Hypoxia (low O2 saturation)

- Tachypnoea (fast respiration) or low rate of respiration (if drug sedation or brain injury)

Question 31

What are test results for type 2 respiratory failure?

Answer 31

• PaO2 decreased (< 10.0 kPa)
• PaCO2 increased (> 6.0 kPa)
• pH decreased (respiratory acidosis)

Question 32

Medical treatment for type 2 respiratory failure?

Answer 32

• Identify and treat underlying cause
• Low flow oxygen (high flow may reduce the respiratory drive of the
brain and cause reduced ventilation with CO2 increase)
• Ventilatory support may be required

Question 33

1ary and 2ary prevention for type 2 respiratory failure?

Answer 33

If the respiratory failure resulted from an overdose of sedative drugs such as morphine / heroin or benzodiazepines, then the appropriate antidote such as naloxone or flumazenil should be given.