Respiratory Failure

Question 1

Definition of respiratory failure

Answer 1

Impaired gas exchange between the lungs and the blood that causes HYPOXIA with OR without HYPERCAPNIA

Question 2

Aetiology of Type 1 respiratory failure

Answer 2

• Type 1 Respiratory failure:
• Hypoxic respiratory failure
• PaO2 <8kPa
• WITHOUT hypercapnia
• Due to Pulmonary Failure (affecting gas exchange, e.g due to alveolar flooding)
• Can be due to:
◦ Lobe collapse
◦ Pulmonary oedema
◦ Pneumonia
◦ PE
◦ Pulmonary fibrosis
◦ Aspiration
◦ Pneumonia
◦ Pneumothorax

Question 3

Aetiology of type 2 respiratory failure

Answer 3

• Type 2 Respiratory Failure:
• Hypercapnic respiratory failure
• With associated hypoxia
• Due to ventilatory failure (decreased ventilation or increased dead space ventilation)
• Some causes are:
◦ Airway obstruction (COPD, severe asthma)
◦ Neuromuscular (weak resp muscles due to MND, Guillain-Barré syndrome)
◦ Chest wall deformity (trauma)

Question 4

History and Examination of respiratory failure

Answer 4

• Dyspnoea
• Direct trauma to throat and/or neck
• Confusion (can be seen in Type 2 due to CO2 CNS depression)
• Tachypnoea: can be a sign of respiratory distress
• Accessory breathing muscle use: sign of severe respiratory distress
• Stridor: can indicate upper respiratory tract obstruction
• Hypoventilation: can then cause hypercapnia
• Headache: due to hypoxia and/or hypercapnia
• Loss of gag reflex: needs emergency intubation

Question 5

Investigations for respiratory failure

Answer 5

• ABG: used to check PaO2 and PaCO2 in order to determine which respiratory failure is present
• Pulse oximetry
• Chest X Ray

Question 6

Treatment of respiratory failure

Answer 6

Unstable:
1) Supplemental Oxygen: give via nasal cannula, mask or NIV. 15L O2 in acute setting
Endo tracheal intubation and mechanical ventilation: needed if there is progressive hypoxia or hypercapnia

TREAT UNDERLYING CAUSE

Airway obstruction:
1) airway clearance + supplemental oxygen: can use laryngoscope or bronchoscope to clear obstruction

Question 7

Prevention and prognosis of respiratory failure

Answer 7

• Offer influenza and pneumococcal vaccination to those at risk of respiratory failure
• Smoking cessation

Related to patient’s overall health and severity of respiratory illness