What is Type I respiratory failure?
PaO2 < 8kPa, normal PaCO2 (<6 kPa)
What can cause Type I respiratory failure?
Infection
Oedema
A shunt
What is Type II respiratory failure?
PaO2 < 8kPa, PaCO2 >6 kPa
What can cause Type II respiratory failure?
Gas trapping
Chest wall deformities
Muscle weakness
Central causes of respiratory depression
What are the signs of hypercapnia?
- Dilated pupils
- Bounding pulse
- Hand flap
- Myoclonus
- Confusion
- Drowsiness
- Coma
How does COPD cause Type II respiratory failure?
Loss of elastic recoil of the lungs causes gas trapping and reduced excretion of CO2
What complications can occur due to COPD?
• Exacerbations
• Pneumonia
• Pneumothorax
Alveolar destruction can rupture through pleural surface
• RV failure
• Peripheral neuropathy
• CachexiaWhat are the symptoms of a COPD exacerbation?
- Preceding coryzal (cold) symptoms
- Worsening breathlessness
- Increased cough
- Increased sputum
- Sputum purulence
- Ankle swelling
What are the most common infective causes of a COPD exacerbation?
- Haemophilus influenzas
- Streptococcus pneumoniae
- Moraxella catarrhalis
- Viruses
- Pseudomonas aeruginosa
If hospitalisation is not required for an exacerbation, how would you treat a patient?
o Increase dose or frequency of SABA
o 30 mg prednisolone o.d. for 5 days
o Antibiotics if there is an infection (broad spectrum)
If hospital admission is required for an exacerbation, how would you treat a patient?
o Give O2 to raise saO2, not more than 92%
o High dose SABAs, usually nebulised
o High dose corticosteroids (usually prednisolone 40mg/day – 7 days)
o Antibiotics -> broad spectrum
o Physiotherapy -> help clear sputum
o Reassess after 1 hour
What would you give for an exacerbation that is not responding to 1st line treatment?
o IV aminophylline
o Non-invasive ventilation (NIV)
o Intubation and ventilation with admission to intensive care
o Doxapram can be used as a respiratory stimulant where NIV or intubation is not appropriate
What would you do with a patient with Type II respiratory failure and respiratory acidosis?
- IV bronchodilator (salbutamol or theophylline)
- Urgent intensive care opinion
- Non-invasive ventilation
- Intubation and assisted ventilation
What are the extrapulmonary effects of COPD?
- Weight loss
- Skeletal muscle dysfunction
- CV disease
- Cerebrovascular disease
- Metabolic syndrome
- Osteoporosis
- Depression
- Pitting oedema
- Secondary polycythaemia
What are the indications for antibiotics?
- Purulent and increased sputum production
- Raised inflammatory markers
- Temperature >38 degrees Celsius
AND
- SOB
- Fairly severe COPD
- OR consolidation on X-ray
What are the indications for NIV?
- Respiratory acidosis (pH <7.35, pCO2 >6.5) despite controlled oxygen therapy and optimum medical treatment
- Moderate to severe breathlessness with accessory muscle use and paradoxical abdominal motion
- RR >25
What are the contraindications for NIV?
• pH >7.25 • confusion • Somnolence, agitation, lack of cooperation • High risk of gastric aspiration • GCS <8 • Facial trauma/deformity o As mask needs a good seal • Recent gastro-oesophageal surgery • Untreated pneumothorax
