Chronic ventilatory failure

Question 1

chronic ventilatory failure is defined by what parameters on arterial blood gas

Answer 1

elevated partial pressure of CO2, low partial pressure of oxygen, normal blood pH and elevated bicarbonate

Question 2

causes

Answer 2

airways disease eg COPD, chest wall abnormalities eg kyphoscoliosis, respiratory muscle weakness eg motor neuron disease, central hypoventilation eg obesity hypoventilation syndrome

Question 3

symptoms

Answer 3

reflect cause of illness so variable. SOB, orthopnoae, ankle swelling, morning headaches, recurrent chest infections, disturbed sleep

Question 4

exam findings

Answer 4

reflect cause of illness so variable. paradoxical abdominal wall movement sometimes, ankle oedema sometimes

Question 5

investigations

Answer 5

spirometry standing up and lying flat, mouth pressures and `snip, early morning ABG, overnight oximetry, transcutaneous CO2 monitoring, fluoroscopic screening of diaphragm.

Question 6

treatment

Answer 6

non invasive ventilation, oxygen therapy, tracheostomy ventilation