Respiratory Failure Flashcards
What is respiratory failure?
Defect in pulmonary gas exchange leading to hypoxia
What is hypoxia hypoxia?
PaO2 reduced
What is anaemic hypoxia?
Reduced Hb
What is stagnant hypoxia?
Reduced blood flow
What is histotoxic hypoxia?
O2 can’t be used
What are signs of respiratory compensation?
Tachypnoea, use of accessory muscles, nasal flaring, intercostal or suprasternal recession
What are signs of increased sympathetic tone?
Tachycardia, hypertension, sweating
What are signs of respiratory failure? (4)
Bradycardia and hypotension. Cyanosis from Hb desaturation. Flaps and bounding pulse from CO2 retention. End organ hypoxia leading to altered metal status.
What is type 1 respiratory failure?
Hypoxaemia. PaO2 < 8kPa
What is type 2 respiratory failure?
Hypoxaemia and hypercapnia. PaO2 < 8kPa. PaCO2 > 6.5kPa
What are some causes of type 1 respiratory failure?
Pneumonia, pulmonary oedema, asthma, COPD, PE, pneumothorax, obesity, atelactasis, pulmonary confusion
What’s the pathophysiology of type 1 respiratory failure?
Alveoli less perfused due to obstructed pulmonary vessels-> inc RH work-> dilation-> tricuspid leaks-> JVP rises
How does type 2 respiratory failure develop? (3)
Loss of ventilation capacity, loss of chest wall ability, failure of central control of respiration
How does the body respond to a drop in PaO2?
Picked up in aortic and carotid bodies. Nerve output from carotid via vagus to brainstem. O2 sensitive K+ channels and haem based cytochrome enzymes are responsible for local PaCO2.
What is Cheyne Stokes breathing?
Alternating hypo and hyperventilation
When does Cheyne Stokes happen?
Stage 1 sleep, newborns, altitude hypoxia, HF and uraemia. From inc sensitivity to PCO2 and prolonged lung-brain circulation
What are some indications for oxygen therapy?
Respiratory failure, cardiac/ respiratory arrest, tachypnoea, cyanosis, hypotension, metabolic acidosis
When would you use oxygen masks or nasal cannulae?
Normal vital signs eg post op
When would you use an NRB?
When a higher O2 conc is needed- asthma, pneumonia, sepsis
When would you use a venturi mask?
CONTROLLED treatment- long term respiratory failure eg COPD
When would you use BiPAP?
Type 2 respiratory failure
What are some indications for CPAP (respiratory failure)?
Chest wall trauma, pneumonia, OSA
What is an important patient group that require Venturi masks?
COPD drivers that are hypoxia drivers- around 10%. Too much oxygen will cause them to stop breathing.
