Oxygen and Respiratory Failure Flashcards
In what 2 ways can oxygen be present in blood?
- bound to Hb
- dissolved in plasma
What is the relationship between partial pressure and saturation of O2? (PaO2 and SpO2)
they are proportional, as the amount of O2 dissolved in the blood increases, the O2 saturation of the blood increases
(this is shown by the oxyhemoglobin dissociation curve)
What is SaO2
the saturation of O2 in the arterial blood
what is SpO2
the saturation of O2 as detected by the pulse oximeter (thing on finger)
what is PaO2
the partial pressure of oxygen (the amount of O2 dissolved in the arterial blood pressure)
What is the normal pH of the body
7.35-7.45
How do you measure the PaO2
by the ABG gas machine
What happens to Hb when blood becomes acidic?
Hb denatures as it is a protein - therefore saturation of O2 decreases as it can’t bind to Hb
What can happen to COPD patients when they have too much O2?
they can retain CO2, causing hypercarbia/hypercapnia and acidosis of the blood
What is the difference between acidosis in chronic and acute acidosis?
Chronic - there is time for the bicarbonate buffer to react; producing more bicarbonate and lowering the acidity of the blood = normal pH
Acute - no time for buffer to react, so pH will stay low and acidic
what is FiO2
the fraction of inspired O2 - how much O2 is given to a patient
What can CO2 retention be caused by?
COPD Obesity CF Neuromuscular problems Kyphoscoliosis
What are the 3 explanations for CO2 retention?
- Ventilation-perfusion matching
- The Haldane Effect
- Hypoxic drive
What can Hypoxemia cause at each stage of increasing severity?
- Dyspnoea, tachypnoea, cyanosis, altered mental state
- hyperventilation
- death
