Oxygen Therapy Flashcards
Why should oxygen always be prescribed?
Because it is a drug. There are relevant places on drug charts to do this, usually defined with two options: 88-92% or >94%
What is the aim for oxygen saturations in non-COPD patients?
- 94-98%. There is no point in aiming for sats of 100%
- In fact saturations of 100% are less helpful than 98-99% as they can reflect a normal PaO2 (10-13 kPa) but may also reflect an inappropriately high kPa of e.g. 30 (in an over-oxygenated patient).
What would you do if your patient has sats of 100% on 35% Venturi?
- Decrease it to 28% and see if saturations stay in the target range. If they do, use the lowest oxygen delivery percentage available to reliably maintain sats in the required range
What is the aim for oxygen saturations in patients with COPD?
88-92%
What percentage and maximum flow rate of oxygen do nasal cannulae use?
24-30% O2
Flow rate maximum 4L/min
When are nasal cannulae used?
- Use for non-acute ward use, or if mildly hypoxic
What are the advantages and disadvantages to using nasal cannulae?
- Comfortable and well-tolerated but can dry the nose. If patient complain of this use a humidified circuit (oxygen passed through water prior to getting to patient)
What percentage and maximum flow rate of oxygen does the hudson mask use? (rarely used)
- Delivers 30-40%
- Flow rate 5-10L/min
What percentage and maximum flow rate of oxygen does a venturi mask use?
- Delivers 24-60% oxygen depending on colour of fitting.
- Flow rate (oxygen flow rate is set on the O2 wall tap) is shown on mask along with the % O2 delivery. Each colour must be used with a given flow rate (written on the mask) to give the correct oxygen percentage.
What are the different types of venturi mask and their oxygen percentages/flow rates?
- BLUE = 2-4L/min = 24% O2
- WHITE = 4-6L/min = 28% O2
- YELLOW = 8-10L/min = 35% O2
- RED = 10-12L/min = 40% O2
- GREEN = 12-15L/min = 60% O2
Why are venturi masks often used in COPD?
It the most accurate way of giving variable percentage inspired oxygen.
What percentage oxygen and flow rate does a non-rebreather mask use?
- Delivers 85-90% with 15L flow rate.
When is a non-rebreathe mask used and how does it work?
- Bag on mask with valves stopping almost all rebreathing of expired air
- Used for acutely unwell patients BUT note that uncontrolled high flow oxygen is damaging (see notes opposite). As such, a non-rebreather is rarely indicated for long-term treatment.
What are the two non-invasive means of ventilation?
CPAP and BiPAP
What is CPAP and how does it work?
CPAP= continuous positive airway pressure = high pressure air/oxygen with a tight fitting mask. Positive pressure all the time.
- Keeps airways open in sleep apnoea or heart failure.