Oxygen Therapy Flashcards
How do you treat anemic hypoxia
Use the highest FiO2
The PaO2 level may be normal but the blood has a reduced capacity to carry o2. You must determined the Hb value.
If patient has low PaO2 and low or normal PaCO2 what is the low ph level usually caused by?
Lactic acidosis
Hazards of oxygen therapy
Oxygen toxicity Depression of ventilation Absorption atelectasis Retinopathy of prematurity Fire hazard Bacterial contamination
Estimating the delivered FiO2
How much can a nasal cannula deliver
Delivers 24% to 44% @ flow rates of 1 to 6 lpm.
Every time you raise a liter on NC, the FiO2 goes up about 4%
FiO2 in low flow devices is effected by
Vt (consistent, >300ml <700 ml )
RR >25
Ventilatory pattern (regular and consistent)
If patient doesnt meet those criteria they must have high flow device.
Nasal cannula
1-6 LPM for short periods of time
FiO2 24-44%
Humidification required if flows are greater than 4 lpm
Reservoir system 2 basic types
Reservoir cannula (pendant or mustache )
Simple oxygen mask
Flow of >5. Lpm to flush exhaled CO2
Delivers FiO2 of 25-50%
Partial rebreathing mask
6-10 lpm
Prevent bag collapse on inspiration
Non rebreathing mask
60-80 % @ 8-15 lpm
6-10 lpm prevent bag collapse on inspiration
Air entrainment mask
FiO2 of 24, 28, 31,35, 40, 50 , 60% size of jets
Calculation of total flow
The magic box trick..
- Insert 20 in top left corners
- Insert 100 in lower left corner
- Insert FiO2 In middle
- Subtract 20 from FiO2
- Subtract FiO2 from 100
- Place step 4 over step 5 for fraction and calculate
- This is the amount of air entrained for every 1 lpm of o2 to obtain desired FiO2
Delivered FiO2 equation
Del. FiO2= (air flow x .21) +(o2 flow x 1.0) total flow
Blending device
Blender is a device that matches oxygen and air at high pressures and delivers precise FiO2 if the patients inspiratory demands are met
Air entrainment aerosols
Tandem units
2 units should always be used whenever FiO2 is 60% or greater to provide adequate flow to the patient
