Download - Oxygen Delivery Devices
Oxygen Delivery DevicesOxygen Delivery Devices
they’re not what you thinkthey’re not what you think
Indications for oxygen useIndications for oxygen use
Low ambient OLow ambient O22
HypoxemiaHypoxemia Suspected hypoxemiaSuspected hypoxemia
Increased work-of-breathingIncreased work-of-breathing FlaringFlaring TachypneaTachypnea
Increased myocardial workIncreased myocardial work Acute head injuryAcute head injury
OO22 delivery systems delivery systems
High-flowHigh-flow Venti-masks (air entrainment masks)Venti-masks (air entrainment masks) Mechanical aerosol systemsMechanical aerosol systems High-flow humidifier systemsHigh-flow humidifier systems
Low-flowLow-flow Nasal cannulaNasal cannula Simple masksSimple masks Partial rebreathing masksPartial rebreathing masks Non-rebreathing masksNon-rebreathing masks
Entrainment ratiosEntrainment ratios
Entrainment ratio
FiO2 Minimal flow to operate
Total flow (L/min)
1/25 0.24 4 104
1/10 0.28 4 44
1/7 0.31 6 48
1/5 0.35 8 48
1/3 0.40 8 32
1/1.7 0.50 12 32
1/1 0.60 12 24
1/0.6 0.70 12 19
Delivered FiODelivered FiO22 with low-flow with low-flow
What’s my PaOWhat’s my PaO22??
a: On room air?a: On room air? b: On 0.50 FiOb: On 0.50 FiO22??
c: On 0.80 FiOc: On 0.80 FiO22??
The answers:The answers:
PaOPaO22 = FiO = FiO22 x (barometric pressure - x (barometric pressure - water vapor pressure) - PaCOwater vapor pressure) - PaCO22/RQ/RQ
PaOPaO22 = FiO = FiO22 X (760 - 43) - PaCO X (760 - 43) - PaCO22/0.8/0.8
a: PaOa: PaO22 = .21 X 713 - 40/0.8 = 100 = .21 X 713 - 40/0.8 = 100
b: PaOb: PaO22 = .50 X 713 - 40/0.8 = 306 = .50 X 713 - 40/0.8 = 306
c: PaOc: PaO22 = .80 X 713 - 40/0.8 = 520 = .80 X 713 - 40/0.8 = 520
OO22Hgb dissociation curveHgb dissociation curve
0 20 40 60 80 100 120 140 1600
20
40
60
80
100
% S
at
PO2 mmHg
Resorption atelectasisResorption atelectasis
A B A B
100% O2
oxygennitrogen
PO2 =673PCO2 = 40PH2O = 47
A BAfter ~15 minutes,blood N2 is depleted.Poorly ventilated &well perfused units (A)become atelectactic.
Non-rebreathing systemNon-rebreathing system
Reservoir
Gas source
Room air
Expiratorygas
To patientOne way valves
Air entrainment devicesAir entrainment devices
oxygen
room air
exhaled gas
OO22Hgb dissociation curve shiftHgb dissociation curve shift
0 20 40 60 80 100 120 140 1600
20
40
60
80
100
% S
at
PO2 mmHg
pH CO2
temp
What happens to your pOWhat happens to your pO22 and and sats when your pH changes?sats when your pH changes?
ph = 7.4, pOph = 7.4, pO22 = 100, sat 96% = 100, sat 96%
ph = 7.0, pOph = 7.0, pO22 = = ??, sat = , sat = ??
Oxygen delivery Oxygen delivery = # trucks = # trucks XX how full they are loaded how full they are loaded XX
how fast they gohow fast they go
DODO22 = 1.38(hgb X sat X CI) = 1.38(hgb X sat X CI)
+ (pO+ (pO22 X 0.003) X 0.003)
Entrainment ratiosEntrainment ratios
System FiO2
Entrainment ratio (O2/air)
Flow rate
(L/min)
Total flow
(L/min)
Ventimasks 0.24 1-25 4 1040.28 1-10 4 440.31 1-7 6 480.35 1-5 8 480.4 1-3 8 320.5 1-1.7 12 320.6 1-1 12 24
Aerosol 0.7 1-0.6 12 19
Estimating FiOEstimating FiO22
O2 Flow rate FiO2 O2 Flow rate FiO2 O2 Flow rate FiO2
Nasal cannula Oxygen mask Mask with reservoir1 0.24 5-6 0.4 6 0.62 0.28 6-7 0.5 7 0.73 0.32 7-8 0.6 8 0.84 0.36 9 0.80+5 0.4 10 0.80+6 0.44
Simple maskSimple mask
O2 inlet
Exhalation ports
Open ports for Open ports for exhaled gas exhaled gas
Air entrained Air entrained through ports if Othrough ports if O22 flow through does flow through does not meet peak insp not meet peak insp flowflow
35-55% O35-55% O22 at 6-10 at 6-10 L/minL/min
Partial rebreather maskPartial rebreather mask
Exhalationports
O2
Reservoir
OO22 directed into directed into reservoirreservoir
Insp: draw gas from Insp: draw gas from bag & ? room airbag & ? room air
Exp: first 1/3 of Exp: first 1/3 of exhaled gas goes into exhaled gas goes into bag (dead space)bag (dead space)
Dead space gas mixes Dead space gas mixes with ‘new’ Owith ‘new’ O22 going going into baginto bag
Deliver ~60% ODeliver ~60% O22
Non-rebreathing maskNon-rebreathing mask
Valve prevents Valve prevents exhaled gas flow exhaled gas flow into reservoir baginto reservoir bag
Valve over Valve over exhalation ports exhalation ports prevents air prevents air entrainmententrainment
Delivers ~100% ODelivers ~100% O22, , ifif bag does not bag does not completely collapse completely collapse during inhalationduring inhalation
O2
Reservoir
One-way valves