Low flow systems
Do not meet the patients inspiratory flow demands.,Normal inspiratory flow rate is 25 to 30 L/min,Additional flow comes from RA
Low flow systems include
Nasal Cannula,Nasal,Catheters,Transtracheal Catheters, Simple masks, Partial Rebreathing Masks, Non-rebreathing Mask
High Flow Oxygen Systems Include
Venturi Mask or air-entrainment masks,Aerosol Mask, Face Tent, T-Piece, Trach Mask, Oxygen Tent
Nasal Cannula and Nasal Catheters
Delivers 24 to 44% oxygen at 1 to 6 L/min
1 = 24, 2 = 28, 3 = 32, 4 = 36, 5 = 40, 6 = 44
Nasal Catheters
measured from nose to ear, lubricated, inserted to just above the uvula
Nasal Catheters cons
deep insertion can cause air swallowing and gastric distension , must be repositioned every 8 hours to prevent breakdown
Transtracheal Catheters
Delivers low flow rates (1 to 3 L/min) directly to the trachea through a small incision,
Requires less oxygen (lower flows) because the upper airway deadspace is bypassed
Transtracheal Catheters cons
Can develop infection and irritation at site and there is a risk of accidental removal, If pt becomes SOB or has increased, Flush with saline, Cleaning Rod, reposition
Cannulas
better tolerated, may be humidified but often not if run @ less than 5 L/min, there are two types of O2-conserving cannulas
Nasal reservoir
reservoir just below the nose stores ~ 20 mL of O2 ,allows for lower flows because of increase O2 delivery
Pendent reservoir
pendent stores O2 ,must exhale through nose
Pendent reservoir cons
HFNC - 6-15lpm
Simple masks
Delivers 35 to 55 % O2 at flows of 5 to 12 L/min
Simple masks cons
Must never be used at flows less than 5 L/min to prevent rebreathing of CO2
Partial Rebreathing Masks
Delivers 35 to 60 % O2 at flow rates of 8 to 15 L/min
Partial Rebreathing Masks Cons
Flow rate must be sufficient to keep bag 1/3 to 1/2 inflated at all times
Non-rebreathing Mask
Delivers 60 to 90% O2 at flow rates of 8 to 15 L/min (NBRC says 100%)
Non-rebreathing Mask Cons
Flow rate must be sufficient to keep bag 1/3 to 1/2 inflated at all times ,Is equipped with a one-way valve that does not allow exhaled gas into the reservoir, One way valves are located on both expiratory ports of the mask to prevent RA entrainment
Methods for setting up high flow oxygen
air entrainment mask, mechanical aerosol systems, Gas Injection Nebulizer- need high flow flowmeters, High FiO2 Misty Ox- for FiO2 of .60+ , Blender and titration system
High flow O2 systems provide
all of the inspiratory flow required by the patient at consistent FiO2s, These devices are normally attached to nebulizers (Venti-mask may or may not be)
Venturi Mask or air-entrainment masks
provide FiO2's from 24 to 50%
what happens with Venturi Mask or air-entrainment masks
Increasing flow will not alter FiO2 (precise)
The size of the entrainment port determines FiO2
The larger the port, the more RA entrained, the lower the FiO2
Aerosol Mask
Delivers 21-100% FiO2 depending on nebulizer setting, Flow rates of 8 to 15 L/min
Aerosol Mask Cons
On 100% the device will probably not meet flow demands.(>60%) (No air entrained so flow = flowmeter setting)
Face Tent
21% to 40% depending on nebulizer setting
Flow rates of 8 to 15 L/min
Face Tent Cons
Used mainly for patients who can not tolerate a mask
T-Piece
21-100% depending on nebulizer setting
Flow rates of 8 to 15 L/min
T-Piece Cons
Used on intubated or trached patients
Trach Mask
35-60% O2 depending on nebulizer setting
Flow rates of 10 to 15 L/min
Trach Mask limits
Adequate flow shown by mist flowing out the exhalation port at all times
Oxygen Tent
21 -50% at flow rates of 10 to 15 L/min Used mainly on children with croup or pneumonia
Oxygen Tent Cons
Problem with leakage ,Fire hazard
High FiO2's Important Points
High FiO2's (>.60) may not meet the patient's inspiratory flow demands
To insure adequate flow with stable FiO2's, a special made high flow device should be used or two flowmeters set up to provide at least 40 L/min total flow
High FiO2's Cons
A restriction, such as a kink, or water in the tubing, causes back-pressure into the nebulizer. This decreases the amount of RA entrained and INCREASES the delivered FiO2.
increasing flow on a high flow device will not increase FiO2, only total flow
Head box-
small, clear plastic enclosures over infant's head or head and upper torso
Head boxes allow
for a higher oxygen concentration and more accessibility to patient without disturbing oxygen delivery.
Best not to entrain room air into head box because of noise and microorganism introduction (Blender)
air: oxygen entrainment ratios:
.60 1:1, .50 1.7:1, .40 3:1, .35 5:1,.30 8:1