2 Let’s Start with the Basics! How much O2 is in room air?How much O2 comes out of a flowmeter?
3 Oxygen Therapy O2 delivery systems: design and performance Three basic designs existLow-flow systemsReservoir systemsHigh-flow systemsThere are numerous oxygen modalities available to choose from when treating pts.Design and performance = Proper device selection requires knowledge of the general performance characteristics as well as the individual capabilities.O2 delivery devices are categorized by design – low flow, high flow and reservoir.
4 We need to answer 2 key questions… How much O2 can the system deliver?What is the FiO2 or FiO2 range of the device?Does the FiO2 vary or remain fixed with changing pt demands?Does everyone know what I mean when I say FiO2?? Fractional concentration of O2 = the concentration of O2 on inspirationDifferent devices can deliver different O2 concentrations, so we need to know what FiO2 we need or what range before we make our choice.Secondly, is it important to provide a fixed or variable FiO2?
5 Fixed or Variable FiO2?Depends on how much of the pt’s inspired gas the device deliversFixed means the FiO2 stays the sameVariable mean the FiO2 fluctuates.
6 Fixed or Variable FiO2? Fixed FiO2 The device is designed to deliver ALL the pt’s inspired gas FiO2 is constant or fixedFixed delivers ALL the pts inspired gas even under changing pt demands ie increased RR or Vt
7 Fixed or Variable FiO2? Variable FiO2 The device provides only SOME of the inspired gasThe pt must draw the rest from the surrounding environment (room air)What happens if we mix O2 with room air?Dilutes the delivered O2 lowers FiO2The result = variable FiO2 from breath to breath depending on pt demands
8 Low Flow Systems: Uses low flows (< 8 Lpm) They are variable systems therefore the pts demands will affect the FiO2Keep in mind flow > 6Lpm are very drying (no humidity in O2, the humidity is removed when it is processed) and can lead to nasal dryness and bleeding.Factors that affect (decrease) FiO2 = Examples: increased RR, large Vt and open mouth breating
9 Low Flow Systems: Nasal cannula Delivers an FIO2 of 0.24 to 0.40 Used with flow rates of ¼ to 8 L/minFIO2 depends on how much room air the patient inhales in addition to the O2.Device is usually well tolerated.Humidifier should be used with flows > 4 LpmBooks say 8 Lpm, but we don’t recommend >6 Lpm unless there are extenuating circumstances
11 How to Estimate the FiO2 for Nasal Cannula: FiO2 = 21% + (4 x #Lpm)Example: What is the approximate FiO2 when the flow meter is set at 2 Lpm?FiO2 = 21% + ( 4 x Lpm)FiO2 = 21% + ( 4x 2)FiO2 = 29%
12 Reservoir SystemsIncorporate a mechanism to gather and store O2 between pt breathsPts draw from this reservoir when their inspiratory flows exceed the oxygen flow delivered by the deviceInstead of diluting with room air, they dilute with O2 results in a higher FiO2Incorporates this mechanism into a low flow system.Normally with low flow systems the pt dilutes or draws in r/a to meet their needs.With reservoir systems, they breath in from the reservoir to make up the difference…if they still require more, then they draw in r/a diluting the FiO2.
13 Reservoir Systems Reservoir cannula Designed to conserve oxygen Nasal reservoirPendant reservoirCan reduce oxygen use as much as 50% to 75%Humidification usually not neededTypically found in home care.Aesthetically not too pleasing.Need lower flows to achieve the same saturations b/c of less dilution with room air. B/c of low flows, don’t typically need humidification
16 Reservoir Systems Reservoir masks Most commonly used reservoir systems Three typesSimple maskPartial rebreathing maskNonrebreathing maskAll masks themselves are a type of reservoir to store O2 b/c they gather and store O2 b/w pt breaths.Some systems incorporate another storing device ie. bagInc.
19 High Flow SystemsSupply a given (or fixed) O2 concentration at a flow equaling or exceeding the patient’s peak inspiratory flowUse air-entrainment or blending system to mix air and oxygen at very specific ratios to determine a specific oxygen concentrationCan ensure a fixed FIO2These devices are designed to mix in specific ratios.Example a 1:1 ratio of Air to O2 will produce an FiO2 of 0.60 (60%)The higher the FiO2 the lower the total flowThe lower the FiO2 the greater the total flowWhy? B/c to get a lower FiO2 we have to mix more room air with it. Ex. 30% = 8 parts air and 1 part O2 = 9 total parts.Therefore, lower FiO2 are gaurenteed to have flows high enough to meet or exceed the pts demands.Higher FiO2 may not have flows great enough to meet the pts demandsWhat happens if the total flow is not enough to meet the pts demands? They will dilute with room air.
21 High Flow Jet NebsMisty Ox is a brand name. It can deliver fixed FiO2 at 0.60 – 0.96 when the flowmeter is set at minimun 40LpmHow is this possible? Crank it all the way open = approx. 45 Lpm will come out of the flowmeter.
22 Equipment for Aerosol Therapy Airway appliancesAerosol maskFace tentT-tubeTracheostomy maskAll used with large-bore tubingThese devices are connected to the large volume nebulizer or High flow nebulizers.
23 Equipment for Bland Aerosol Therapy Masks – traditionalFacetent – facial burns, claustrophobic pts can sometimes benefit from there, pts with nasal packing for epistaxis.Trach mask – trachs
24 Equipment for Bland Aerosol Therapy T-piece is used with ETT.
25 How do we know what to use? Nasal CannulaUses:Stable pts requiring low FiO2Home care pts requiring long term O2AdvantagesAdults, peds and infantsEasy to applyDisposable, inexpensiveWell toleratedCan eat with them in place
26 How do we know what to use? Nasal CannulaDisadvantagesEasily dislodgedHigh flows uncomfortableCan cause dryness and bleedingVariable FiO2s
27 How do we know what to use? Reservoir (NRBR)UsesEmergenciesUnstable pts (MI)Acute hypoxemiaSmoke inhalation / CO poisoningCHF
28 How do we know what to use? Reservoir (NRBR)AdvantagesHigh FiO2Adults and pedsQuick and easy to applyDisposable and inexpensiveDisadvantagesUncomfortableCan’t eat with mask onRisk of aspiration if pt vomitsPotential suffocation hazard
29 How do we know what to use? Venti maskUses:Unstable pts requiring precise low FiO2Pts with variable RR and Tidal VolumeAdvantages:Easy to applyDisposable and inexpensiveStable, precise FiO2Disadvantages:UncomfortableCan’t eat with mask onNoisyRisk of aspiration if pt vomits
30 How do we know what to use? Large Volume (Jet) NebulizersUses:Pts with artificial airwaysPts with supraglottic swellingTo help mobilize secretionsAdvantages:Provides humidificationProvides fixed FiO2Disadvantages:FiO2 varies with back pressure (ie condensation in tubing)Increased risk for infection
31 FYIs O2 is a prescribed drug For every connection there is a possibility for a leakVasoline and O2 don’t mix use a water based lubricant to treat nasal and lip drynessWhen in doubt, call RT, we are there to help!!