Oxygen delivery devices

oxygen delivery

1. OXYGEN DELIVERY DEVICES Dr. Himanshu

2. Indications of O2 therapy 1. Documented hypoxemia In adults, children, and infants older than 28 days, arterial oxygen tension (PaO2) of < 60 mmHg or arterial oxygen saturation (SaO2) of < 90% in subjects breathing room air or with PaO2 and/or SaO2 below desirable range for specific clinical situation In neonates, PaO2 < 50 mmHg and/or SaO2 < 88% or capillary oxygen tension (PcO2) < 40 mmHg

3. 2 . An acute care situation in which hypoxemia is suspected Substantiation of hypoxemia is required within an appropriate period of time following initiation of therapy 3. Severe trauma 4. Acute myocardial infarction 5. Short-term therapy (e.g., post-anesthesia recovery) 6. Increased metabolic demands, i.e. burns, multiple injuries, and severe infections.

4. Three clinical goals of O 2 therapy 1. Treat hypoxemia 2. Decrease work of breathing (WOB) 3. Decrease myocardial Work

5. FACTORS THAT DETERMINE WHICH SYSTEM TO USE 1. Patient comfort / acceptance by the Pt 2. The level of FiO2 that is needed 3. The requirement that the FiO2 be controlled within a certain range 4. The level of humidification and /or nebulization 5. Minimal resistance to breathing 6. Efficient & economical use of oxygen

6. O 2 delivery methods Low flow oxygen delivery system (variable performance, Pt dependent ) High flow oxygen delivery system (fixed performance, Pt independent )

7. Low flow O 2 delivery system Nasal cannula Nasopharyngeal catheter Nasal mask Simple face mask Partial rebreathing mask Non - rebreathing mask Stable breathing pattern Minute Venti- <8-10l/min RR- <20 /min VT- <0.8 l Normal insp. Flow – 10-30 l/min No capacity Small capacity High Capacity

8. Nasal cannula Simple plastic tubing + prongs with an over the ear adjustments. Sizing available for adults children and infants. Fio2 increases app. 1-2% with every increase in o2 flow per litre. Flow > 5lt/min is less tolerated due to flow jet in nasal cavity 1 - 24% 2 - 28% 3 - 32% 4 - 36% 5 - 40% 6 - 44%

9. Correct placement No nasal obstruction Advantages Disadvantages Inexpensive Pressure sores well tolerated, comfortable Crusting of secr . easy to eat, drink Drying of mucosa used in pt with long Epistaxis term therapy(COPD) 80% of O2 gets wasted during used with humidity expiration

10. Nasopharyngeal Catheter Soft tubes with several distal holes. Available in 8-14 FG sizes. Catheter has to be well lubricated and inserted in to the pt’s nose to the depth equal to the distance from ext nares to tragus. and the tip should lie just above the uvula. Oropharynx acts as a anatomical reservoir. Limitations : less popular due to complexity, limited use in ex. mucus secretion, mucosal edema, DNS, Pt’s incooperation due to gag or cough on insertion. Nasal obstruction, sinusitis, skin irritation are potential complications

11. Nasal Mask Hybrid of nasal cannula and a face mask Applied by either an over the ear lariat ar a headband strip Lower end rests on upper lip covering the external nose Adv.- comfortable , no air jetted in nares . Disadv . – sores on long term use

12. Simple face mask Simple or non reservoir, oxigen free mask is a disposible plastic devise that covers both nose and face. The placing of mask over the patient’s face increases the size of the oxygen reservoir beyond the limits of the anatomic reservoir ;therefore a higher FiO2 can be delivered. The oxygen flow must be run at a sufficient rate, usually 5 lpm or more to prevent rebreathing of exhaled gases. Best suited for those who require more o2 than prongs. O2 therapy for short period like post op in recovery room,transport of patients.

13. Advantages: simple, lightweight, FiO2 upto 0.50, can be used with humidity Disadvantages: need to remove when speak, eat, drink, vomiting, expectoration of secretions, drying / irritation of eyes, uncomfortable when facial burns / trauma, application problem when RT in situ, lack of seal proof borders so pure o2 gets mixed with air.

14. Reservoir Mask Two types are commonly used: 1) Partial rebreathing mask 2) Non rebreathing Both are disposable, light wt.,transperent plastic under the chin reservoirs. Diff. between two is placement of a valve between mask and bag and over mask. “Partial rebreather ” part of a patients expired air refilling the bag. “Non rebreather ” same as above except for the position of the valves. Inboard leaking is common, lack of good facial seal system can affect o2 conc.

15. Partial Rebreathing Mask Simple mask with reservoir bag. Oxygen flow to maintain the reservoir bag should be at least 1/3 to ½ full on inspiration. Oxygen conc. Of exhaled gas combined with supply of fresh oxygen, permits the lower flow than non rebreathing masks. 6-10L/min provides 40-70% of oxygen.

16. Non rebreathing mask Sufficient flow of o2 is used so the reservoir bag is at least partially full during inspiration Minimum flow-10-15 l/min Fio2 – 35 to 60% may reach up to 100% at 15 l/min. Either style of mask indicated for pts suspected for significant hypoxemia , with relatively normal spont. Respiration.

17. Advantages: FiO2 delivered >0.60 is delivered in mod. to severe hypoxia. exhaled oxygen from anatomic dead space is conserved. Disadvantages: insufficient flow rate may lead to rebreathing of CO2. Claustrophobia;drying and irritation of eyes, sometimes uncomfortable to pt.

18. High flow O 2 delivery system Venturi mask Face tent Aerosol mask Tracheostomy collar T-piece Pt with variable ventilatory level and breathig pattern Profoundly Dyspnoeic and hypoximic pts For those who require consistent high fio2 and with late inspiratory flow of gas(>40 lt /min)

19. Venturi effect Based on bernoulli principle. As the velocity of a fluid increases, the pressure exerted by that fluid decreases. Applied on both liquid and gases. Venturi principle describes how a second fluid can be entrained into the stream of first fluid.

20. Venturi effect

21. Venturi Mask Also called “Air entrainment venti masks” OR “High Air Flow with Oxygen-Entrainment” (HAFOE). Goal is to create an open system with high flow about the nose and mouth, with a fixed FIo2. O2 is directed by a small bore tubing to a mixing jet. Final conc. depends on the ratio of air drawn in through enrainment ports. Due to high flow , excess gas flushes out the expired co2 through the holes on the sides of mask. Good for those with hypoxemia cannot be controlled with low fio2.

22. VENTURI VALVE

23. Color FiO2 O2 Flow Blue 24% 2 L/min White 28% 4 L/min Orange 31% 6 L/min Yellow 35% 8 L/min Red 40% 10 L/min Green 60% 15 L/min Venturi valve

24. Entrained Air Flow = O2 flow x(1- FiO2) FiO2 – 0.2

25. Fio2 can be increased if the entrainment ports are obstructed by the patients hands, bed sheets or water condensate. Depending upon the pt’s clinical condition , respiratory rate, pattern, o2 saturation, mask can be changed to higher or lower range.

26. Bag Valve Mask systems Self inflating bags are AMBU bags, with an oxygen inlet reservoir Anaesthesia bag is a non self inflating reservoirs with gas inlet and valve. Mask are designed to provide comfortable leak free seal for manual ventilation. Flow to the reservoirs should be kept high so bags do not deflate substantially. These devices have a potential for a constant FiO2 of >90%. Limitation: in spont . Breathing person flow has to be adjusted with the valve, chances of aspiration, constant adequate flow of gases has to be maintained.

27. Air Entrainment Nebulizers Large volume, High Output ,all purpose nebulizers provide bland mist therapy with some control of FiO2. Commonly placed on patients following extubation for their aerosol produsing properties. Nebulizer system can be applied with many devices: aerosol,tracheostomy dome/ colar,face tents,T piece adapter. If T-piece is used if visible mist disappear during inspiration, the flow is inadequate. Excess water may collect in tubing and may obstuct and develop resistance to flow. Sometimes Bronchospasm may occure due to irritant nature of sterile water.

28. Air Entrainment Nebulizers

29. Aerosol Mask Delivers 21-100% FiO2 depending on nebulizer setting Flow rates of 8 to 15 L/min

30. Pediatric oxygen delivery system Oxygen hood Covers only head allowing access to the lower body. Ideal for short term use for neonates and infants. O2 and air premixed passed through heated humidifiers. Nebulizers should be avoided. Mini. Flow >7 lt /min. avg flow 10-15 lt /min results in 80-90% oxygen conc.

31. Oxygen hood

32. Oxygen tents Transparent enclosures in larger sizes for adult pts. Co2 is removed by soda lime and water vapour by calcium chloride. Temp.is regulated by flowing oxygen and air over ice. 60-70% O2 conc. Achieved by flow rates of 10-12L/min. The air changes 20 times/hour. Limitations : Confining and isolating Fio2 can vary from 0.21 to 1.0 Fungal infection risk.

33. Oxygen tent

34. Other devices Face tent : 21 % to 40% depending on nebulizer setting Flow rates of 8 to 15 L/min Used mainly for patients who can not tolerate a mask