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oxygen support devices...............ppt
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- 2. OBJECTIVES Describe whenoxygen (O2) therapy is needed. Assess the need for O2 therapy. Describe what precautions and complications are associated with O2 therapy. Select an O2 delivery system appropriate for the respiratory care plan. Describe how to administer O2 to adults, children, and infants. Describe how to identify and correct malfunctions of O2 delivery systems. Assess and monitor a patient’s response to O2 therapy. Describe how and when to modify or recommend modification of O2 therapy. Describe how to implement protocol-based O2 therapy. Identify the indications, complications, and hazards of hyperbaric O2 therapy.
- 3. GOAL OF OXYGENTHERAPY The overall goal of O2 therapy is to maintain adequate tissue oxygenation, while minimizing cardiopulmonary work. Clinical objectives for O2 therapy are the following: Correct documented or suspected acute hypoxemia Decrease symptoms associated with chronic hypoxemia Decrease the workload hypoxemia imposes on the cardiopulmonary system
- 4. PaO2 ator below 60 mm Hg Saturation O2 < 90% resting A drop in PO2 10 mm Hg or 5% in O2 sat. during sleep Symptoms or signs of heart failure (cor pulmonale), pulmonary hypertension, erythrocytosis, “P” pulmonale on EKG O2 THERAPY : INDICATIONS
- 5. Barometric Pressure •High altitude PIO2 PAO2 IncO2 Consumption •Convulsions •Thyrotoxicosis •Shivering •pyrexia (7 % / o C) Alveolar Ventilation decreased •Resp. depression •Resp. muscle paresis •Dec resp. effort (trauma) •Airway obstruction FiO2 •Low FiO2 during anaesthesia •Rebreathing
- 6. Low VA/Q • Abn.Pulmonary shunt •Pneumonia •Lobar atelectasis •ARDS Normal Anat. shunt • Abn.extra Pulm. Shunt •Cong. heart disease •Right to left shunts PaO2 Cell PO2 Low Hb concentration •Anaemia •CO poisoning Low Perfusion •local - PVD, thrombosis •gen – shock,Hypovol, card. Failure HYPOXIA
- 7. PaO2 AS ANINDICATOR FOR OXYGEN THERAPY PaO2 80 – 100 mm Hg : Normal 60 – 80 mm Hg : cold, clammy extremities < 60 mm Hg : cyanosis < 40 mm Hg : mental deficiency memory loss < 30 mm Hg : bradycardia cardiac arrest PaO2 < 60 mm Hg IS A STRONG INDICATOR FOR OXYGEN THERAPY
- 8. CLINICAL ASSESSMENT OF HYPOXIA MILDTO MODERATE SEVERE CNS : restlessness somnolence, confusion disorientation impaired judgement lassitude loss of coordination headache obtunded mental status Cardiac : tachycardia bradycardia, arrhythmia mild hypertension hypotension peripheral vasoconst. Respiratory: dyspnea increasing dyspnoea, tachypnea tachypnoea, possible shallow & bradypnoea laboured breathing Skin : paleness, cold, clammy cyanosis
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- 12. LOW FLOW SYSTEM The gas flow is insufficient to meet patient’s peak inspiratory and minute ventilatory requirement O2 provided is always diluted with air FiO2 varies with the patient’s ventilatory pattern Deliver low and variable FiO2 → Variable performance device
- 13. Flow ratesare <8 l/min Includes Nasal cannula Nasal catheter Transtracheal catheter
- 15. NASAL CANNULA Aplastic disposable device consisting of two tips or prongs 1 cm long, connected to oxygen tubing Inserted into the vestibule of the nose FiO2 – 24-40% Flow – ¼ - 8L/min (adult) < 2 L/min(child)
- 17. ESTIMATION OF FiO2 O2 Flowrat e (L/min) FiO2 1 0.21 - 0.24 2 0.24 – 0.28 3 0.28 – 0.34 4 0.34 – 0.38 5 0.38 – 0.42 6 0.42 – 0.46 Patient of normal ventilatory pattern - each litre/min of nasal O2 increases the FiO2 approximately 4%. E.g. A patient using nasal cannula at 4 L/min, has an estimated FiO2 of 37% (21 + 16)
- 18. NASAL CATHETER • Asoft plastic tube with several small holes at the tip • Inserted along the floor of either nasal passage under visualization till the tip is just above and behind the uvula
- 19. • Blindly insertedto a depth equal to the distance from nose to tragus • Should be replaced every 8 hrs • Avoided in patients with maxillofacial trauma, basal skull #, nasal obstruction and coagulation abnormalities
- 21. TRANSTRACHEAL CATHETER Athin Teflon catheter Inserted surgically with a guidewire between 2nd and 3rd tracheal rings FiO2 – 22-35% Flow – ¼ - 4L/min Increased anatomic reservoir Replace every 90 days
- 23. Estimation of Fio2from a low-flow system for patient with normal ventilatory pattern Cannula 6 L/min VT, 500 mL Mechanical reservoir None Rate, 20 breaths per min Anatomic reservoir 50 mL I/E ratio, 1:2 100% O2 provided/sec 100 mL Inspiratory time, 1 sec Volume inspired O2 expiratory time, 2 sec Anatomic reservoir 50 mL Flow/sec 100 mL Inspired room air 0.2 × 350 mL = 70 mL O2 inspired 220 mL FiO2 220 O2 = 0.44 500 TV A patient with ideal ventilatory pattern who receives 6L/min O2 by nasal cannula is receiving FiO2 of 0.44.
- 24. If VT isdecreased to 250 mL: Volume inspired O2 Anatomic reservoir 50 mL Flow/sec 100 mL Inspired room air (0.20 × 100 cm3 ) 0.2 × 100 mL = 20 mL O2 inspired 170 mL FiO2 170 = 0.68 250 The larger the Vt or faster the respiratory rate, the lower the Fio2. The smaller the Vt or lower the respiratory rate, the higher the Fio2. ↑minute ventilation → ↓ Fio2 ↓minute ventilation Fio → ↑ 2
- 27. RESERVOIR SYSTEM Reservoirsystem stores a reserve volume of O2, that equals or exceeds the patient’s tidal volume Delivers moderate - high FiO2 Variable performance device To provide a fixed FiO2, the reservoir volume must exceed the patient’s tidal volume
- 28. Includes Reservoircannula Simple face mask Partial rebreathing mask Non rebreathing mask
- 29. RESERVOIR CANNULA NASAL RESERVOIRPENDANT RESERVOIR
- 31. RESERVOIR MASKS Commonlyused reservoir system Simple face mask Partial rebreathing masks Non rebreathing masks
- 32. SIMPLE FACE MASK Reservoir - 100-200 ml Variable performance device FiO2 varies with O2 input flow mask volume extent of air leakage patient’s breathing pattern FiO2: 40 – 60% Input flow range is 5-10 L/min Minimum flow – 5L/min to prevent CO2 rebreathing
- 33. MERITS Moderate butvariable FiO2. Good for patients with blocked nasal passages and mouth breathers Easy to apply DEMERITS Uncomfortable Interfere with further airway care Proper fitting is required Risk of aspiration in unconscious patient Rebreathing (if input flow is less than 5 L/min) O2 Flowrate (L/min) Fi O2 5-6 0.4 6-7 0.5 7-8 0.6
- 34. Reservoir masks Partial rebreathingmask Nonrebreathing mask
- 35. PARTIAL REBREATHING MASK No valves FiO2 - 60-80% FGF > 8L/min The bag should remain inflated to ensure the highest FiO2 and to prevent CO2 rebreathing Reservoir capacity : 600 – 1000 ml
- 36. During expiration O2 + first 1/3 of exhaled gas (anatomic dead space) enters the bag and last 2/3 of exhalation escapes out through ports During inspiration The first exhaled gas and O2 are inhaled
- 37. NON REBREATHING MASK Has 3 unidirectional valves FiO2 - 0.80 – 0.90 FGF – 10 – 15L/min To deliver ~100% O2, bag should remain inflated Factors affecting FiO2 air leakage patient’s breathing pattern
- 38. Expiratory valvesallow the exhaled gases to escape but prevent inhalation of room air gases Inspiratory valve prevents exhaled gas flow into reservoir bag
- 40. HIGH FLOW SYSTEM •The gas flow is sufficient to meet patient’s peak inspiratory and minute ventilatory requirement • FiO2 is independent of the the patient’s ventilatory pattern • Deliver low- moderate and fixed FiO2 → Fixed performance device
- 41. High-Flow Devices To qualifyas a high-flow device, a system should provide at least 60 L/min total flow. This flow criterion is based on the fact that the average adult peak inspiratory flow during tidal ventilation is approximately three times the minute volume. Because 20 L/min is close to the upper limit of sustainable minute volume for an ill person, a flow of 3 × 20, or 60 L/min, should suffice in most situations.
- 42. Usually flowsare kept at >3 times patient’s MV) Includes Ventimask (HAFOE) Aerosol mask and T-piece with nebulizers
- 43. AIR ENTRAINMENT DEVICES Basedon Bernoulli principle – For an inviscid flow of a nonconducting fluid, an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy.
- 44. VENTURI PRINCIPLE A rapidvelocity of gas exiting from a restricted orifice will create subatmospheric lateral pressures, resulting in atmospheric air being entrained into the mainstream.
- 46. CHARACHTERISITICS OF AIR ENTRAINMENTDEVICES Amount of air entrained varies directly with Size of the port Velocity of O2 at jet They dilute O2 source with air - FiO2 < 100% The more air they entrain, the higher is the total output flow but the lower is the delivered FiO2
- 47. STEP 2: ADDTHE AIR-TO-OXYGEN RATIO PARTS 1.7 + 1 = 2.7 STEP 3: MULTIPLY THE SUM OF THE RATIO PARTS BY THE OXYGEN INPUT FLOW 2.7 X 15L/min = 41L/min
- 48. Calculation of Airto O2 Entrainment Ratio using a magic box 20 100 60 20 40 60 = 3 : 1 20
- 49. Approximate Air EntrainmentRatio and Gas Flows for different Fio2 Fio 2 (%) Ratio Recommended O2 Flow (L/min) Total Gas Flow (to Port) (L/min) 24 25.3:1 3 79 26 14.8:1 3 47 28 10.3:1 6 68 30 7.8:1 6 53 35 4.6:1 9 50 40 3.2:1 12 50 50 1.7:1 15 41
- 50. VENTURI / VENTI/ HAFOE MASK Mask consists of a jet orifice around which is an air entrainment port FiO2 regulated by size of jet orifice and air entrainment port FiO2 – Low to moderate (0.24 – 0.60) HIGH FLOW FIXED PERFORMANCE DEVICE
- 51. Varieties of VentiMasks A fixed Fio2 model A variable Fio2 model
- 52. AIR ENTRAINMENT NEBULIZERS Have a fixed orifice, thus, air-to-O2 ratio can be altered by varying entrainment port size. Fixed performance device FiO2 - 28-100% Max. gas flows – 14-16L/min Device of choice for delivering O2 to patients with artificial tracheal airways. Provides humidity and temperature control
- 53. Aerosol mask Facetent Tracheostomy collar T tube
- 54. How to increasethe FiO2 capabilities of air-entrainment nebulizers? Adding open reservoir (50-150ml aerosol tube) Provide inspiratory reservoir (a 3-5 L anaesthesia bag) with a one way expiratory valve Connect two or more nebulizers in parallel Set nebulizer to low conc (to generate high flow) and providing supplemental O2 into delivery tube
- 56. BLENDING SYSTEMS Witha blending system, separate pressurized air and oxygen sources are input. The gases are mixed either manually or with a blender FiO2 – 24 – 100% Provide flow > 60L/min Allows precise control over both FiO2 and total flow output - True fixed performance devices
- 58. OXYGEN TENT Consistsof a canopy placed over the head and shoulders or over the entire body of a patient FiO2 – 40-50% Flow rates - 12-15L/minO2 Variable performance device Provides concurrent aerosol therapy
- 59. Disadvantage Expensive Cumbersome Difficult to clean Constant leakage Limits patient mobility
- 60. OXYGEN HOOD Anoxygen hood covers only the head of the infant O2 is delivered to hood through either a heated entrainment nebulizer or a blending system Fixed performance device Fio2 – 21-100% Minimum Flow > 7/min to prevent CO2 accumulation
- 61. INCUBATOR Incubators arepolymethyl methacrylate enclosures that combine servo-controlled convection heating with supplemental O2 Provides temperature control FiO2 – 40-50% Flow 8-15 L/min Variable performance device
- 62. Hyperbaric oxygen therapy Hyperbaric oxygen (HBO) therapy is the therapeutic use of O2 at pressures greater than 1 atm Most HBO therapy is conducted at pressures between 2 ATA and 3 ATA
- 63. Methods of Administration Multiplace chamber capable of holding a dozen or more people air locks that allow entry and exit without altering the pressure can achieve pressures of 6 ATA or more multiplace chambers are ideal for the management of decompression sickness and air embolism Monoplace chamber Transparent Plexiglas cylinder large enough only for a single patient
- 65. Complications of Oxygentherapy 1. Oxygen toxicity 2. Depression of ventilation 3. Retinopathy of Prematurity 4. Absorption atelectasis 5. Fire hazard
- 70. 1.O2 Toxicity Primarilyaffects lung and CNS 2 factors PaO2 Exposure time CNS O2 toxicity (Paul Bert effect) occurs on breathing O2 at pressure > 1 atm tremors, twitching, convulsions
- 71. Pulmonary Oxygen toxicity C/F Acute tracheobronchitis Cough and substernal pain ARDS like state
- 72. Pulmonary O2 Toxicity(Lorrain- Smith effect) High pO2 for a prolonged period of time Intracellular generation of free radicals e.g.: superoxide,H2O2 , singlet oxygen React with cellular DNA, sulphydryl proteins &lipids Cytotoxicity Damages capillary endothelium Interstitial edema Thickened alveolar capillary membrane Pulmonary fibrosis and hypertension
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- 74. How much O2is safe? Limit patient exposure to 100% O2 to less than 24 hours whenever possible. High FiO2 is acceptable if the concentration can be decreased to 70% within 2 days and 50% or less in 5 days. Goal should be to use lowest possible FiO2 compatible with adequate tissue oxygenation
- 75. Indications for 70%- 100% oxygen therapy Resuscitation Periods of acute cardiopulmonary instability Patient transport
- 76. Seen inCOPD patients with chronic hypercapnia 2. Depression of Ventilation
- 77. 3. Retinopathy ofprematurity (ROP) Premature or low-birth-weight infants who receive supplemental O2 Mechanism Increased PaO2 Retinal vasoconstriction Necrosis of blood vessels New vessels formation Hemorrhage retinal detachment and blindness → To minimize the risk of ROP - PaO2 below 80 mmHg
- 78. 100% O2 oxygen nitrogen PO2 =673 PCO2= 40 PH2O = 47 A B A – UNDERVENTILATED B – NORMAL VENTILATED
- 79. 5. Fire hazard High FiO2 increases the risk of fire Preventive measures Lowest effective FiO2 should be used Use of scavenging systems Avoid use of outdated equipment such as aluminium gas regulators Fire prevention protocols should be followed for hyperbaric O2 therapy
- 80. Oxygen challenge concept ↑FiO2 by 0.2 ↑ PaO2 > 10 mmHg ↑PaO2 < 10 mmHg ( true shunt – 15 %) ( true shunt – 30 %) ↑PaO2 < 10 mmHg in response to an oxygen challenge of 0.2 – refractory hypoxemia
- 81. Implications of Oxygenchallenge concept To identify refractory hypoxemia (as it does not respond to increased FiO2) Refractory hypoxemia depends on increased cardiac output to maintain acceptable PaO2 Potentially deleterious effect of increased FiO2 can be avoided
- 82. SUMMARY Therapeutic effectiveness ofoxygen therapy is limited to 25% - 50% • Low V/Q hypoxemia is reversed with less than 50% • DAA occurs with FiO2 more than 50% • Pulmonary oxygen toxicity is a potential risk factor with FiO2 more than 50% Bronchodilators, bronchial hygiene therapy and diuretic therapy decreases the need for high FiO2
Editor's Notes
- #4 Group I criteria include any of the following: Initial coverage for patients meeting Group I criteria is limited to 12 months or the physician-specified length of need, whichever is shorter. (Refer to the Documentation section for information on recertification.) An arterial PO2 at or below 55 mm Hg or an arterial oxygen saturation at or below 88 percent taken at rest (awake) An arterial PO2 at or below 55 mm Hg, or an arterial oxygen saturation at or below 88 percent, for at least 5 minutes taken during sleep for a patient who demonstrates an arterial PO2 at or above 56 mm Hg or an arterial oxygen saturation at or above 89% while awake A decrease in arterial PO2 more than 10 mm Hg, or a decrease in arterial oxygen saturation more than 5 percent, for at least 5 minutes taken during sleep associated with symptoms or signs reasonably attributable to hypoxemia (e.g., cor pulmonale, "P" pulmonale on EKG, documented pulmonary hypertension and erythrocytosis) An arterial PO2 at or below 55 mm Hg or an arterial oxygen saturation at or below 88 percent, taken during exercise for a patient who demonstrates an arterial PO2 at or above 56 mm Hg or an arterial oxygen saturation at or above 89 percent during the day while at rest. In this case, oxygen is provided for during exercise if it is documented that the use of oxygen improves the hypoxemia that was demonstrated during exercise when the patient was breathing room air.
- #10 Performance is based on whether a device delivers a a fixed or variable FiO2
- #12 Provide supplemental o2 directly to airway at a flow < 8L/min. because insp. Flow of a healthy adult exceeds 8L/min o2 provided by a low flow device is always diluted with air, result is low and variable fio2
- #15 Nasal canula is aplastic disposable device consisting of two tips or prongs 1 cm long and is connected to oxygen tubing, is inserted into the vestibule of the nose, Humidifier is needed when the input flow exceeds 4 L/min.
- #18 A soft plastic tube with several small holes at the tip. It is inserted along the floor of either nasal passage under visualiszation till the tip is just above and behind the uvula. Once in position it is taped to bridge of nose. It is blindly inserted to a depth equal to the distance from nose to tragus. Should be replaced every 8 hrs. avoided in pts with maxillofacial trauma, basal skull #, nasal obstruction and coag prob.
- #21 Because the catheter resides directly in trachea, O2 builds up both there and in upper airway during expiration. expands anat reservoir and increases fio2 at any flow
- #27 Incorporates a mechanism for gathering and storing O2 between patient breaths. Pt draws on this reserve supply whenever insp flow exceedsO2 flow into the device. Air dilution is reduced. Prov higher fio2. can decrease O2 use by prov comparable at a lower rate
- #29 a reservoir that fills with 20ml of expired air at the initial phase of expiration, which is then enriched or replaced with oxygen during the remainder of expiration. a diaphragm which immediately collapses on initial inspiration, delivering a dose of highly oxygen-enriched air to the deepest portion of the lungs. soft nasal prongs which offer maximum comfort and place less pressure on the septum. Fio2 22-35% flow ¼ - 4 l/min Pendant Reservoir hides under patients clothing on ant chest wall, extra wt can cause ear and facial discomfort
- #32 Open ports for exhaled gas .Air entrained through ports if O2 flow does not meet peak insp flow Because air dilution easily occurs during inspiration through its ports and around its body, it provides a variable fiO2 Gas flow>8 doesn’t significantly inc. fio2 bcoz o2 reservoir is filled
- #34 Have a 600 ml-1l reservoir bag attached to o2 inlet, because bag inc the reservoir vol, prov higher fio2
- #35 If the total ventilatory demands are met without RA entrainment, it acts as fixed performance device
- #40 Flows - 30 - 40 L/min (or > 3 times patient’s minute ventilation) thus provides a fixed FiO2.
- #51 Have a restricted orifice or jet through which o2 flows at high velocity. The smaller the orifice, the greater is the velocity of o2 and the more air is entrained.
- #52 These masks come in the following varieties: 1. A fixed Fio2 model, which requires specific inspiratory attachments that are color coded and have labeled jets that produce a known Fio2 with a given flow. 2. A variable Fio2 model, which has a graded adjustment of the air entrainment port that can be set to allow variation in delivered Fio2.
- #54 O2 is delivered with a T tube, tracheostomy mask, aerosol mask or a face tent. Parts- container for water for humidification,o2 inlet connected to o2 flowmeter, air entrainment port, outlet for total outflow, attachment to pt- brigg’s apparatus,trach masketc
- #55 to the expiratory side of T tube
- #59 Cooled to provide a comfortable temp within a plastic sheet canopy