Oxygen therapy by Dr.Vinod Ravaliya


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Oxygen therapy by Dr.Vinod Ravaliya

  1. 1. OXYGEN THERAPY Dr. Vinod K. Ravaliya Resident –I year KMPIP
  2. 2. Oxygen is in the air we breathe and isnecessary to live. The three basic nutrients withoutwhich planet earth could not exist as a home forliving things are OXYGEN, LIGHT and WATER.
  3. 3.  Oxygen may be classified as an element, a gas, and a drug. Definition Oxygen therapy is the administration of oxygen at concentrations greater than that in room air to treat or prevent hypoxemia (not enough oxygen in the blood)
  4. 4. Purpose The body is constantly taking in O2 & releasing CO2. If this process is inadequate, oxygen levels in the blood decrease, and the patient may need supplemental oxygen. Oxygen therapy is a key treatment in respiratory care. The purpose is to increase oxygen saturation in tissues where the saturation levels are too low due to illness or injury.
  5. 5. Oxyhemoglobin Dissociation Curve Definition : A relationship between the amount of oxygen dissolved in the blood and the amount attached to the hemoglobin. This is called the normal Oxyhemoglobin dissociation curve. Oxygen can be measured in two forms: - partial atmospheric pressure of oxygen (PaO2) - oxygen saturation (SaO2) - calculated estimate of oxygen saturation (SpO2): an indirect SaO2
  6. 6. Normal Oxyhemoglobin Dissociation Curve97% saturation = 97 PaO2 (normal)90% saturation = 60 PaO2 (danger)80% saturation = 45 PaO2 (severe hypoxia)
  7. 7. Reference Arterial blood Venous bloodrangespH 7.35 – 7.45 7.35 – 7.43pCO2 35 – 45 mmHg 38 – 50 mmHgpO2 80 – 100 mmHg 30 – 50 mmHgHCO3- 22 - 26 mM 23 – 27mMO2 saturation 95 – 100 % 60 – 85 %
  8. 8. SHIFT TO LEFT • Increase in pH • Decrease in CO2 • Decrease in 2.3-DPG • Decrease in temperatureSHIFT TO RIGHT• Decrease in pH• Increase in CO2• Increase in 2,3-DPG• Increase in temperature
  9. 9. Markers of O2 monitoringPiO2 = (760 – 47) x 0.21 = 150 mmHgFiO2 = 0.21PAO2 = 100 mmHgPaO2 = 90 mmHgSaO2 = O2 saturation derived from arterialized cap. Blood.SpO2 = O2 saturation by pulse. ox
  10. 10. Oxygen Flux and Requirements The supply of oxygen is dependent upon the hemoglobin (Hb), O2 saturation % (SaO2) and cardiac output (Q). "Oxygen flux" denotes the total amount of oxygen delivered to the body per minute and is given by the equation:Oxygen flux = 1.34 x Hb in g/dL x (SaO2/100) x (Q in mL/min)/100 = 1000 mL/min
  11. 11. Assessment of need Need is determined by measurement of inadequate oxygen tensions and/or saturations, by invasive or noninvasive methods, and/or the presence of clinical indicators as previously described. • Arterial blood gases • Pulse oximetry • Clinical presentation
  12. 12. How to assess oxygenation ? Arterial blood gases Pulse oximetry Errors in pulse oximetry Artificial fingernails •Nail Polish Dark pigmentation •Pulsatile venous system Electrical •Radiated light Intravenous dyes •Edema Movement
  13. 13. Indications of O2 therapy1. 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
  14. 14. 2. An acute care situation in which hypoxemia is suspected Substantiation of hypoxemia is required within an appropriate period of time following initiation of therapy3. Severe trauma4. Acute myocardial infarction5. Short-term therapy (e.g., post-anesthesia recovery)6. Increased metabolic demands, i.e. burns, multiple injuries, and severe infections.
  15. 15.  Goal directed approach - post operative (thoracic/abdominal surgery) - post extubation - conscious state/coughing - redistribution of fluid - positioning
  16. 16. Three clinical goals of O2 therapy 1. Treat hypoxemia 2. Decrease work of breathing (WOB) 3. Decrease myocardial Work
  17. 17. FACTORS THAT DETERMINE WHICH SYSTEM TO USE1. Patient comfort / acceptance by the Pt2. The level of FiO2 that is needed3. The requirement that the FiO2 be controlled within a certain range4. The level of humidification and /or nebulization5. Minimal resistance to breathing6. Efficient & economical use of oxygen
  18. 18. O2 delivery methods Low flow oxygen delivery system ( variable performance ) High flow oxygen delivery system ( fixed performance )
  19. 19. Low flow O2 delivery systemFio2 depends on O2 flow, patient factors anddevice factors  Nasal cannula  Simple face mask  Partial rebreathing mask  Non - rebreathing mask
  20. 20. Nasal cannula Simple plastic tubing + prongs Flow from 1-6 LPM of O2 Fio2 ranges from 24-44% of O2 1 - 24% 2 - 28% 3 - 32% 4 - 36% 5 - 40% 6 - 44%
  21. 21.  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 COPD Epistaxis used with humidity
  22. 22. Low flow O2 delivery systemFio2 depends on O2 flow, patient factors anddevice factors  Nasal cannula  Simple face mask  Partial rebreathing mask  Non - rebreathing mask
  23. 23. Simple face mask The placing of mask over the patient’s faceincreases the size of the oxygen reservoir beyond thelimits of the anatomic reservoir ;therefore a higherFiO2 can be delivered. The oxygen flowmust be run at a sufficientrate, usually 5 lpm ormore to preventrebreathing of exhaledgases.
  24. 24.  Advantages: simple, lightweight, FiO2 upto 0.60, 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
  25. 25. Low flow O2 delivery systemFio2 depends on O2 flow, patient factors anddevice factors  Nasal cannula  Simple face mask  Partial rebreathing mask  Non - rebreathing mask
  26. 26. Partial rebreathing bag 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
  27. 27. Low flow O2 delivery systemFio2 depends on O2 flow, patient factors anddevice factors  Nasal cannula  Simple face mask  Partial rebreathing mask  Non - rebreathing mask
  28. 28.  Non-rebreathing bag
  29. 29. High flow O2 delivery system  Venturi mask  Face tent  Aerosol mask  Tracheostomy collar  T-piece
  31. 31. Venturi valveColor FiO2 O2 FlowBlue 24% 2 L/minWhite 28% 4 L/minOrange 31% 6 L/minYellow 35% 8 L/min Red 40% 10 L/minGreen 60% 15 L/min
  32. 32. Venturi mask
  33. 33. Face tent Tracheostomy collar
  34. 34. Pediatric oxygen delivery system Oxygen hood
  35. 35. Oxygen hood
  36. 36. Oxygen tent
  37. 37. Long-term oxygen therapy
  38. 38.  Long-term oxygen therapy (LTOT) improves survival, exercise, sleep and cognitive performance. Reversal of hypoxemia supersedes concerns about carbon dioxide (CO2) retention. Arterial blood gas (ABG) is the preferred measure and includes acid-base information. Oxygen sources include gas, liquid and concentrator. Oxygen delivery methods include nasal continuous flow, pulse demand, reservoir cannulae and transtracheal catheter.
  39. 39.  Physiological indications for oxygen include an arterial oxygen tension (Pa,O2) <7.3 kPa (55 mmHg). The therapeutic goal is to maintain Sa,O2 >90% during rest, sleep and exertion. Active patients require portable oxygen. If oxygen was prescribed during an exacerbation, recheck ABGs after 30–90 days. Withdrawal of oxygen because of improved Pa,O2 in patients with a documented need for oxygen may be detrimental. Patient education improves compliance
  40. 40. In-patient oxygen therapy-COPD The goal is to prevent tissue hypoxia by maintaining arterial oxygen saturation (Sa,O2) at >90%. Main delivery devices include nasal cannula and Venturi mask. Alternative delivery devices include non-rebreathing mask, reservoir cannula, nasal cannula or transtracheal catheter. Arterial blood gases should be monitored for arterial oxygen tension (Pa,O2), arterial carbon dioxide tension (Pa,CO2) and pH.
  41. 41.  Arterial oxygen saturation as measured by pulse oximetry (Sp,O2) should be monitored for trending and adjusting oxygen settings. Prevention of tissue hypoxia supercedes CO2 retention concerns. If CO2 retention occurs, monitor for acidaemia. If acidaemia occurs, consider mechanical ventilation.
  42. 42. Monitoring oxygen therapy Oxygen therapy should be given continuously andshould not be stopped abruptly until the patient hasrecovered, since sudden discontinuation can wash-outsmall body stores of oxygen resulting in fall of alveolaroxygen tension. The dose of oxygen should be calculatedcarefully. Partial pressure of oxygen can be measured inthe arterial blood. Complete saturation of hemoglobin inarterial blood should not be attempted. Arterial PO2 of 60mmHg can provide 90% saturation of arterial blood, but ifacidosis is present, PaO2 more than 80 mmHg is required.In a patient with respiratory failure, anaemia should becorrected for proper oxygen transport to the tissue.
  43. 43. A small increment in arterial oxygen tension resultsin a significant rise in the saturation of hemoglobin.Under normal situations, no additional benefit issecured by raising PaO2 level to greater than 60 to 80mmHg. An increase of 1% oxygen concentrationelevates oxygen tension by 7 mmHg. It is necessary tomaintain normal hemoglobin level in the presence ofrespiratory disease as proper oxygen transport to thetissues is to be maintained. Measurement of arterialblood gases repeatedly is difficult so a simple and non-invasive technique like pulse oximeter may be used toassess oxygen therapy.
  44. 44. When to stop oxygen therapy Weaning should be considered when the patientbecomes comfortable, his underlying disease isstabilized, BP, pulse rate, respiratory rate, skincolor, and oxymetry are within normal range. Weaning can be gradually attempted bydiscontinuing oxygen or lowering its concentrationfor a fixed period for e.g., 30 min. and reevaluatingthe clinical parameters and SpO2 periodically. Patients with chronic respiratory disease mayrequire oxygen at lower concentrations forprolonged periods.
  45. 45. Impact on the patient Fear death is likely to occur sooner Become less active Experience a sense of loss of freedom May become more socially isolated
  46. 46. Hazards & complications of oxygen therapy  Oxygen-induced hypoventilation  Oxygen toxicity/O2 narcosis  Absorption atelectasis  Retinopathy  Drying of mucous membranes  Infection  Fire hazards
  47. 47. Oxygen is one of the most important drugs youwill ever use, but it is poorly prescribed by medicalstaff. In 2000, a Nicola Cooper and colleague didsurvey of treatment with oxygen. The first looked atprescriptions of oxygen in postoperative patients in alarge district hospital. They found that there weremany ways used to prescribe oxygen and that theprescriptions were rarely followed.
  48. 48. Oxygen dissociation curveShift to the left in O2 curve { O2 affinity } 1. Causes: pH, CO2, 2-3 DPG, Temp. 2. Results: O2 sat. for any pao2 but resulting in less gradient to move O2 to tissue. (Carries more O2 but more difficult to release it at tissue level) 3. Examples: stored blood loses 2-3 dpg a shift to the left results from this. Hyperventilation, Hypothermia.
  49. 49. Shift to the right in O2 curve { O2 affinity } 1. Causes: pH , CO2 , 2-3 DPG, Temp. 2. Results: O2 sat for any PaO2 but resulting in more gradient to move o2 into the tissues. 3. Examples: hypoventilation, fever, metabolic acidosis.
  50. 50. Transtracheal oxygen