1. Chapter 38 Medical Gas Therapy

2. Learning Objectives Describe when oxygen therapy is needed.
Assess the need for oxygen therapy.
Describe what precautions and complications are associated with oxygen therapy.
Select an oxygen delivery system appropriate for the respiratory care plan.
Describe how to administer oxygen to adults, children, and infants.

3. Learning Objectives (cont.)
Describe how to check for proper function and to identify and correct malfunctions of oxygen delivery systems.
Explain how to evaluate and monitor a patient’s response to oxygen therapy.
Describe how to modify or recommend modification of oxygen therapy on the basis of patient response.
Review how to implement protocol-based oxygen therapy.

4. Learning Objectives (cont.)
Identify what indications, complications, and hazards apply to hyperbaric oxygen therapy.
Explain when and how to provide nitric oxide therapy.
Identify when and how to administer helium-oxygen therapy.
Summarize other forms of medical gas therapy and alternatives to such therapy.

5. Oxygen Therapy General Goals & clinical objectives
Correct documented or suspected acute hypoxemia
Decrease symptoms associated with chronic hypoxemia
Decrease workload hypoxemia imposes on cardiopulmonary system

6. Decrease the workload hypoxemia imposes on the cardiopulmonary system
All of the following are the major clinical goals and objectives for oxygen therapy, except:
Decrease the workload hypoxemia imposes on the cardiopulmonary system
Correct documented or suspected acute hypoxemia
Prevent hypoxemic induced multiple system failure
Decrease the symptoms associated with chronic hypoxemia
Answer: C

7. Oxygen Therapy (cont.) Assessing need for O2 therapy
Laboratory documentation
PaO2, SaO2, SpO2
Specific clinical problem
e.g., patient suspected of carbon monoxide poisoning
Clinical findings at bedside
Tachypnea, tachycardia, confusion, etc.

8. Oxygen Therapy (cont.) Precautions & hazards of supplemental O2
Oxygen toxicity
Primarily affects lungs & central nervous system
Determining factors include PO2 & exposure time
Prolonged exposure to high FIO2 can cause infiltrates in lung parenchyma

9. Oxygen Toxicity

10. Oxygen Therapy (cont.)
Precautions & hazards of supplemental O2 (cont.)
Depression of ventilation
Occurs in COPD patients with chronic hypercapnia
Retinopathy of prematurity
Excessive blood O2 levels cause retinal vasoconstriction & necrosis

11. Oxygen Therapy (cont.)
Precautions & hazards of supplemental O2 (cont.)
Absorption atelectasis
Can occur with FIO2 above 0.50
Patients breathing small tidal volumes at greatest risk

12. Absorption Atelectasis

13. Oxygen Therapy (cont.)
Precautions & hazards of supplemental O2 (cont.)
Fire hazard
Fires in O2-enriched environments continue to occur
Practitioners in surgery suites & in presence of hyperbaric O2 therapy need to be most careful

14. Depression of ventilation Retinotopathy of prematurity
All of the following are major precautions and hazards of supplemental oxygen therapy, except:
Oxygen toxicity
Depression of ventilation
Retinotopathy of prematurity
Oxygen induced encephalopathy
Answer: D

15. Oxygen Therapy (cont.) O2 delivery systems: design & performance
3 basic designs exist
Low-flow systems
Reservoir systems
High-flow systems

16. Oxygen Delivery Systems

17. Oxygen Therapy (cont.)
Nasal cannula (excluding High-flow version discussed later)
Delivers FIO2 of 0.24 to 0.40
Used with flow rates of ¼ to 8 L/min
FIO2 depends on how much room air patient inhales in addition to O2
Device is usually well tolerated

18. Oxygen Therapy (cont.)

19. Oxygen Therapy (cont.) Nasal catheter Used at flows of ¼ to 8 L/min
Delivers FIO2 of 0.22 to 0.45
Rarely used in modern health care facilities today
Has been replaced by nasal cannula

20. Oxygen Therapy (cont.)

21. Oxygen Therapy (cont.) Transtracheal catheter
Surgically placed in trachea through neck by physician
Uses 40-60% less O2 to achieve same PaO2 by nasal cannula
Used with flow rates of ¼ to 4 L/min
Requires careful maintenance & cleaning
Complications such as infection are possible

22. Oxygen Therapy (cont.)

23. Oxygen Therapy (cont.) Reservoir cannula Designed to conserve oxygen
Nasal reservoir
Pendant reservoir
Can reduce oxygen use as much as 50% to 75%
Humidification usually not needed

24. Oxygen Therapy (cont.)

25. Oxygen Therapy (cont.) Reservoir masks
Most commonly used reservoir systems
3 types
Simple mask
Partial rebreathing mask
Nonrebreathing mask

26. Oxygen Therapy (cont.)

27. Oxygen Therapy (cont.)

28. Oxygen Therapy (cont.) High-flow systems
Supply given O2 concentration at flow equaling or exceeding patient’s peak inspiratory flow
Can ensure fixed FIO2
Most suitable for patients requiring precise FIO2, with high or variable minute ventilation
Include air-entrainment or blending systems
Venturi masks
Air-entrainment nebulizers

29. Oxygen Therapy (cont.)

30. Oxygen Therapy (cont.)

31. Other Oxygen Delivery Devices
Enclosures
Oxygen hood (AKA: Oxyhood): Generally is best method for delivering controlled oxygen to infants
Incubators (AKA Isolette): Can be used in conjunction with oxyhood
Oxygen tent: Regulating cooling & FIO2 can be difficult

32. Oxygen Therapy (cont.)

33. Other Oxygen Delivery Devices (cont.)
High Flow Nasal Cannula - Provide high FIO2, high relative humidity & positive pressure
Demand & Pulse - dose Systems-Conserve by providing flow during inspiration only
Bag-Mask Device - Provide 100% FIO2, often during emergencies

34. Selecting a delivery approach

35. Oxygen Therapy (cont.)

36. Air-entrainment (venturi) Non-rebreather mask
The most suitable oxygen delivery device for a patient with an unstable minute ventilation, needing a precise, moderate FIO2 is:
Nasal cannula
Simple mask
Air-entrainment (venturi)
Non-rebreather mask
Answer: C

37. Transtracheal oxygen system Simple mask Nasal catheter
The most suitable oxygen delivery device for a patient who requires a low FIO2, desires to conserve oxygen and objects to appearance of a nasal cannula, is:
Pendant cannula
Transtracheal oxygen system
Simple mask
Nasal catheter
Answer: B

38. Physiological effects

39. Hyperbaric Oxygen Therapy (cont.)
Methods of administration
HBO is administered in either multiplace or monoplace chamber
Multiplace chamber can hold 12 or more people
Monoplace chamber can hold only 1 patient

40. Hyperbaric Oxygen Therapy

41. Hyperbaric Oxygen Therapy (cont.)
Indications
2 most common acute conditions for which HBO is administered by RTs are:
Air embolism
Carbon monoxide poisoning

42. Hyperbaric Oxygen Therapy (cont.)

43. Complications & hazards

44. Air emboli and CO poisoning Wound healing and gas gangrene
The most common indications for hyperbaric oxygen therapy (HBO) administered by RTs are:
Air emboli and CO poisoning
Wound healing and gas gangrene
Neovascularization and wound healing
Cardiac anomalies and lung transplantation
Answer: A

45. Other Medical Gas Therapies
Nitric oxide therapy
Improves blood flow to lung
Reduces shunting
Improves oxygenation
Decreases pulmonary vascular resistance
Lower cost alternative drug therapies, including inhaled epoprostenol sodium, are gaining popularity

46. Nitric Oxide Therapy

47. Nitric oxide therapy

48. Nitric oxide therapy

49. Other Medical Gas Therapies (cont.)

50. Persistent Pulmonary Hypertension of the Newborn Sickle cell disease
All of the following are major indications for Nitric Oxide therapy, except:
ARDS
Persistent Pulmonary Hypertension of the Newborn
Sickle cell disease
Cerebral encephalopathy
Answer: D

51. Other Medical Gas Therapies (cont.)
Helium-oxygen therapy
Value of helium as therapeutic gas is based solely on its low density
Can decrease work of breathing for patients with airways obstruction (e.g., asthma, croup, etc.)

52. Other Medical Gas Therapies (cont.)
Heliox therapy
Guidelines for use
Helium must always be mixed with O2
Heliox can be prepared at bedside or used from premixed cylinders
In general, heliox should be delivered to patients via tight-fitting nonrebreathing mask with high flow

53. Other Medical Gas Therapies (cont.)
Heliox therapy (cont.)
Troubleshooting & hazards
Poor vehicle for aerosol transport
Reduces effectiveness of coughing
Badly distorts patient’s voice
Hypoxemia can be problem

54. The main indication for heliox therapy is: Upper airway obstruction
Pulmonary hypertension
Pulmonary embolism
Refractory hypoxemia
Answer: A

55. Other Medical Gas Therapies (cont.)
Carbon Dioxide-Oxygen (Carbogen) Therapy
Not common, but used for:
Hiccoughs
Carbon monoxide poisoning
Preventing complete washout of CO2 during cardiopulmonary bypass
Available in mixtures of: 5%:95% or 7%:93%