Oxygen Therapy-Current Guidelines

1. OXYGEN THERAPY
Dr. Hameed Uddin Ahmed
Assistant Professor of Paediatrics,
Silchar Medical College & Hospital

2. OXYGEN
▪ 8TH Element on the Periodic table
▪ O2
▪ 20.9% of air by volume
▪ 50% of earth’s crust by weight
▪ Oxidizer
▪ Non-flammable

3. ▪ OXYGEN THERAPY IS USUALLY DEFINED AS
THE ADMINISTRATION OF OXYGEN AT
CONCENTRATIONS GREATER THAN THOSE
FOUND IN AMBIENT AIR.

4. GOALS
HYPOXIA- a condition where the amount of oxygen available to the cells is not adequate to
meet the metabolic need. It can exist even though hypoxemia has been corrected with oxygen
therapy.
(high altitudes,reduced hct,CO poisoning,shock,cyanide poisoning etc)
HYPOXEMIA- decrease in the partial pressure of Oxygen - < 55mmHg.
( high alt,copd,cardiac shunts,atelectasis,ILD, Hb def)
TO PREVENT OR TREAT HYPOXEMIA, THEREBY PREVENTING TISSUE HYPOXIA,
WHICH IF NOT TREATED OR PREVENTED MAY LEAD TO TISSUE INJURY OR EVEN
CELL DEATH.

5. ▪ Primary goal of oxygen therapy is to treat hypoxemia.
▪ However, a very small number of patients with COPD have sensitivity to Higher Levels Of Oxygen.
▪ Normal CO2 35-45 mmHg
▪ Normally inc CO2 will stimulate ventilation, but in COPD there is reduced sensitivity to inc levels of
CO2 .
▪ HYPOXIC DRIVE: dependent on low levels of PaO2 to stimulate breathing (COPD)
If too much oxygen is delivered to such a patient – PaO2 will rise ,alongwith CO2 level, - this will
lead to RESPIRATORY ACIDOSIS AND FAILURE.

6. EFFECTS OF HYPOXIA
▪ RS-
Inc ventilation
Pulm vasoconstriction
Pulm HTN
▪ CVS-
CO
Tachycardia
MI/Isch
Decreased BP
Arrhythmias
▪ MET-
Inc 2,3 diphosphoglycerate
Lactate acidosis
▪ CNS-
Confusion,delirium,coma
▪ RENAL-
RA axis activation
Inc Erythropoetin production
ATN

7. QUICK GLANCE AT OXYGEN TRANSPORT
▪ Partial Pressure of Oxygen in ALVEOLUS – 100mmHG
▪ In venous blood returning to the lungs for oxygenation – 40mmHg
▪ Pressure gradient for Oxygen Diffusion into blood – 60mmHg
▪ PAO2 is never = PaO2 ( v/q mismatch, shunts R to L )
▪ Normal PaO2 90-95 mmHg (in practice taken as 80-100mmHg)
▪ In neonates – 50-80 mmHg ( fetal Hb,shunts at birth)

8. GUIDING PRINCIPLES
▪ Factors to consider when choosing appropriate oxygen source.
▪ Home / hospital
▪ DECIDE ???
Continuous flow / oxygen conserving
Ensure therapy meets pt’s requirement --Physiological needs
Cognitive ability
Environmental considerations
Geographic considerations

9. INDICATIONS
▪ Respiratory failure
▪ MI
▪ Cardiac failure
▪ Shock
▪ Anaemia
▪ Trauma, burns, sepsis – hypermetabolic state
▪ CO/Cyanide poisoning
▪ CPR
▪ Recovery from anaesthesia

10. ▪ Respiratory Failure
Type I – resp system cannot adequately provide oxygen to the body =
HYPOXEMIA
Cardiogenic/non cardiogenic PE, ARDS, COVID 19, pneumonia
Type II – resp system cannot sufficiently remove carbon dioxide = HYPERCAPNIA
COPD, RESP MUSCLE WEAKNESS, chest wall deformities, CNS depression

11. ASSESSMENT
Oxygenation may be assessed by -
▪ clinical assessment,
▪ pulse oximetry and
▪ arterial blood gases.
▪ Each of these methods of assessment of oxygenation has strengths and limitations that
should be understood by clinicians if assessment and subsequent management of
oxygenation is to optimize patient care.

13. OXYGEN CONCENTRATORS
• Extract oxygen from
atmosphere through zeolite
seal and filters
• Proved lifesaving during COVID
2ND WAVE
• Portable ( 5L/min) and High
Flow variants (15L/min)

16. OXYGEN CYLINDERS
▪ Steel or aluminium
▪ High pressure
▪ Different sizes
▪ REGULATOR must be used
▪ REDUCTION GAUGE- shows amount in tank
▪ FLOWMETER – regulates flow control – litres per minute
▪ HUMIDIFIER

20. Parts
Flow meter with humidifier
Pressure gauge
T handle to be turned
anticlockwise

23. This Photo by Unknown Author is licensed under
CC BY
WALL MOUNT AND THE MANIFOLD SYSTEM

25. METHODS OF ADMINISTRATION

26. This Photo by
Unknown Author is
licensed under CC
BY

30. ECMO

31. ❖DESIGNS
▪ LOW FLOW – nasal cannula, nasal catheter
▪ RESERVOIR – simple face mask, rebreathing mask, tracheostomy
mask
▪ HIGH FLOW – ventimask, aerosol mask, T-piece with nebulizers
▪ ENCLOSURES –
❖PERFORMANCES
• FIXED
• VARIABLE

32. NASAL PRONGS
▪ Disposable
▪ Plastic or silicone
▪ Nostrils
▪ Connected to oxygen source
▪ LOW to MEDIUM concentrations of
oxygen
▪ 24 % - 44%
▪ FiO2 DELIVERED:
✔ 1 L/min – 24%
✔ 2 L/min – 28%
✔ 3 L/min – 32%
✔ 4 L/min – 36%
✔ 5 L/min – 40%
✔ 6 L/min – 44%

34. ADVANTAGES OF NASAL PRONGS
▪ Can talk and communicate
▪ Easy to use ( home/hospital )
▪ Safe and simple
▪ Easily tolerated
DISADVANTAGES OF NASAL PRONGS
▪ Nasal obstruction – no use
▪ Easily dislodged
▪ Habitual mouth breathers – no use
▪ Drying of mucous membranes ..
> 4 L/min , humidify
▪ Breathing pattern affects FiO2

35. FACE MASK (SIMPLE)
▪ Clear, flexible,molded plastic to fit the
face
▪ Held with elastic bands
▪ Metal clip over nasal bridge area for
closer comfortable fit
▪ Exhalation ports
▪ 35% - 60%
▪ 6 to 10 L/min
▪ Can be used when increased oxygen
delivery is needed for periods of < 12
hrs.
DISADVANTAGES:
. Tight seal required
. Difficult to maintain position
. Skin affected – pressure / moisture
. Eating / talking hampered
. Costs more than nasal prongs

36. PARTIAL RE-BREATHER MASK ▪ Minimum 6 L/min flow rate
▪ To ensure patient does not re-breathe
large amounts of exhaled air
▪ Exhaled air exits through vents
ADVANATAGES
Can inhale room air in case oxygen
supply is interrupted.
DISADVANTAGES
Tight seal – eating/talking
difficult/uncomfortable

37. NON-RE-BREATHER MASK (NRBM)
▪ 6 – 15 L/min
▪ Highest conc of 95% - 100%
▪ 2 one way valves prevent conservation
of exhaled air
▪ Bag – oxygen reservoir
ADVANTAGES
. High O2 conc delivered
. Suitable for Spontaneous breathing
patients with severe hypoxemia.
DISADVANTAGES
. Long term use impractical
. CO2 buildup in case of malfunction
. Expensive , maybe uncomfortable

39. VENTURI MASK
HIGH flow oxygen delivery system
40 – 50 %
4 – 15 L/min
Constant flow of room air blended with a Fixed concentration of
Oxygen

40. AMBU BAG
▪ ARTIFICIAL MANUAL BREATHING UNIT
▪ PPV

41. TRACHEOSTOMY COLLAR/MASK
▪ Placed in the trachea
▪ Chronic Oxygen therapy
▪ 8 – 10 L/min
▪ Accurate FiO2 provided
▪ Good humidity
▪ Comfortable
▪ efficient
This Photo by Unknown Author is licensed under CC BY

42. CPAP / BIPAP
INDICATIONS:
COPD / Ac BRONCHITIS / PNEUMONIA / FLAIL CHEST / OBESITY / OSA / CHF
▪ BIPAP / Bi-Level PAP –
. inspiratory PAP and expiratory PAP
. Ramp Time – period during which the therapy pressure increases from a low
start pressure to the prescribed treatment pressure.
. pressure range – 4 to 30 cmH2O
. initial settings –
8 to 10 cmH2O ( upto 24 cmH2O ) INHALATION
2 TO 4 cmH2O (upto 20 cmH2O ) EXHALATION

43. ▪ CPAP
.Continuous Positive Airway Pressure
. 4 to 20 cmH2O – pressure range
. Avg pressure for OSA – 9 cmH2O
. Continuous positive pressure to keep the
airways open
CONTRAINDICATIONS:
Inability to protect airway
Secretion clearance is poor
Depressed sensorium
GI bleed with intractacble emesis
Status epilepticus
Patients on pressor support

44. SIDE EFFECTS / COMPLICATIONS OF OXYGEN THERAPY
▪ Toxicity
▪ Retrolental fibroplasia
▪ atelectasis
▪ To avoid oxygen toxicity FiO2 is typically
maintained below 50% even with
mechanical ventilation, but sometimes we
have to use 100% .

45. OXYGEN TOXICITY
▪ Due to high conc of oxygen inspired over a prolonged period of time
▪ Oxygen Conc > 50% over 24 – 48 hrs – pathological changes in the lung
▪ Oxidative damage to cell membranes leading to collapse of lungs
Muscle twitching
Vision loss, near sightedness, cataract formation,bleeding,fibrosis,
Seizures
Jerky breathing,irritation,coughing,pain,SOB, tracheobronchitis, ARDS

46. RETROLENTAL FIBROPLASIA
▪ Vasoconstriction and ischemia – blindness
▪ Premature infants

47. ABSORPTION ATELECTASIS
▪ 100% oxygen = washing out of Nitrogen in alveoli = oxygen entirely fills up the alveoli
▪ Oxygen diffuses faster than Nitrogen into blood in the pulmonary vasculature
=
decreased amount of gas in the alveoli to maintain patency of the alveoli
=
alveolar collapse