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1. OXYGEN THERAPY
 Dr. S.Parthasarathy
 MD, DA, DNB., Dip.,Diab., Dip. Software
based statistics. PhD (physio)
 Mahatma Gandhi medical college
and research institute , puducherry –
India
 painfreepartha@gmail.com

2. After food-- 0xygen flow is

3. DEFINITION
 Oxygen therapy is the
administration of oxygen at
concentrations greater than
ambient air (i.e. >21 %) with the
intent of correction or
prevention of hypoxemia

4. INDICATIONS
 Patients with documented hypoxemia.
 PaO2 < 60 mm Hg or SaO2 < 90 % in
subjects breathing room air.
 PaO2 less than acceptable for that
specific clinical situation.
 An acute care situation in which
hypoxemia is suspected. It should be
substantiated within a reasonable period
of time

5. INDICATIONS
 Severe trauma.
 Acute myocardial infarction.
 Post anaesthesia period.
Supplemental oxygen is to be
administered to all patients during
emergence to prevent tissue hypoxia.
Some factors favour prolonged therapy.

6. Factors
Patient factors
 Cardio respiratory disease.
 Obesity
 Elderly
 Shivering
Surgical factors.
 Upper abdominal surgeries.
 Thoracic surgeries

7. Pathophysiological factors.
 Hypovolumia
 Hypotension.
 Anaemia.
Analgesia factors.
 Patient controlled analgesia.
 IV opioid infusion.
 Epidural opioids

8. REGARDING OXYGEN THERAPY

9. Hypoxemia- clinical clues
 Pulmonary: tachypnea, dyspnea
 CVS: tachycardia, hypertension,
dysryhthmias, palpitation
 Haemotology: anaemia.
 CNS: restlessness, disorientation, coma,
paraesthesia.
 Others : cyanosis, clubbing, nausea,
vomiting
 What is the inference ??

10. 1000 ml o2 supplied
 250 ml consumed
 750 ml returned
 SvO2 75%
 Oxygen flux = CARDIAC OUTPUT × 1.34 ×
Hb × SATURATION

11. Curve to know about!!!pao2 of 60
mm is almost ok

12. Sigmoid curve

13.  Suppose in pneumonia there is hypoxemia
what are we doing by giving oxygen ??
 See next !!

15. Why to give?
 Relieve hypoxemia.
 Prevent hypoxemia.
 Reduce the work of breathing.
 Decrease the work of myocardium.
 Improve exercise tolerance.
 It is for us to see that the right patient
receives the right amount of oxygen for the
right length of time

16. FDO2 and FiO2
 FDO2 -fractional percentage of delivered
oxygen by the oxygen delivery device.
 FiO2 - fractional percentage of oxygen in
the inspiratory air of patients.
 In simple words the device may give 100%
O2 but the patient may breathe 24 % O2.
why?

17. 1.The device itself
 Device Oxygen flow FiO2
 Nasal catheter 2 l/min 0.28
 Transtracheal 2 l/min 0.4
catheter

18.  2.Oxygen flow
 3.Patients inspiratory flow.
 4. Minute ventilation
 5. The mouth breathers

19. The oxygen delivery devices can be
categorized as
 Low flow systems.
 Reservoir systems.
 High flow systems.
 Enclosure systems.

20. a short break
 An executive rang up the doctor to say ‘
My wife has abdominal pain’.
 The doctor asker her to come and
examined to detect appendicitis. she was
operated and went home fine.
 Six months later the phone from same
executive ‘ My wife has got appenticitis.’
The doctor angrily said ‘A man can have
one appendix’

21. The executive said coolly
‘a man can have two wives.

22. Variable performance devices (Low flow
systems)
 devices which supply oxygen at flow
rates lower than the patients’
inspiratory demands.
 Varying amounts of room air added to
provide inspiratory volume.
 Deliver FiO2 ranging from 0.22- 0.6
depending on patients’ inspiratory flow,
tidal volume and oxygen flow.
E.g. 1. Nasal cannula. 2.Transtracheal
catheter. 3. Simple mask.4. Partial
rebreathing masks. 5. Nonrebreathing
masks.

23. Fixed performance devices
(high flow systems)
 provide oxygen at flow rates high
enough to satisfy patients’
inspiratory demands. Such high flows (i.e.
35-40 litres approx.) are possible by
 Entrainment of room air.
 High flow rates and reservoirs.
E.g. Venturi masks.
Incubators.
Tents.
Hoods.

24.  Both systems can deliver a wide range of
FiO2.
 It is a misconception that low flow systems
deliver low FiO2 and high flow systems
deliver high FiO2.
 DO NOT CONFUSE LOW FLOW AND
HIGH FLOW WITH LOW FiO2 AND HIGH
FiO2.

25. Nasal cannula
 The two soft prongs are inserted into
nares.The tubing is secured to the patients’
face.
 FiO2 0.22-0.4
 ADVANTAGES
 Simple, well tolerated,
 Nonclaustrophobic.
 Available for infants also. Feeding
 mobility better.
 Humidification not required.

26. Transtracheal cath.- home
O2
 In hospital sterile surgical percutaneous
transtracheal insertion of a stent followed
by a suitable catheter a week later.
 Improved compliance
 cosmetic appearance.
 Reduced cost of oxygen
 no nasal irritation.

29. Simple mask
 A plastic reservoir designed to fit over the
nose and mouth. Internal capacity of the
mask is reservoir. Holes on each side of the
mask serve both as exhalation and room
air entrainment ports.
 ADVANTAGES :
 High FiO2.
 Interim therapy.
 Better humidification

30. Problems – simple mask
 High flow (5-6 l/min) necessary.
 Variable performance device.
 Speaking, eating difficult.
 Potential for aspiration.
 Co2 rebreathing possible.
 Ideal for short periods

31. Partial rebreathing mask

32. Partial rebreathing mask
 FiO2 of 0.4-0.6
 Child and adult sizes √
 Better humidification.
 Simple.
 Useful in distress for high humidified FiO2.
 High flow (6-10 l/min) necessary.
 Variable performance device.
 Speaking, eating difficult.
 Potential for aspiration.
 Uncomfortable for extended period

33. Nonrebreathing mask
Similar to partial
rebreathing mask but
attached with one or two
one way valves in the
side of the mask.
Total non rebreathing
and 100% FiO2 is
difficult to achieve
because of face leaks
and small reservoir bags

34. High flow systems.Air
entrainment mask(venturi)
FiO2 – 0.24-0.5
 Oxygen forced through a jet orifice
entering the mask. As there is a pressure
drop across jet orifice room air
entrainment occurs through side ports.
(venturi effect.)
 High flows.
 Fixed FiO2.

35. Venturi effect

36. Should be like this

37. Should not be like this!
No extra length tube

38. beware!
 The performance of venturi mask may be
altered by obstruction distal to the orifice
resulting in higher FiO2 and lower total
flows.
 The performance - altered by blocks of
entrainment ports.
 Obstruction of the device by coughed out
secretions and the altered delivery of FiO2
should be borne in mind.

39. High flow aerosol
 Oxygen forced through a jet orifice entrains
both room air and gets humidified from a
bottle of water. The output is given through a
Brigg’s adapter.
 High flows
 Fixed FiO2.
 Noise.
 At a higher FiO2, (>0.8) the flow may
decrease to 15-20 litres /min.Hence in
dyspnoeic patients needing high FiO2, it may
be less useful.

40.  Oxygen hoods - transparent enclosures
designed to surround the head of an
infant.
 continuous humidified oxygen supplied to
hood.
 short term use in active infants.
 A minimum flow of >7 litres - necessary.
 continuous oxygen analysis and alarm
systems required for safe use.

41.  Oxygen tents -- electrically powered
appliances that incorporate an air
circulation system and provide
temperature control. The nebulizer is
connected to a transparent canopy placed
over the patient. distinct fire hazard with
the tent.

42.  Supplemental oxygen is a relatively benign
drug.
 Before going to the possible hazards, it is
to be mentioned that many patients die
of hypoxia than due to potential
complications of oxygen therapy

43.  Physiological:
 Beware-- preterm infants. PaO2 of more
than 80 torr may be linked to retinopathy.
 may cause imbalance in systemic and
pulmonary blood flows in certain
congenital heart diseases.
 may induce pulmonary fibrosis in patients
of paraquat poisoning and bleomycin
intake.

44. Hazards
 may cause CO2 narcosis in patients with COPD if
the hypoxic respiratory drive is suppressed.
 Inappropriate therapy ---hypoxia or hyperoxia.
 Persistent high FiO2 (>60%) can induce lung
damage to produce a clinical ARDS picture.
 Physical.
 Oxygen delivery devices can malfunction
to deliver insufficient oxygen.
 The devices may physically cause injuries
to the face, lips nasopharynx etc.

45. Others.
 Fire hazard is increased with oxygen
therapy.
 Bacterial contamination is associated with
humidification systems.
 Sometimes water in the humidifier
may be there for years.
 Dry gases can cause airway irritation.

46. FACTORS THAT DETERMINE WHICH
SYSTEM TO START, USE,
** PATIENT COMFORT.
** THE LEVEL OF FIO2
** DISTRESSED OR NORMAL
**REQUIREMENT CAN BE CONTROLLED
WITHIN A CERTAIN RANGE.
**THE LEVEL OF HUMIDIFICATION AND
OR NEBULIZATION
START—MONITOR—CHANGE--STABILIZE

47. A case of acute asthma
comes with respiratory
distress.
These patients are hypoxemic and have rapid
respiratory rates.
 If there is no CO2 retention, venturi masks
with humidification or aerosol nebulizers are
useful to start with FiO2 of 0.4- 0.5.
 Dry gases can be irritant to increase spasm.

48. 2. A case of pneumothorax
with respiratory distress.
 These patients may need 100% O2 to wash
off nitrogen (Case of air in body cavities).
 patient is in distress so ideal to give 100% O2
with a Gas Injection Nebulization (GIN)
because it can give high flows to meet patient
demands.
 A case of pneumothorax without much
distress, a nonrebreathing mask to give 100%
O2 is enough

49. 3. A routine postoperative laparotomy patient.
 These patients may need supplemental O2
through a venturi mask or a nasal cannula.
FiO2 of 0.3 is usually enough.
4. A routine myocardial infarction patient
 A nasal cannula or catheter is started with
FiO2 of 0.3.This will not hinder talking or
drinking by the patient as opposed to masks.

50. 5. A case of faciomaxillary trauma with
hypoxemia.
 A partial rebreathing mask with FiO2 0f 0.6 is
ideal. Nasal cannula or catheter is
contraindicated in faciomaxillary trauma.
6. An infant with croup.
 An oxygen hood with supply of humidified
Fio2 of 0.4 is to be set up. Mobility of the
infant may displace the hood and should be
taken care of.

51.  7. COPD patient on FiO2 of 0.4.The patient’s
conscious status slowly deteriorated .ABG
showed PaO2 of 80 mmHg and PaCO2of
75mmHg.
 This patient slowly goes for CO2 narcosis.
The FiO2 can be decreased to 0.3 to
maintain a PaO2of 60 mmHg and sustain
some hypoxic ventilatory drive to wash
CO2

52. Supplemental oxygen may not
correct all hypoxemias.
Think of adding
 mechanical ventilation.
 CPAP.
 PEEP.
 Fluids.
 Blood --- as appropriate.

53. THE MESSAGE IS---
Oxygen is a drug
 Don’t say “ Staff, give O2 for some time.”
 Say
 “ continuous humidified O2 – VENTURI
MASK 40% --- 8 litres/min.
 “UNHUMIDIFIED O2- NASAL CANNULA
-2L/MIN.”

54. As postgraduates focus on
three things
 1. anaesthesia
 2. anaesthesia
 3. anaesthesia

55. THANK YOU