oxygen support devices...............ppt

o2 support devices

1. Dr. Rohit

2. OBJECTIVES
Describe when oxygen (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 OXYGEN THERAPY
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. PaO
2 at or below 60 mm Hg
Saturation O
2
< 90% resting
A drop in PO
2 10 mm Hg or 5% in O
2 sat.
during sleep
Symptoms or signs of heart failure (cor
pulmonale), pulmonary hypertension,
erythrocytosis, “P” pulmonale on EKG
O
2 THERAPY : INDICATIONS

5. Barometric Pressure
•High altitude
PIO
2
PAO
2
Inc O
2

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
PaO
2
Cell
PO
2
Low Hb
concentration
•Anaemia
•CO poisoning
Low Perfusion
•local - PVD,
thrombosis
•gen – shock,Hypovol,

card. Failure
cardiac arrest
HYPOXIA

7. PaO2 AS AN INDICATOR 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
MILD TO 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

10. CLASSIFICATION

12. LOW FLOW SYSTEM
The gas flow is insufficient to meet patient’s peak
inspiratory and minute ventilatory requirement
O
2 provided is always diluted with air
 FiO
2 varies with the patient’s ventilatory pattern
Deliver low and variable FiO
2
→
Variable
performance device

13. Flow rates are <8 l/min
Includes
Nasal cannula
Nasal catheter
Transtracheal catheter

15. NASAL CANNULA
A plastic disposable
device consisting of two
tips or prongs 1 cm long,
connected to oxygen
tubing
Inserted into the
vestibule of the nose
FiO
2 – 24-40%
Flow – ¼ - 8L/min (adult)
< 2 L/min(child)

17. ESTIMATION OF FiO2
O
2
Flowrat
e
(L/min)
Fi O
2

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 O
2 increases the
FiO
2 approximately
4%.
E.g. A patient using
nasal cannula at 4
L/min, has an
estimated FiO2 of 37%
(21 + 16)

18. NASAL CATHETER
•A soft 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 inserted to 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
A thin Teflon catheter
Inserted surgically with
a guidewire between 2
nd

and 3
rd
tracheal rings
FiO
2
– 22-35%
Flow – ¼ - 4L/min
Increased anatomic
reservoir
Replace every 90 days

23. Estimation of Fio
2
from 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% O
2
provided/sec100 mL Inspiratory time, 1 sec
Volume inspired O
2
   expiratory time, 2 sec
 Anatomic reservoir 50 mL  
 Flow/sec 100 mL  
 Inspired room air 0.2 × 350 mL = 70 mL 
O
2
inspired 220 mL  
 FiO
2
220 O
2
= 0.44
500 TV
 
A patient with ideal ventilatory pattern who receives 6L/min O2 by
nasal cannula is receiving  FiO
2
of 0.44.

24. If V
T is decreased to 250 mL:  
Volume inspired O
2
 
Anatomic reservoir 50 mL
Flow/sec 100 mL
Inspired room air (0.20 × 100 cm
3
) 0.2 × 100 mL = 20 mL
O
2
inspired 170 mL
 FiO
2
170 = 0.68
250
The larger the Vt or faster the respiratory rate, the lower the Fio
2
.
The smaller the Vt or lower the respiratory rate, the higher the Fio
2
.
↑minute ventilation → ↓ Fio
2
↓minute ventilation Fio
→↑
2

27. RESERVOIR SYSTEM
Reservoir system stores a reserve volume of O
2,
that equals or exceeds the patient’s tidal volume
Delivers moderate - high FiO
2
Variable performance device
To provide a fixed FiO
2, the reservoir volume must
exceed the patient’s tidal volume

28. Includes
Reservoir cannula
Simple face mask
Partial rebreathing mask
Non rebreathing mask

29. RESERVOIR CANNULA
NASAL RESERVOIR PENDANT RESERVOIR

31. RESERVOIR MASKS
Commonly used reservoir system
Simple face mask
Partial rebreathing masks
Non rebreathing masks

32. SIMPLE FACE MASK
Reservoir - 100-200 ml
Variable performance device
FiO
2 varies with
O
2 input flow
mask volume
extent of air leakage
patient’s breathing pattern
FiO
2: 40 – 60%
Input flow range is 5-10 L/min
Minimum flow – 5L/min to
prevent CO
2
rebreathing

33. MERITS
Moderate but variable 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)
O
2

Flowrate
(L/min)
Fi O
2

5-6 0.4
6-7 0.5
7-8 0.6

34. Reservoir masks
Partial rebreathing mask
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
FiO
2 - 0.80 – 0.90
FGF – 10 – 15L/min
To deliver ~100% O
2,
bag should remain
inflated
Factors affecting FiO
2
 air leakage
patient’s breathing
pattern

38. Expiratory valves allow 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
•FiO
2
is independent of the the patient’s
ventilatory pattern
•Deliver low- moderate and fixed FiO
2
→
Fixed performance device

41. High-Flow Devices
To qualify as 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 flows are kept at >3 times
patient’s MV)
Includes
Ventimask (HAFOE)
Aerosol mask and T-piece with
nebulizers

43. AIR ENTRAINMENT DEVICES
Based on 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 rapid velocity 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
ENTRAINMENT DEVICES
Amount of air entrained varies directly with
Size of the port
Velocity of O2 at jet
They dilute O
2 source with air - FiO
2 < 100%
The more air they entrain, the higher is the
total output flow but the lower is the
delivered FiO
2

47. STEP 2: ADD THE 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 Air to O
2

Entrainment Ratio using a magic
box
20
100
60
20
40 60 = 3 : 1
20

49. Approximate Air Entrainment Ratio and Gas
Flows for different Fio
2
Fio 2 (%) Ratio
Recommended
O
2 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
FiO
2 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 Venti Masks
 A fixed Fio
2 model  A variable Fio
2
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 Face tent Tracheostomy
collar
T tube

54. How to increase the FiO
2 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
With a blending system,
separate pressurized air
and oxygen sources are
input.
The gases are mixed
either manually or with a
blender
FiO
2
– 24 – 100%

Provide flow > 60L/min
Allows precise control
over both FiO
2 and total
flow output - True fixed
performance devices

58. OXYGEN TENT
Consists of a canopy
placed over the head and
shoulders or over the
entire body of a patient 
FiO
2 – 40-50%
Flow rates - 12-15L/minO
2
Variable performance
device
Provides concurrent
aerosol therapy

59. Disadvantage
Expensive
Cumbersome
Difficult to clean
Constant leakage
Limits patient mobility

60. OXYGEN HOOD
An oxygen 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 are polymethyl
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 Oxygen therapy
1. Oxygen toxicity
2. Depression of ventilation
3. Retinopathy of Prematurity
4. Absorption atelectasis
5. Fire hazard

70. 1.O
2 Toxicity
Primarily affects lung and CNS
2 factors
PaO
2
Exposure time
CNS O
2 toxicity (Paul Bert effect)
 occurs on breathing O
2
at pressure > 1 atm
tremors, twitching, convulsions

71. Pulmonary Oxygen toxicity
C/F
Acute tracheobronchitis
Cough and substernal pain
ARDS like state

72. Pulmonary O
2
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

73. A Vicious Cycle

74. How much O2 is 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 in COPD patients with chronic hypercapnia
2. Depression of Ventilation

77. 3. Retinopathy of prematurity
(ROP)
Premature or low-birth-weight infants who receive
supplemental O
2

Mechanism
Increased PaO
2
Retinal vasoconstriction
Necrosis of blood vessels
New vessels formation
Hemorrhage retinal detachment and blindness
→
To minimize the risk of ROP - PaO
2
below 80 mmHg

78. 100% O
2
oxygen
nitrogen
PO
2
=673
PCO
2 = 40
PH
2
O = 47
A
B
A – UNDERVENTILATED
B – NORMAL VENTILATED

79. 5. Fire hazard
High FiO
2 increases the risk of fire
Preventive measures
Lowest effective FiO
2 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 O
2 therapy

80. Oxygen challenge concept
↑ FiO
2
by 0.2
↑ PaO
2 > 10 mmHg
↑
PaO
2 < 10 mmHg
( true shunt – 15 %) ( true shunt – 30 %)
↑

PaO
2
< 10 mmHg in response to an oxygen
challenge of 0.2 – refractory hypoxemia

81. Implications of Oxygen challenge
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 of oxygen 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