2. Oxygen source
Inspired Oxygen (Fio2)
Alveolar Oxygen
(PAO2)
Arterial Oxygen
(PaO2)
Caplillary Oxygen
(PcO2)
Tissue Oxygen Mitochondrial
Oxygen
Venous Oxygen
(PvO2)

3. Atmospheric Oxygen (21%)
Oxygen Cylinders
Liquid Oxygen
Oxygen Concentrator

4.  PIO2= (P B - P H2O)FiO2
 At sea level:
PIO2= (760-47)X 0.21
= 149.7 mmHg

5. PAO2= PIO2- (PACO2/R)
R: Exchange Ratio= 0.8
PACO2=PaCO2 ( CO2 is freely diffusible)
PAO2= 150- (40/0.8)
= 100 mmHg

6. Diffusion Capacity
•Property of the alveolar-capillary
membrane
•Ease with which oxygen moves
from inhaled air to the red blood
cells in the pulmonary capillaries

7.  The arterial PaO2 is less than PAO2 due to
presence of:
 Intrapulmonary Shunts
Deep true bronchial veins
Thebesian veins
 Normal venous admixture <5%
 Blood through low V/Q
units
 Total shunt because of the above factors is 2% of
CO.

10.  Low FiO2 Low PIO2 Low PAO2 Low
PaO2
 High altitude
 Exposure to fires which consume O2
 Exhaled gas used for CPR.

11.  Results in: Hypoxemia
CO2 retention
 Causes: Airway Obtruction
Low Minute ventilation : Low RR or Low
TV
PaO2 + PaCO2 = 140 mmHg.

13.  Focal Hypoventilation
 Shunt Effect
 Wasted Perfusion
HYPOXEMIA
Hypoxemia without
hypercarbia
(Type 1 RF)
 Dead Space Effect
 Wasted Ventilation
INCREASED WORK
OF BREATHING
Minute Ventilation-
PaCO2 Disparity
( Type II RF )
V/Q <1
Low V/Q Units
V/Q >1
High V/Q Units
V/Q=1.0
V/Q=0 V/Q= infinity

14. Type I or Hypoxemic (PaO2 <60 at sea level): Failure of oxygen
exchange
 Increased shunt fraction (Q S /QT )
 Due to alveolar flooding
 Hypoxemia refractory to supplemental oxygen.
Type II or Hypercapnic (PaCO2 >45): Failure to exchange or remove
CO2
 Decreased alveolar minute ventilation (V A )
 Often accompanied by hypoxemia that corrects with supplemental
oxygen
Type III Respiratory Failure: Perioperative RF
Type IV Respiratory Failure: Shock

15. Alveolar arterial oxygen difference P(A-a)O2
 Normal is 5-15 mm Hg because oxygenated blood is
mixed with deoxygenated blood.
 Affected by:
Age : Increases with age
FiO2: Increases with increasing FiO2.
 Indicator of pulmonary parenchymal dysfunction.

16.  Normal P/F > 400; Maximum P/F = 700
 Relation between PaO2 and FiO2 is non linear and influenced by:
- Denitrogenation Absorption Atelectesis
-PEEP
 Advantage: Simple - bypasses need to calculate PAO2
 Disadvantage: Cannot distinguish between Type 1 and Type II RF
 S/F = 64+ 0.84 X (P/F)

17.  Thickened interface between air and blood:
Collagen deposition
Cellular infiltration
 Reduced surface area for diffusion: Low V/Q due to partially
collapsed alveoli
 Decreased Delivery with Normal Oxygen Extraction:
Reduced Hb
Reduced SaO2
Reduced Blood Volume
Reduced CO
 Normal delivery with increased O2 consumption or extraction

19. : 0.003 X PaO2 ( Normal is 0.3-0.5ml )
(19.5 ml)
 % of heme binding sites saturated with oxygen is the Hb
oxygen saturation %.
 CaO2 = (1.34 X Hb X SaO2) + 0.003 X PaO2
 Eg at 100% SaO2, Hb 15g%, PaO2 120 mm Hg
 CaO2= (1.34 X 15 X 100/100)+(0.003 X 120)
=20.46ml

22.  Depends on oxygen content and cardiac output
= CO X CaO2
= 5000 X 20/100
= 1000ml/min
: Oxygen consumption by tissue per min.
250ml/min at rest
: Oxygen Extraction Ratio
VO2/DO2 = 0.25 (Normal range is 0.22-0.32)
Indicates balance b/w delivery and uptake
Low Values: Flow Maldistribution
Metabolic Poison
High Values: Compensatory increase in extraction for reduced
delivery.

23. Inspired Air: 150
Alveolar : 100
Arterial :95
Capillary: 50
Tissue: 20
Mitochondria:
1-20
Mitochondrial function is jeopardized at PO2<30mmHg or SPO2 of
30%

25.  Documented hypoxemia: Pa02 <60 mm Hg or Sa02 <90%
 An acute care situation in which hypoxemia is suspected &
substantiation of hypoxemia is required within an appropriate period
of time following initiation of therapy.
 Severe trauma
 Acute myocardial infarction
 Short-term therapy (e.g., postanesthesia recovery)

26. Low Flow Devices
 Nasal cannula
 Nasal catheter
 Transtracheal catheter
Reservoir
 Simple mask
 Partial rebreathing mask
 Nonbreathing mask
High Flow Devices
 Air-entrainment mask
 Air-entrainment nebulizer
 T-piece with a venturi
device
 Breathing circuits with
reservoir bags
Enclosure
 Oxyhood
 Tent
 Isolette

27. Patient's inspiratory flow > flow delivered by the
device
Air dilution
Variable flow

29.  Flow: 1-6 L/min (adults), <2 L/min (infants)
 FiO2: 24%-44%
 Advantages: Use on adults, children, infants;
Easy to use; well tolerated
Disposable; low cost.
 Disadvantages: Unstable, easily dislodged
High flow uncomfortable
Can cause dryness, bleeding; polyps; deviated septum
Mouth breathing may reduce FIO2.
 Use: Patient in stable condition who needs low FIO2
Home care patient who needs long term therapy.

31.  Flow: 1-6 L/min
 FiO2 Range: 22%-45%
 Advantages: Use on adults, children, infants
Good stability
Disposable; low cost.
 Disadvantages: Difficult to insert
May provoke gagging, air swallowing, aspiration
Polyps, deviated septum may block insertion;
Needs regular changing
 Use: Procedures in which cannula is difficult to use (bronchoscopy)
Long-term care of infants.

32.  Oxygen enters directly into the lungs by a small flexible catheter
which passes from the lower neck to trachea.
 Flow: 1/4-4 L/min
 FiO2: 22%-35%
 Advantages: Lower 0 2 use and cost;
Eliminates nasal and skin irritation
Improved compliance
Increased mobility
 Disadvantages: High cost
Surgical complications
Infection
Mucus plugging
Lost tract
 Use: Home care or ambulatory patients who need
increased mobility or do not accept nasal oxygen

33. Reserve volume (flow x time) ≥ patient's tidal
volume
Fixed flow devices if RV > Inspiratory flow

34.  Flow: 1/4-4 L/min
 FiO2: 22%-35%
 Advantages: Lower 02 use and cost
Less discomfort because of lower flow
 Disadvantages: Unattractive, cumbersome
Poor compliance
Must be regularly replaced
Breathing pattern affects performance
 Use: Home care or ambulatory patients who need
increased mobility

35.  Flow: 5-10 L/min
 FiO2: 35%-50%, Variable.
 Advantages: Use on adults, children, infants
Quick, easy to apply
Disposable, inexpensive.
 Disadvantages: Uncomfortable
Must be removed for eating
Skin irritation
Pressure sores
Blocks vomitus in unconscious patients.
 Uses: Emergencies, short term therapy requiring moderate FIO2,
mouth breathing patients requiring moderate FIO2.

36. Partial Rebreathing System Non Rebreathing System

37.  Flow: 6-10 L/min (prevent bag collapse on inspiration)
 FiO2: Maximum of 40-70%
 Advantages: Use on adults, children, infants
Quick, easy to apply;
Disposable, inexpensive.
 Disadvantages: Uncomfortable
Must be removed for eating
Prevents radiant heat loss
Blocks vomitus in unconscious patients.
 Use: Emergencies
Short term therapy requiring moderate FIO2
Mouth breathing patients requiring moderate FIO2

38.  6-10 L/min (prevent bag collapse on inspiration)
 FiO2: 60-80%
 Advantages: Same as simple mask;
High FIO2
 Disadvantages: Same as simple mask
Potential suffocation hazard
 Use: Emergencies
Short term therapy requiring high FIO2

39. The High-flow system always exceeds the patient's
flow
Provide fixed FIO2.

41.  Flow: Varies
 FiO2: 24%-60%
 Advantages: Easy to apply;
disposable,
inexpensive;
stable,
precise Fio2
 Disadvantages: Limited to adult use,
 Use: Patients in unstable condition who need precise Fio2.

42.  Flow: 10-15 L/min input,
Should provide output flow of atleast 60 lit/min
 FiO2: 28%-100%
 Advantages: Provide temperature control and humidification
 Disadvantage: FiO2<0.28 and >0.40 not ensured
FiO2 varies with back pressure
High infection risk

43.  T-piece:
Attaches to ETT or tracheostomy tubes
Can be variable performance or fixed performance.
 Breathing Circuits:
Consist of inspiratory and expiratory limb with reservoir bag.
Two limbs are connected through a Y-connector to either a tight
fitting mask or an endotracheal tube.

44. Cover the face and the body

45.  Flow: >7 L/min
 FiO2: 21 %-100%
 Advantages: Full range of FIO2
 Disadvantage: Difficult to clean & disinfect
.
 Use: Infants who need supplemental
oxygen

46.  Flow: 12-15 L/min
 FiO2: 40%-50%
 Advantages: Provides concurrent aerosol therapy
 Disadvantages: Expensive, cumbersome;
Unstable FIO2 (leaks);
Requires cooling;
Difficult to clean, disinfect;
Limits patient mobility
Fire hazard
 Use: Toddlers or small children who need
low to moderate FIO2 and aerosol

47.  Hyperbaric oxygen therapy is the therapeutic use of oxygen at
pressures greater than 1 atm.
 Indications:

48.  Inhibition of Hypoxic pulmonary vasoconstriction
 Increased SVR with reduced coronary, cerebral and renal blood
flows.
 Reduced cardiac output & haemodynamic instability.
 Increased production of reactive oxygen species.
 Paradoxical decrease in O2 consumption due to maldistribution of
blood flow due to peripheral shunts which open up to protect the
vital organs from non-physiological effects of hyperoxia.

49.  CO2 Narcosis: In COPD patients, high FiO2 removes the hypoxic
drive & causes hypoventilation and narcosis.
 Denitrogenation Adsorption Atelectasis
 O2 Toxicity:
 Respiratory: ARDS Like syndrome
 Neurological: Seizures (Hyperbaric)
 Children: Bronchopulmonary dysplasia
Retrolental fibroplasia