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Oxygen Therapy & O 2 Delivery Systems Dr. J. S Dali MAMC

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1 Oxygen Therapy & O 2 Delivery Systems Dr. J. S Dali MAMC

2 Oxygen Therapy ?

3 Partial Pr of O 2 in insp. gas (P i o 2 )

4 Oxygen Therapy Conc. of O 2 (Fi o 2 ) (Orthobaric) Total Pressure (Hyperbaric) Partial Pr of O 2 in insp. gas (P i o 2 )

5 Father of modern O 2 Therapy ?

6 J.S Haldane-1917 O 2 lack not only stops the machine, but totally ruins the supposed machinery

7 Aim of O 2 Therapy ?

8 To restore tissue O 2 towards normal

9 O 2 Cascade Air mitochondria

10 O 2 Cascade Atm. Air (dry) Lower Resp. Tract (moist 37 o c) 159mm Hg (20.95 % of 760) 149mm Hg (20.95 % of 713) ?

11 O 2 Cascade Atm. Air (dry) Lower Resp. Tract (moist 37 o c) 159mm Hg (20.95 % of 760) 149mm Hg % of 713 (760-47) Humidification 6 Vol % (47mm Hg)

12 O 2 Cascade 149mm Hg (20.95 % of 713) ? Lower Resp. Tract (moist 37 o c) ? Alveolar air 101mm Hg (14 % of 713) o r (15 % of 673) 673 = 760 – 47 – 40 P A O 2 = F I O 2 (Pb – 47) – PaCo 2 x F = P I O 2 – PaCo 2 = P I O 2 – PaCo 2 if breathing 100% O 2 R.Q

13 O 2 Cascade 149mm Hg (20.95 % of 713) O 2 consumption Lower Resp. Tract (moist 37 o c) Alv. ventilation Alveolar air 101mm Hg (14 % of 713) o r (15 % of 673) 673 = 760 – 47 – 40 P A O 2 = F I O 2 (Pb – 47) – PaCo 2 x F = P I O 2 – PaCo 2 = P I O 2 – PaCo 2 if breathing 100% O 2 R.Q

14 O 2 Cascade ? 101mm Hg (14 % of 713) o r (15 % of 673) 673 = 760 – 47 – 40 Alveolar air Arterial blood 97mm Hg P a O 2 = 100 – 0.3 x age (years) mm Hg A – a = 4 – 25 mmHg

15 O 2 Cascade Venous admixture 101mm Hg (14 % of 713) o r (15 % of 673) 673 = 760 – 47 – 40 Alveolar air Arterial blood 97mm Hg P a O 2 = 100 – 0.3 x age (years) mm Hg A – a = 4 – 25 mmHg

16 Venous admixture ( physiological shunt) O 2 Cascade Low VA/QNormal True shunt (normal anatomical shunt)

17 Venous admixture ( physiological shunt) O 2 Cascade Low VA/QNormal True shunt (normal anatomical shunt) Pulmonary (Bronchial veins) Extra Pulm. (Thebesian veins)

18 Venous admixture ( physiological shunt) O 2 Cascade Low VA/QNormal True shunt (normal anatomical shunt) Pulmonary (Bronchial veins) Extra Pulm. (Thebesian veins) Normal = upto 5 % of cardiac output

19 O 2 Cascade Venous admixture P A O 2 = 101mm Hg (14 % of 713) o r (15 % of 673) 673 = 760 – 47 – 40 Alveolar air Arterial blood P a O 2 = 97mm Hg P a O 2 = 100 – 0.3 x age (years) mm Hg A – a = 4 – 25 mmHg ? ?

20 O 2 Cascade Venous admixture P A O 2 = 101mm Hg (14 % of 713) o r (15 % of 673) 673 = 760 – 47 – 40 Alveolar air Arterial blood P a O 2 = 97mm Hg P a O 2 = 100 – 0.3 x age (years) mm Hg A – a = 4 – 25 mmHg P I O 2 P V O 2

21 O 2 Cascade Utilization by tissue Arterial blood P a O 2 = 97mm Hg (Sat. > 95 %) Mixed Venous blood P V O 2 = 40mm Hg Sat. 75% Cell Mitochondria PO 2 7 – 37 mmHg – The critical level for aerobic metab. to continue

22 O 2 Cascade Utilization by tissue Arterial blood P a O 2 = 97mm Hg (Sat. > 95 %) Mixed Venous blood P V O 2 = 40mm Hg Sat. 75% Cell Mitochondria PO 2 7 – 37 mmHg Pasteur point – The critical level for aerobic metab. to continue (1 – 2 mmHg PO 2 in mitochondria)

23 AB Hb 14gm (normal) 7gm (Anaemic) C.O. 5 L (normal) 4 L (Low) P a O 2 23 mm 60 mm O 2 Flux 375ml 350ml Which patient is better placed – ?

24 AB Hb 14gm (normal) 7gm (Anaemic) C.O. 5 L (normal) 4 L (Low) SPO 2 40 % 90 % P a O 2 23 mm 60 mm O 2 Flux 375ml 350ml Which patient is better placed – ? Min. gradient for O 2 transfer from cap. to cell (app. 20 mm Hg) = sat. 20 – 30% = 200 – 300ml O 2 flux Critical Level for O 2 delivery / critical O 2 flux Critical Level for O 2 delivery / critical O 2 flux

25 O 2 Cascade Utilization by tissue Arterial blood P a O 2 = 97mm Hg (Sat. > 95 %) Mixed Venous blood P V O 2 = 40mm Hg Sat. 75% Cell Mitochondria PO 2 7 – 37 mmHg Pasteur point – The critical level for aerobic metab. to continue (PO mmHg in mitochondria, 22mmHg in capillary)

26 O 2 Cascade Utilization by tissue Arterial blood P a O 2 = 97mm Hg (Sat. > 95 %) Mixed Venous blood P V O 2 = 40mm Hg Sat. 75% Cell Mitochondria PO 2 7 – 37 mmHg Pasteur point – The critical level for aerobic metab. to continue (PO mmHg in mitochondria, 22mmHg in capillary) ? ?

27 O 2 Cascade Utilization by tissue Arterial blood P a O 2 = 97mm Hg (Sat. > 95 %) Mixed Venous blood P V O 2 = 40mm Hg Sat. 75% Cell Mitochondria PO 2 7 – 37 mmHg Pasteur point – The critical level for aerobic metab. to continue (PO mmHg in mitochondria, 22mmHg in capillary) Perfusion O 2 content (Hb Conc.)

28 O 2 contentPer 100 ml Art. blood 14g x 1.39 x 100% = 20 ml Ven. blood 14g x 1.39 x 75% = 15ml Tissue extraction 25% = 5ml O 2 contentPer 100 ml Art. blood 14g x 1.39 x 100% = 20 ml Ven. blood 14g x 1.39 x 75% = 15ml Tissue extraction 25% = 5ml

29 O 2 contentPer 100 ml Art. blood 14g x 1.39 x 100% = 20 ml Ven. blood 14g x 1.39 x 75% = 15ml Tissue extraction 25% = 5ml 1% = 0.2ml Art. blood 7g x 1.39 x 100% = 10 ml Ven. blood 7g x 1.39 x 50% = 5ml Tissue extraction 50% = 5ml 1% = 0.1ml

30 PO 2 O 2 contentPer 100 ml 97mmArt. blood 14g x 1.39 x 100% = 20 ml 40mmVen. blood 14g x 1.39 x 75% = 15ml Tissue extraction 25% = 5ml 1% = 0.2ml 97mmArt. blood 7g x 1.39 x 100% = 10 ml ? Ven. blood 7g x 1.39 x 50% = 5ml Tissue extraction 50% = 5ml 1% = 0.1ml PO 2 O 2 contentPer 100 ml 97mmArt. blood 14g x 1.39 x 100% = 20 ml 40mmVen. blood 14g x 1.39 x 75% = 15ml Tissue extraction 25% = 5ml 1% = 0.2ml 97mmArt. blood 7g x 1.39 x 100% = 10 ml ? Ven. blood 7g x 1.39 x 50% = 5ml Tissue extraction 50% = 5ml 1% = 0.1ml

31 PO 2 O 2 contentPer 100 ml 97mmArt. blood 14g x 1.39 x 100% = 20 ml 40mmVen. blood 14g x 1.39 x 75% = 15ml Tissue extraction 25% = 5ml 1% = 0.2ml 97mmArt. blood 7g x 1.39 x 100% = 10 ml 27mmVen. blood 7g x 1.39 x 50% = 5ml Tissue extraction 50% = 5ml 1% = 0.1ml PO 2 O 2 contentPer 100 ml 97mmArt. blood 14g x 1.39 x 100% = 20 ml 40mmVen. blood 14g x 1.39 x 75% = 15ml Tissue extraction 25% = 5ml 1% = 0.2ml 97mmArt. blood 7g x 1.39 x 100% = 10 ml 27mmVen. blood 7g x 1.39 x 50% = 5ml Tissue extraction 50% = 5ml 1% = 0.1ml

32 Oxygen Therapy Indications

33 Oxygen Therapy Indications FIO2 FIO2 Barometric Pressure PIO2PIO2

34 Oxygen Therapy Indications F I O 2 - F I O 2 during anaes. - Rebreathing Barometric Pressure - High altitude PIO2PIO2

35 Oxygen Therapy Indications F I O 2 - F I O 2 during anaes. - Rebreathing Barometric Pressure - High altitude PIO2PIO2 PAO2PAO2 O 2 ConsumptionAlveolar Ventilation

36 Oxygen Therapy Indications F I O 2 - F I O 2 during anaes. - Rebreathing Barometric Pressure - High altitude PIO2PIO2 PAO2PAO2 O 2 Consumption -convulsions -thyrotoxicosis -shivering -pyrexia Alveolar Ventilation -resp. depression -Resp. muscle paresis - resp.effort (trauma) -airway obstruction

37 Oxygen Therapy Indications F I O 2 - F I O 2 during anaes. - Rebreathing Barometric Pressure - High altitude PIO2PIO2 PAO2PAO2 O 2 Consumption -convulsions -thyrotoxicosis -shivering -pyrexia (7 % / o C) Alveolar Ventilation -resp. depression -Resp. muscle paresis - resp.effort (trauma) -airway obstruction

38 Oxygen Therapy Indications Low VA/QNormal Anat. shunt PaO 2

39 Oxygen Therapy Indications Low VA/Q Abn. Pulmonary shunt - pneumonia -lobar atelectasis -ARDS Normal Anat. shunt Abn.extra Pulm. Shunt cong. heart disease (R L ) PaO 2

40 Oxygen Therapy Indications Low VA/Q Abn. Pulmonary shunt - pneumonia -lobar atelectasis -ARDS Normal Anat. shunt Abn.extra Pulm. Shunt cong. heart disease (R L ) PaO 2 Hypoxic hypoxia

41

42 Hypoxia due to hypoventilation Slight increase in O 2 conc. (Thus the importance of ventimask) Higher O 2 conc. – Simple Rule

43 Hypoxia due to hypoventilation Slight increase in O 2 conc. (Thus the importance of ventimask) Higher O 2 conc. – hypercapnoea – absence of cynosis Simple Rule

44

45 Oxygen Therapy Indications Low VA/Q Abn. Pulmonary shunt - pneumonia -lobar atelectasis -ARDS Normal Anat. shunt Abn.extra Pulm. Shunt cong. heart disease (R L ) PaO 2 Cell PO 2 Hb concentration Perfusion

46 Oxygen Therapy Indications Low VA/Q Abn. Pulmonary shunt - pneumonia -lobar atelectasis -ARDS Normal Anat. shunt Abn.extra Pulm. Shunt cong. heart disease (R L ) PaO 2 Cell PO 2 Hb concentration -Anaemia -CO poisoning Perfusion local - PVD, thrombosis gen – shock, Hypovol., card. Failure cardiac arrest

47 AB Anaemic patientPatient with Hb 14gm% Hb = 7gm % Normal Hb 7gm% Hb Co 7gm% Which patient is better placed – ?

48 AB Anaemic patientPatient with Hb 14gm% Hb = 7gm % Normal Hb 7gm% Hb Co 7gm% 2,3 DPG Shift to RShift to L unloading of O 2 unloading of O 2(blood tissue) P V O 2 – ?P V O 2 – ? Which patient is better placed – ?

49 AB Anaemic patientPatient with Hb 14gm% Hb = 7gm % Normal Hb 7gm% Hb Co 7gm% 2,3 DPG Shift to RShift to L unloading of O 2 unloading of O 2(blood tissue) P V O 2 – 27 mm HgP V O 2 – ? Which patient is better placed – ?

50 AB Anaemic patientPatient with Hb 14gm% Hb = 7gm % Normal Hb 7gm% Hb Co 7gm% 2,3 DPG Shift to RShift to L unloading of O 2 unloading of O 2(blood tissue) P V O 2 – 27 mm HgP V O 2 – 14mmHg Which patient is better placed – ?

51 Hypoxia in co poisoning is out of proportion to degree of anemia

52 AB Anaemic patientPatient with Hb 14gm% Hb = 7gm % Normal Hb 7gm% Hb Co 7gm% 2,3 DPG Shift to RShift to L unloading of O 2 unloading of O 2(blood tissue) P V O 2 – 27 mm HgP V O 2 – 14mmHg Cardiac Output Which patient is better placed – ?

53 Dissolved O 2 in plasma 0.003ml / 100ml of blood / mm PO 2 Breathing Air (P a O 2 100mm Hg) 0.3ml / 100ml of blood

54 Dissolved O 2 in plasma 0.003ml / 100ml of blood / mm PO 2 Breathing Air (P a O 2 100mm Hg) 0.3ml / 100ml of blood Breathing 100% O 2

55 Dissolved O 2 in plasma 0.003ml / 100ml of blood / mm PO 2 Breathing Air (P a O 2 100mm Hg) 0.3ml / 100ml of blood Breathing 100% O 2 (P a O 2 600mm Hg) 1.8ml / 100ml of blood

56 Dissolved O 2 in plasma 0.003ml / 100ml of blood / mm PO 2 Breathing Air (P a O 2 100mm Hg) 0.3ml / 100ml of blood Breathing 100% O 2 (P a O 2 600mm Hg) 1.8ml / 100ml of blood Breathing 100% O2 at 3 Atm. Pressure

57 Dissolved O 2 in plasma 0.003ml / 100ml of blood / mm PO 2 Breathing Air (P a O 2 100mm Hg) 0.3ml / 100ml of blood Breathing 100% O 2 (P a O 2 600mm Hg) 1.8ml / 100ml of blood Breathing 100% O2 at 3 Atm. Pressure 5.4ml / 100ml of blood

58 Dissolved O 2 in plasma 0.003ml / 100ml of blood / mm PO 2 Breathing Air (P a O 2 100mm Hg) 0.3ml / 100ml of blood Breathing 100% O 2 (P a O 2 600mm Hg) 1.8ml / 100ml of blood Breathing 100% O2 at 3 Atm. Pressure 5.4ml / 100ml of blood Basis of Hyperbaric O 2 therapy

59 Benefit of O 2 therapy in Hypoxia Hypoxic hypoxia (gas phase) Anaemic hypoxia (fluid phase – const.)+ Stagnant hypoxia (fluid phase – flow)+ Histotoxic hypoxia (tissue phase)-

60 Benefit of O 2 therapy in Hypoxia Hypoxic hypoxia (gas phase) Anaemic hypoxia (fluid phase – const.)+ Stagnant hypoxia (fluid phase – flow)+ Histotoxic hypoxia (tissue phase)- Normal Person (breathing 100% O 2 ) 14gm x 1.34ml = 18.7ml + 1.8ml = 20.5ml (1.8 is 9% 20.5)

61 Benefit of O 2 therapy in Hypoxia Hypoxic hypoxia (gas phase) Anaemic hypoxia (fluid phase – const.)+ Stagnant hypoxia (fluid phase – flow)+ Histotoxic hypoxia (tissue phase)- Normal Person (breathing 100% O 2 ) 14gm x 1.34ml = 18.7ml + 1.8ml = 20.5ml (1.8 is 9% 20.5) Anaemic patient (breathing 100% O 2 ) 4gm x 1.34ml = 5.4ml + 1.8ml = 7.2 ml (1.8 is 25% of 7.2)

62 Physical effects of O 2 Oxygen Therapy Indications

63 Physical effects of O 2 “Air in the body – where it should not be” Oxygen Therapy Indications

64 Physical effects of O 2 “Air in the body – where it should not be” Surgical emphysema Pneumothorax Air embolism Bowel decompression Oxygen Therapy Indications

65 mmHg Art. bloodVen. blood Breathing air PO PCo P N Breathing 100% O 2 PO 2 600? PCo P N 2 00 Gas Tensions

66 mmHg Art. bloodVen. blood Breathing air PO PCo P N Breathing 100% O 2 PO PCo P N 2 00 Gas Tensions

67 Tissue requirement per 100ml = 5ml Dissolved Fraction = 1.8 ml Balance = 3.2 ml 0.2ml x 16% = 3.2ml 84% saturation = PO 2 50mm Hg

68 Pre oxygenation / ? Oxygen Therapy Indications

69 Pre oxygenation / denitrogenation To the O 2 reserve in the body – ? Oxygen Therapy Indications

70 O 2 stores in the body Breathing air Breathing 100% O 2 Lungs (FRC)450 ml3000 ml Blood1000 ml1090 ml Tissue fluids / myoglobin++

71 O 2 Delivery systems

72 Ambient pressure – Variable performance devices – Fixed performance devices

73 O 2 Delivery systems Ambient pressure – Variable performance devices – Fixed performance devices Positive pressure ventilation – Non invasive (BIPAP, CPAP) – Invasive

74 O 2 Delivery systems Ambient pressure – Variable performance devices – Fixed performance devices Positive pressure ventilation – Non invasive (BIPAP, CPAP) – Invasive ECMO

75 O 2 Delivery systems Ambient pressure – Variable performance devices (Pt. dependent) low flow No capacity system – no rebreathing nasal catheter / cannulae Capacity system – chance of rebreathing –Small – (mass shell only) –Large – (with reservoir bag) – Fixed performance devices (Pt. independent) high flow HAFOE (ventimask) Anaesthesia circuits

76 High flow system The gas flow is sufficient to meet all inspiratory requirement Low flow system The gas flow is insufficient to meet all inspiratory requirement. Part of tidal volume is provided by room air.

77 Variables O 2 flow rate Patient factors – Device factors –

78 Variables O 2 flow rate Patient factors – Inspiratory flow rate – Expiratory time (active exp. flow + exp. pause) Device factors –

79 Variables O 2 flow rate Patient factors – Inspiratory flow rate – Expiratory time (active exp. flow + exp. pause) Device factors – Physical volume (capacity) – Vent resistance (tight fit)

80 Variable + = – = No cap. Devices Capacity devices FIO2FIO2FIO2 F I CO 2 O 2 flow rate+ – Patient Factors Insp. Flow rate + – Exp. time + – Device Factors Physical volume + – Vent resistance + –

81 Variable + = – = No cap. Devices Capacity devices FIO2FIO2FIO2 F I CO 2 O 2 flow rate+ – Patient Factors Insp. Flow rate + – Exp. time + – Device Factors Physical volume + – Vent resistance + –

82 Variable + = – = No cap. Devices Capacity devices FIO2FIO2FIO2 F I CO 2 O 2 flow rate+ – Patient Factors Insp. Flow rate + – Exp. time + – Device Factors Physical volume + – Vent resistance + –

83 Variable + = – = No cap. Devices Capacity devices FIO2FIO2FIO2 F I CO 2 O 2 flow rate+ – Patient Factors Insp. Flow rate + – Exp. time + – Device Factors Physical volume + – Vent resistance + –

84 Variable + = – = No cap. Devices Capacity devices FIO2FIO2FIO2 F I CO 2 O 2 flow rate+ – Patient Factors Insp. Flow rate + – Exp. time + – Device Factors Physical volume + – Vent resistance + –

85 Variable + = – = No cap. Devices Capacity devices FIO2FIO2FIO2 F I CO 2 O 2 flow rate+ – Patient Factors Insp. Flow rate + – Exp. time + – Device Factors Physical volume + – Vent resistance + –

86 Variable + = – = No cap. Devices Capacity devices FIO2FIO2FIO2 F I CO 2 O 2 flow rate+ – Patient Factors Insp. Flow rate + – Exp. time + – Device Factors Physical volume + – Vent resistance + –

87 Variable + = – = No cap. Devices Capacity devices FIO2FIO2FIO2 F I CO 2 O 2 flow rate+ – Patient Factors Insp. Flow rate + – Exp. time + – Device Factors Physical volume + – Vent resistance + –

88

89

90

91 Nasal Catheter O 2 Flowrate (L/min) Fi O

92 Normal Anatomic Reservoir (50ml) 6 Ltr/min = 100ml/sec = 50ml/1/2 Sec

93 Nasal Catheter Merits Easy to fix Keeps hands free Not much interference with further airway care Useful in both spont. breathing and apnoeic

94

95

96 10-15 Ltr/min flow rate % O 2 conc.

97 Nasal Catheter Merits Easy to fix Keeps hands free Not much interference with further airway care Useful in both spont. breathing and apnoeic Small but definite rise in FiO 2 (dose not critical) Demerits Mucosal irritation (uncomfortable) Gastric dilatation (especially with high flows)

98

99

100

101 For higher O 2 Concentration gadgets with storage capacity (reservoir) problem of re-breathing minimized / avoided by higher flows

102 Simple face mask Simple Face Mask – ?

103 Simple face mask NO YES Simple Face Mask

104 Simple face mask O 2 Flowrate (L/min) Fi O

105 Partial Rebreathing mask (polymask)

106

107 O 2 Flowrate (L/min) Fi O

108 Poly mask What type of circuit it is – ?

109 Poly mask What type of circuit it is – ? Modified T – Piece

110 Non Rebreathing mask Non Rebreathing Mask

111

112 10 – 15 Ltr/min flow rate – O 2 conc.

113 Face Masks Merits Higher Oxygen Conc. Demerits Rebreathing (if O 2 flow is inadequate) Interfere with further airway care Proper fitting is required Uncomfortable (sweating, spitting)

114 Bag – Valve – Mask assembly (Ambu Resuscitator)

115

116 Delivers O 2 during BOTH spont. & artf. Vent O 2 concentration –30 – 50% (without reservoir) –80 – 100% (with reservoir) To deliver 100% O 2

117 Bag – Valve – Mask assembly (Ambu Resuscitator) Delivers O 2 during BOTH spont. & artf. Vent O 2 concentration –30 – 50% (without reservoir) –80 – 100% (with reservoir) To deliver 100% O 2 –Reservoir – as large as bag vol –O 2 flow rate > minute volume (10 l/m)  Drawback – keeps rescuer’s hands engaged

118

119 Pocket Mask Delivers O 2 in BOTH spont. & aponeic Allows use of both hands – for maintaining airway Upto 4 ltr reserve vol. (rescuer’s vital capacity) O 2 Flowrate (L/min) Fi O (Spont.) 0.54 (M - mask)

120 Incubator Small infants – not on ventilator Works on venturi principle Complete air change – 10 times / hour Control of humidity & temperature O 2 conc. falls rapidly when access ports are open

121 O 2 tents For children – not tolerating mask / catheter Large capacity system Upto 50% O 2 concentration Large tent cap. and leak port – limited CO 2 build up.  Disadvantage – Limited access – Risk of fire – Conflict in O 2 therapy / nursing care

122 Can You name the device ? Written over it – 28 4 L P M – ? If flow is doubled (8 LPM) – what will the %age of O 2 delivered by the device ? If flow is halved 2 LPM) – what will be the %age of O 2 received by the patient ? What is the likely entertainment ratio of this device ? What precaution to be taken for humidification of gases while using this device ?

123

124 Works on principle of constant pressure jet – mixture. O 2 jet entrains air as per entrain. ratio. Total flow > PIFR (30 – 35 L/min) Eliminates the problem of dead space & leak free connection.

125 Ventimask

126 Simple face mask NO YES Simple Face Mask

127 Works on principle of constant pressure jet – mixture. O 2 jet entrains air as per entrain. ratio. Total flow > PIFR (30 – 35 L/min) Eliminates the problem of dead space & leak free connection. Upper limit is 60 %. Humidification of O 2 supply is not sensible.

128

129 If conc. of O 2 which a patient is getting is not known then the situation is similar to a drug being administered without knowing the dose which can do harm if given more or provide insufficient effect if given less

130 100% - not more than 12hrs 80% - not more than 24hrs 60% - not more than 36hrs O 2 Toxicity

131 Rest (read it yourself)

132


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