Oxygen transport & odc

OXYGEN TRANSPORTOXYGEN TRANSPORT
&&
OXYGEN DISSOCIATION CURVEOXYGEN DISSOCIATION CURVE
Dr Gopal Krishna NayakDr Gopal Krishna Nayak
22ndnd
Year, PG Department Of AnesthesiologyYear, PG Department Of Anesthesiology
MKCG Medical College, BerhampurMKCG Medical College, Berhampur

Hemoglobin is the main carrier of oxygen. Each gram of
hemoglobin can carry 1.34ml of oxygen. This means that
with a hemoglobin concentration of 15g/dl, the O2
content is approximately 20ml/100ml. With a normal
cardiac output of 5l/min, the delivery of oxygen to the
tissues at rest is approximately 1000 ml/min: a huge
physiologic reserve.
Hemoglobin has 4 binding sites for oxygen, and if all of
these in each hemoglobin molecule were to be occupied,
then the oxygen capacity would be filled or saturated.
This is rarely the case: under normal conditions, the
hemoglobin is 97% to 98% saturated. The amount of
oxygen in the blood is thus related to the oxygen
saturation of hemoglobin.

Composition of AirComposition of Air
•The air around us has a total pressure ofThe air around us has a total pressure of
101kPa ( 1 atmosphere of pressure = 760101kPa ( 1 atmosphere of pressure = 760
mmHg = 101kPa)mmHg = 101kPa)

Oxygen, HistoryOxygen, History
• It was first prepared by Joshep Pristly (1774)
and called it as DEPHLOGISTICATED AIR

IntroductionIntroduction
It is tasteless, ordorlessIt is tasteless, ordorless
Supports combustionSupports combustion
Critical temperature is -118.6 °CCritical temperature is -118.6 °C
Can be stored as a liquid or gasCan be stored as a liquid or gas
Stored in cylinders or bulk supply systemsStored in cylinders or bulk supply systems
Used in the home with concentratorsUsed in the home with concentrators
Is a FDA drug, must be at least 99% pure,Is a FDA drug, must be at least 99% pure,
prescribed by a MD and approved byprescribed by a MD and approved by
insurance before use by a pulmonary stressinsurance before use by a pulmonary stress
testtest

More About OxygenMore About Oxygen
 Oxygen FlushOxygen Flush: Amount of O2 leaving Left: Amount of O2 leaving Left
ventricle/ min It is 1000 ml/ minventricle/ min It is 1000 ml/ min
 Heliox (He 79 % + O2 21%) & Entenox (50 %O2+Heliox (He 79 % + O2 21%) & Entenox (50 %O2+
50 % N2O)50 % N2O)
 1 gram of Hb carry 1.34 ml of O21 gram of Hb carry 1.34 ml of O2
 O2 content of Arterial blood is 20ml/dl and forO2 content of Arterial blood is 20ml/dl and for
venous is 15ml/dlvenous is 15ml/dl
 O2 cylinders are made of Molybdenum steel.O2 cylinders are made of Molybdenum steel.

 1 ml of liquid O2 gives 840 ml of gases.1 ml of liquid O2 gives 840 ml of gases.
 Medical oxygen is stored in Cylinders (EMedical oxygen is stored in Cylinders (E
Types) having Black body with White shoulderTypes) having Black body with White shoulder
and PIN Index 2,5 with a pressure of 2000and PIN Index 2,5 with a pressure of 2000
psi (pounds per square inch)psi (pounds per square inch)
 The delivery of oxygen to the tissues per minute is
calculated from: DO2 = [1.34 x Hb x SaO2 +
(0.003 x PaO2)] x Q.
 oxygen content of blood where the PO2 is 100mmHg,
and the hemoglobin concentration is 15g/L:
[1.34 x Hb x (saturation/100)] + 0.003 x PO2 =
20.8ml

Oxygen saturation can be clinically determined by Pulse
Oxymeter.

Sources of oxygen in medicalSources of oxygen in medical

Oxygen failure protection devicesOxygen failure protection devices

Oxygen delivery devicesOxygen delivery devices

Principal stores of Oxygen in our BodyPrincipal stores of Oxygen in our Body

OXYGEN SATURATION &OXYGEN SATURATION &
CAPACITYCAPACITY
 Ratio of oxygen bound to Hb compared toRatio of oxygen bound to Hb compared to
total amount that can be bound istotal amount that can be bound is
Oxygen SaturationOxygen Saturation
 Maximal amount of O2 bound to Hb isMaximal amount of O2 bound to Hb is
defined as thedefined as the Oxygen CapacityOxygen Capacity

ARTERIAL O2 CONTENTARTERIAL O2 CONTENT
 O2 CONTENT -O2 CONTENT -
The sum of O2 carried on Hb and dissolved inThe sum of O2 carried on Hb and dissolved in
plasma.plasma.
 CaO2 (ml/dL) = (SaO2 x Hb x 1.34) + (PO2 x0.003)CaO2 (ml/dL) = (SaO2 x Hb x 1.34) + (PO2 x0.003)
 O2 content in 100 ml blood (in normal adult with HbO2 content in 100 ml blood (in normal adult with Hb
15 gm/dl) ~ 20 ml/dl15 gm/dl) ~ 20 ml/dl
(19.4 ml as Oxy Hb + 0.3 ml in plasma)(19.4 ml as Oxy Hb + 0.3 ml in plasma)

Venous O2 content (CvO2)Venous O2 content (CvO2)
 CvO2 =(SvO2 x Hb x 1.34) + (PvO2 x 0.003)CvO2 =(SvO2 x Hb x 1.34) + (PvO2 x 0.003)
Normally - 15ml/dl.Normally - 15ml/dl.
 Mixed venous saturation (SvO2 ) measured in the PulMixed venous saturation (SvO2 ) measured in the Pul
Artery represents the pooled venous saturation fromArtery represents the pooled venous saturation from
all organs.all organs.
 Normally, the SvO2 is about 75%, however, clinicallyNormally, the SvO2 is about 75%, however, clinically
an SvO2 of about 65% is acceptablean SvO2 of about 65% is acceptable

TOTAL O2 DELIVERYTOTAL O2 DELIVERY
 DO2 (ml/min) = Cardiac Output x CaO2 x 10DO2 (ml/min) = Cardiac Output x CaO2 x 10
 DO2 = COx Hb x SaO2 x 1.34 x 10DO2 = COx Hb x SaO2 x 1.34 x 10
 Q=Cardiac Output and multiplier of 10 is used toQ=Cardiac Output and multiplier of 10 is used to
convert CaO2 from ml/dl to ml/L)convert CaO2 from ml/dl to ml/L)
 N =(900-1,100 ml/min)N =(900-1,100 ml/min)
 Decreased oxygen delivery occurs when there is:Decreased oxygen delivery occurs when there is:
↓↓ed cardiac outputed cardiac output
ed hemoglobin concentration↓ed hemoglobin concentration↓
↓↓ed blood oxygenationed blood oxygenation

O2 CONSUMPTIONO2 CONSUMPTION
 The amount of oxygen extracted by the peripheralThe amount of oxygen extracted by the peripheral
tissues during the period of one minute is calledtissues during the period of one minute is called
oxygen consumption or VO2.oxygen consumption or VO2.
(N- 200-300ml/min)(N- 200-300ml/min)
 VO2 = Cardiac Output x (CaO2 - CvO2) x 10VO2 = Cardiac Output x (CaO2 - CvO2) x 10
 VO2 = Q x 1.34 x Hb x (SaO2-SvO2) x 10VO2 = Q x 1.34 x Hb x (SaO2-SvO2) x 10
 O2 consumption is commonly indexed by the patientsO2 consumption is commonly indexed by the patients
body surface area (BSA) and calculated by: VO2 /body surface area (BSA) and calculated by: VO2 /
BSABSA
 Normal VO2 index is between 110-160ml/min/m2Normal VO2 index is between 110-160ml/min/m2

OXYGEN EXTRACTION RATIOOXYGEN EXTRACTION RATIO
 The oxygen extraction ratio (O2ER) is the amount ofThe oxygen extraction ratio (O2ER) is the amount of
oxygen extracted by the peripheral tissues dividedoxygen extracted by the peripheral tissues divided
by the amount of O2 delivered to the peripheral cells.by the amount of O2 delivered to the peripheral cells.
Also known As:Also known As: Oxygen coefficient ratio &Oxygen coefficient ratio &
Oxygen utilization ratio.Oxygen utilization ratio.
 Index of efficiency of O2 transport :O2ER = VO2 /Index of efficiency of O2 transport :O2ER = VO2 /
DO2 ( Oxygen consumption / Oxygen Delivery)DO2 ( Oxygen consumption / Oxygen Delivery)
 Normally ~ 25% but increases to 70-80% duringNormally ~ 25% but increases to 70-80% during
maximal exercise in well trained athletesmaximal exercise in well trained athletes

FACTORS THAT AFFECTFACTORS THAT AFFECT
O2ERO2ER
 Increased withIncreased with::
Decreased CODecreased CO
Increased VO2Increased VO2
ExerciseExercise
SeizuresSeizures
ShiveringShivering
HyperthermiaHyperthermia
AnemiaAnemia
Low PaO2Low PaO2
 Decreased withDecreased with::
Increased Cardiac OutputIncreased Cardiac Output
Skeletal Muscle RelaxationSkeletal Muscle Relaxation
Peripheral Shunting, Certain Poisons, Hypothermia, IncreasedPeripheral Shunting, Certain Poisons, Hypothermia, Increased
Hemoglobin, Increased PaO2Hemoglobin, Increased PaO2

What is the Oxygen Cascade?What is the Oxygen Cascade?
 The oxygen cascade describes the process of
declining oxygen tension from atmosphere to
mitochondria
 The purpose of the cardio-respiratory system is toThe purpose of the cardio-respiratory system is to
extract oxygen from the atmosphere and deliver it toextract oxygen from the atmosphere and deliver it to
the mitochondria of cells. Oxygen, being a gas, exertsthe mitochondria of cells. Oxygen, being a gas, exerts
a partial pressure, which is determined by thea partial pressure, which is determined by the
prevailing environmental pressure. At sea level, theprevailing environmental pressure. At sea level, the
atmospheric pressure is 760mmHg, and oxygen makesatmospheric pressure is 760mmHg, and oxygen makes
up 21% of inspired air: so oxygen exerts a partialup 21% of inspired air: so oxygen exerts a partial
pressure of 760 x 0.21 = 159mmHg.pressure of 760 x 0.21 = 159mmHg.
 This is the starting point of the oxygen cascade, asThis is the starting point of the oxygen cascade, as
one moves down through the body to the cell, oxygenone moves down through the body to the cell, oxygen
is diluted down, extracted or otherwise lost, so thatis diluted down, extracted or otherwise lost, so that
at cellular level the POat cellular level the PO22 may only be 3 or 4mmHg.may only be 3 or 4mmHg.

KEY STEPS IN OXYGEN CASCADEKEY STEPS IN OXYGEN CASCADE
 Uptake in the lungsUptake in the lungs
 Carrying capacity of bloodCarrying capacity of blood
 Delivery to capillariesDelivery to capillaries
 Delivery to interstitiumDelivery to interstitium
 Delivery to individual cellsDelivery to individual cells
 Cellular use of oxygenCellular use of oxygen

Four factors influence transmissionFour factors influence transmission
of oxygen from the alveoli to theof oxygen from the alveoli to the
capillariescapillaries
1. Ventilation perfusion mismatch
2. Right to left shunt
3. Diffusion defects
4. Cardiac output.

UPTAKE IN THE LUNGS FROM ATMOSPHEREUPTAKE IN THE LUNGS FROM ATMOSPHERE
 The alveolar partial pressure of oxygen PAO2 can be calculatedThe alveolar partial pressure of oxygen PAO2 can be calculated
from the following equationfrom the following equation: PAO2 = FIO2 – PaCO2/R. R is the
respiratory quotient ( 0.8 ), ( Vol of CO2/ Vol Of O2)
 The Alveolar Air Equation, represents the partial pressure ofThe Alveolar Air Equation, represents the partial pressure of
oxygen in alveolar air at the prevailing barometric pressureoxygen in alveolar air at the prevailing barometric pressure
after accounting for the vapor pressure of water with whichafter accounting for the vapor pressure of water with which
tracheal air becomes saturated at body temperature .tracheal air becomes saturated at body temperature .
 It defines the oxygen partial pressure in the steady stateIt defines the oxygen partial pressure in the steady state
accounting for oxygen extracted and CO2 added by theaccounting for oxygen extracted and CO2 added by the
respiratory gas exchange. This is the oxygen partial pressurerespiratory gas exchange. This is the oxygen partial pressure
with which blood in the pulmonary capillaries equilibrates duringwith which blood in the pulmonary capillaries equilibrates during
its rapid transit through the capillary.its rapid transit through the capillary.
 Approximate normal value ofApproximate normal value of pAO2 is 104 mm Hg.

GAS DIFFUSION PRINCIPLEGAS DIFFUSION PRINCIPLE
 The Fick equation of diffusion ofThe Fick equation of diffusion of
a gas in a liquid medium describesa gas in a liquid medium describes
the determinants of the oxygenthe determinants of the oxygen
flux asflux as
V = A * D * P1-P2/d where,V = A * D * P1-P2/d where,
A is the area available forA is the area available for
diffusion;diffusion;
D is the diffusion constant forD is the diffusion constant for
the gas(the gas( D= 1 for O2 and D = 20D= 1 for O2 and D = 20
for CO2) ;for CO2) ;
P1-P2 is the gas partialP1-P2 is the gas partial
pressure difference;pressure difference;
d is the diffusion distance,d is the diffusion distance,
 Thus DP/d is the partial pressureThus DP/d is the partial pressure
gradient.gradient.
 Normal O2 diffusionNormal O2 diffusion
capacity at alveolo-capacity at alveolo-
capillary membrane is 25capillary membrane is 25
ml/min/mmHgml/min/mmHg

UPTAKE OF O2 BY PULMONARY CAPILLARYUPTAKE OF O2 BY PULMONARY CAPILLARY
BLOODBLOOD
 Alveolar PO2 = 104 mmHgAlveolar PO2 = 104 mmHg
 Pulmonary Arterial PO2 = 40 mmHgPulmonary Arterial PO2 = 40 mmHg
 Difference =>Difference => 104-40 = 64 mmHg104-40 = 64 mmHg
 Therefore, along the Pressure Gradient, O2Therefore, along the Pressure Gradient, O2
diffuses through the Alveolo-Capillarydiffuses through the Alveolo-Capillary
Membrane causing a rapid rise in PO2 as bloodMembrane causing a rapid rise in PO2 as blood
passes through the capillaries and becomespasses through the capillaries and becomes
equal to alveolar PO2.equal to alveolar PO2.
 Thus, Pulmonary Venous PO2 =104mmHgThus, Pulmonary Venous PO2 =104mmHg

TRANSPORT OF OXYGEN IN THE ARTERIALTRANSPORT OF OXYGEN IN THE ARTERIAL
BLOODBLOOD
 98% of blood enters the left Atrium98% of blood enters the left Atrium
Oxygenated up to a PO2 of about 104 mmHgOxygenated up to a PO2 of about 104 mmHg
 Shunt Flow: 2 percent >> Shunt FlowShunt Flow: 2 percent >> Shunt Flow
 Venous admixture of blood >> PO2 change 104Venous admixture of blood >> PO2 change 104
to 95 mmHgto 95 mmHg

PULMONARY SHUNTINGPULMONARY SHUNTING
 SHUNTING = PERFUSION WITHOUTSHUNTING = PERFUSION WITHOUT
VENTILATIONVENTILATION
 Pulmonary shunt is that portion of the cardiac outputPulmonary shunt is that portion of the cardiac output
that enters the left side of the heart without comingthat enters the left side of the heart without coming
in contact with an alveolus.in contact with an alveolus.
 ““True” ShuntTrue” Shunt – No contact– No contact
 Anatomic shuntsAnatomic shunts (Thebesian, Pleural, and Bronchial(Thebesian, Pleural, and Bronchial
Veins)Veins)
 ““Shunt-Like” (Relative) ShuntShunt-Like” (Relative) Shunt
Some ventilation, but not enough to allow forSome ventilation, but not enough to allow for
complete equilibration between alveolar gas andcomplete equilibration between alveolar gas and
perfusion.perfusion.
Shunts are refractory to oxygen
therapy

VENOUS ADMIXTUREVENOUS ADMIXTURE
 Venous admixture is the mixing of shunted,Venous admixture is the mixing of shunted,
non-reoxygenatednon-reoxygenated blood withblood with reoxygenatedreoxygenated
blood distal to the alveoli resulting in ablood distal to the alveoli resulting in a
reduction in:reduction in:
–– PaO2PaO2
–– SaO2SaO2
 Normal Shunt: 3 to 5%Normal Shunt: 3 to 5%
 Shunts above 15% are associated withShunts above 15% are associated with
significant hypoxemia.significant hypoxemia.

EFFECT OF VENOUS ADMIXTUREEFFECT OF VENOUS ADMIXTURE

DIFFUSION OF O2 FROM PERIPHERALDIFFUSION OF O2 FROM PERIPHERAL
CAPILLARIES TO THE CELLSCAPILLARIES TO THE CELLS
 O2 is constantly used by the cells, and thereby PO2 inO2 is constantly used by the cells, and thereby PO2 in
peripheral tissue cells remains lower in the peripheral capillariesperipheral tissue cells remains lower in the peripheral capillaries
at the venous end. The arterial PO2 of 95 mmHg is thus reducedat the venous end. The arterial PO2 of 95 mmHg is thus reduced
to PO2 of around 40mmHg at the venous end of the capillaries.to PO2 of around 40mmHg at the venous end of the capillaries.
 There is considerable distance between capillaries and cells .There is considerable distance between capillaries and cells .
Therefore, cellular PO2 ranges b/w 5-40mmHg (averageTherefore, cellular PO2 ranges b/w 5-40mmHg (average
23mmHg).23mmHg).
 Only 1-3mmHg of O2 pressure normally required for full supportOnly 1-3mmHg of O2 pressure normally required for full support
of chemical processes that incorporates O2 in the cellof chemical processes that incorporates O2 in the cell..
{PASTEUR POINT– Critical mitochondrial PO2{PASTEUR POINT– Critical mitochondrial PO2
below which aerobic metabolism cannot occur.below which aerobic metabolism cannot occur.
Normally it ranges from 1.4 to 2.3 mm Hg}Normally it ranges from 1.4 to 2.3 mm Hg}
 Low intracellular PO2 of 23 mmHg is enough and provides largeLow intracellular PO2 of 23 mmHg is enough and provides large
safety factor.safety factor.

DIFFUSION OF O2 FROM PERIPHERALDIFFUSION OF O2 FROM PERIPHERAL
CAPILLARIES IN TO TISSUE FLUIDCAPILLARIES IN TO TISSUE FLUID

OXYGEN UTILIZATIONOXYGEN UTILIZATION
 Arterial BloodArterial Blood
- 100 ml of blood combines with 19.4ml of O2- 100 ml of blood combines with 19.4ml of O2
––Po2 95 mmHgPo2 95 mmHg
––%Hb saturation 97%%Hb saturation 97%
 Venous BloodVenous Blood
- 100 ml of blood combines with 14.4ml of O2- 100 ml of blood combines with 14.4ml of O2
––Po2 40 mmHgPo2 40 mmHg
––% Hb saturation 75%% Hb saturation 75%
 Thus,Thus, 5ml of O2 is transported by each 100 ml of
blood through tissues per cycle(250 ml/5L/ min)

Summary of Gas Exchange andSummary of Gas Exchange and
TransportTransport

THE OXYGEN DISSOCIATION CURVE(ODC)THE OXYGEN DISSOCIATION CURVE(ODC)

The flat upper portion means that even if PO2
fall somewhats, loading of O2 wont be affected
much.

CHARACTERISTICS OF THE CURVECHARACTERISTICS OF THE CURVE
 Sigmoid Shaped Curve.Sigmoid Shaped Curve.
 The amount of oxygen that is saturated onThe amount of oxygen that is saturated on
the hemoglobin (SO2) is dependent on thethe hemoglobin (SO2) is dependent on the
amount dissolved (PO2).amount dissolved (PO2).
 Amount of O2 carried by Hb rises rapidly upAmount of O2 carried by Hb rises rapidly up
to PO2 of 60mmHg(Steep Slope) but aboveto PO2 of 60mmHg(Steep Slope) but above
that curve becomes flatter(Flat Slope).that curve becomes flatter(Flat Slope).
 Combination OfCombination Of 1st Heme with O2 increases
affinity of 2nd
Heme for the 2nd
O2 and so on.
It is known as “Positive Co-Operativity”.

THE “P50”THE “P50”
 A common point of reference on the oxygenA common point of reference on the oxygen
dissociation curve is the P50.dissociation curve is the P50.
 The P50 represents the partial pressure atThe P50 represents the partial pressure at
which the hemoglobin is 50% saturated withwhich the hemoglobin is 50% saturated with
oxygen, typically 26.6 mm Hg in adults.oxygen, typically 26.6 mm Hg in adults.
 The P50 is a conventional measure ofThe P50 is a conventional measure of
hemoglobin affinity for oxygen.hemoglobin affinity for oxygen.

SHIFTS IN THE P50SHIFTS IN THE P50
 In the presence of disease or other conditions thatIn the presence of disease or other conditions that
change the hemoglobin’s oxygen affinity and,change the hemoglobin’s oxygen affinity and,
consequently, shift the curve to the right or left, theconsequently, shift the curve to the right or left, the
P50 changes accordingly.P50 changes accordingly.
 An increased P50 indicates a rightward shift of theAn increased P50 indicates a rightward shift of the
standard curve, which means that a larger partialstandard curve, which means that a larger partial
pressure is necessary to maintain a 50% oxygenpressure is necessary to maintain a 50% oxygen
saturation, indicating a decreased affinity.saturation, indicating a decreased affinity.
 Conversely, a lower P50 indicates a leftward shift andConversely, a lower P50 indicates a leftward shift and
a higher affinitya higher affinity

FACTORS AFFECTING ODCFACTORS AFFECTING ODC

Left shift Vs Right shiftLeft shift Vs Right shift
Right shift decrease the loading of oxygen onto Hb at the Alveolo-Capillary membrane. Right shift curvesRight shift decrease the loading of oxygen onto Hb at the Alveolo-Capillary membrane. Right shift curves
enhance the unloading of oxygen at the tissue level.enhance the unloading of oxygen at the tissue level.
Left shift curves enhance the loading capability of oxygen at the Alveolo-Capillary membrane. Left shiftLeft shift curves enhance the loading capability of oxygen at the Alveolo-Capillary membrane. Left shift
curves decreases the unloading of oxygen at the tissue levelcurves decreases the unloading of oxygen at the tissue level

FACTORS AFFECTING DISSSOCIATIONFACTORS AFFECTING DISSSOCIATION

HEMOGLOBIN ,MYOGLOBIN & HbFHEMOGLOBIN ,MYOGLOBIN & HbF
Myoglobin is single chained heme pigment found in skeletal muscle.Myoglobin is single chained heme pigment found in skeletal muscle.
Myoglobin has an increased affinity for O2 (binds O2 at lower Po2)Myoglobin has an increased affinity for O2 (binds O2 at lower Po2)
Mb stores O2 temporarily in muscles & acts as a reserve in muscles, which canMb stores O2 temporarily in muscles & acts as a reserve in muscles, which can
be used during exercisebe used during exercise

FETAL HEMOGLOBINFETAL HEMOGLOBIN
 It has no Beta chain.It has no Beta chain.
 It has more affinity to Oxygen than theIt has more affinity to Oxygen than the
Adult Hemoglobin.Adult Hemoglobin.
 This helps the fetus to extract Oxygen fromThis helps the fetus to extract Oxygen from
the maternal bloodthe maternal blood

ROLE OF 2,3-DPGROLE OF 2,3-DPG

 2,3 DPG is an organic phosphate normally found in the2,3 DPG is an organic phosphate normally found in the
RBC.RBC.
 Produced during Anaerobic glycolysis in RBCS.Produced during Anaerobic glycolysis in RBCS.
 2,3 DPG has a tendency to bind to β chains of Hb and2,3 DPG has a tendency to bind to β chains of Hb and
thereby decrease the affinity of Hemoglobin forthereby decrease the affinity of Hemoglobin for
oxygen.oxygen.
 HbO2 + 2,3 DPG Hb-2,3 DPG + O2→HbO2 + 2,3 DPG Hb-2,3 DPG + O2→
 It promotes a rightward shift and enhances oxygenIt promotes a rightward shift and enhances oxygen
unloading at the tissuesunloading at the tissues
 This shift is longer in duration than that due to [H+]This shift is longer in duration than that due to [H+]
or PCO2 or temperatureor PCO2 or temperature

 The levels increase with:The levels increase with:
Cellular hypoxia.Cellular hypoxia.
AnemiaAnemia
Hypoxemia secondary toHypoxemia secondary to
COPDCOPD
Congenital Heart DiseaseCongenital Heart Disease
Ascent to high altitudesAscent to high altitudes
 The levels decrease withThe levels decrease with
Septic ShockSeptic Shock
AcidemiaAcidemia
Stored blood has No DPG after 2 weeks of storage.Stored blood has No DPG after 2 weeks of storage.
In banked blood,the 2,3-BPG level falls and the ability of thisIn banked blood,the 2,3-BPG level falls and the ability of this
blood to release O2 to the tissues is reduced.blood to release O2 to the tissues is reduced.

HAEMOGLOBIN SATURATION DURINGHAEMOGLOBIN SATURATION DURING
EXERCISEEXERCISE

HAEMOGLOBIN SATURATION AT HIGHHAEMOGLOBIN SATURATION AT HIGH
ALTITUDESALTITUDES

ODC And AnesthesiaODC And Anesthesia

BOHR’S EFFECTBOHR’S EFFECT
 During Exercise there is increase conc. OfDuring Exercise there is increase conc. Of
CO2 so oxygen releases easilyCO2 so oxygen releases easily

Double Bohr effectDouble Bohr effect

Double Bohr EffectDouble Bohr Effect

Reverse Chloride ShiftReverse Chloride Shift

Clinical use of O2Clinical use of O2
As Hyperbaric O2
Preoxygenation
Crisis management
Anoxic gas mixture with N2O (GA)
Diffusion hypoxia
Post operative oxygen
IV O2 Therapy ( Breathing problem
Cases)

Definition of hyperbaric O2Definition of hyperbaric O2
 A mode of medical treatment in which theA mode of medical treatment in which the
patient is entirely enclosed in a pressurepatient is entirely enclosed in a pressure
chamber and breathes 100% oxygen at achamber and breathes 100% oxygen at a
pressure greater than 1 atmosphere absolutepressure greater than 1 atmosphere absolute
(ATA).(ATA).

Increased PaOIncreased PaO22 has fOurhas fOur
PharmacOlOgIc effectsPharmacOlOgIc effects::
 1. Increased blood O1. Increased blood O22 contentcontent

 2. Vasoconstriction 2. Vasoconstriction
   3. Antibacterial action, particularly3. Antibacterial action, particularly
against anaerobic bacteria   against anaerobic bacteria
 4. Inhibition of endothelial neutrophil4. Inhibition of endothelial neutrophil
adhesion in injured tissueadhesion in injured tissue

Indications of hyperbaric O2Indications of hyperbaric O2
 1.. Air or Gas Embolism1.. Air or Gas Embolism
 2. Carbon Monoxide Poisoning2. Carbon Monoxide Poisoning
 3. Clostridial Myositis and Myonecrosis (Gas3. Clostridial Myositis and Myonecrosis (Gas
Gangrene)Gangrene)
 4. Crush Injury, Compartment Syndrome4. Crush Injury, Compartment Syndrome
 5. Decompression Sickness5. Decompression Sickness
 6. Arterial Insufficiencies:6. Arterial Insufficiencies:
 Central Retinal Artery OcclusionCentral Retinal Artery Occlusion
 Enhancement of Healing In Selected ProblemEnhancement of Healing In Selected Problem
WoundsWounds
 7. Severe Anemia7. Severe Anemia

Types of hypoxiaTypes of hypoxia

Indications for OxygenIndications for Oxygen
 PneumothoraxPneumothorax:: Give 100% for NitrogenGive 100% for Nitrogen
washoutwashout
 COPD/chronic lung diseaseCOPD/chronic lung disease:: LowLow
concentrations (below 30%)concentrations (below 30%)
 Pulmonary FibrosisPulmonary Fibrosis:: low flow, 25-40%low flow, 25-40%
O2O2
 Trauma/emergenciesTrauma/emergencies: typically give: typically give
100% O2 with a non-rebreathing mask100% O2 with a non-rebreathing mask
Ex: Car accident, hypovolemiaEx: Car accident, hypovolemia

Determining the requirement ofDetermining the requirement of
oxygen you must assessoxygen you must assess
 Neurologic statusNeurologic status (is there lethargy,(is there lethargy,
anoxic events…)anoxic events…)
 Pulmonary statusPulmonary status (check all O2 indices(check all O2 indices
and assessments)and assessments)
 Cardiac statusCardiac status (HR, recent MI, poor EF,(HR, recent MI, poor EF,
cardiac inflammation, valve problems…)cardiac inflammation, valve problems…)

Oxygen toxicityOxygen toxicity

Oxygen toxicityOxygen toxicity
 100% O2 for 8-12 hr safe for Adult100% O2 for 8-12 hr safe for Adult
 100% O2 for 2-3 hr can cause pulmonary100% O2 for 2-3 hr can cause pulmonary
toxicity. Depends on ALVEOLAR concn. NOTtoxicity. Depends on ALVEOLAR concn. NOT
Arterial.Arterial.
 oxygen free radicals (which damage
tissues), and by causing Absorption
atelectasis and V/Q mismatch.
 In neonates ---- Bronchopulmonary dysplasiaIn neonates ---- Bronchopulmonary dysplasia
 Retrolental fibroplasiaRetrolental fibroplasia: Depends on Arterial: Depends on Arterial
O2 in Premature babyO2 in Premature baby
 Paulbert effectPaulbert effect: convulsion due to O2 toxicity: convulsion due to O2 toxicity

““Absorption atelectasis”:”:
Absorption atelectasis refers to the tendency forAbsorption atelectasis refers to the tendency for
airways to collapse if proximally obstructed.airways to collapse if proximally obstructed.
Alveolar gases are reabsorbed; this process isAlveolar gases are reabsorbed; this process is
accelerated by nitrogen washout techniques.accelerated by nitrogen washout techniques.
It is a problem associated with prolonged O2It is a problem associated with prolonged O2
administration.administration.

Take home messagesTake home messages

Oxygen transport & odc

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