Chapter 6 Oxygen and Carbon Dioxide Transport

what are the two forms O2 is carried in the blood

1 as dissolved O2 in the blood plasma 2 chemically bound to hemoglobin

normal CaO2 is

20 vol%

The ratio of HCO3- to H2CO3 is

20:1

how many mL of O2 are extracted form each 100 mL of blood for tissue metabolism

20vol%-15vol%=5vol% or 5ml

normal HCO3- arterial venous

22-28 Meq/L arterial 24-30 mEq/L venous

normal O2ER is

25%

each RBC contains approximately how many hemoglobin molecules

280 million

about what % of Qt is shunted

3%

hemoglobin constitutes about what percent of RBC

33%

Normal Pco2 arterial and venous

35-45 torr arterial 42-48 torr venous

normal pH arterial and venous

7.35-7.45 arterial 7.30-7.40 venous

Normal Po2 arterial and venous

80-100 torr arterial 35-45 torr venous

what is your PAO2 stand for and the equation

PAO2= [(Pb-PH20)FIO2]-(PCO2x1.25) Amount of O2 in the Alveoli

the H2CO3 concentration can be determined by

PCO2x0.03

the amount of O2 bound to Hb is directly related to the

PaO2

anemic hypoxia

PaO2 is normal but the O2 carrying capacity of the Hb is inadequate

shunt equation is

Qs/Qt=CcO2-CaO2/CcO2-CvO2

Factor that increase the C (a-v)O2 ,ERO2, VO2 and decrease Svo2

Seizures hyperthermia exercise decreased cardiac output(Qt for VO2 remains the same) shivering periods of increased O2 consumption(doesn't apply to VO2) (SHEDS P) (For O2 ER anemia &Decreased arterial O2)

when the pulmonary capillary blood is in excess of the alveolar ventilation this condition causes pulmonary relative shunting

V/Q mismatch

O2 consumption equation is

V2O = QT [ C(a-v) O2 x 10 ] Normal 250mL O2/Min

hypoventilation is caused by

COPD CNS depressant Head trauma neuromuscular disorders (myasthenia gravis or Guilain barre syndrome)

content of the arterial blood O2

Cao2:[ (Hbx 1.34 xSao2) + (Pao2 x 0 .003)]

content of the venous blood O2

Cvo2[:( Hb x 1.34 x Sv O2 ) + (PvO2 x 0.003)]

Total O2 delivery equation

DO2=Qt x (CaO2 x 10): 5L x (20vol%x10)=1000mL/min

name the tree transport for CO2 in the RBC

Dissloved in the RBC 5% or 10ml combine to Hb 21% or 42 ml (carbomino Hb) HCO3- 63% or 126ml

most CO2 that is produced at the tissue cell is carried to the lungs in the form of

HCO3- by the RBC

the fact that deoxygenated blood enhances the loading of CO2 and oxygenation of blood enhances the unloading of CO2 is called the

Haldane effect

the quantity of oxygen that dissolves in the plasma at a given temperature is proportional to partial pressure of gas is a function of what law

Henry's law

Second part of all the equation tell you

How much O2 is dissolved in the plasma

Hb F is

Normal fetal hemoglobin (has two alpha chanins and two gamma chains)

shunt like effect respond well to

O2 treatment

the O2 extraction ratio equation is

O2ER= CaO2-CvO2/CaO2

the amount of O2 extracted by the peripheral tissues during the period of 1 minute is called

Oxygen Comsuption

a shunt between 10-20% is indicative of

intrapulmonary abnormality but seldom of clinical significance

carbonic acid is

ionized into HCO3- H+

in the center of each of the 4 heme there is a

iron -containing non protein portion

In terms of total O2 transport is the dissolved O2 a high or low percentage of O2 transport

low percentage

volume percent can be also be written as

mL O2/ 100 ml of blood

when various drugs and chemicals such as nitrites change the iron molecule in the heme from the ferrous state to the ferric state eliminating the ability of hemoglobin to transport oxygen this type of hemoglobin is called

methemoglobin

Hb A is

normal adult hemoglobin

pulmonary shunting below 10% indicates

normal lung status

to determine the total amount of O2 in 100 ml of blood the dissolved o2 and the O2 to hemoglobin must be

added

globin portion that has 141 amino acids chains is called

alpha

capillary is commonly caused by

alveolar collapse or atelectasis alveolar fluid accumulation alveolar consolidation

in a normal person your vol% of CaO2 should be

around 20.1 vol% but because of normal physiologic shunt it is 19.5 vol%

name diffusion limited problems (defects)

atelectasis alveolar fibrosis emphysema pneumonia interstitial edema pulmonary edema (APE PIA)

At a normal Pa O2 of 100 torr the hemoglobin saturation is only about 97% why

because of the normal physiologic shunts

Why can high altitude cause hypoxic hypoxia

because the barometric pressure decreases as altitude increases causing the PAO2 to decrease as well

globin portion that has 146 amino acids is called

beta

circulatory hypoxia or stangant

blood flow to the tissue cell is inadequate

O2 delivery decrease when there is a decrease in

blood oxygenation (CaO2) Hb concentration Qt

The total amount of O2 delivered or transported to the peripheral tissues is dependent on the

body's ability to oxygenate blood the Hb concentration Qt

three common abnormalities that cause anatomic shunting

congenital heart disease intrapulmonary fistula vascular lung tumors

Common cause of anemic hypoxia

decreased Hb anemia hemorrhage abnormal Hb (carboxyhemoglobin and methemoglobin)

an increased SvO2 indicates that the C(a-v)O2, VO2, and O2ER are

decreasing

hemoglobin not bound with O2 is called

deoxyhemoglobin

Hb is encased in the

erythrocytes or red blood cells

First part of all the equation tell you

how much O2 is combine to Hb

CO2 combines with water in a process called

hydrolysis

the bulk of dissolved CO2 that enters the RBC undergoes

hydrolysis(it is much faster in the RBC because of an enzyme called carbonic anhydrase.)

common causes of relative shunt is

hypoventilation diffusion defects V/Q mismatches (Chronic emphysema, bronchitis, asthma,and excessive airway secretions

refers to a condition which there is inadequate O2 at the tissue cells casued by an abnormally low arterial oxygen tension

hypoxemia

refers to low or inadequate O2 for aerobic cellular metabolism

hypoxia

P(A-a)O2 tell you

if there is a diffusion defect

histotoxic hypoxia

impaired ability of the tissue cells to metabolize O2

hemoglobin bound with O2 is called

oxyhemoglobin

If the ratio of HCO3- to H2CO3 increase it does what to pH and if it decrease it does what to pH

pH is more alkaline with increase pH is more acid with decrease

absolute shunting respond how to O2 therapy

poorly (refractory Hypoxemia)

an increase in your (c-v) difference will do what to your consumption

increase

the reduced level of O2 in the arterial blood may be offset by an

increased cardiac output

a decreased Svo2 indicates that the C(a-v)O2, VO2, and O2ER are

increasing

is the portion of the cardiac output that moves from the right side to the left side of the heart without being exposed to the alveolar O2

pulmonary shunting

Calculating the degree of pulmonary shunting is not reliable in Pt who demonstrate

questionable perfusion status a decreased myocardial output an unstable O2 consumption demand(this effect the CaO2 and CvO2 two major components of the shunt equation)

Hb is

reduced hemoglobin (uncombined or deoxygenated hemoglobin)

a shunt between 20-30% denote

significant intrapulmonary disease ( may be life threatening to Pt with CHF)

there are how many ways to transport CO2

six three in the plasma three in the RBC

common causes of circulatory hypoxia

slow or stagnant pooling peripheral blood flow arterial venous shunts

hypoxia is characterized by

tachycardia hypertension peripheral vasoconstriction dizziness mental confusion

use for venous blood samples

the dissolved carbon dioxide in the plasma

the H+ is buffered by

the plasma proteins

O2 ER provides what information

the pt O2 transport status

when hydrolysis take place in the RBC two things happen

the reduced Hb picks up the H+ ions( in other words buffered) the left over HCO3- is diffused out of the RBC

name the normal physiologic shunts

thebesian venous drainage into the left atrium bronchial venous drainage into the pulmonary veins alveoli that are under ventilated relative to pulmonary blood flow

the sum of the anatomic shunt and capillary shunt is referred to as the

true shunt or absolute shunt

the end result of pulmonary shunting is

venous admixture (drops PaO2)

Pulmonary artery is the truest place to get what type of sample

venous blood sample

in a normal person your vol% of CvO2 should be

around 15 vol%

a decrease in your (c-v) difference will do what to your consumption

decrease

at normal body temperature about how much O2 will dissolve in 100ml of plasma for every 1 torr of Pressure

0.003ml

in the healthy individual with an PaO2 of 100 torr what is the dissolved vol%

0.3 vol% (0.003 x 100 torr = 0.3 ml ) ( this is equal to about 5 L )

each g% of hb is capable of carrying approximately how much O2

1.34 ml of O2

cyanosis may appear whenever the blood contains at least

1/3 reduction in Hb g% (ex. 15g% for male Pt is normal if Pt Hb g% is 10g% you know there would present with cyanosis)

5 ml are extracted from 100 ml of blood but total O2 delivery is 1000 ml O2/Min how many ml O2/L is available ?

1000ml/100ml O2=10x5=50mL O2/L

normal Hb for male and female is and infant

14-16 g % 12-15 g % 14-20 g %

normal CvO2 is

15 vol %

normal adult hemoglobin contains

4 heme groups (non-protein) 4 globin or amino acid chains (a protein)

how many O2 molecule can be transported in each heme/iron groups

4 one per heme

normal RBC

4-6 million

normal hematocrit level is

50%

Since normal Qt is about 5L/min what would be the amount of O2 extracted from the blood?

50ml O2/L X 5L/min= 250 ml O2/Min

arterial venous O2 content difference equation

C(a-v)O2= CaO2-CvO2 Normal is 5 Vol%=20vol%-15vol%

content of the pulmonary capillary blood O2

Cco2:[( Hb x 1.34 )+ (PAo2 x 0 .003)]

Factor the Decrease the C(a-V)O2 ,ERO2,VO2 and increase the SvO2

Certain poison Hypothermia increased Qt(Qt in VO2 remain the same) peripheral shunting skeletal muscle relaxation (CHIPS) (For O2 ER increased Hb and Increased arterial O2)

when HCO3 diffuses out the what moves into the RBC

Cl- because the HCO3 combines with the Na+ found in out blood in the form of NaCl and Cl is now free and NaCHO3 is form and transported to lungs in the plasma venous blood.

inadequate O2 at the tissue cells caused by low arterial O2 tension

Hypoxic hypoxia or hypoxemic hypoxia

under normal circumstances an individual's hemoglobin returns to the alveoli approximately how saturated

SvO2 75%- 65%

the transport of O2 between the lungs and the cells of the body is a function of what organ

The heart and the blood

polycythemia is

abnormally high RBC

if the diffusion defect is severe enough to completely block gas exchange across the alveolar capillary membrane than the shunt would be referred to as an

absolute or true shunt

can be grouped under two major categories anatomic shunts and capillary shunts

absolute shunts or true shunt

exists when the blood flows form the right side of the heart to the left side without coming in contact with an alveolus for gas exchange

anatomic shunt

name the three transport for CO2 in the plasma

bound/protein -Carbamino Compound =1% HCO3- anion 5% or 10ml dissloved in plasma (PaCo2x0.03) 5% or 10ml

when hydrolysis occur this creates

carbonic acid (H2CO3)

common causes of histotoxic hypoxia

cyanide poisoning

are abnormal anatomic alteration of the lungs that result in an impedance of oxygen transfer across the alveolar capillary membrane

diffusion defects

hemoglobin molecules are

highly specialized to transport O2 and CO2

a nonvolatile acid and causes the pH to decrease

lactic acid

when hypoxia exist alternate anaerobic mechanism are activated in the tissues that produce dangerous metabolites such as

lactic acid

common causes of Hypoxic hypoxia

low PAO2 (Hypoventilation, High altitude) Diffusion impairment V/Q mismatch shunting

when pulmonary capillary perfusion is in excess of alveolar ventilation

relative shunt or shunt-like effect (caused by a diffusion defect)

as the venous blood enters the alveolar capillaries the chemical reaction occurring at the tissue level are

reversed and continue until equilibrium is reached in CO2

Hb S is

sickle cell hemoglobin (has a different amino acid substituted into the Beta chain)

also during the chloride shift what causes the RBC to slightly swell in the venous blood

some water that moves into the RBC

the term dissolve means

that when a gas like O2 enters the plasma it maintains it precise molecular structure and moves freely throughout the plasma in it normal gaseous state.

what are two major reason absolute shunting does not respond to O2 treatment

the alveoli are unable to accommodate any form of ventilation the blood that bypasses functional alveoli cannot carry more O2 once full saturated except for what is dissolved in the plasma .003

volume percent represent s the amount of

the amount of O2 in milliliter that is in 100 ml of blood

the exchange of HCO3- for Cl- is know as

the chloride shift or the hamburger phenomenon or the anionic shift to equilibrium