Assessment of Oxygen Ch.6 Flashcards
In a healthy individual, over _______% of the oxygen diffuses into ____________ capillary blood chemically combines with __________.
99%; pulmonary; hemoglobin
The normal hb value for men is
14 to 16 g/dL
The normal hb value for women is
12 to 15 g/ dL
The normaL hb for infants is
14 to 20 g/dL
Each gram of hb is capable of carrying about _______ of oxygen.
1.34 mL
an S- shaped curve on a nomogram that illustrates the percentage of hb that is saturated with oxygen related to oxygen at a specific oxygen partial pressure.
Oxyhemoglobin dissociation curve
The steep portion of the oxyhemoglobin dissociation curve falls between
10 and 60 mm Hg
The upper flat portion falls between
70 and 100 mm Hg
The oxygen tension difference between the alveoli and arterial blood
Alveolar- arterial oxygen tension difference (P[A-a]O2)
Pulmonary shunting below 10% is considered
normal
Pulmonary shunting that is 10%- 20%
indicates a pulmonary abnormality
Pulmonary shunt that may be life threatening and POSSIBLE requiring cardiopulmonary support, is what percentage?
20%-30 %
Pulmonary shunting greater than 30%
Serious life threatening condition
Abnormally low arterial oxygen tension (PaO2) in the blood
Hypoxemia
Inadequate level of TISSUE oxygenation
Hypoxia
Nonvolatile acid and causes the pH to decrease
Lactic acid
Normal oxygenation
80-100
Mild hypoxemia
60-80
Moderate hypoxemia
40-60
Severe hypoxemia
<40
An INCREASED level of red blood cells
Polycythemia
Inadequate oxygen at the tissue cell caused by low arterial oxygen tension (PaO2)
Hypoxic hypoxia (hypoxemic hypoxia)
PaO2 is normal but the oxygen carrying capacity and thus the oxygen content of the BLOOD is inadequate
Anemic hypoxia
Blood flow to the tissue cells is inadequate; therefore adequate oxygen is not available to meet the tissue
Circulatory hypoxia ( stagnant or hypoperfusion hypoxia)
Impaired ability to the tissue cells to metabolize oxygen
Histotoxic hypoxia
Common causes of hypoxic hypoxia
Low PAO2 caused by:
- Hypoventilation
- High altitude
- Diffusion impairment
- Intersitial fibrosis
- Interstial pulmonary edema
Common causes of anemic hypoxia
- Decreased hb concentration
- Anemia
- Hemmorrhage
- Abnormal hb
- Carboxyhb
- Methemoglobin
Common causes of CIRCULATORY hypoxia (3)
- Hypotension
- Slow flow or stagnant (pooling) or peripheral blood
- Arterial- venous shunts
Common causes of histotoxic hypoxemia
Cyanide poisoning
Oxygen is carried in the blood in two ways
- Dissolved o2 in the blood plasma
- o2 bound to the hb
CaO2: o2 content of arterial blood equation
CaO2=(Hb x 1.34 x SaO2) +( PaO2 x 0.003)
CvO2: o2 content of venous blood equation
CvO2= (Hb x 1.34x SvO2) + (PvO2 x 0.003)
CcO2: o2 content of pulmonary capillary blood equation (long)
CcO2= ( Hb x 1.34^3) + PAO2^4x 0.003
Normally the SvO2 is about _____%
75%
This Is the amount of oxygen consumed by the tissue cells divided by the total amount of oxygen delivered
Oxygen extraction ratio (O2ER)
This is useful in determining the extent of lung diffusion defects (ARDS) also called oxygenation ratio
PaO2/FIO2 ratio
On room air, the normal PaO2/ FIO2 ratio is between ______ and _____
350 and 450
Known as oxygen uptake is the amount of oxygen consumed by the peripheral tissue cells during a 1- minute period
Oxygen consumption (VO2)
The amount of o2 delivered to the peripheral tissue cells
Total oxygen delivery (DO2)
Another name for oxyhb dissociation curve
oxyhb equilibrium curve
Ideal alveolar gas equation
PAO2=[PB-PH2O]-FIO2-PaCO2(1.25)
