Oxygen Tension (Po 2 ) - Siemens Rapidlab 1200 Operator's Manual

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Oxygen Tension (pO
Oxygen (O
system is responsible for transporting oxygen to the cells. Oxygen transport involves 4
major steps: convection and diffusion from the air into the pulmonary circulation,
combination of O
O through the arteries to the cell, and finally the release into the tissues and utilization of
2
O at the cellular level.
2
Because it is not possible to measure intra-cellular oxygen tension (pO
become a standard for clinical evaluation of arterial oxygenation status. Measurement of
pO (A), which indicates the oxygen tension in arterial blood, reflects the pressure or
2
driving force for moving oxygen from 1 location to the next due to pressure differential; it
is not a measurement of the O
pulmonary gas exchange efficiency from an arterial blood sample.
Complete laboratory evaluation of oxygenation often requires much more than simple
blood gas measurements. Assessment of ventilatory system and acid-base status is
essential to properly interpret clinical significance of arterial oxygenation status. However,
many patients can be evaluated and treated successfully using blood gases alone if clinical
observations and patient history are taken into account.
This analyte reflects the ability of the lungs to deliver oxygen to the blood. Hypoxia (low
pO ) may occur despite adequate respiration due to parenchymal lung diseases
2
(pneumonia, asthma, pulmonary edema, and pulmonary fibrosis) due to pulmonary
shunting of blood. Extremely low pO
state that must be corrected promptly.
The measurement of pO
deficiency of O
pO is usually 95 mmHg (12.7 kPa) for a healthy young adult living near sea level.
2
However, as with pCO
action is indicated. Generally a pO
significant hypoxemia. Above this value is very little change in oxygen saturation or
oxygen content with changes in oxygen tension, but below this value changes in saturation
can occur rapidly. Exceptions to this limit are newborns, who have an acceptable range of
40 to 70 mmHg (5.3 to 9.3 kPa) and adults over 50 years old, who have a normal
deterioration of lung function that causes a decrease in expected pO
1 mmHg (0.13 kPa) per year.
02087462 Rev. V
Rapidlab 1200 Operator's Guide: System Overview and Intended Use
)
2
) is essential for cell and tissue metabolism in the body. The cardiopulmonary
2
from the lungs with hemoglobin in red blood cells, transportation of the
2
content, but it provides a measurement tool to evaluate the
2
is significant in evaluating the degree of hypoxemia (a
2
in arterial blood) present in a patient. The laboratory reference value for
2
and pH, a wider range of values may occur before any therapeutic
2
10
9
is a potentially life-threatening pathophysiologic
2
6,7
of 80 mmHg (10.7 kPa) signals therapeutically
2
), arterial pO has
2 2
values of about
2