Lower than normal oxygen pressure in the tissues or alveoli.
What is hypoxemia?
A low arterial blood oxygen pressure (<80 mm Hg).
What is ventilation/perfusion abnormalities? (V/Q)
The existence of ventilation or perfusion changes in the lungs that result in an abnormal ratio. An ideal ratio is 1.0, with ventilation equally balanced with perfusion to a lung unit.
What is a shunt?
A bypass between the righ (venous) and left (arterial) sides of the circulation. A right-toleft shunt results in the dilution of arterial blood oxygen content (CaO2) with venous blood. If left-to-right, CaO2 is not affected, but cardiac workload will increase.
What is a diffusion defect?
Abnormalities of lung tissue that prevent or inhibit the normal diffusion process of the molecular transfer of oxygen (O2) and carbon dioxide (CO2) across the alveolar capillary membrane.
What valuable information do ABGs provide about a patient? (2)
1) Oxygenation and ventilatory status
2) Acid-base status
What are limitations of ABGs? (3)
1) An arterial blood gas value represents only one point in time.
2) Clinicians should look at trends in blood gas values rather than a single number.
3) Excessive blood sampling is a common practice and should be avoided.
What are normal arterial blood gas values for the following? (Name arterial and venous)