what is the implication of PaO2 level at 122 mmHg with O2 at 98%?

Question

answer to question is needed in the case preparation for a COPD patient

Answer 1

This is normal value.

Answer 2

The PaO2 is a component of ABG (Arterial Blood Gas).PaO2 is defined as the partial pressure of oxygen in arterial blood. Its normal value ranges from 80-100 mmHG. While O2 saturation (SaO2) measures the percent of hemoglobin which is fully combined with oxygen.

While this measurement can be obtained from an arterial or venous blood sample, it's major attractive feature is that it can be obtained non-invasively and continuously through the use of a "pulseoximeter."Normally, oxygen saturation on room air is in excess of 95%. With deep or rapid breathing, this can be increased to 98-99%. While breathing oxygen-enriched air (40% - 100%), the oxygen saturation can be pushed to 100%.

While Fi02 (Fractioned of Inspired Oxygen)- is the amount of oxygen being delivered to a patient.

A PaO2 level at 122 mmHg - means that the COPD patient is getting a lot of oxygen (FiO2) . I am assuming that the patient is placed either on a non-rebreather mask or on a ventilator since the ABG values gave you this result. You mentioned that the oxygen is at 98%, can you clarify if that is the FiO2 or the O2 Sat? Also, can you give me pH, PCO2 and Bicarbonate values in the ABG results?

If the patient is not on a ventilator or does not have other problems such as cardiac, the COPD patient does not need a high oxygen supply (not more than 4 Liters/min), because you may suppress the patient's respiratory drive (being controlled by the brain). If the patient is in a life and death situation and needs to be placed on a ventilator, I would say yes and the pulmonologist probably needs to decrease the FiO2 setting on the ventilator.

Answer 3

Using alveolar gas equation:
Expected PaO2 = PiO2 - PACO2 / R + F
Breathing 98% O2 at 1 atm,
PiO2 = 0.98 * ( 760 - 47 ) = 699mmHg
Assume normal PACO2 = 40mmHg
Assume normal R = 0.8
F = PACO2 * FiO2 * ( 1 - R ) / R = 10
Therefore expected PaO2 = 699 - 40 / 0.8 + 10 = 659mmHg
The subject's PaO2 of 122mmHg is therefore much lower than would be expected in a normal subject breathing 98% O2. This can be due to several factors such as V/Q mismatch, shunts and diffusion defects in the lung. This patient is having severe COPD.

Answer 4

well, in a NORMAL individual, the PaO2 should be much higher given the FiO2 delivered...would need the rest of the blood gas to accurately answer. Most COPD'ers have a PaO2 around 50-60, so decreasing the FiO2 in this case would be warranted. Again, depends on the Ph and the CO2.

The implication in giving too much O2 to a COPD'er will knock out their drive to breath and they will go into respiratory failure.

Answer 5

Is the O2 the sat or the FiO2?? If the sat, with levels like that, it sounds to me that the patient is on O2 and needs to be turned down. If a COPD CO2 retainer, you're in big trouble! You're going to knock out his hypoxic drive and I'm gonna have to come in there and intubate the sick fu*ker and shake my head. Kind of like radiology transporting pt's on NRB at 4lpm!!!

Stefsun, you're way off, you can't assume normal PaCO2 on a COPD pt!!

Answer 6

The patient has pulmonary hypertension, but is adequately oxygenated at this time. I think everyone here is confusing PaO2 with SaO2!!

Answer 7

Do I look like a effing sciencist??
stfu and get a life

MUDFACKSAYWHA!