Pulmonary embolism and ABGs

[twarlik]

What would the ABGs of someone who had a pulmonary embolism look like? I know that the O2 would be down and HCO3 would be normal, but what is going on with the CO2? With PE, do patients hyperventilate and start blowing off CO2 or are they going to retain it?

I'm having a difficult time wrapping my mind around this and hope that one of you kind people could help.

Thanks. :)

[leslie :-D]

co2 is lowered secondary to hyperventilation, especially at the alveolar level.

[Tweety, BSN, RN]

Can be a bit tricky if the patient is already a CO2 retainer, such as someone with COPD. Be interesting to hear the answers as I'm not the expert on ABGs either.

But the biggie is the hypoxia. That's a major symptom of a PE. :)

[critcarenurse16]

Due to hyperventilation the patient will present in respiratory alkalosis. Hypoxemia may be masked by the hyperventilation so normal values do not necessarily rule out PE.

[twarlik]

Thanks for the responses. Makes more sense now.

[Tweety, BSN, RN]

Due to hyperventilation the patient will present in respiratory alkalosis. Hypoxemia may be masked by the hyperventilation so normal values do not necessarily rule out PE.

True, one should always look at the patient as well. He may not have hypoxia but is breathing 50 breaths a minute to maintain an adequate saturation. :)

[VickyRN, MSN, DNP, RN]

Usually respiratory alkalosis due to extreme anxiety and rapid breathing, "impending doom." PaC02 is down. However Pa02 is down also and sats will be dropping. So will have an element of hypoxemia along with the respiratory alkalosis.