hi, is there any way to differentiate if it is an acute or chronic respiratory acidosis or alkalosis based on Blood gas Analysis data only?
i am now working in emergency department and i often have decreased mental status patients,usually geriatric, and people who bring them usually were unable to give us any clue about the onset of the patient's disease..this confuses me because i need to evaluate if there is another primary metabolic problem besides the compensation from the compensation calculation..
please help, thanks
regards,Ketap🙂
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Yeah, you're working in an emergency department all right.
Your question is a good one, and I'm sure plenty of people will be happy to answer it.
What I will say is that in usual clinical EM practice, the abg is not the test you want when you are faced with an elderly patient with a inadequate history of "decreased mental status." Practicing in the ER, you frequently (on an overwhelming scale) don't care about whether their respiratory acidosis/alkalosis is acute or chronic.
Instead, you want to be asking these questions:
1) can I get a better history? Can I call the snf, or get records from the patient's last hospitalization or doctor visit? Often, if the patient is coming from a snf, it will turn out that they have no mental status changes, and that they were sent to the ER because the staff that night did not know that their GCS of 11 was chronic.
2) are they infected? MS changes in old people are frequently due to infection - pneumonia, uti, etc.
3) can I get a urine sample? An old person with decreased mental status often has an infection, but usually that infection is a UTI. Check the UA.
4) Are they bleeding in the head? Have a low threshold for CT scanning the head, especially if there's any suggestion they may have fallen and hit their head on something.
5) did they OD on drugs, illicit or prescribed? SNF-residents, especially, often get a bit too many percocets and get real sleepy. Their anticonvulsant levels might be way too high. They might be drunk.
6) are they having an MI? Get an ekg on all old AMS patients.
If I could order only one test on an elderly patient with questionable hx of AMS it would be a UA.
Most of these patients never need an ABG.
