Comments on: Status Panicus

By: ee

ee — Sun, 01 Jun 2008 04:23:27 +0000

Regardless of all the finite details and shit, it’s still fucking cool.

By: Bram

Bram — Sat, 31 May 2008 21:09:34 +0000

I’ve seen a few that were alkalotic. Usually it is early on in the course. I do have to agree that a pH of 7.7 is very high and requires almost a profound respiratory or mixed respiratory/metabolic alkalosis. It would be hard to maintain that pH with any metabolic acidosis. Somehow the serum bicarb just doesn’t fit (unless she took something unmeasured and basic…)

By: TK

TK — Sat, 31 May 2008 20:32:16 +0000

Hmmmm - I know about the mixed acid base picture that can be seen in ASA poisoning - but I have never seen anyone alkalotic with it. I have seen some people partially compensated with a slightly low or almost normal Ph but never over 7.4. And some of these were acute poisoning and some were chronic poisoning. Anyway, no one I have spoken to about it had heard of a Ph so high and not ultimately found to be really sick.

By: Bram

Bram — Sat, 31 May 2008 20:13:52 +0000

ASA toxicity can present with any pH. They get a mixed disorder due to salicylate’s direct stimulation of the respiratory center. The classic initial presentation is a mixed respiratory alkalosis with a metabolic acidosis, presenting with an alkalotic or normal pH. When they present acidotic, they are extremely sick and compensatory mechanisms have failed. The stages of ASA toxicity are usually defined by the presenting pH (although serum K is also involved).

Glad to hear that ASA was considered and ruled out as that could have been a disaster if she was given lorazepam.

By: TK

TK — Sat, 31 May 2008 11:09:37 +0000

Small Correction, the PCo2 was 11 and the bicarb 14 not the other way around. I followed up on this case and in fact the acid base disturbance resolved the following day once she started breathing at a normal rate. Otherwise, completely negative tox screen. I am still shocked that someone could hyperventilate this much and not pass out. I have never seen a Ph above 7.7 either!

By: Anders

Anders — Sat, 31 May 2008 08:22:00 +0000

I’m not quite sure this can be dismissed as hyperventilation:
1. As mentioned above regulating the st-HCO3 to a level of 11 is something that takes hours to days
2. Why is the patients respiratory work suddently greatly insufficient, as the PC02 of 14 indicates? She should be compensating for her (secondary) metabolic alkalosis. Could this be explained as a effect of the sedation?

/Anders, MD

By: Liz

Liz — Fri, 30 May 2008 17:12:48 +0000

Hmm, nevermind, salicylates cause a mixed disorder, initially a respiratory alkalosis and then a metabolic acidosis (according to Merck Manual)…guess I have some more studying to do for Step 1

By: Liz

Liz — Fri, 30 May 2008 17:07:05 +0000

Bram, the bicarb dumping is to compensate for the respiratory alkalosis, the primary acid-base disturbance here. In salicylate poisoning, the initial insult is a metabolic acidosis, and we blow off CO2 to compensate.

By: TK

TK — Fri, 30 May 2008 14:53:08 +0000

Her tox screen including salicylates and tylenol was negative. However, if you have ASA poisoning, you would be acidotic not alkylotic.

By: Bram

Bram — Fri, 30 May 2008 11:45:54 +0000

With those numbers I’m hoping you ruled out salicylate toxicity. Probably not with a pH that high, but it is hard to acutely dump bicarb that fast.