Need help on ventilator settings!

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Hi Everyone!

First I'd like to say how glad I am I found this site, everyone is SO helpful! :)

I'm doing a case study right now and I'm getting stuck on a question about ventilator settings. I've looked through my book and online and just can't seem to find what I'm looking for. I was given the following ABG results for the patient:

HEMODYNAMICS pH 7.38

PO2 96 mmHg

PCO2 24 mmHg

HCO3 16 mmol/L

SaO2 96%

And these are the current ventilator settings:

HEMODYNAMICS IMV 10

Vt 1000 mL

FIO2 90%

PEEP 5 cm

The question is asking me based on these results should the ventilator settings be adjusted and if so what would I recommend? I do know that these are abnormal results so the settings would need to be changed but how? We have not done anything with ventilators in class yet and there really isn't anything in the book that says if certain values are low ____ should be done.

Can anyone offer any insight? Or maybe there is a good website with ventilator setting parameters that I'm not finding?

Thanks so much for your help in advance!!!:)

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my question to you is do those lab values look normal to you?

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No they do not look normal, specifically the PCO2 and HCO3 seem low to me. I've got that much but I guess I just don't understand how I would change the ventilator settings to improve this. Do I increase something? Decrease? As I said, we have not gone over ventilator settings so I'm a little lost and I can't seem to find a good resource to go to.

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Do you think you patient is in an acidic state or alkaline and if so is it resp or metabolic

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or are they trying to compensate?

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I'm going to say compensated respiratory alkalosis

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I think your patient is trying to compensate. I would leave things as is for now and recheck gases in a few

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Great thanks for your help in hashing that out:)

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I am no expert, so read at own risk, but I would not wait and recheck gases in a bit:

*Patient is on a vent, so while trying to compensate for respiratory alkalosis (by secreting HCO3) which which is being iatrogenically caused, the patient will eventually be unable to keep up (unless vent settings are adjusted)

*ph7.38 is normal because so far patient able to compensate by secreting HCO3 sufficiently. That will burn out soon.

*The PCO2 is something which vent can adjust - right now, the patient is "blowing off" all of his/her CO2 causing the alkalosis (pH normal because compensating thus far).

-Most often, this occurs when patients are hyperventilating, like in asthmatics, but in this cause (i believe) it is because the tidal volume is quite large (1000ml/breath), and the rate is reasonable (10)

-Unless the patient is shaquille oneils size, it is probably excessive. By decreasing the tidal volume (usually 5 -10cc/kg or about 500-700ml for average person), less CO2 will be blown off, and the alkalosis will improve

let us know how "the pt" does

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i agree that adjusting the tidal volume would be something to consider but again we dont have sufficient info such as the weight and previous trend in gasess or when vent settings were last made and thats why i suggested rechecking in a few to see how this patient is trending then make the adjustments.

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Thanks everyone. I guess I should add that the patient underwent CABG and these are his results upon admission to the post-op recovery area. I'm not sure if that changes anything, should have said that to begin with. Sorry!

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please take the timehttp://emedicine.medscape.com/article/810126-overview to read this article

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