Metformin in unstable glucose control in ICU

[emergiQ]

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Curious about the practice pattern of others with respect to metformin in ICU.

A few starting parameters:

1) Assume patient has normal renal function, thus forego the discussion of metformin-induced lactic acidosis.

2) Patient, 60 y/o Type II DM, takes metformin at home.

3) POD 3 s/p thoracotomy. Poor glucose control necessitating insulin infusion.


My strategy is to wean the infusion until able to go to q6 insulin injections +/- SSI, and once control and stability established, re-start metformin.

Pharmacy team wants to start metformin now while infusion still on. Patient also taking stress dose steroids (takes chronic at home due to ocular issue). Just starting oral feeds today (extubated this morning).


Would you guys start the metformin now or wait?

 

[SLUser11]

Curious about the practice pattern of others with respect to metformin in ICU.

A few starting parameters:

1) Assume patient has normal renal function, thus forego the discussion of metformin-induced lactic acidosis.

2) Patient, 60 y/o Type II DM, takes metformin at home.

3) POD 3 s/p thoracotomy. Poor glucose control necessitating insulin infusion.


My strategy is to wean the infusion until able to go to q6 insulin injections +/- SSI, and once control and stability established, re-start metformin.

Pharmacy team wants to start metformin now while infusion still on. Patient also taking stress dose steroids (takes chronic at home due to ocular issue). Just starting oral feeds today (extubated this morning).


Would you guys start the metformin now or wait?

Does normal renal function really allow you to forego the issue of metabolic acidosis altogether?

It just seems to me that patients that are critically ill will often need radiologic studies that may require IV contrast, and they may also need emergent surgical intervention (or re-intervention)....things that don't tend to mix well with metformin.

Is there literature that I'm unaware of that says the dangers of metformin-induced acidosis only exist for patients with renal insufficiency? I'm currently having all my patients hold their metformin for IV contrast and for major surgery, regardless of renal function.

Also, I'm not sure how much is gained by its use in the ICU. I have to admit that I usually just use insulin in my critically-ill patients. If they improve and become more stable, then I use other agents for blood sugar control.

 

[Bobblehead]

I don't use metformin for ICU patients. You could make an argument for starting a long-acting insulin if they were stably eating. Someone who just started tube feeds and has been extubated less than 24 hours may very well end up back on the ventilator requiring imaging by the evening.

The only instance I'd consider using metformin would be if the patient was merely in the ICU due to a lack of floor beds (i.e. not an ICU patient but simply physically located in the ICU0.

 

[emergiQ]

Does normal renal function really allow you to forego the issue of metabolic acidosis altogether?

It just seems to me that patients that are critically ill will often need radiologic studies that may require IV contrast, and they may also need emergent surgical intervention (or re-intervention)....things that don't tend to mix well with metformin.

Is there literature that I'm unaware of that says the dangers of metformin-induced acidosis only exist for patients with renal insufficiency? I'm currently having all my patients hold their metformin for IV contrast and for major surgery, regardless of renal function.

Also, I'm not sure how much is gained by its use in the ICU. I have to admit that I usually just use insulin in my critically-ill patients. If they improve and become more stable, then I use other agents for blood sugar control.

Actually, I just wanted to avoid the whole metformin/renal failure issue because I knew it would be a logical rejoinder to the question "Do you use metformin in the ICU" since the Cochrane review from 2006 considered renal insufficiency a contraindication:

"At present, metformin is considered to be contraindicated in patients
with chronic renal insufficiency, liver function abnormalities,
congestive heart failure, peripheral vascular disease, pulmonary
disease, or age greater than 65, as these conditions may
increase the risk of tissue anoxia and therefore the development
of lactic acidosis."

However, the real reason I wanted to avoid the whole discussion is because my pharmacists are of the opinion that this risk is overblown (which, incidentally, is supported by the same Cochrane Review) and so I was looking for others' opinion on using metformin notwithstanding the lactic acidosis issue.

It would seem most are in agreement that metformin isn't really the best choice in the ICU.

I've tried to build consensus among my team, but they're unwilling to listen. I'm beginning to think they have shares in the makers of metformin. Anyway, I've been objective, and let this play out in our unit as a discussion topic, but at the end of the day, I'm the decision-maker.