Antibiotic prophylaxis practice

[cognitus]

I have 2 issues regarding ABx prophylaxis:

1. I usually give ABx within 60 minutes of incision. However, during training, I didn’t give ABx if patient was already on an ABx regimen, even if the last dose of the ABx would be more than 60 minutes before incision. Is this correct practice? Anyone have literature suggesting what to do here?

2. In some cases, after I’ve given ABx prophylaxis, the surgeon requests for me to give another dose, WELL before the time to redose (1-2 hrs after first) if he feels that the field got contaminated. This is usually instead of or in addition to a topical ABx. I’ve spoken with other colleagues and they agree this sounds off but just recommend to give dose anyway but perhaps document to take me off the hook or lie about giving it. Does anyone have any literature that can help me?

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[BobLoblaw78]

I don't have any literature just my understanding. Just boring regulatory meetings and JC (so probably no chance that it is EBM!)

1. Prophylactic antibiotics have to be 60 min prior to incision. Has to be appropriate antibiotics for the surgery, NOT for a possible/ongoing infection. If active infection in the area then it should fall out and not be part of PROPHYLACTIC antibiotics. I even think that an inappropriate dose can pass the measure as long as it is timed correctly, which is silly.

2. Redosing is based on required minimal inhibitory concentration. Most are 4 hours but Cefoxitin, Cefotetan is actually 2 hours, but listed as 4 hours on most charts which further confuses me. I would just redose and document reasoning. It is obviously not supported by any EBM but reasonable

(Addendum for insomnia and literature request) http://www.ajhp.org/content/70/3/195?sso-checked=true#sec-3

 

[Psai]

I redose early for significant blood loss, not surgeon request.

 

[woopedazz]

I have 2 issues regarding ABx prophylaxis:

1. I usually give ABx within 60 minutes of incision. However, during training, I didn’t give ABx if patient was already on an ABx regimen, even if the last dose of the ABx would be more than 60 minutes before incision. Is this correct practice? Anyone have literature suggesting what to do here?

2. In some cases, after I’ve given ABx prophylaxis, the surgeon requests for me to give another dose, WELL before the time to redose (1-2 hrs after first) if he feels that the field got contaminated. This is usually instead of or in addition to a topical ABx. I’ve spoken with other colleagues and they agree this sounds off but just recommend to give dose anyway but perhaps document to take me off the hook or lie about giving it. Does anyone have any literature that can help me?

I did a 5 min presentation on this once.
Giving too early = same as giving too late
Giving within 1 hour pre-knife-to-skin = recommended in guidelines; however data suggests 15-30mins prior = best timing.

• IV bolus: ≤60 minutes before skin incision (optimal 15-30 minutes).
• IV infusion: Commenced 30-60 minutes prior to skin incision (can complete infusion after knife-to-skin with no problemos.

If they are given Abx more than 1-2 hours pre-knife-to-skin (either on the ward/prophylactic), they have a higher infection rate and the literature suggests you should strongly consider redosing. If the Abx were given within the 2 hour window, then it's up to the surgeons and what they want; but if the half-life allows you should probably be redosing, particularly if it is closer to the 2 hour mark than 1 hour.
You should 100% be redosing if it is over the 2 hour mark - unless specifically contraindicated.
You should re-dose with the same initial dose every 2-3 half-lives intra-op to ensure adequate tissue saturation - unless specifically contraindicated (i.e. Gent)
I never saw any evidence to suggest redosing Abx in the setting of new contamination has any effect; you give the same dose if it's clean contaminated vs filthy... so this makes no sense. If there is a perforated viscous and you need additional coverage, then sure that makes sense.

 

[dhb]

however data suggests 15-30mins prior = best timing.

What data?

 

[woopedazz]

What data?

Timing of Antimicrobial Prophylaxis and the Risk of Surgical Site Infections: Results From the Trial to Reduce Antimicrobial Prophylaxis Errors
Timing of Antimicrobial Prophylaxis and the Risk of Surgical Site Infections: Results From the Trial to Reduce Antimicrobial Prophylaxis Errors

Although, reading that I'm not so sure why all the guidelines specifically say 15-30 and not just "less than 30," unless they are considering theoretical pharmacokinetics and tissue saturation...

 

[cognitus]

Bump

 

[anbuitachi]

seems like its all over the place and here most attendings just give whatever the surgeon wants as long as its not something outrageous. i think most of them dont want to be fighting that battle. we usually give it >20 min prior to incision unless its vanc.

 

[nimbus]

just give whatever the surgeon wants.

That’s what I do.

Do people give prophylactic antibiotics to patients already on antibiotics for known infection? We don’t but I’ve wondered if we should. Often they would be different antibiotics for different indications.

 

[psychbender]

That’s what I do.

Do people give prophylactic antibiotics to patients already on antibiotics for known infection? We don’t but I’ve wondered if we should. Often they would be different antibiotics for different indications.

It depends on what they are currently being given. Already on vanc for an endocarditis, with a good trough? Not much of a reason to give a dose of ancef for that knee scope. Received ertapenem three hours ago in the ED while waiting to head up to the OR for an appy? You're likely fine.

On micafungin for a fungemia? Yeah, you may need something that'll actually cover skin flora.

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[woopedazz]

That’s what I do.

Do people give prophylactic antibiotics to patients already on antibiotics for known infection? We don’t but I’ve wondered if we should. Often they would be different antibiotics for different indications.

You are supposed to unless they had their ward Abx within 2 hours of knife-to-skin.

 

[nimbus]

It depends on what they are currently being given. Already on vanc for an endocarditis, with a good trough? Not much of a reason to give a dose of ancef for that knee scope. Received ertapenem three hours ago in the ED while waiting to head up to the OR for an appy? You're likely fine.

On micafungin for a fungemia? Yeah, you may need something that'll actually cover skin flora.

Sent from my SM-G930V using SDN mobile

You are supposed to unless they had their ward Abx within 2 hours of knife-to-skin.

Increasingly we are seeing patients who come to the OR on q24hr ceftriaxone dosing. Normally ceftriaxone is adequate for surgical prophylaxis but they often receive their dose much longer than 2 hours prior to incision. So is it safe to assume tissue levels are inadequate and redose? If tissue levels are inadequate, why are they on a q24hr dosing schedule?

Another thing I’d like to point out is that in my training days it was considered malpractice to give more than 120-160mg of gentamicin. We were told that the patients would end up deaf and on dialysis if you overdose them. Nowadays people are frequently getting 400-500mg (7mg/kg) q24hrs. So much dogma in medicine. Sometimes it seems more like the fashion world than a science.

 

[woopedazz]

Increasingly we are seeing patients who come to the OR on q24hr ceftriaxone dosing. Normally ceftriaxone is adequate for surgical prophylaxis but they often receive their dose much longer than 2 hours prior to incision. So is it safe to assume tissue levels are inadequate and redose? If tissue levels are inadequate, why are they on a q24hr dosing schedule?

Another thing I’d like to point out is that in my training days it was considered malpractice to give more than 120-160mg of gentamicin. We were told that the patients would end up deaf and on dialysis if you overdose them. Nowadays people are frequently getting 400-500mg (7mg/kg) q24hrs. So much dogma in medicine. Sometimes it seems more like the fashion world than a science.

Had the same discussion re: Ceftriaxone with attending surgeon and anaesthetist last week. I pushed to blindly follow guidelines, but our hospital didn't have any. In the end we never re-dosed. Looking at a few US/Australian guidelines and talking to pharmacy --> redosing is not required with ceftriaxone in any surgical prophylactic setting - be it ward/pre-incision, as long as they've had a dose within 20 hours or so --> no need to redose. Pharmacy couldn't tell me why, just that "half-life, excretion, good site levels... uhhh... so I assume there isn't any good evidence for these recommendations.

Re: Gent. and other highly toxic Abx; toxicity is definitely an absolute contraindication to re-dosing. But they say aim to redose at 8 hours... Personally I wouldn't push it unless the surgeon wanted me to.

Certainly interesting finding a whole load of guidelines with little to no actual evidence behind them.

I'll just follow along with what my bosses tell me and try not to kill anyone.

 

[anbuitachi]

Yea i agree, theres a lot of BS in this area of practice. It also doesn't make that much sense that redosing schedules are different in the OR vs on the floor, especially since floor dosing is more often for people who actually has an infection while intraop dosing is for prophylaxis. Example of this is Zosyn/Unasyn. Intraop dosing is every two hours. You'd never see this stuff on the floor. It's one thing if the patient is losing a lot of blood, but another when totally stable with minimal I/Os.

And that gentamicin is insane. and im guessing we dont stick around long enough to see the side effects. 1.5mg/kg q8h. An average 100k KG man is getting 150mg per dose. And i bet a lot of people aren't following recommended administration standards when giving gentamicin. (dilution ratio, infusion rate,

 

[abolt18]

Yea i agree, theres a lot of BS in this area of practice. It also doesn't make that much sense that redosing schedules are different in the OR vs on the floor, especially since floor dosing is more often for people who actually has an infection while intraop dosing is for prophylaxis. Example of this is Zosyn/Unasyn. Intraop dosing is every two hours. You'd never see this stuff on the floor. It's one thing if the patient is losing a lot of blood, but another when totally stable with minimal I/Os.

And that gentamicin is insane. and im guessing we dont stick around long enough to see the side effects. 1.5mg/kg q8h. An average 100k KG man is getting 150mg per dose. And i bet a lot of people aren't following recommended administration standards when giving gentamicin. (dilution ratio, infusion rate,

One of my attendings gave me a hard time for trying to drip it in at the recommended rate (just diluted it and threw it on a pump)... Seems like a stupid thing to nitpick.

 

[Psai]

One of my attendings gave me a hard time for trying to drip it in at the recommended rate (just diluted it and threw it on a pump)... Seems like a stupid thing to nitpick.

Do you dilute ancef down and give it over 10 minutes slow infusion like the pharmacy wants you to? Because I just slam it in like it owes me money

 

[abolt18]

Do you dilute ancef down and give it over 10 minutes slow infusion like the pharmacy wants you to? Because I just slam it in like it owes me money

Cefazolin gets pushed at a rate limited only by the size of my PIV. I should have clarified that I was taking about gentamicin before.

 

[jwk]

We generally follow SCIP guidelines - but we also note specific exceptions in our EMR, including "no antibiotics per surgeon order".

It's a shame that anesthesia gets dinged for what is essentially a surgeon issue. We're only involved because we're able to time the dosing better than the pre-op nurses.

 

[vector2]

Yea i agree, theres a lot of BS in this area of practice. It also doesn't make that much sense that redosing schedules are different in the OR vs on the floor, especially since floor dosing is more often for people who actually has an infection while intraop dosing is for prophylaxis. Example of this is Zosyn/Unasyn. Intraop dosing is every two hours. You'd never see this stuff on the floor. It's one thing if the patient is losing a lot of blood, but another when totally stable with minimal I/Os.

And that gentamicin is insane. and im guessing we dont stick around long enough to see the side effects. 1.5mg/kg q8h. An average 100k KG man is getting 150mg per dose. And i bet a lot of people aren't following recommended administration standards when giving gentamicin. (dilution ratio, infusion rate,

Zosyn and other beta lactams bactericidal activity depends on time spent above the MIC. That's why there's been a shift to a zosyn 4h continuous infusion because we know floor nurses are incapable of giving a medication every 2 hrs.

Intuitively, a surgical pt requires more frequent dosing than a floor patient because you never really have source control while an incision exists, therefore the time above MIC should be close to continuous to catch new bacteria which are perpetually seeding the field. Even with all the chloraprep and ioban in the world, skin is not totally sterilized and there is a direct highway between skin to some muscle or viscera which typically is sterile (assuming we're not talking about GU/GI).

 

[anbuitachi]

Zosyn and other beta lactams bactericidal activity depends on time spent above the MIC. That's why there's been a shift to a zosyn 4h continuous infusion because we know floor nurses are incapable of giving a medication every 2 hrs.

Intuitively, a surgical pt requires more frequent dosing than a floor patient because you never really have source control while an incision exists, therefore the time above MIC should be close to continuous to catch new bacteria which are perpetually seeding the field. Even with all the chloraprep and ioban in the world, skin is not totally sterilized and there is a direct highway between skin to some muscle or viscera which typically is sterile (assuming we're not talking about GU/GI).

Zosyn 4h continuous infusion every how often? Over here the floor is still doing the zosyn q6h.
Yea i get the part about the seeding and stuff but still you are comparing prophylaxis vs active infection. You have a patient with florid pneumonia on the floor getting zosyn q6h, while an intraoperative patient gets it q2h makes no sense to me.

I would say vast majority of antibiotics just get slammed in, even though they can cause AKI etc in patients afterwards. yet we give vanco slowly to prevent red man syndrome in a patient under general anesthesia.

 

[vector2]

Zosyn 4h continuous infusion every how often? Over here the floor is still doing the zosyn q6h.
Yea i get the part about the seeding and stuff but still you are comparing prophylaxis vs active infection. You have a patient with florid pneumonia on the floor getting zosyn q6h, while an intraoperative patient gets it q2h makes no sense to me.

I would say vast majority of antibiotics just get slammed in, even though they can cause AKI etc in patients afterwards. yet we give vanco slowly to prevent red man syndrome in a patient under general anesthesia.

With the zosyn extended infusion the first dose is given over 30 minutes and the subsequent doses are delivered over 4h every 8h. Even with the 4h gap, over the course of 24h the pt spends significantly more time with a bactericidal MIC compared to the peaks and troughs of slamming in a dose and then waiting 6h.

With even a florid pneumonia, the lungs are pretty much sterilized of pathogens after one or two doses unless theres an empyema, parenchymal lung abscess, or resistant biofilm forming bug which prevents source control. That's the reason you very rarely will get a positive pathogen BAL if antibiotics are given before obtaining a sample. Skin, on the other hand, still contains hundreds if not thousands of CFUs per cm2 even after prep. Unlike the pneumonia, you dont get source control of someone's entire integument (or the OR environment) just because you gave one dose of ancef. Your argument about the floor should be based around making floor dosing more frequent or continuous, not making the OR less frequent.