Lidocaine Max dose coming off bypass.

[sevoflurane]

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Say you have a cardiac surgeon that likes lidocaine. You're doing a routine CABG for a 100kg patient:

Say.. perfusion gives 200mg before Acx comes off as per protocol.
Then another 150mg 5 minutes later due to vtach.

Shock. Nothing... Shock again. You get a decent rhythm for 2 minutes before you see V-tac again. Surgeon wants another 150mg bolus of lido.... He says, "no time for infusion to kick in".

Do you say: "No, this would be near a toxic dose?" Or... do you say sure, why not, we have implemented hemodilution by going on bypass so we must still be well within our theraputic window.

Would it be wrong to give one more dose of lidocaine? Surgeon really wants it. How about 2 more doses? How much total would you give over 30 minutes?

Disclaimer: If unstable=back onto bypass. I would just give amio 150mg push/ + gtt and forgett the lido after the first couple of doses, keeping in mind that amio can decrease the clearance of lidocaine. OR.... lido bolus + gtt.

 

[seinfeld]

Routine CABG should not have this much trouble coming off. How much time has lapsed since cross clamp off (do you have effective wash out of cardioplegia), whats the systemic K+ coming off? Mg2+? are the grafts patent?

My opinion is that if the first couple doses of lidocaine dont work then onto amiodarone. Another thing would be attempting to pace coming out of a Defib to help establish a consistent rhythm.

 

[sevoflurane]

Routine CABG should not have this much trouble coming off. How much time has lapsed since cross clamp off (do you have effective wash out of cardioplegia), whats the systemic K+ coming off? Mg2+? are the grafts patent?

Agree completely. Sick Fatty, PVD, DM, 2ppd smoker, pulm htn (65/40), 4 mets at best. Good washout, K+ 4.1, Mag on board, labs all good. Doppler on grafts sound beautiful. We did have to implement retrograde CP due to trace AI at the beginning of the case cause we couldn't arrest. Added PA vent. So cardiac stand still took a little extra time, but not much.
I was thinking of one of Jets pearls that he recently posted: Reperfusion injury, Air, etc.. He was being paced after defib.

What do you say to your surgeon who has done this for many many years?: No or Sure. You would say no and move on to amio. The surgeon insists on 100 mg more of lido in addition to your amio. He asks if it is a toxic dose.

 

[IN2B8R]

Say you have a cardiac surgeon that likes lidocaine. You're doing a routine CABG for a 100kg patient:

Say.. perfusion gives 200mg before Acx comes off as per protocol.
Then another 150mg 5 minutes later due to vtach.

Shock. Nothing... Shock again. You get a decent rhythm for 2 minutes before you see V-tac again. Surgeon wants another 150mg bolus of lido.... He says, "no time for infusion to kick in".

Do you say: "No, this would be near a toxic dose?" Or... do you say sure, why not, we have implemented hemodilution by going on bypass so we must still be well within our theraputic window.

Would it be wrong to give one more dose of lidocaine? Surgeon really wants it. How about 2 more doses? How much total would you give over 30 minutes?

Disclaimer: If unstable=back onto bypass. I would just give amio 150mg push/ + gtt and forgett the lido after the first couple of doses, keeping in mind that amio can decrease the clearance of lidocaine. OR.... lido bolus + gtt.

Hiya, bro': 1mg/kg bolus, then 1-4mg/min gtt. Seems that dose has been easily exceeded with all of the bolusing.... I guess if you do not exceed 5mg/kg max dose, then you are OK....I don't know if there's further benefit from an anti-arrhythmia perspective, but the risks as clear: neuro risk and cardiac risk, which is hard to reverse once you've overdosed (I hope to never have to give intralipid for local overdose s/p a CABG!). The good thing is that your patient, who is in V-tac, is not at a terrible neuro toxicity risk, since there's, at such time, little perfusion to the brain. This happend when cannulas were out, no? But the down side is that most (if not all) of the extra lidocaine is sitting right by--if not within!--the heart. Evenutally, once you circulate once or twice and you have gotten a blood pressure, there goes a bolus to the brain and another to the liver for first pass metabolism (which, I suppose is your friend from a toxicity stand point...). Perpetual V-tac s/p CABG: I'd look for other causes after I have given all the anti-arrhythmics (mg, lido, amio), definitely consider going back on pump if things are not improving, check your gas, look at preservation technique (ST changes everywhere?), kinked graft, didn't de-air coronaries?, heart still cold? etc, etc....Have the balloon pump ready if needs be....

 

[sevoflurane]

Hiya, bro': 1mg/kg bolus, then 1-4mg/min gtt. Seems that dose has been easily exceeded with all of the bolusing.... I guess if you do not exceed 5mg/kg max dose, then you are OK....I don't know if there's further benefit from an anti-arrhythmia perspective, but the risks as clear: neuro risk and cardiac risk, which is hard to reverse once you've overdosed (I hope to never have to give intralipid for local overdose s/p a CABG!). The good thing is that your patient, who is in V-tac, is not at a terrible neuro toxicity risk, since there's, at such time, little perfusion to the brain. This happend when cannulas were out, no? But the down side is that most (if not all) of the extra lidocaine is sitting right by--if not within!--the heart. Evenutally, once you circulate once or twice and you have gotten a blood pressure, there goes a bolus to the brain and another to the liver for first pass metabolism (which, I suppose is your friend from a toxicity stand point...). Perpetual V-tac s/p CABG: I'd look for other causes after I have given all the anti-arrhythmics (mg, lido, amio), definitely consider going back on pump if things are not improving, check your gas, look at preservation technique (ST changes everywhere?), kinked graft, didn't de-air coronaries?, heart still cold? etc, etc....Have the balloon pump ready if needs be....

Everything went fine. Went back on bypass 150 amio IV push +gtt. Explained to the surgeon I wasn't comfortable giving another bolus of lido. Shocked him a third time... started competing with pacer, turned it off. SR in the mid 80's. Pressures 130's systolic with .5 mcg/min epi landing in the ICU (homeopathic dose).
Spoke to perfusion after the case. Well, it seems the cardiac anesthesiologist who was here before I arrived used to give some pretty massive doses of lido. His argument was hemodilution and the pump run allows you to give higher doses. With 1mg/kg IV bolus, you may not be achieving the levels you would be on a non-cardiac case. If perfusion is giving the Lido, it is not going directly into the heart. Going systemic first. Academic Dogma? Maybe, maybe not. I don't have experience with such doses. However, it is an entertaining thought. 1mg/kg in a cardiac vs noncardiac case will most definitely have different plasma levels. Lido toxicity may manifests itself with CV collapse under GA. So I'm sticking to my guns as it can not be easily defended in court.

 

[IN2B8R]

Everything went fine. Went back on bypass 150 amio IV push +gtt. Explained to the surgeon I wasn't comfortable giving another bolus of lido. Shocked him a third time... started competing with pacer, turned it off. SR in the mid 80's. Pressures 130's systolic with .5 mcg/min epi landing in the ICU (homeopathic dose).
Spoke to perfusion after the case. Well, it seems the cardiac anesthesiologist who was here before I arrived used to give some pretty massive doses of lido. His argument was hemodilution and the pump run allows you to give higher doses. With 1mg/kg IV bolus, you may not be achieving the levels you would be on a non-cardiac case. If perfusion is giving the Lido, it is not going directly into the heart. Going systemic first. Academic Dogma? Maybe, maybe not. I don't have experience with such doses. However, it is an entertaining thought. 1mg/kg in a cardiac vs noncardiac case will most definitely have different plasma levels. Lido toxicity may manifests itself with CV collapse under GA. So I'm sticking to my guns as it can not be easily defended in court.

Very good point. I bet that if one is actually on pump, perhaps 30-50% of the drug is actually getting delivered.... I think that Dr. Mets actually published a paper on this very topic...