Post Your Cases > LAST Manifesting as STE and QRS Changes after Pediatric Caudal
Thanks, Dr Lee for posting this most instructive and very well-handled case. You raise a number of interesting questions. Here's my best attempt:
1) When do you stop giving intralipid? Would you have started/kept the patient on a gtt, and if so, for how much time?
I think your decision to rely on bolus-only was very reasonable given the patient was entirely stable at that point. If I were to continue a drip it would only be for a short period, e.g., 5-10 minutes and this is entirely empirical. One most always be mindful not to overdose with lipid by staying below total doses ~10-12mL/kg. This is easy to do in cases where the lipid exerts benefit and the drip is kept going for that purpose...or if someone forgets to turn it off - this being a much more likely problem in an infant where you could creep up on the dosing limits pretty easily. The next important issue is how long to continue monitoring after that point, which leads in to your next question.
2) How long would you keep the patient in the hospital for?
The concern here is for late recurrence which has been reported in cases after recovery from full cardiac arrest. I think the clue here is that the patient already showed signs of recovery before the lipid started, suggesting that the blood/tissue levels of bupivacaine were already in decline. Generally, if there were only brief CNS symptoms I'm ok watching for a couple of hours (this can be in the OR, no need to cancel a case if the patient is recovered) and patients can go home absent any cardiovascular instability. However, with CV signs as in your patient's case some longer level of monitoring is indicated...the degree depending on the patient's clinical course. Given he was already improving and then treated with lipid, I think your choice of a 5 hour stay is entirely reasonable.
3) Would a test dose have helped in this case?
I should note from an anecdotal standpoint that before I developed an interest in LAST, I had a few OB cases where a threaded epidural showed just a tiny blush of heme on aspiration, so minimal in fact that I decided to try a test dose and was appalled to find in all cases the catheter was intravascular - no surprise, except that I was surprised. I think this speaks to our general state of denial...even in the face of heme. Such was not the case in your instance, since you saw heme at the same time as hemodynamics changed and you knew what was happening and what to do. You were injecting incrementally, in effect a test dose. The only thing to consider is whether you used a trace marker (epinephrine, for instance)? There is a bit of controversy about this, but it has saved me on a few occasions (including recently) - so I'm pretty strongly on the plus side there. Do you use epi? It might have helped.
4) Where do you think the bupivacaine was delivered? The block was clearly working, but the patient also had cardiac signs of LAST. Neither the patient nor I moved the needle during injection.
The timing (and heme) speaks in favor of intravascular entrainment, so as you point out, it was likely either into a vessel, or intraosseous (you describe the pop as 'drastic'). Either way, in my mind the needle orifice was partially in the vessel or medullary space and though most volume was delivered where intended, some of the delivered drug (but enough) went where you don't want it to.
Anyway, this is not an unusual occurrence - I was called about another nearly identical event last week - you handled it well and I'm so glad the patient did well, too.
1) When do you stop giving intralipid? Would you have started/kept the patient on a gtt, and if so, for how much time?
I think your decision to rely on bolus-only was very reasonable given the patient was entirely stable at that point. If I were to continue a drip it would only be for a short period, e.g., 5-10 minutes and this is entirely empirical. One most always be mindful not to overdose with lipid by staying below total doses ~10-12mL/kg. This is easy to do in cases where the lipid exerts benefit and the drip is kept going for that purpose...or if someone forgets to turn it off - this being a much more likely problem in an infant where you could creep up on the dosing limits pretty easily. The next important issue is how long to continue monitoring after that point, which leads in to your next question.
2) How long would you keep the patient in the hospital for?
The concern here is for late recurrence which has been reported in cases after recovery from full cardiac arrest. I think the clue here is that the patient already showed signs of recovery before the lipid started, suggesting that the blood/tissue levels of bupivacaine were already in decline. Generally, if there were only brief CNS symptoms I'm ok watching for a couple of hours (this can be in the OR, no need to cancel a case if the patient is recovered) and patients can go home absent any cardiovascular instability. However, with CV signs as in your patient's case some longer level of monitoring is indicated...the degree depending on the patient's clinical course. Given he was already improving and then treated with lipid, I think your choice of a 5 hour stay is entirely reasonable.
3) Would a test dose have helped in this case?
I should note from an anecdotal standpoint that before I developed an interest in LAST, I had a few OB cases where a threaded epidural showed just a tiny blush of heme on aspiration, so minimal in fact that I decided to try a test dose and was appalled to find in all cases the catheter was intravascular - no surprise, except that I was surprised. I think this speaks to our general state of denial...even in the face of heme. Such was not the case in your instance, since you saw heme at the same time as hemodynamics changed and you knew what was happening and what to do. You were injecting incrementally, in effect a test dose. The only thing to consider is whether you used a trace marker (epinephrine, for instance)? There is a bit of controversy about this, but it has saved me on a few occasions (including recently) - so I'm pretty strongly on the plus side there. Do you use epi? It might have helped.
4) Where do you think the bupivacaine was delivered? The block was clearly working, but the patient also had cardiac signs of LAST. Neither the patient nor I moved the needle during injection.
The timing (and heme) speaks in favor of intravascular entrainment, so as you point out, it was likely either into a vessel, or intraosseous (you describe the pop as 'drastic'). Either way, in my mind the needle orifice was partially in the vessel or medullary space and though most volume was delivered where intended, some of the delivered drug (but enough) went where you don't want it to.
Anyway, this is not an unusual occurrence - I was called about another nearly identical event last week - you handled it well and I'm so glad the patient did well, too.
November 1, 2016 |
[Guy Weinberg]
[Guy Weinberg]
The operation proceeded smoothly without adverse surgical or anesthetic events. The patient remained stable for the entire case.
In the PACU, the patient woke up from anesthesia without issues. At two hours post-op, patient was fully awake, smiling, interactive at his baseline, moving all extremities, and appeared very comfortable. Approximately 5 hours and 45 minutes into his PACU stay, it was felt he had been stable enough to be discharged home.
Some questions that came up within our institution I would like to pose to the community:
1) When do you stop giving intralipid? Would you have started/kept the patient on a gtt, and if so, for how much time?
2) How long would you keep the patient in the hospital for?
3) Would a test dose have helped in this case?
4) Where do you think the bupivacaine was delivered? The block was clearly working, but the patient also had cardiac signs of LAST. Neither the patient nor I moved the needle during injection.
Thanks very much and I appreciate your opinion and expertise!