Total Local Anesthetic Administered Is Integral to the Syndrome of Local Anesthetic Systemic Toxicity
Bibliographic record
Abstract
We read with interest the report of local anesthetic systemic toxicity in the recent issue of Anesthesiology.1 The authors deserve credit for their review of the subject and detailed analysis of factors culminating in the death of their patient. The transparency required to present such a case is of benefit to all anesthesiologists, who can apply the principles described to improve safety for patients undergoing regional anesthesia techniques.However, we were concerned that one integral factor contributing to the poor outcome in this case was not discussed, and that is the total dose of local anesthetic (LA) administered. We believe that a relative overdose of LA was administered and subsequent systemic absorption was likely a factor in the toxicity observed.Total doses of LA used include 30 ml of mepivacaine 1.5% without epinephrine (450 mg) plus 10 ml of bupivacaine 0.25% with epinephrine 1:200,000 (25 mg). The dose of mepivacaine exceeds the manufacturer’s recommended maximum dose of 400 mg for an adult.2 Of note, the manufacturer’s product information inserts for mepivacaine and bupivacaine additionally caution that the dose should be reduced for elderly or debilitated patients.*†Further to this point, maximum adult doses for LAs cited in textbooks often assume a adult patient of 70 kg.2 When treating a patient less than the assumed weight, 45 kg in this case, the dose must be reduced. Lastly, an elderly, American Society of Anesthesiologists physical status 4 patient is presumed to have impaired hepatic and renal function, as well as increased susceptibility to toxicity because of cardiovascular disease and reduced serum protein binding capacity.3 All these factors conspire to put such a patient at risk of local anesthetic systemic toxicity from seemingly “normal” doses of LA.When a regional technique is chosen, LA dosing must take into account patient factors predisposing to local anesthetic systemic toxicity, and doses of LA must be reduced accordingly.The authors declare no competing interests.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.018 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.003 |
| Scholarly communication | 0.002 | 0.005 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.010 | 0.013 |
| Insufficient payload (model declined to judge) | 0.003 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".