A Comparison of an Injection Cephalad or Caudad to the Division of the Sciatic Nerve for Ultrasound-Guided Popliteal Block
Bibliographic record
Abstract
To the Editor In a recent paper describing perioperative management of children with long QT syndromes (LQTS), Nathan et al.1 assert that normal transmural dispersion of repolarization (TDR), as measured by Tp-e interval (the interval from the peak to the end of the T wave on the surface electrocardiogram [ECG]) in children “is 40 to 50 milliseconds with the upper limit of normal considered to be 65 milliseconds. A TDR of >75 milliseconds has been found in patients with LQTS.” Neither of these assertions is referenced. Our group has published 4 studies of the effects of sevoflurane, propofol, droperidol, and ondansetron on transmural dispersion of repolarization in healthy children.2–5 All had preoperative baseline 12-lead ECGs. Table 1shows the mean (SD) preoperative Tp-e values from these studies. The mean pooled Tp-e value from 191 children in the latest 3 studies, wherein ECG analysis was performed by a pediatric electrophysiologist with a research interest in inherited arrhythmia substrates, was 64 ± 13 milliseconds. By the criteria of Nathan et al., 50% of these healthy children have Tp-e values above the upper limit of normal.Table 1: Preoperative Baseline Tp-e Values in Healthy ChildrenThe value of Tp-e as a surrogate marker of TDR remains to be proven; circumstantial evidence for its utility in this regard is reviewed in the article by Nathan et al. and in our manuscripts. If it is to be of clinical use, clearly, a normal reference range needs to be defined. Perhaps Nathan et al. can provide the source and provenance of the normal range data they have cited to allow a determination as to why they are so different than our reported normal values. Shubhayan Sanatani, MD, BSC, FRCPC Division of Pediatric Cardiology British Columbia's Children's Hospital Department of Pediatrics University of British Columbia Vancouver, British Columbia, Canada Simon Whyte, MBBS, FRCA Department of Pediatric Anesthesia British Columbia's Children's Hospital Department of Anesthesia, Pharmacology and Therapeutics University of British Columbia Vancouver, British Columbia, Canada [email protected]
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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 | 0.004 | 0.022 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".