Thoracic Epidural Catheter Placement in Infants via the Caudal Approach Under Electrocardiographic Guidance: Simplification of the Original Technique
Bibliographic record
Abstract
To the Editor: In a previous study published in this journal (1), we proposed the use of electrocardiography (ECG) to guide the tip of an epidural catheter from caudal space to thoracic region. In this prospective study, simultaneous ECG tracings were recorded via the epidural catheter and the target spinal surface ECG using a modified 2-channel 5-lead ECG system with lead II, III mode. This technique required replacing a commonly used standard 3-lead cable with a 5-lead ECG cable, which is not always readily available in pediatric anesthesia. To solve this problem, we have simplified our ECG technique to allow the use of a standard 3-lead ECG (Fig. 1). First, a standard ECG (lead II) is recorded by connecting the right-arm electrode (white) to a skin electrode on the patient’s back at the target spinal level, while the left-arm electrode (black) and left-leg electrode (red) are placed at their standard position. The shape of this initial ECG must be remembered or a hard copy must be taken as a reference for later. Next, the right-arm electrode is connected to the metal hub of the ECG adapter to record a tracing from the epidural catheter. A satisfactory tracing (lead II) is obtained when the epidural catheter is filled with saline allowing the catheter tip to become a unipolar ECG electrode. The catheter is then advanced from the caudal space until the tip reaches the target level as demonstrated by a match between its ECG configuration and the initial surface ECG. Figure 1.: Simplification of the epidural ECG technique.Ban C. H. Tsui, MD, FRCP(C)
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.011 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.005 | 0.006 |
| Insufficient payload (model declined to judge) | 0.001 | 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".