Hemidiaphragmatic Paralysis Following Ultrasound-Guided Supraclavicular Versus Infraclavicular Brachial Plexus Blockade
Bibliographic record
Abstract
BACKGROUND AND OBJECTIVES: The comparative incidences of hemidiaphragmatic paralysis associated with contemporary ultrasound-guided supraclavicular versus infraclavicular blockade have not received extensive study. We tested the hypothesis that the infraclavicular approach results in a lower incidence of hemidiaphragmatic paralysis compared with supraclavicular blockade when a standard local anesthetic volume and concentration are used. METHODS: With institutional human ethics board approval, we enrolled 64 patients undergoing right-sided upper extremity surgery in a randomized, blinded, parallel-group trial. Patients were assigned to ultrasound-guided supraclavicular or infraclavicular blockade with 30 mL of 0.5% ropivacaine. The primary end point was complete hemidiaphragmatic paralysis at 30 minutes, defined as a greater than 75% reduction in diaphragmatic excursion measured with the voluntary sniff test using M-mode ultrasonography. Partial paralysis was defined as a 25% to 75% reduction. RESULTS: Eleven (34%) of 32 patients in the supraclavicular group versus 1 (3%) of 32 in the infraclavicular group had complete hemidiaphragmatic paralysis (P = 0.001 [1-tailed]; relative risk, 11.0 [95% confidence interval, 1.5-80.3]); 44% versus 13% had any (complete or partial) paralysis (P = 0.006; relative risk, 3.5 [95% confidence interval, 1.3-9.5]). Eight (25%) of 32 patients in the supraclavicular group versus 5 (16%) of 32 in the infraclavicular group reported dyspnea (P = 0.54). CONCLUSIONS: Ultrasound-guided supraclavicular blockade with 30 mL of 0.5% ropivacaine produced complete hemidiaphragmatic paralysis in approximately one-third of patients. The infraclavicular approach greatly reduced this risk but did not eliminate it. These data may aid in the selection of the approach to brachial plexus blockade, particularly in ambulatory patients and/or those with respiratory comorbidities.
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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 | 0.005 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".