Abstract: Epidural Nerve Blocks Increase Intraoperative Vasopressor Consumption and Delay Surgical Start Time Compared to General Anesthesia Alone in DIEP Free Flap Breast Reconstruction
Bibliographic record
Abstract
PURPOSE: The use of epidural anesthesia (EA) as an adjunct to general anesthesia (GA) has been widely used in abdominal and thoracic surgeries, and recently shown efficacy in autologous breast reconstruction.1–3 While the utility of reducing postoperative narcotic consumption, nausea, and length-of-stay in hospital cannot be understated, concerns remain as to the whether these blocks reduce operating room efficiency by delaying case start time and whether block-induced hypotension is associated with increased intraoperative vasopressor requirements. The purpose of this study was to examine the effectiveness of epidural blocks in patients undergoing deep inferior epigastric perforator (DIEP) flap breast reconstruction. METHODS: A retrospective analysis from 2015–2017 of patients who underwent DIEP flap reconstruction under GA, with and without EA and no supplementary local anesthetic. Electronic records were analyzed for patient demographics, intraoperative data, and postoperative outcomes. Primary outcome was 48-hour narcotic usage. Secondary outcomes were intraoperative vasopressor consumption, surgical delay time, and safety. RESULTS: Fifty-one patients underwent DIEP reconstruction, 40(78%) underwent EA in addition to GA, and 11(22%) underwent GA alone. There was a significant delay in OR start time in the EA/GA group (67min vs 43min, p=0.001.) Patients in the EA/GA group also had a statistically significant increase in vasopressor use (n=33 vs n=5, p=0.021). Postoperatively, patients who received an epidural block had a reduced average pain score (1 vs 2, p=0.05), but there was no difference in 48-hour narcotic usage. CONCLUSION: Epidural blocks improve average postoperative pain, while increasing intraoperative vasopressor use and delaying the start time of the case. The benefits of improved pain control must continue to be weighed against the potential for increased surgical complications, as well as increased costs to the health care system. REFERENCES: 1. Pei, Lijian, et al. “Ultrasound-assisted thoracic paravertebral block reduces intraoperative opioid requirement and improves analgesia after breast cancer surgery: a randomized, controlled, single-center trial.” PloS one 10.11 (2015): e0142249. 2. Zhong, Toni, et al. “Transversus abdominis plane (TAP) catheters inserted under direct vision in the donor site following free DIEP and MS-TRAM breast reconstruction: a prospective cohort study of 45 patients.” Journal of Plastic, Reconstructive & Aesthetic Surgery 66.3 (2013): 329–336. 3. Lou, Feifei, et al. “Epidural combined with general anesthesia versus general anesthesia alone in patients undergoing free flap breast reconstruction.” Plastic and reconstructive surgery 137.3 (2016): 502e-509e.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 teacher head, 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".