Epidural Hematoma After Anticoagulation with a Thoracic Epidural Catheter in Place: A Mere Coincidence?
Bibliographic record
Abstract
To the Editor: We read with great interest the article by Rosen et al. (1), who present a case of epidural hematoma after aortic valve surgery. Since we regularly use epidural analgesia in aortic valve surgery (2), we would like to comment on a few issues of the above-mentioned article. There are plenty of cases in the literature where epidural hematomas occurred in patients under anticoagulation or with coagulative disorders without surgery and without epidural catheter in place (3–6). The combination of full heparinization and the application of a thrombolytic drug greatly increase the risk of hematoma formation (7). The mere fact that there is an epidural catheter in place (for almost 50 h without problems) and blood is apparent in the catheter does not necessary mean that the catheter is the reason for bleeding. In a causal sense, the hematoma was formed when the patient was fully heparinized and a thrombolytic drug was injected more than 49 h after surgery and placement of the catheter—it could also have occurred without the catheter. The authors hypothesized that blood loss through the catheter helped to decrease the pressure effects and that—had the catheter not been removed but left in place—the same progression of symptoms would have occurred, only over a longer period of time. We believe that another hypothesis is also possible: since the disturbed coagulation was the key factor to cause the problems, would a correction of these disturbances before catheter removal not have avoided the formation of hematoma? Until the correction of the apparent coagulation problems, the catheter could have been used to release the pressure (and the blood); after removal of the catheter during normal coagulation, no hematoma might have had developed. It is very important to note that the initial anticoagulation during surgery did not create problems; almost 50 h after surgery went by without any complication. There is one study (8) presenting more than 300 cases of epidural catheters in aortic valve surgery without any neurological complication. However, epidural analgesia after heart valve surgery is more complicated because of the need of anticoagulation whenever a mechanical prosthesis is installed. It is important to remove the catheter before warfarin causes an elevation of INR of more than 1.5 (7). Removal of epidural catheter at a greatly elevated aPTT has been causing hematomas before in other types of surgery (9). It is not a unique feature of cardiac surgery. It is very important that major disturbances of the coagulation system are corrected or, if possible, avoided in any patient having an epidural catheter in place. We would like to stress that the formation of epidural hematoma in this patient occurred at inadvertent postoperative anticoagulation with full heparinization and application of a thrombolytic drug. This, in our view, would have been able to occur after any type of surgery, with or without epidural catheter. The disturbances of coagulation after surgery are common after other types of major surgery where the use of epidural anesthesia is well established, such as major vascular surgery or abdominal surgery. Thomas M. Hemmerling, MD, DEAA Jean-François Olivier, MD Perioperative Cardiac Research Group (PECARG) Department of Anesthesiology Fadi Basile, MD, FRCP(S) Ignatio Prieto, MD, FRCP(S) Perioperative Cardiac Research Group (PECARG) Department of Cardiac Surgery Université de Montréal Montréal, Canada
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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".