Apnea Testing for the Determination of Brain Death in Patients Supported by Extracorporeal Membrane Oxygenation
Bibliographic record
Abstract
The neurological criteria for brain death include coma, absent brain stem reflexes, and apnea. For patients on extracorporeal membrane oxygenation (ECMO), routine apnea testing is not possible because gas exchange occurs entirely through the membrane oxygenator. We describe the protocol we used to perform the apnea test and declare brain death in a patient on ECMO and review the literature of brain death testing in patients on ECMO. A 39-year-old female presented with cardiogenic shock followed by pulseless electrical activity (PEA) and eventually started on veno-arterial (VA) ECMO. Neurology was consulted for prognostication. Initial exam 48 hours after arrest showed absent brain stem reflexes. Another neurological exam 72 hours after arrest was compatible with brain death, so apnea test was performed. The apnea test involved preoxygenation, then she was disconnected from ventilator and the gas sweep rate decreased to 1 L/minute while maintaining the same blood flow rate. At 10 minutes, the PCO 2 level needed to declare brain death was achieved. With increasing use of ECMO to support critically ill patients, physicians should become familiar with the challenges this technology has created when testing for apnea in the determination of brain death. In this case report, we showed that apnea testing can be done in patients on ECMO without the need for ancillary testing. The mainstay of performing apnea testing on these patients is decreasing the gas sweep rate to 0.5 - 1 L/minute while maintaining the same blood flow rate. J Neurol Res. 2016;6(1):28-34 doi: http://dx.doi.org/10.14740/jnr376w
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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 | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".