Evidence-based guideline update for determining brain death in adults
D. AlanShewmon, UCLA, Neurology Dept., 2C135, Olive View-UCLA Med. Ctr., 14445 Olive View Dr., Sylmar, CA 91342-1495ashewmon@mednet.ucla.edu
Joseph L. Verheijde (Phoenix, AZ; Verheijde.Joseph@mayo.edu), Mohamed Y. Rady (Phoenix, AZ; rady.mohamed@mayo.edu)
Submitted August 31, 2010
The authors of the AAN’s guideline update primarily set out to use evidence-based methodology to reduce variations in brain death (BD) determination. [1] Although we agree with Wijdicks et al.’s conclusion that severe limitations remain in the scientific, evidence-based knowledge of this neurological condition and its accurate diagnosis, classifying the guidelines as evidence-based raises the following concerns.
The Uniform Determination of Death Act (UDDA) states that death is to be determined in accordance with accepted medical standards. These standards must confirm that the UDDA brain criterion of death has been met. Wijdicks et al. should reliably establish the irreversible cessation of all functions of the entire brain including the brainstem, yet neither “irreversibility” nor “function of the brain” (or “of the entire brain”) is defined. Both of these terms have engendered unresolved controversies. The Subcommittee does not identify the gold standard by which sensitivity, specificity, and predictive accuracy of the guidelines as a diagnostic tool are measured, with respect to either the irreversibility or the totality aspects. This gold standard does not and will never exist. Therefore, diagnostic guidelines for BD are inherently unable to be validated through an evidence-based methodology.
Critical elements in the guidelines received evidence level “U” including: safety of apnea test; time interval necessary to ascertain irreversibility of clinical examination findings; and interpretation of complex coordinated movements of supraspinal versus spinal origin. Guidelines largely relying on expert consensus rather than empirical facts should respect diversity of views. [10]
The lack of reports showing BD recovery following BD determination is a spurious form of validation, given that in nearly all cases either support is stopped or organs are harvested upon the diagnosis. Medico-legal concerns may also hamper submission of recovery cases to medical journals. There have been calls for editorial censorship of articles that heighten public doubts about death criteria for organ donation. [11] Finally, the bias in selecting supporting versus opposing articles of similar evidence level and excluding non-English articles to answer the five critical questions can weaken the scientific authority of the guidelines.
We agree with Dr. Wijdicks’ follow-up commentary [12]: “So, what are neurologists confirming? If documentation of a loss of all neuronal function is the ultimate goal for the definition of brain death, the goal is not attainable because no confirmatory test can provide such documentation with certainty.”
The same could be said about the clinical criteria, the “accuracy” of which is simply declared, not scientifically demonstrated. Concern regarding the validity of the clinical criteria has been reinforced by a recent report of two cases of well documented clinical BD with return of spontaneous respiration during the period of preparation for organ harvesting. [13]
11. Dubois JM. The ethics of creating and responding to doubts about death criteria. J Med Philos 2010;35:365-380.
12. Wijdicks EFM. The case against confirmatory tests for determining brain death in adults. Neurology 2010;75:77-83.
13. Roberts DJ, MacCulloch KAM, Versnick EJ, Hall RI. Should ancillary brain blood flow analyses play a larger role in the neurological determination of death? Can J Anesth/J Can Anesth. Epub 8/13/2010. DOI 10.1007/s12630-010-9359-4.
The authors of the AAN’s guideline update primarily set out to use evidence-based methodology to reduce variations in brain death (BD) determination. [1] Although we agree with Wijdicks et al.’s conclusion that severe limitations remain in the scientific, evidence-based knowledge of this neurological condition and its accurate diagnosis, classifying the guidelines as evidence-based raises the following concerns.
The Uniform Determination of Death Act (UDDA) states that death is to be determined in accordance with accepted medical standards. These standards must confirm that the UDDA brain criterion of death has been met. Wijdicks et al. should reliably establish the irreversible cessation of all functions of the entire brain including the brainstem, yet neither “irreversibility” nor “function of the brain” (or “of the entire brain”) is defined. Both of these terms have engendered unresolved controversies. The Subcommittee does not identify the gold standard by which sensitivity, specificity, and predictive accuracy of the guidelines as a diagnostic tool are measured, with respect to either the irreversibility or the totality aspects. This gold standard does not and will never exist. Therefore, diagnostic guidelines for BD are inherently unable to be validated through an evidence-based methodology.
Critical elements in the guidelines received evidence level “U” including: safety of apnea test; time interval necessary to ascertain irreversibility of clinical examination findings; and interpretation of complex coordinated movements of supraspinal versus spinal origin. Guidelines largely relying on expert consensus rather than empirical facts should respect diversity of views. [10]
The lack of reports showing BD recovery following BD determination is a spurious form of validation, given that in nearly all cases either support is stopped or organs are harvested upon the diagnosis. Medico-legal concerns may also hamper submission of recovery cases to medical journals. There have been calls for editorial censorship of articles that heighten public doubts about death criteria for organ donation. [11] Finally, the bias in selecting supporting versus opposing articles of similar evidence level and excluding non-English articles to answer the five critical questions can weaken the scientific authority of the guidelines.
We agree with Dr. Wijdicks’ follow-up commentary [12]: “So, what are neurologists confirming? If documentation of a loss of all neuronal function is the ultimate goal for the definition of brain death, the goal is not attainable because no confirmatory test can provide such documentation with certainty.”
The same could be said about the clinical criteria, the “accuracy” of which is simply declared, not scientifically demonstrated. Concern regarding the validity of the clinical criteria has been reinforced by a recent report of two cases of well documented clinical BD with return of spontaneous respiration during the period of preparation for organ harvesting. [13]
References
10. Sniderman AD, Furberg CD. Why guideline-making requires reform. JAMA 2009;301:429-431.
11. Dubois JM. The ethics of creating and responding to doubts about death criteria. J Med Philos 2010;35:365-380.
12. Wijdicks EFM. The case against confirmatory tests for determining brain death in adults. Neurology 2010;75:77-83.
13. Roberts DJ, MacCulloch KAM, Versnick EJ, Hall RI. Should ancillary brain blood flow analyses play a larger role in the neurological determination of death? Can J Anesth/J Can Anesth. Epub 8/13/2010. DOI 10.1007/s12630-010-9359-4.
Disclosure: The authors report no disclosures.