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George E. Karras Jr is medical director of the intensive care unit at Mercy Medical Center, Springfield, Mass.
To purchase reprints, contact The InnoVision Group, 101 Columbia, Aliso Viejo, CA 92656. Phone, (800) 809-2273 or (949) 362-2050 (ext 532); fax, (949) 362-2049; e-mail, reprints{at}aacn.org.
Many excellent articles have been written about the diagnosis of brain death.1–9 These reviews present standards used in making a determination of brain death and highlight potential sources of confusion associated with brain death that may complicate or delay making the diagnosis.1–9
As part of the performance improvement program at Mercy Medical Center in Springfield, Mass, a decision was made to update the hospital’s brain death policy, implementing the most recent standards of practice. In addition to rewriting the hospital’s policy for diagnosing brain death, a decision was made to develop a user-friendly guideline in the form of a checklist and an instruction sheet to assist clinicians involved in determining and documenting brain death (Figures 1
and 2). The use of a checklist is not unique to one organization but is a commonly used approach. The checklist identified in this article is unique because it includes instructions for conducting the clinical examination, interpreting the findings, and documenting the results. The primary advantage of this approach is that all members of the healthcare team are aware of the criteria being used to make the diagnosis. Ease of access to this information also makes it more likely that consistent information will be communicated to all members of the healthcare team and to patients’ families.
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Criteria for Determining Brain Death
Brain death is defined as the irreversible loss of function of the brain, including the brain stem.2 The most common causes of brain death in adults are traumatic brain injury and subarachnoid hemorrhage.1
In the United States, principles of making a diagnosis of brain death are guided by the Uniform Determination of Death Act.8 Although this document sets the standards for using brain-based criteria to diagnose death, it does not specify the elements to be used in making the diagnosis. However, both individual experts1 and organizations, such as the American Academy of Neurology,2 have published guidelines for brain death protocols. Consequently, although fairly consistent criteria are used to diagnose brain death, variability exists across states and practice settings as a result of local legislation and institutional policy.8 Individual hospital practice may also vary, depending on available resources and physicians’ experience.
Current standards for making a diagnosis of brain death require (1) identification of the suspected cause of the coma, (2) determination that the coma is irreversible, (3) performance of a clinical examination, and (4) interpretation of appropriate neurodiagnostic and laboratory tests.1 Identification of the cause of coma is based on the patient’s history and the results of neurodiagnostic tests such as computed tomographic scans. Common causes of brain death detected on computed tomographic scans include brain masses with or without herniation and edema.1 In determining the cause of the coma, conditions that could confound the clinical assessment must also be ruled out, such as hypothermia, hypotension, severe acid-base abnormalities, drug or alcohol intoxication, sedation, and neuromuscular blockade.
The next step in diagnosing brain death is performing a directed, clinical examination. According to the American Academy of Neurology,2 each criterion of the clinical examination should be satisfied on 2 separate occasions. The length of time between examinations has not been defined and varies depending on the cause of the coma. The American Academy of Neurology2 has suggested that a 6-hour interval between examinations is reasonable; others1 have recommended a period of up to 48 hours in instances in which unknown toxins may be responsible for the coma. In addition, 2 conditions must be met before the clinical examination is conducted: the patient’s blood pressure should be greater than 90 mm Hg, and the patient’s body temperature should be greater than 32°C (90°F).
The clinical examination includes an evaluation of overall responsiveness, brain-stem reflexes, and apnea testing. The patient should be deeply comatose, with no response to painful or verbal stimuli, including decorticate or decerebrate posturing. He or she should also have no spontaneous movement, including shivering, seizures, or respiratory movement. The single exception is movement resulting from spinal reflexes. The assessment of responsiveness and movement requires that the effects of all neuromuscular blocking agents and sedatives have worn off completely (see Table).
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Once responsiveness and brain stem reflexes are deemed to be absent, an apnea test is performed as the final evaluation of brain stem function. Clinicians involved in performing the apnea test must be skilled in carrying out the procedure in order to avoid complications such as hypoxia and hypotension. (See Figure 2 for more details on conducting an apnea test.)
Because brain death is a clinical diagnosis, laboratory and radiological tests are indicated only when confounding variables must be ruled out (eg, drug or alcohol intoxication) or confirmatory evidence of brain death must be provided, when the findings on clinical examination are equivocal or a full examination cannot be performed (eg, with severe facial trauma).
Recommendations on the number and specialty of physicians required to make a diagnosis of brain death are not standardized. Although no data have indicated that a second assessment by a different physician will result in reduced error,1 hospital policies often require that 2 physicians be involved in making the diagnosis, particularly when organ retrieval is involved.4
Checklist for Determining Brain Death
Our guideline is in the form of a checklist that a patient’s physician initiates when the patient is suspected of being brain dead. The checklist includes an area for documenting the suspected cause of coma, findings of the clinical examination, and results of the apnea, laboratory, radiological, and other confirmatory tests, as well as the physician’s overall assessment. The checklist also includes an area for physicians’ signatures, allowing it to serve as a legal document.
Instructions for Completing the Determination of Brain Death Guideline
On the reverse side of the checklist is a comprehensive instruction sheet for clinicians. In addition to detailing the procedure for completing the checklist, it also provides information about the clinical examination and a brief description of the neurological assessment. The instruction sheet also includes information about performing and interpreting an apnea test (Figure 2).
Nurses’ Role in the Determination of Brain Death
Nurses play a critical role in the determination of brain death. Because of the role of nurses in the ongoing evaluation of patients, a nurse is often the first person to determine that a patient’s condition may warrant an assessment of brain death. Nurses also play a pivotal role in providing ongoing information to other team members and patients’ families.
It is vital, therefore, that nurses be aware of current standards for the determination of brain death. Nurses are intimately involved in the conduct of the clinical examination. This involvement requires knowledge of the specific indices that make up a clinical examination as well as an awareness of factors that may limit an evaluation or confound its findings (see Table).
Perhaps the most critical role of nurses in the determination of brain death is to provide support to patients’ family members during and after the diagnostic period. Accurate, understandable, timely, and consistent information is crucial to meeting important needs of patients’ family members during this time of crisis. It is impossible to overestimate the difference a caring and skilled nurse can make at this time. The ability to provide effective nursing care in this setting depends heavily on the level of communication and collaboration among members of the multidisciplinary team.
Conclusion
The importance of making an accurate diagnosis of brain death is obvious. What is not as obvious is the potential harm to patients’ family members that could result when the process used to make the diagnosis is less than optimal. Well-intentioned, yet uninformed clinicians can cause unnecessary stress for patients’ family members by prolonging the diagnostic process or inaccurately interpreting findings (eg, mistaking spinal reflexive movements as indicative of intact brain stem function).
No guideline or checklist can substitute for the extensive knowledge and judgment required to make a diagnosis of brain death. Because of the fast pace and complexity of the critical care setting, however, tools such as guidelines and protocols have obvious appeal, and their use in other complex processes, such as weaning from mechanical ventilation, has resulted in improve outcomes.
The multidisciplinary nature of critical care necessitates that all members of the team be knowledgeable about important care processes. Collaborating on a plan of care is critically important in the case of a potentially brain-dead patient. An awareness of the criteria for making a diagnosis of brain death ensures that this collaboration occurs, so that optimal outcomes can be achieved for all involved.
References
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