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Evidence-based guideline update: Determining brain death in adults : Report of the Quality Standards Subcommittee of the American Academy of Neurology

Eelco F.M. Wijdicks, Panayiotis N. Varelas, Gary S. Gronseth, et al. Neurology 2010;74;1911 DOI 10.1212/WNL.0b013e3181e242a8 This information is current as of January 11, 2012

The online version of this article, along with updated information and services, is located on the World Wide Web at: http://www.neurology.org/content/74/23/1911.full.html

Neurology is the official journal of the American Academy of Neurology. Published continuously since 1951, it is now a weekly with 48 issues per year. Copyright 2010 by AAN Enterprises, Inc. All rights reserved. Print ISSN: 0028-3878. Online ISSN: 1526-632X.

SPECIAL ARTICLE

Evidence-based guideline update: Determining brain death in adults

Report of the Quality Standards Subcommittee of the American Academy of Neurology

Eelco F.M. Wijdicks, MD, PhD Panayiotis N. Varelas, MD, PhD Gary S. Gronseth, MD David M. Greer, MD, MA

ABSTRACT

Objective: To provide an update of the 1995 American Academy of Neurology guideline with regard

to the following questions: Are there patients who fulfill the clinical criteria of brain death who recover neurologic function? What is an adequate observation period to ensure that cessation of neurologic function is permanent? Are complex motor movements that falsely suggest retained brain function sometimes observed in brain death? What is the comparative safety of techniques for determining apnea? Are there new ancillary tests that accurately identify patients with brain death?

Address correspondence and reprint requests to the American Academy of Neurology, 1080 Montreal Avenue, St. Paul, MN 55116 [email protected]

Methods: A systematic literature search was conducted and included a review of MEDLINE and EMBASE from January 1996 to May 2009. Studies were limited to adults (aged 18 years and older). Results and recommendations: In adults, there are no published reports of recovery of neurologic

function after a diagnosis of brain death using the criteria reviewed in the 1995 American Academy of Neurology practice parameter. Complex-spontaneous motor movements and falsepositive triggering of the ventilator may occur in patients who are brain dead. There is insufficient evidence to determine the minimally acceptable observation period to ensure that neurologic functions have ceased irreversibly. Apneic oxygenation diffusion to determine apnea is safe, but there is insufficient evidence to determine the comparative safety of techniques used for apnea testing. There is insufficient evidence to determine if newer ancillary tests accurately confirm the cessation of function of the entire brain. Neurology 2010;74:1911–1918

GLOSSARY

AAN American Academy of Neurology; CI confidence interval; CPAP continuous positive airway pressure; CTA CT angiography; HMPAO Tc 99mHexametazime; MRA magnetic resonance angiography; PEEP pos

itive end-expiratory pressure; SSEP somatosensory evoked potential; TCD transcranial Doppler; UDDA Uniform Determination of Death Act.

The President’s Commission report on “guidelines for the determination of death”1 culminated in a proposal for a legal definition that led to the Uniform Determination of Death Act (UDDA). The act reads as follows: “An individual who has sustained either 1) irreversible cessation of circulatory and respiratory functions, or 2) irreversible cessation of all functions of the entire brain, including the brain stem, is dead. A determination of death must be made with accepted medical standards.”2 Most US state laws have adopted the UDDA. Several states have added amendments regarding physician qualifications, confirmation by a second physician, or religious exemption.

Supplemental data at www.neurology.org

The UDDA does not define “accepted medical standards.” The American Academy of Neurology (AAN) published a 1995 practice parameter to delineate the medical standards for the determination of brain death.3 The parameter emphasized the 3 clinical findings necessary to confirm irreversible cessation of all functions of the entire brain, including the brain stem: coma (with a known cause), absence of brainstem reflexes, and apnea. Despite publication of the practice parameter, considerable practice variation remains. In leading US hospitals, variations were found in prerequisites, the lowest acceptable core temperature, and the number of required examinations, among oth-

From the Division of Critical Care Neurology (E.F.M.W.), Mayo Clinic, Rochester, MN; Department of Neurology (P.N.V.), Henry Ford Hospital, Detroit, MI; Department of Neurology (G.S.G.), University of Kansas Medical Center, Kansas City; and Department of Neurology (D.M.G.), Massachusetts General Hospital, Boston. Appendices e-1– e-4 and references e1– e5 are available on the Neurology Web site at www.neurology.org. Approved by the Quality Standards Subcommittee on August 22, 2009; by the Practice Committee on October 15, 2009; and by the AAN Board of Directors on February 11, 2010. Disclosure: Author disclosures are provided at the end of the article. Copyright 2010 by AAN Enterprises, Inc. 1911

ers.4 Additionally, audits of charts of patients diagnosed with brain death show common deficiencies in documentation.5 This update sought to use evidence-based methods to answer 5 questions historically related to variations in brain death determination4 to promote uniformity in diagnosis: 1. Are there patients who fulfill the clinical criteria of brain death who recover brain function? 2. What is an adequate observation period to ensure that cessation of neurologic function is permanent? 3. Are complex motor movements that falsely suggest retained brain function sometimes observed in brain death? 4. What is the comparative safety of techniques for determining apnea? 5. Are there new ancillary tests that accurately identify patients

with brain death?

DESCRIPTION OF THE ANALYTIC PROCESS A literature search was conducted of MEDLINE and EMBASE from January 1996 to May 2009. Search terms included the MeSH term “brain death” and the text words “brain death,” “irreversible coma,” and “apnea test.” Studies were limited to those involving adults (aged 18 years and older) and those in English. Articles were included if they contained evidence relevant to one of the questions. We excluded articles that confirmed prior observations, review articles, bioethical reviews, articles without description of a brain death examination, articles with questionable practices (e.g., using laboratory tests in patients treated with sedative drugs), and articles describing infrequently used ancillary technology (e.g., jugular venous saturation). Articles were independently rated by at least 2 panel members based on the AAN evidence classification system (appendix e-3 on the Neurology Web site at www.neurology.org). Articles pertinent to questions 1, 2, 4, and 5 were rated using the diagnostic accuracy scheme. Articles pertinent to question 3 were rated using the screening scheme. Differences in rating were resolved by discussion. Recommendations were linked to the strength of the evidence (appendix e-4). ANALYSIS OF EVIDENCE

ance.6-14 The description of the examinations provided in these studies indicated that a complete brain death examination was not performed in any of these patients. We found no reports in peer-reviewed medical journals of recovery of brain function after a determination of brain death using the AAN practice parameter. Conclusion. In adults, recovery of neurologic function has not been reported after the clinical diagnosis of brain death has been established using the criteria given in the 1995 AAN practice parameter.

What is an adequate observation period to ensure that cessation of neurologic function is permanent? Rec-

ommendations for the length of observation periods have varied extensively throughout the world and the United States.5,15 There are no detailed studies on serial examinations in adult patients who have been declared brain dead. Conclusion. There is insufficient evidence to determine the minimally acceptable observation period to ensure that neurologic functions have ceased irreversibly.

Are complex motor movements that falsely suggest retained brain function sometimes observed in brain death? Six Class III studies described spontaneous

The search yielded 367 articles, and 38 met inclusion criteria.

Are there patients who fulfill the clinical criteria of brain death who recover brain function? Nine Class

IV studies have been published on the recognition of brain-death mimics, including fulminant GuillainBarre syndrome, organophosphate intoxication, ´ high cervical spinal cord injury, lidocaine toxicity, baclofen overdose, and delayed vecuronium clear1912 Neurology 74 June 8, 2010

and reflex movements in patients meeting criteria for brain

death. These included single reports of facial myokymia, transient bilateral finger tremor, repetitive leg movements, ocular microtremor, and cyclical constriction and dilatation in light-fixed pupils.16-21 One Class III study of 144 patients pronounced brain dead found 55% (95% confidence interval [CI] 47– 63) of patients had retained plantar reflexes, either flexion or “stimulation induced undulating toe flexion.”22 Another study documented plantar flexion and flexion synergy bilaterally that persisted for 32 hours after the determination of brain death.23 Two Class III studies suggested that the ventilator may sense small changes in tubing pressure and provide a breath that could suggest breathing effort by the patient where none exists.24,25 This phenomenon is more common in current ventilators and in patients who have had chest tubes placed. Changes in transpleural pressure from the heartbeat may also trigger the ventilator. These studies suggest that the determination of apnea can be assessed reliably only by disconnecting the ventilator.24,25 Conclusion. For some patients diagnosed as brain dead, complex, non– brain-mediated spontaneous movements can falsely suggest retained brain function. Additionally, ventilator autocycling may falsely suggest patient-initiated breathing.

What is the comparative safety of techniques for determining apnea? There have been 4 published studies

on the technique of apnea tests, none of which com-

pared 1 technique to another; thus, all were Class IV. One study used preoxygenation and an apneic oxygenation-diffusion technique in 212 patients.26 In 16 patients (7%) apnea testing was not attempted due to inability to maintain a stable blood pressure, high positive end expiratory pressure requirements, or refractory hypoxemia despite pretest oxygenation using 100% oxygen for 10 minutes. The apnea test was aborted in 3% of patients due to progressive hypotension or hypoxemia after ventilator disconnection.26 One study of 20 adults examined disconnection of the ventilator using a T-piece and continuous positive airway pressure (CPAP) valve (CPAP valve of 10 cm of water and oxygen administration at 12 L/min). Apnea testing could be completed in all patients with the additional use of a CPAP valve.27 Two studies have suggested monitoring of the apnea test with transcutaneous carbon dioxide partial pressure monitoring. However, comparison with predicting PCO2 rise using an estimated 3 mm Hg increase per minute has not been performed. It is unclear whether this device reduces blood gas testing (and thus cost) during the apnea test.28,29 Conclusion. Apneic oxygenation diffusion to determine apnea is safe, but there is insufficient evidence to determine the comparative safety of techniques used for apnea testing.

Are there new ancillary tests that accurately identify patients with brain death? MRI and magnetic resonance

One Class II30 and 3 Class IV31-33 studies examined MRI and magnetic resonance angiograp

hy (MRA). Two Class IV31,32 case series of 19 patients meeting clinical and EEG criteria for brain death documented loss of flow voids in the cavernous portion of the carotid artery with MRA. In these studies, MRA attained a sensitivity for brain death by clinical and EEG criteria of 100% (95% CI 83%–100%). Because patients not meeting clinical criteria for brain death were not included in these studies, it was not possible to determine the false-positive rate of MRA for brain death from these Class IV studies. A Class II30 case-control study of 20 patients who were clinically diagnosed as brain dead also included 10 patients who were comatose but not brain dead. MRA revealed absent arterial flow in the intracerebral circulation only in patients diagnosed as brain dead (sensitivity 100%, 95% CI 84%–100%; specificity 100%, 95% CI 72.2%–100%).30 This study lacked the statistical precision to confidently state that the false-positive rate of MRA was acceptably low (study consistent with a false-positive rate up to 27.8%). CT angiography. Five Class IV studies34-38 and 1 Class III study documented the results of CT angiogangiography.

raphy (CTA) in patients meeting clinical criteria for brain death. One case series showed intracranial opacification of blood vessels in 10 of 21 patients (48%; 95% CI 26%– 69%) with isoelectric EEGs.34 In another case series, 13 of 43 patients with absent opacification of intracranial blood vessels on cerebral angiography had CTA-demonstrated intracranial blood flow (30%; 95% CI 17%– 43%).35 A Class IV study36 of 105 patients found residual opacified vessels on CTA in up to 56% of patients. A Class IV study of 27 patients found CTA evidence of opacification of intracranial vessels in 3 patients.37 One case report documented preserved flow on transcranial Doppler (TCD) but no opacification of intracranial vessels in 1 patient.38 These Class IV studies included only patients meeting criteria for brain death. One Class III case-control study39 included patients meeting criteria for brain death and normal controls. CTA demonstrated no flow in 14 patients diagnosed with brain death (sensitivity 100%, 95% CI 78.5%–100%). CTA demonstrated cerebral flow in all normal controls (false-positive rate 0%, 95% CI 0%–25.9%). This study did not include nonbrain-dead comatose patients. Thus, the falsepositive rate of CTA in patients with loss of most brainstem reflexes, but who are not brain dead, cannot be determined. Somatosensory evoked potentials. Two Class III studies examined the use of nasopharyngeal electrode recording of somatosensory evoked potentials (SSEPs) to confirm brain death.40,e1 One cohort survey of 181 comatose patients found disappearance of P14 (presumably generated in the medial lemniscus and cuneate nucleus) on nasopharyngeal electrode SSEP recordings in all 108 patients diagnosed with brain death by clinical criteria (sensitivity 100%, 95% CI 96.6%–100%). In comatose patients who were not brain

dead, the P14 was never absent (specificity 100%, 95% CI 95%–100%).40 In this study it was unclear if SSEPs were interpreted without knowledge of the patient’s brain death status. A Class III cohort survey of 28 patients demonstrated similar findings.e1 These studies suggest that P14 recordings using midfrontal scalp-nasopharyngeal montage could be a valuable confirmatory test. However, the technique has not been used on a routine basis and interobserver variability studies have not been performed.40 Bispectral index. One Class III study evaluated bispectral index monitoring in 54 patients and noted a gradual decline in bispectral index values to 0 in 9 patients, implicating isoelectric EEG. Bispectral index was compared with EEG in 24 patients and with TCD in 18 patients; no discrepancies were found.e2

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The technology is rarely used in intensive care units and has not been compared to flow studies. Conclusion. Because of a high risk of bias and inadequate statistical precision, there is insufficient evidence to determine if any new ancillary tests accurately identify brain death.

RECOMMENDATIONS

amining the safety of the apnea test, seeking alternative methods of apnea testing, performing an audit of adequate documentation, and studying the competence of examiners. Details of the neurologic examination may be subjected to an expert panel review, possibly including international organizations.

PRACTICAL (NON–EVIDENCE-BASED) GUIDANCE FOR DETERMINATION OF BRAIN DEATH Many of

1. The criteria for the determination of brain death given in the 1995 AAN practice parameter have not been invalidated by published reports of neurologic recovery in patients who fulfill these criteria (Level U). 2. There is insufficient evidence to determine the minimally acceptable observation period to ensure that neurologic functions have ceased irreversibly (Level U). 3. Complex-spontaneous motor movements and false-positive triggering of the ventilator may occur in patients who are brain dead (Level C). 4. There is insufficient evidence to determine the comparative safety of techniques used for apnea testing (Level U). 5. There is insufficient evidence to determine if newer ancillary tests accurately confirm the cessation of function of the entire brain (Level U). This review highlights severe limitations in the current evidence base. Indeed, there is only 1 study that prospectively derived criteria for the determination of brain death.e3 Despite the paucity of evidence, much of the framework necessary for the development of “accepted medical standards” for the declaration of brain death is based on straightforward principles. These principles can be derived from the definition of brain death provided by the UDDA. To determine “cessation of all functions of the entire brain, including the brain stem,” physicians must determine the presence of unresponsive coma, the absence of brainstem reflexes, and the absence of respirato

ry drive after a CO2 challenge. To ensure that the cessation of brain function is “irreversible,” physicians must determine the cause of coma, exclude mimicking medical conditions, and observe the patient for a period of time to exclude the possibility of recovery. The UDDA-derived principles define the essential elements needed to determine brain death. However, because of the deficiencies in the evidence base, clinicians must exercise considerable judgment when applying the criteria in specific circumstances.

CLINICAL CONTEXT RECOMMENDATIONS FOR FUTURE RESEARCH

the details of the clinical neurologic examination to determine brain death cannot be established by evidence-based methods. The detailed brain death evaluation protocol that follows is intended as a useful tool for clinicians. It must be emphasized that this guidance is opinion-based. Alternative protocols may be equally informative. The determination of brain death can be considered to consist of 4 steps. I. The clinical evaluation (prerequisites). A. Establish irreversible and proximate cause of coma. The cause of coma can usually be established by history, examination, neuroimaging, and laboratory tests. Exclude the presence of a CNS-depressant drug effect by history, drug screen, calculation of clearance using 5 times the drug’s half-life (assuming normal hepatic and renal function), or, if available, drug plasma levels below the therapeutic range. Prior use of hypothermia (e.g., after cardiopulmonary resuscitation for cardiac arrest) may delay drug metabolism. The legal alcohol limit for driving (blood alcohol content 0.08%) is a practical threshold below which an examination to determine brain death could reasonably proceed. There should be no recent administration or continued presence of neuromuscular blocking agents (this can be defined by the presence of a train of 4 twitches with maximal ulnar nerve stimulation). There should be no severe electrolyte, acidbase, or endocrine disturbance (defined by severe acidosis or laboratory values markedly deviated from the norm). B. Achieve normal core temperature. In most patients, a warming blanket is needed to raise the body temperature and maintain a normal or near-normal temperature ( 36°C). After the initial equilibration of arterial CO2 with mixed central venous CO2, the PaCO2 rises steeply, but then more slowly when the body metabolism raises PaCO2.To avoid delaying an increase in

Future prospective studies of brain death determination are needed. Areas of future research include ex1914 Neurology 74 June 8, 2010

PaCO2, normal or near-normal core temperature is preferred during the apnea test. C. Achieve normal systolic blood pressure. Hypotension from loss of peripheral vascular tone or hypovolemia (diabetes insipidus) is common; vasopressors or vasopressin are often required. Neurologic examination is usually reliable with a systolic blood pressure 100 mm Hg. D. Perform 1 neurologic examination (sufficient to pronounce

brain death in most US states). If a certain period of time has passed since the onset of the brain insult to exclude the possibility of recovery (in practice, usually several hours), 1 neurologic examination should be sufficient to pronounce brain death. However, some US state statutes require 2 examinations. Legally, all physicians are allowed to determine brain death in most US states. Neurologists, neurosurgeons, and intensive care specialists may have specialized expertise. It seems reasonable to require that all physicians making a determination of brain death be intimately familiar with brain death criteria and have demonstrated competence in this complex examination. Brain death statutes in the United States differ by state and institution. Some US state or hospital guidelines require the examiner to have certain expertise. II. The clinical evaluation (neurologic assessment). A. Coma. • Patients must lack all evidence of responsiveness. Eye opening or eye movement to noxious stimuli is absent. Noxious stimuli should not produce a motor response other than spinally mediated reflexes. The clinical differentiation of spinal responses from retained motor responses associated with brain activity requires expertise. B. Absence of brainstem reflexes. • Absence of pupillary response to a bright light is documented in both eyes. Usually the pupils are fixed in a midsize or dilated position (4–9 mm). Constricted pupils suggest the possibility of drug intoxication. When uncertainty exists, a magnifying glass should be used. • Absence of ocular movements using oculocephalic testing and oculovestibular reflex testing.

Once the integrity of the cervical spine is ensured, the head is briskly rotated horizontally and vertically. There should be no movement of the eyes relative to head movement. The oculovestibular reflex is tested by irrigating each ear with ice water (caloric testing) after the patency of the external auditory canal is confirmed. The head is elevated to 30 degrees. Each external auditory canal is irrigated (1 ear at a time) with approximately 50 mL of ice water. Movement of the eyes should be absent during 1 minute of observation. Both sides are tested, with an interval of several minutes. • Absence of corneal reflex. Absent corneal reflex is demonstrated by touching the cornea with a piece of tissue paper, a cotton swab, or squirts of water. No eyelid movement should be seen. • Absence of facial muscle movement to a noxious stimulus. Deep pressure on the condyles at the level of the temporomandibular joints and deep pressure at the supraorbital ridge should produce no grimacing or facial muscle movement. • Absence of the pharyngeal and tracheal reflexes. The pharyngeal or gag reflex is tested after stimulation of the posterior pharynx with a tongue blade or suction device. The tracheal reflex is most reliably tested by examining the cough response to tracheal suctioning. The catheter should be inserted into the trachea

and advanced to the level of the carina followed by 1 or 2 suctioning passes. C. Apnea. • Absence of a breathing drive. Absence of a breathing drive is tested with a CO2 challenge. Documentation of an increase in PaCO2 above normal levels is typical practice. It requires preparation before the test. Prerequisites: 1) normotension, 2) normothermia, 3) euvolemia, 4) eucapnia (PaCO2 35–45 mm Hg), 5) absence of hypoxia, and 6) no prior evidence of CO2 retention (i.e., chronic obstructive pulmonary disease, severe obesity). Procedure: • Adjust vasopressors to a systolic blood pressure 100 mm Hg.

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• Preoxygenate for at least 10 minutes with 100% oxygen to a PaO2 200 mm Hg. • Reduce ventilation frequency to 10 breaths per minute to eucapnia. • Reduce positive end-expiratory pressure (PEEP) to 5 cm H2O (oxygen desaturation with decreasing PEEP may suggest difficulty with apnea testing). • If pulse oximetry oxygen saturation remains 95%, obtain a baseline blood gas (PaO2, PaCO2, pH, bicarbonate, base excess). • Disconnect the patient from the ventilator. • Preserve oxygenation (e.g., place an insufflation catheter through the endotracheal tube and close to the level of the carina and deliver 100% O2 at 6 L/min). • Look closely for respiratory movements for 8–10 minutes. Respiration is defined as abdominal or chest excursions and may include a brief gasp. • Abort if systolic blood pressure decreases to 90 mm Hg. • Abort if oxygen saturation measured by pulse oximetry is 85% for 30 seconds. Retry procedure with T-piece, CPAP 10 cm H2O, and 100% O2 12 L/min. • If no respiratory drive is observed, repeat blood gas (PaO2, PaCO2, pH, bicarbonate, base excess) after approximately 8 minutes. • If respiratory movements are absent and arterial PCO2 is 60 mm Hg (or 20 mm Hg increase in arterial PCO2 over a baseline normal arterial PCO2), the apnea test result is positive (i.e., supports the clinical diagnosis of brain death). • If the test is inconclusive but the patient is hemodynamically stable during the procedure, it may be repeated for a longer period of time (10–15 minutes) after the patient is again adequately preoxygenated. III. Ancillary tests. In clinical practice, EEG, cerebral angiography, nuclear scan, TCD, CTA, and MRI/MRA are currently used ancillary tests in adults (see appendix 1). Most hospitals will have the logistics in place to perform and interpret an EEG, nu1916 Neurology 74 June 8, 2010

clear scan, or cerebral angiogram, and these 3 tests may be considered the preferred tests. Ancillary tests can be used when uncertainty exists about the reliability of parts of the neurologic examination or when the apnea test cannot be performed. In some protocols, ancillary tests are used to shorten the duration of the observation period. The interpretation of each of these tests requires expertise. In adults, ancillary tests are not needed for the clinical diagnosis of brain death and canno

t replace a neurologic examination. Physicians ordering ancillary tests should appreciate the disparities between tests and the potential for false-positives (i.e., the test suggests brain death, but the patient does not meet clinical criteria). Rather than ordering ancillary tests, physicians may decide not to proceed with the declaration of brain death if clinical findings are unreliable. IV. Documentation. The time of brain death is documented in the medical records. Time of death is the time the arterial PCO2 reached the target value. In patients with an aborted apnea test, the time of death is when the ancillary test has been officially interpreted. A checklist is filled out, signed, and dated (appendix 2). Federal and state law requires the physician to contact an organ procurement organization following determination of brain death.e4,e5

DISCLOSURE

Dr. Wijdicks serves as an editorial board member of Clinical Neurology and Neurosurgery, The Neurologist, Liver Transplantation, and Journal of Clinical Neurology, as a section editor of Medical Reviews in Neurology and First Consult, and as Editor-in-Chief of Neurocritical Care; and receives royalties from The Comatose Patient (2008), Neurological Complications of Critical Illness (2009), and The Practice of Emergency and Critical Care Neurology (2010) (all published by Oxford University Press). Dr. Varelas serves on a scientific advisory board for Gift of Life of Michigan; serves on the editorial board of Neurocritical Care; has received funding for travel from and serves on the speaker’s bureau for The Medicines Company; receives royalties from the publication of Seizures in the ICU (Springer, 2004 –2008); receives research support from Alsius Company and The Medicines Company; and holds stock in The Medicines Company. Dr. Gronseth serves as an editorial advisory board member of Neurology Now; serves on a speakers’ bureau for Boehringer Ingelheim; and receives honoraria from Boehringer Ingelheim and the American Academy of Neurology. Dr. Greer receives royalties from publication of Acute Ischemic Stroke: An Evidence-Based Approach (Wiley and Sons, 2007); served on the speakers’ bureau for Boehringer Ingelheim; received research support from Boehringer Ingelheim; and has served as a consultant in a medico-legal case.

DISCLAIMER

This statement is provided as an educational service of the American Academy of Neurology. It is based on an assessment of current scientific and clinical information. It is not intended to include all possible proper methods of care for a particular neurologic problem or all legitimate criteria for choosing to use a specific procedure. Neither is it intended to exclude any reasonable alternative methodologies. The AAN recognizes that specific patient care decisions are the prerogative of the patient and

the physician caring for the patient, based on all the circumstances involved. The clinical context section is made available in order to place the evidence-