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and surrogates when clinical findings warrant discussion or when a prognostic milestone is reached. How much information is conveyed to achieve this objective and how determinative it can be will depend upon clinical circumstances. For example, it may be justified to provide an early and definitive prognosis of permanent unconsciousness or death while a patient is comatose following an out-of-hospital cardiac arrest and if there are clear negative prognostic predictors including loss of pupillary function and corneal reflexes and bilateral absence of somatosensory-evoked responses.

In contrast, it would be inappropriate, and premature, to offer a conclusive prognosis in the comatose traumatic brain injury patient who demonstrates brainstem function and appears to be moving quickly into VS. The rate of recovery of such patients may warrant a cautiously optimistic approach70 delineated by a prognostic time trial in which the clinician gives a timedelimited prognosis. Time-delimited prognoses are contingent upon the patient’s continued evolution by certain temporal milestones.

To prepare for and organize such discussions with surrogates, we focus on major clinical and temporal milestones, which are important occasions for speaking with surrogates about the patient’s current status and goals of care.

Brain death involves the most straightforward decision making. In brain death, there are no clinical goals of care as the patient cannot benefit from further therapeutic efforts and the focus for the practitioner should be to communicate these facts and address specific religious or moral concerns in individual cases. Although widely accepted in professional circles, the concept of brain death is not well understood among lay people when consent for organ donation is sought.178 A more challenging issue is that some segments of our society reject this definition of death, most notably members of some orthodox religious groups and others with cultural roots in Asia, most notably Japan, which has only recently legalized brain death determinations.179,180 Two states, New Jersey and New York, have accommodation clauses to accommodate religious and moral objections to determination of death by brain death testing, with New Jersey exempting this standard when it would violate religious beliefs. Working with surrogates who reject brain death standards requires cultural sensitivity and the use

of cultural intermediaries to enhance communication.181

When speaking with surrogate decision makers for a comatose patient, it is important to be as specific about potential outcomes given the nature and etiology of the causative event or process while leaving open the indeterminacy of potential recovery based on time-limited observations of brain state. Because the exact fate of an individual patient for recovery or permanent unconsciousness is often indeterminate, the evolution of brain states from coma to vegetative and minimally conscious states to recovery without independence to full recovery needs to be stressed. The time evolution of states is often not appreciated by surrogates who may be unduly pessimistic or optimistic. At this juncture, it may be prudent to caution surrogates to avoid making a potentially premature decision and waiting until prognostication can be informed by how and when the patient evolves from coma.

Progression from coma to the vegetative state does not herald additional improvement and recovery. This is a natural state of progression in nearly all comatose patients, and movement into VS is an important clinical milestone that requires explanation. Surrogates need to appreciate that the behaviors that are seen in VS, such as sleep-wake cycles, blinking, roving eye movements, or the startle reflex, are not purposeful and do not indicate consciousness or awareness of self, others, or the environment.182 This is a hard concept for lay people to understand. It can be explained and emphasized that these are automatic behaviors, much like breathing and the maintenance of a heartbeat, controlled by brainstem activity. Making these distinctions is important when the patient first enters VS, lest these behaviors be understood as evidence of awareness or consciousness.

Discussion should emphasize that although VS, which is as yet unmodified, may become labeled as persistent once it has persisted for 1 month, it is not predicted to be permanent until 3 months following anoxic injury, or 12 months when the etiology is traumatic brain injury.183 In the competently assessed patient, it is clinically and ethically appropriate to assert that patients become permanently vegetative when they pass through these time intervals.66 Although the 1994 Multisociety Task Force

opined that ‘‘the persistent VS is a diagnosis and that the permanent VS is a prognosis,’’64,65

because of exceedingly rare outlier cases of late recovery from PVS, it is reasonable to maintain the permanent VS as a viable diagnostic category if an appropriate assessment has been made to be sure that the patient is not in the minimally conscious state.

The minimally conscious state presents perhaps the greatest current challenge for communication of prognosis. Although MCS is a recognized plateau from which patients may regain consistent evidence of consciousness; an awareness of self, others, and their environment; and, most critically, the ability to engage in functional communication, the wide clinical spectrum of MCS184 includes some patients who will permanently remain unable to communicate yet retain some aspects of awareness. Because of this complexity, ethical norms for addressing patients in MCS are only now evolving and likely to change as diagnostic precision improves and therapeutic avenues open for some subcategories of patients. The recovery of functional communication appears to represent the principal goal of many but not all surrogates70,185 involved in the care of MCS patients (additional endpoints include self-feeding, pain control, and emotional reactivity, among others). Surrogates may appropriately express the concern that waiting for further recovery from MCS may limit later opportunities to withdraw care so as not to abridge the patient’s prospective wishes not to remain in VS or MCS if the condition were to be permanent.186 Addressing these challenges will require further engagement of surrogates, physicians, and policy makers to consider palliative goals of care for the severely brain-injured patient.187

Emergence from MCS is a major milestone for several key reasons. First, when patients arrive at this functional level, they are able consistently to engage others. This will make the question of whether or not the patient is conscious indisputable and not open to charges of familial emotionality or denial. Second, at this more recovered state of consciousness, patients more fully recapture personhood lost as the result of their injury. As the philosopher William Winslade has observed in an early exploration of ethical issues following traumatic brain injury, ‘‘Being persons requires having a personality, being aware of our selves and our surroundings, and possessing human capacities, such as memory, emotions,

and the ability to communicate and interact with other people.’’187a An additional point about emergence from MCS is that the potential for recovery is open ended and unpredictable. Functional capability beyond mere emergence is an area of active research with emerging evidence that the level of early impaired self-awareness may be considered as a marker for predicting complex functional activities later in the course of recovery from traumatic brain injury.188 Thus, there is a need for ongoing assessment of capabilities and continuing physical and occupational therapy for patients who have managed to recover to this state.

A final note on diagnostics is in order. Families may want confirmatory studies to convince them of the solidity of the clinical diagnosis, trusting the ‘‘objectivity’’ of a scan over the analysis of the clinician. Expectations are raised by the advent of ‘‘neuroethics’’ articles in the popular culture asserting the potential of neuroimaging technologies to read minds and refine marketing techniques.189 Because of these trends, surrogates may invest imaging technologies with more diagnostic ability than they currently possess and seek clearcut answers through this visual medium. It is important to be clear that the diagnosis and assessment of patients with disorders of consciousness is a clinical task informed by a competent history and neurologic examination. Although desperate families may request them, as of this writing, neuroimaging studies are only applied in research settings and at best can be ancillary to clinical evaluation. They must be interpreted in light of the history and physical examination. It is important to be transparent when discussing the capabilities of current technology to assess brain states; indicate that this is an active area of research and caution that many of the experimental protocols portrayed in the media are being utilized in patients who have already been diagnostically assessed.190

Family Dynamics and Philosophic

Considerations

Beyond questions about the process of making decisions and the professional obligation to exchange information with surrogates, it is also important to appreciate that probabilities about

survival and functional status do not translate easily into choices about human values. Sharing prognostic probabilities is not, in itself, sufficient to improve the deliberative process or to effect outcome decisions.

Given the complexity of the decision-making process, this is not wholly unexpected. The quality of how information was conveyed is difficult to assess and may be as critical as what has been conveyed. Families may be distrustful of clinicians and systems of care that are not designed for longitudinal chronic care.177 They may have been the recipients of misinformation about the patient’s brain state and be wary of family meetings that they worry might try to engineer a decision to withhold or withdraw care.

These would be formidable challenges even if there were continuity of care and ongoing doctor-patient/family relationships. In the setting of shifting venues of care from the acute hospital setting to rehabilitation and long-term care facilities, the challenge of building trust is formidable. To help build such relationships, it is critical to be empathic and supportive and try to imagine what has eloquently been described as ‘‘the loneliness of the long-term caregiver’’191 faced with social isolation and family members whose injury has altered them and their relationships with those who hold them dear. These longitudinal stresses and the dependency of loved ones, coupled with the prognostic uncertainties, require compassion when working with families touched by a disorder of consciousness.

Surrogates will articulate a broad range of preferences depending on the patient’s values and their own sense of what constitutes proportionate care, from the rejection of brain death to the decision to remove artificial nutrition and hydration in a patient who is in a minimally conscious state. In most cases, however, most surrogates will struggle with the more nuanced question of the degree of loss of self that would make a life worth living.

This is a highly personal question. Families may benefit by your asking them to consider the ability to relate to others in the context of a broader consideration about the goals of care. This level is not reached until the patient has recovered to the upper end of MCS or emerged from that state. Although all may not agree with the centrality of functional communication, this may be a helpful goal of care when speaking with family members. Appreciating the cen-

trality of functional communication will also help to identify those patients who retain this ability but need assistive devices or special techniques to relate to others.96 One of the most egregious diagnostic errors that can be made in this area of clinical practice is to mistake a locked-in patient for one who is vegetative.98 Locked-in patients retain the ability for functional communication but need to be recognized in order to mobilize emerging technologies that can correlate eye movements, or even electrical brain activity, to the choice of

letters on a computer screen, and thereby help locked-in patients to communicate.94,192

Working toward the achievement of functional communication can also help delineate objectives and time frames against which this level of function needs to be achieved lest it simply remain an elusive hope. For example, if it is agreed that functional communication is a goal of care, it might be prudent to continue to follow a patient for a year following traumatic injury in order for a patient to have the greatest chance of moving into the minimally conscious state from which a capability of functional communication might take root. If a patient remains vegetative a year after injury, the substantially reduced chances of attaining the communicative goal would help support a decision to withdraw care.

In all of these conversations, it may be helpful to reach out to the hospital’s ethics committee, which will have additional expertise to help surrogates interpret technical information, such as patient diagnosis and prognosis, in light of the patient’s prior wishes, preferences, and values.

REFERENCES

1.Broderick JP, Adams HP Jr, Barsan W, et al. Guidelines for the management of spontaneous intracerebral hemorrhage: a statement for healthcare professionals from a special writing group of the Stroke Council, American Heart Association. Stroke 30, 905–915, 1999.

2.Traumatic brain injury: Masson F, Thicoipe M, Aye P, Mokni T, Senjean P, Schmitt V, Dessalles PH, Cazaugade M, Labadens P. Aquitaine Group for Severe Brain Injuries Study. Epidemiology of severe brain injuries: a prospective population-based study. J Trauma. 51, 481–9, 2001. Cardiopulmonary arrest: Booth CM, Boone RH, Tomlinson G, et al. Is this patient dead, vegetative, or severely neurologically impaired? Assessing outcome for comatose survivors of cardiac arrest. JAMA 291, 870–879, 2004.

3.Jennett B, Teasdale G, Braakman R, et al. Prognosis of patients with severe head injury. Neurosurgery 4, 283–289, 1979.

4.Levy DE, Bates D, Caronna JJ, et al. Prognosis in nontraumatic coma. Ann Intern Med 94, 293–301, 1981.

5.Jennett B, Bond M. Assessment of outcome after severe brain damage. Lancet 1, 480–484, 1975.

6.Consensus conference. Rehabilitation of persons with traumatic brain injury. NIH Consensus Development Panel on Rehabilitation of Persons With Traumatic Brain Injury. JAMA 282, 974–983, 1999.

7.Jennett B. Predictors of recovery in evaluation of patients in coma. Adv Neurol 22, 129–135, 1979.

8.Brain Trauma Foundation Management and Prognosis of Severe Traumatic Brain Injury. American Association of Neurological Surgeons, 2001.

9.Gennarelli TA, Champion HR, Copes WS, et al. Comparison of mortality, morbidity, and severity of 59,713 head injured patients with 114,447 patients with extracranial injuries. J Trauma 37, 962–968, 1994.

10.Narayan RK, Greenberg RP, Miller JD, et al. Improved confidence of outcome prediction in severe head injury. A comparative analysis of the clinical examination, multimodality evoked potentials, CT scanning, and intracranial pressure. J Neurosurg 54, 751– 762, 1981.

11.Braakman R, Gelpke GJ, Habbema JD, et al. Systematic selection of prognostic features in patients with severe head injury. Neurosurgery 6, 362–370, 1980.

12.Stocchetti N, Penny KI, Dearden M, et al. Intensive care management of head-injured patients in Europe: a survey from the European brain injury consortium. Intensive Care Med 27, 400–406, 2001.

13.Choi SC, Narayan RK, Anderson RL, et al. Enhanced specificity of prognosis in severe head injury. J Neurosurg 69, 381–385, 1988.

14.Marion DW, Carlier PM. Problems with initial Glasgow Coma Scale assessment caused by prehospital treatment of patients with head injuries: results of a national survey. J Trauma 36, 89–95, 1994.

15.Teasdale G, Knill-Jones R, van der SJ. Observer variability in assessing impaired consciousness and coma. J Neurol Neurosurg Psychiatry 41, 603–610, 1978.

16.Signorini DF, Andrews PJ, Jones PA, et al. Predicting survival using simple clinical variables: a case study in traumatic brain injury. J Neurol Neurosurg Psychiatry 66, 20–25, 1999.

17.Hukkelhoven CW, Steyerberg EW, Rampen AJ, et al. Patient age and outcome following severe traumatic brain injury: an analysis of 5600 patients. J Neurosurg 99, 666–673, 2003.

18.Jennett B, Teasdale G, Galbraith S, et al. Severe head injuries in three countries. J Neurol Neurosurg Psychiatry 40, 291–298, 1977.

19.van Dongen KJ, Braakman R, Gelpke GJ. The prognostic value of computerized tomography in comatose head-injured patients. J Neurosurg 59, 951–957, 1983.

20.Fearnside MR, Cook RJ, McDougall P, et al. The Westmead Head Injury Project outcome in severe head injury. A comparative analysis of pre-hospital, clinical and CT variables. Br J Neurosurg 7, 267–279, 1993.

21.Carlsson CA, von Essen C, Lofgren J. Factors affecting the clinical course of patients with severe head injuries. 1. Influence of biological factors. 2. Signif-

icance of posttraumatic coma. J Neurosurg 29, 242– 251, 1968.

22.Young GB. The EEG in coma. J Clin Neurophysiol 17, 473–485, 2000.

23.Young GB, Wang JT, Connolly JF. Prognostic determination in anoxic-ischemic and traumatic encephalopathies. J Clin Neurophysiol 21, 379–390, 2004.

24.Logi F, Fischer C, Murri L, et al. The prognostic value of evoked responses from primary somatosensory and auditory cortex in comatose patients. Clin Neurophysiol 114, 1615–1627, 2003.

25.Lew HL, Dikmen S, Slimp J, et al. Use of soma- tosensory-evoked potentials and cognitive eventrelated potentials in predicting outcomes of patients with severe traumatic brain injury. Am J Phys Med Rehabil 82, 53–61, 2003.

26.Robe PA, Dubuisson A, Bartsch S, et al. Favourable outcome of a brain trauma patient despite bilateral loss of cortical somatosensory evoked potential during thiopental sedation. J Neurol Neurosurg Psychiatry 74, 1157–1158, 2003.

27.Schwarz S, Schwab S, Aschoff A, et al. Favorable recovery from bilateral loss of somatosensory evoked potentials. Crit Care Med 27, 182–187, 1999.

28.Mazzini L, Zaccala M, Gareri F, et al. Long-latency auditory-evoked potentials in severe traumatic brain injury. Arch Phys Med Rehabil 82, 57–65, 2001.

29.Perrin F, Schnakers C, Schabus M, et al. Brain response to one’s own name in vegetative state, minimally conscious state, and locked-in syndrome. Arch Neurol 63, 562–569, 2006.

30.Pelinka LE, Kroepfl A, Leixnering M, et al. GFAP versus S100B in serum after traumatic brain injury: relationship to brain damage and outcome. J Neurotrauma 21, 1553–1561, 2004.

31.Shutter L, Tong KA, Holshouser BA. Proton MRS

in acute traumatic brain injury: role for glutamate/ glutamine and choline for outcome prediction. J Neurotrauma 21, 1693–1705, 2004.

32.Levy DE, Caronna JJ, Singer BH, et al. Predicting outcome from hypoxic-ischemic coma. JAMA 253, 1420–1426, 1985.

33.Hamel MB, Goldman L, Teno J, et al. Identification of comatose patients at high risk for death or severe disability. SUPPORT Investigators. Understand Prognoses and Preferences for Outcomes and Risks of Treatments. JAMA 273, 1842–1848, 1995.

34.Sacco RL, VanGool R, Mohr JP, et al. Nontraumatic coma. Glasgow coma score and coma etiology as predictors of 2-week outcome. Arch Neurol 47, 1181– 1184, 1990.

35.Sasser H. Association of Clinical Signs with Neurological Outcome After Cardiac Arrest [dissertation]. University of Pittsburg, 1999.

36.Zandbergen EG, de Haan RJ, Stoutenbeek CP, et al. Systematic review of early prediction of poor outcome in anoxic-ischaemic coma. Lancet 352, 1808– 1812, 1998.

37.Madl C, Kramer L, Domanovits H, et al. Improved outcome prediction in unconscious cardiac arrest survivors with sensory evoked potentials compared with clinical assessment. Crit Care Med 28, 721–726, 2000.

38.Rothstein TL. The role of evoked potentials in anoxic-ischemic coma and severe brain trauma. J Clin Neurophysiol 17, 486–497, 2000.

39.Rothstein TL, Thomas EM, Sumi SM. Predicting outcome in hypoxic-ischemic coma. A prospective clinical and electrophysiologic study. Electroencephalogr Clin Neurophysiol 79, 101–107, 1991.

40.Fischer C, Luaute´ J, Adeleine P, et al. Predictive value of sensory and cognitive evoked potentials for awakening from coma. Neurology 63, 669–673, 2004.

41.Goh WC, Heath PD, Ellis SJ, et al. Neurological outcome prediction in a cardiorespiratory arrest survivor. Br J Anaesth 88, 719–722, 2002.

42.Wijdicks EF, Parisi JE, Sharbrough FW. Prognostic value of myoclonus status in comatose survivors of cardiac arrest. Ann Neurol 35, 239–243, 1994.

43.Werhahn KJ, Brown P, Thompson PD, et al. The clinical features and prognosis of chronic posthypoxic myoclonus. Mov Disord 12, 216–220, 1997.

44.Kaplan PW. The EEG in metabolic encephalopathy and coma. J Clin Neurophysiol 21, 307–318, 2004.

45.Golby A, McGuire D, Bayne L. Unexpected recovery from anoxic-ischemic coma. Neurology 45, 1629– 1630, 1995.

46.Britton JW, Ghearing GR, Benarroch EE, et al. The ictal bradycardia syndrome: localization and lateralization. Epilepsia 47, 737–744, 2006.

47.Wijdicks EF, Rabinstein AA. Absolutely no hope? Some ambiguity of futility of care in devastating acute stroke. Crit Care Med 32, 2332–2342, 2004.

48.Pullicino PM, Alexandrov AV, Shelton JA, et al. Mass effect and death from severe acute stroke. Neurology 49, 1090–1095, 1997.

49.Voetsch B, DeWitt LD, Pessin MS, et al. Basilar artery occlusive disease in the New England Medical Center Posterior Circulation Registry. Arch Neurol 61, 496–504, 2004.

50.Rabinstein AA, Tisch SH, McClelland RL, et al. Cause is the main predictor of outcome in patients with pontine hemorrhage. Cerebrovasc Dis 17, 66–71, 2004.

51.Report of World Federation of Neurological Surgeons Committee on a Universal Subarachnoid Hemorrhage Grading Scale. J Neurosurg 68, 985–986, 1988.

52.Rosen DS, Macdonald RL. Grading of subarachnoid hemorrhage: modification of the World Federation of Neurosurgical Societies scale on the basis of data for a large series of patients. Neurosurgery 54, 566– 575, 2004.

53.Schievink WI, Wijdicks EF, Piepgras DG, et al. The poor prognosis of ruptured intracranial aneurysms of the posterior circulation. J Neurosurg 82, 791–795, 1995.

54.Ritz R, Schwerdtfeger K, Strowitzki M, et al. Prognostic value of SSEP in early aneurysm surgery after SAH in poor-grade patients. Neurol Res 24, 756–764, 2002.

55.Hojer C, Haupt WF. [The prognostic value of AEP and SEP values in subarachnoid hemorrhage. An analysis of 64 patients]. Neurochirurgia (Stuttg) 36, 110–116, 1993.

56.van de Beek BD, De Gans J, Spanjaard L, et al. Clinical features and prognostic factors in adults with bacterial meningitis. N Engl J Med 351, 1849–1859, 2004.

57.Pikis A, Kavaliotis J, Tsikoulas J, et al. Long-term sequelae of pneumococcal meningitis in children. Clin Pediatr (Phila) 35, 72–78, 1996.

58.Roos KL, Tunkel AR, Scheld WM. Acute bacterial meningitis. In: Scheld WM, Whitley RJ, Marra CM, eds. Infections of the Central Nervous System, 3rd ed. Philadelphia: Lippincott Williams & Wilkins, pp 347–422, 2004.

59.Xiao F, Tseng MY, Teng LJ, et al. Brain abscess: clinical experience and analysis of prognostic factors. Surg Neurol 63, 442–449, 2005.

60.Yang SY, Zhao CS. Review of 140 patients with brain abscess. Surg Neurol 39, 290–296, 1993.

61.Wingerchuk DM. The clinical course of acute disseminated encephalomyelitis. Neurol Res 28, 341–347, 2006.

62.Pulver M, Plum F. Disorders of consciousness. In: Evans WR, Baskin DS, Yatsu FM, eds. Prognosis of Neurological Disorders, 2nd ed. New York: Oxford, pp 523–534, 2000.

63.Jennett B, Plum F. Persistent vegetative state after brain damage: a syndrome in search of a name. Lancet 1, 434–437, 1972.

64.Medical aspects of the persistent vegetative state (2). The Multi-Society Task Force on PVS. N Engl J Med 330, 1572–1579, 1994.

65.Medical aspects of the persistent vegetative state (1). The Multi-Society Task Force on PVS. N Engl J Med 330, 1499–1508, 1994.

66.Jennett B. The Vegetative State: Medical Facts, Ethical and Legal Dilemmas. Cambridge: Cambridge University Press, 2002.

67.Childs NL, Mercer WN. Brief report: late improvement in consciousness after post-traumatic vegetative state. N Engl J Med 334, 24–25, 1996.

68.Rosenberg GA, Johnson SF, Brenner RP. Recovery of cognition after prolonged vegetative state. Ann Neurol 2, 167–168, 1977.

69.Matsuda W, Matsumura A, Komatsu Y, et al. Awakenings from persistent vegetative state: report of three cases with parkinsonism and brain stem lesions on MRI. J Neurol Neurosurg Psychiatry 74, 1571– 1573, 2003.

70.Whyte J, Katz D, Long D, et al. Predictors of outcome in posttraumatic disorders of consciousness and assessment of medication effects: a multicenter study. Arch Phys Med Rehabil 86, 453–462, 2005.

71.Kampfl A, Schmutzhard E, Franz G, et al. Prediction of recovery from post-traumatic vegetative state with cerebral magnetic-resonance imaging. Lancet 351, 1763–1767, 1998.

72.Laureys S, Lemaire C, Maquet P, et al. Cerebral metabolism during vegetative state and after recovery to consciousness. J Neurol Neurosurg Psychiatry 67, 121–122, 1999.

73.Uzan M, Albayram S, Dashti SG, et al. Thalamic proton magnetic resonance spectroscopy in vegetative state induced by traumatic brain injury. J Neurol Neurosurg Psychiatry 74, 33–38, 2003.

74.Hansotia PL. Persistent vegetative state. Review and report of electrodiagnostic studies in eight cases. Arch Neurol 42, 1048–1052, 1985.

75.Kotchoubey B. Event-related potential measures of consciousness: two equations with three unknowns. Prog Brain Res 150, 427–444, 2005.

76.Giacino JT, Ashwal S, Childs N, et al. The minimally conscious state—definition and diagnostic criteria. Neurology 58, 349–353, 2002.