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The persistent vegetative state: the medical reality (getting the facts straight).

The Persistent Vegetative State: The Medical Reality (Getting the Facts Straight)

The first step in any bioethical dilemma is to collect the facts and to understand the medical reality of the situation. Nowhere is this more necessary than in treatment decisions concerning patients with serious neurologic impairments. Modern medicine's half-way technologies have produced new neurologic creatures and required new terminology to describe syndromes both more complex and more common than anticipated a few decades ago.

Unfortunately, enormous conceptual and scientific confusion persists concerning the characteristics of these new syndromes, which include brain death (whole brain death), persistent vegetative state (PVS), permanent unconsciousness, coma, dementia, irreversible coma, chronic and irreversible coma, neocortical death, and locked-in syndrome.

For example, many over the last ten years mistakenly believed that Karen Quinlan was brain dead. Others, including neurological specialists, continue to consider the persistent vegetative state a form of coma. Many, including physicians, still believe that permanently unconscious patients, such as those in a persistent vegetative state, can experience pain and suffering.

In addition, there is little consensus about the appropriate terminology to describe such syndromes. In its 1986 statement on fluids and nutrition, the American Medical Association's Council on Ethical and Judicial Affairs used the misleading term "irreversible coma." British physicians continue to apply broadly the phrase "brain stem death," a medical syndrome that simply does not exist except in extremely rare situations. Many physicians, especially in Europe, use imprecise and antiquated language such as "coma vigile," "akinetic mutism," and "apallic state" to describe some syndromes. The term "chronically and irreversibly comatose" as used in the Child Abuse Amendments of 1984 will be an endless source of confusion.

If the medical profession persists in failing to understand these syndromes and continues using inconsistent and incorrect terminology, how can the rest of society begin to unravel the complexities of neurology and lay the foundation for a moral and legal analysis of the issues emanating from these neurologic conditions? A full understanding of the medical facts about persistent vegetative state, including an examination of the significant similarities and differences between it and several other syndromes, is essential before we can begin to apply appropriate moral and legal principles to individual cases and to develop meaningful social policies.

The Medical Reality

It is first important to differentiate brain death (whole brain death) from the persistent vegetative state. [1] The brain stem, the lower center of the brain, basically controls vegetative functions, such as respiration, and primitive stereotyped reflexes, such as the pupillary response to light. Additionally, it contains the activating or arousal system for the entire brain called the ascending reticular activating system. The cerebral hemispheres, in turn, contain the function of consciousness or awareness (which is more precisely located in the outer layers of the cerebral hemispheres, the cerebral cortex), as well as other important voluntary and involuntary actions, such as control of movements.

When brain death occurs, these higher cerebral functions cease; in addition, all brain stem functions are lost--eye movements, pupillary response to light, the most primitive protective reflexes such as the cough, gag, and swallowing, and spontaneous respiration. Heart beat, as well as other vegetative functions related to internal homeostasis, can continue, since these functions are semi-autonomous, i.e., they are not completely dependent on the integrity of the brain stem.

By contrast, in cases of patients in a persistent vegetative state, the brain stem, including the ascending reticular activating system, is relatively intact. The brunt of neurological destruction is located in the cerebral hemispheres. This state often results when a patient suffers a cardiac or respiratory arrest with lack of blood flow (ischemia) or oxygen (hypoxia) to the brain for a matter of minutes. The cerebral cortex is the part of the brain most vulnerable to this deprivation because of its high metabolic rate, requiring a constant supply of oxygen, glucose, and blood. The brain stem, however, is fairly resistant to ischemia or hypoxia. It is commonly accepted in medicine that approximately four to six minutes of complete loss of blood flow or oxygen to the brain can result in extensive destruction of the cerebral cortex while relatively sparing the brain stem.

After experiencing ischemia or hypoxia, the patient often will be in a coma that may persist for a few days or from two to four weeks. This transient coma results from a temporary dysfunction of the brain stem, which is not totally immune to the effects of hypoxic-ischemic injury. After this period, the patient will awaken and evolve into a condition of eyes-open unconsciousness, that is, the vegetative state.

Patients in a fully developed persistent vegetative state do manifest a variety of normal brain stem functions. The patient's eyes are open at times, and periods of wakefulness and sleep are present. The eyes wander, but without sustained visual pursuit (that is, following people or objects in the room in a consistent, menaingful, purposeful fashion). The pupils respond normally to light. Such a patient commonly requires a respirator initially, but this technology is usually unnecessary within a few days or weeks. The protective gag and cough reflexes are usually normal, which partially accounts for the long-term survival of these patients.

The patient is also completely unconscious, i.e., unaware of him or herself or the surrounding environment. [2] Voluntary reactions or behavioral responses reflecting consciousness, volition, or emotion at the cerebral cortical level are absent. PVS patients, then, are awake but unaware.

These characteristics allow a distinction to be made between comatose patients and patients in a persistent vegetative state. A coma is a state of sleeplike (eyes-closed) unarousability due to extensive damage to the reticular activating system of the brain stem. Patients in this condition often have impaired cough, gag, and swallowing reflexes with a resultant inability (involuntary) to clear the passages of the throat and lungs. This impairment leads to frequent, often fatal, respiratory infections--a common cause of death in comatose patients, and one of the major reasons why truly comatose patients typically do not experience the long-term survival period associated with the vegetative state. Thus, in one sense it is reasonable to describe comatose patients as "terminally ill," with death anticipated in six months to a year, unless extremely vigorous therapeutic efforts are made to sustain life.

If PVS patients are unconscious, but not comatose, as many mistakenly believe, what is their medical status? "Permanent unconsciousness," as used by the President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research and others, is the best term to apply to the broad category of patients with complete and permanent loss of consciousness or awareness. [3] Permanently unconscious patients fall into two major categories: eyes-closed unconsciousness (coma) and eyes-open unconsciousness (persistent vegetative state and anencephaly). In these patients there are no cerebral cortical functions on clinical examination indicative of consciousness or behavioral interaction with the environment.

The persistent vegetative state should also be distinguished from the medical syndrome of dementia. Neurological impairment of cerebral cortical functions causes abnormalities of content of consciousness. Progressive loss of cerebral cortical functions is termed dementia, which in the case of Alzheimer's disease occurs over a period of years. By contrast, the catastrophic injury that results in the persistent vegetative state produces complete loss of cerebral cortical functions over a period of minutes. Patients in a persistent vegetative state are not simply demented, but amended (a complete loss of mental functions).

The term "irreversible coma" is frequently used with clinically and morally confusing consequences. In retrospect, those who drafted the Harvard Committee criteria for brain death erred in using the term "irreversible coma" as synonymous with brain death. [4] In a superficial sense, the terminology is correct; brain death is the ultimate "irreversible coma"--there is total destruction of the brain with the deepest possible coma and no possibility of reversibility. Beginning in the 1970s, however, neurological specialists began using the same term to apply to patients in the persistent vegetative state, such as Karen Quinlan. Thus, some physicians would use "irreversible coma" to mean brain death while others used it to mean the persistent vegetative state. Even today, physicians use the term "irreversible coma" in at least three different ways: whole brain death, persistent vegetative state, or as a general term for all types of permanently unconscious patients.

The term "chronically and irreversibly comatose" is even more misleading and should be rejected. The life-span of a truly comatose patient is limited to weeks or months, rarely years, hardly the duration appropriately characterized as "chronic." When applied to the persistent vegetative state, such language is medically wrong. Nevertheless, this medical oxymoron now will be emblazoned forever in the annals of medical ethics by its inclusion in the Amendments to the Child Abuse Prevention and Treatment Act of 1984 and the implementing Health and Human Services regulations of 1985. [5] I doubt that the various parties responsible for the language of the Amendments had a clear idea of what they intended to mean and which specific neurologic conditions fell under the designation "chronically and irreversibly comatose."

The case of Lance Steinhaus in Minnesota graphically illustrates the confusion that ensues when unclear or medically inaccurate language is relied on in legal decisions. [6] Lance was a normally developing five-week old child, who was assaulted by his father on April 23 and 24, 1986, sustaining multiple abdominal and chest injuries and severe brain damage. Subsequent to the father's conviction on assault charges, Lance's mother requested that life-sustaining treatment be discontinued. When local authorities were alerted to the possibility that the case could fall under the jurisdiction of the Child Abuse Amendments and a corresponding state statute, a preliminary hearing was held to assess the mother's request. Prior to the hearing, briefs were submitted that claimed the vegetative state was not a form of coma. In testimony before the court, a pediatric intensivist asserted that Lance was in a persistent vegetative state. Based on this testimony, and interpreting the law in its most literal sense, the judge ruled that treatment could not be discontinued because the child was not "chronically and irreversibly comatose."

Subsequently, a pediatric neurologist, who was familiar with both the new neurologic syndromes and the precise terminology, was asked to see the child as an independent medical expert. After carefullyd examining Lance on several occasions, and reviewing the results of the the magnetic resonance imaging scan (MRI), the physician testified at a second hearing that Lance was in a coma from which he would not recover. The neurologist noted that Lance exhibited no sleep-wake cycles and only extremely infrequent and brief episodes of eye opening; there was significant impairment of brain stem functions on clinical examination; and the MRI scan showed extensive damage to the cerebral hemispheres and brain stem.

On the basis of this evaluation, the judge concluded that Lance was in a chronic and irreversibly comatose state and thus fell within that exception to the Child Abuse Amendments treatment requirements. With respect to the mother's decision, he ruled that some forms of treatment could be withheld (e.g., no cardiopulmonary resuscitation and no re-intubation), but that other forms should be continued (appropriate nutrition, hydration, and medication).

The child, following a course typical of one who is truly comatose and has impaired brain stem functions, died of recurrent infections three months after this second ruling. Yet it would have been a far more tragic situation had the child been in a vegetative state, for the Child Abuse Amendments would have supported the initial decision to continue maximal treatment indefinitely. Lance could have then survived for months or perhaps years in this hopeless condition. Applied literally, which is surely the intent of some, the Amendments permit nontreatment of a newborn who is unconscious (comatose) and who will die soon, but do not permit nontreatment of an equally unconscious (but amented) child who could live in this condition for years.

Diagnostic and Prognostic Complexities

The Steinhaus case also indicates some of the difficulties involved in clinical diagnosis of the persistent vegetative state. Indeed, in the minds of many, the reliability of a diagnosis of persistent vegetative state is a controversial issue that has yet to be adequately resolved.

A diagnosis of the persistent vegetative state usually can be made with a reasonably high degree of reliability within weeks or months after the original injury by a physician skilled in neurological diagnoses. However, for several reasons, the degree of certainty about diagnosis of this syndrome is less absolute than a diagnosis of brain death.

In the majority of cases, the diagnosis of brain death is not extremely difficult for a neurological specialist (neurologist, neurosurgeon, or pediatric neurologist) or physician knowledgeable and experienced in neurological diagnosis. If the accepted criteria are properly applied, the diagnosis reaches absolute certainty. The current national standards for the diagnosis of brain death are presented in the report of the Consultants to the President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research. [7] In addition to the clinical criteria, these standards recommend specific confirmatory studies, for example, no blood flow to the brain as measured by various blood flow studies, or a flat electroencephalogram (electrocerebral silcence).

Wtih the persistent vegetative state, however, there is no broadly accepted, published set of specific medical criteria with as much clinical detail and certainty as the brain death criteria. Furthermore, even the generally accepted criteria, when properly applied, are not infallible. There have been a few unexpected, but unequivocal and well documented, recoveries of cognitive functions in situations where it was believed that the criteria were correctly applied by several neurologists experienced in the diagnosis of this condition. In cases in New Mexico and Minnesota, the patients recovered full cognitive functioning, although they were left with a severe and permanent paralysis of all extremities and some paralysis of facial and head movements, i.e., a locked-in syndrome. [8] The locked-in syndrome is a medical condition in which, though both level and content of consciousness may be fairly normal, the patient is so severely paralyzed it may appear on superficial examination that he or she has diminished consciousness.

Presently, there are no specific laboratory studies to confirm the clinical diagnosis of the persistent vegetative state. After a variable period of time (weeks to months), some studies such as MRI and CAT (computerized axial tomography) scanning will show extensive structural damage to the cerebral hemispheres consistent with the clinical diagnosis, but these studies are not quantifiable. The most promising test on the horizon that will be of value in confirming a clinical diagnosis of the persistent vegetative state is the PET (positron emission tomography) scan. [9] This test measures in a quantitative fashion the metabolic rates of glucose and oxygen in various parts of the brain, including the cerebral cortex, an important index since consciousness cannot be sustained below certain quantifiable levels of metabolism. This method was used in the Nancy Jobes case in New Jersey to support the clinical diagnosis of the persistent vegetative state. However, PET scanning is new and extremely expensive; only a few centers in the country currently have the equipment necessary to carry out PET scanning. Furthermore, there is not yet sufficient data to document unequivocally the value of this test in the diagnosis of the persistent vegetative state.

The electroencephalogram (EEG) also does not provide absolute certainty because the degree of abnormality of the EEG will vary widely in individual cases. Some appear remarkably normal considering the extent of damage to the cerebral hemispheres. In a small percentage (probably less than 5 percent) of persistent vegetative cases, the EEG will display no electrical activity whatsoever, that is, electrocerebral silence, as in brain death. Thus it is possible for a patient whose eyes are open and who manifests sleep/wake cycles to have a completely flat EEG. Some neurologists refer to this specific neurologic syndrome as "neocortical death." It is important to note that neocortical death is now being used in two different ways. Physicians may use this term in a very specific way: to denote persistent vegetative state patients with no electrical activity on the EEG. Others, such as philosophers and lawyers, use this term in a much more general sense--for patients permanently unconscious (whether persistently vegetative or permanently comatose) who have lost all neocortical functions.

Prognostic assessments of patients in a persistent vegetative state are not free of controversy. A major problem is attributable to the multiple causes and pathophysiologic changes associated with the syndrome. In brain death, the underlying cause of the brain injury is not so important once the basic sequence of pathophysiologic events begins and leads inexorably to its conclusion (severe primary injury--brain swelling--marked increased in intracranial pressure--increased intracranial pressure exceeding blood pressure, causing secondary loss of blood flow to the entire brain--infarction of cerebral hemispheres and the brain stem). In the persistent vegetative state, however, there are multiple causes for the syndrome, and no single pathophysiologic sequence of events. Therefore, the prognosis about recovery of neurologic function, when the prognosis can be made, and its degree of certainty will vary considerably according to the underlying cause of the brain damage and the specific pathophysiology.

For example, hypoxic-ischemic injuries to the brain, such as those experienced by Karen Quinlan and Nancy Jobes, result primarily in the death of neurons of the cerebral cortex. [10] Other injuries may cause the persistent vegetative state by different mechanisms, and the primary damage may not even be to the cerebral cortex itself. In head trauma the damage may be due to shearing injuries (mechanical distortion) of the subcortical white matter, the fiber tracts deep in the cerebral hemispheres. In Paul Brophy's case, the primary damage was to the upper brain stem and deep cerebral hemispheres. [11] This resulted from the rupture of a saccular, berry aneurysm (a ballooning of a blood vessel secondary to weakening of the arterial wall), which caused a vasospasm (constriction of the arteries) that resulted in infraction of the brain tissue. This brain destruction disrupted the connections between the cerebral cortex and the rest of the brain.

Long-Term Survival

It is abundantly clear that with the combination of cardiopulmonary resuscitation, more effective means of intubation, intensive care units, and other emergency resuscitative measures, there will continue to be an increase in the disparity between the effectiveness of cardiac and pulmonary resuscitation and the relative ineffectiveness thus far of cerebral (brain) resuscitation. The most commonly cited estimate of the number of PVS patients in the United States is 5,000 to 10,000, and this number can be anticipated to significantly increase in the future, especially when coupled with their increased longevity. [12]

It is not uncommon for patients to survive in this condition for five, ten, and twenty years. The longest reported, well documented, survival (without recovery) was thirty-seven years, 111 days. [13] In a recent medical/legal case involving an adolescent in a persistent vegetative state for several years, I testified that it was more likely than not that he would not be alive in ten years, and much more likely than not that he would not be alive in twenty years. I was not willing to be more specific than that. These were the limits of my certainty.

The duration is contingent upon several major factors: (1) age (elderly patients develop more medical complications secondary to prolonged immobility and unresponsiveness than younger patients); (2) economic, family, and institutional factors (in general, wealthier patients receive better care and more attention than indigent patients); (3) natural resistance of the body to infections and the effectiveness of cough and gag reflexes; and (4) changing moral and social views on the appropriateness of stopping treatment, especially medical means of providing nutrition and hydration. The variable survival periods of patients in persistent vegetative state makes it important to examine what forms of care can be provided to such patients and the costs of this care.

Because PVS patients often have an intact involuntary swallowing reflex in addition to intact gag and cough reflexes, it is theoretically, and in rare cases practically possible, to feed these patients by hand. However, this usually requires an enormous amount of time and effort by health care professionals and families. If the patient is positioned properly, and food is carefully placed in the back of the throat, the patient's involuntary swallowing reflex will be activated. However, the overwhelming majority of patients are given fluids and nutrition by nasogastric tubing, gastrostomy, or other medical means.

Withholding of all fluids and nutrition will normally result in death within one to thirty days. If given adequate nursing care during this withdrawal, including good oral hygiene, PVS patients will not manifest the horrible signs ascribed to this process by some (e.g., mouth dried out and caked or coated with thick material, lips parched and cracked or fissured, tongue swollen and cracked, eyes sunk back into their orbits, cheeks hollow, lining of the nose cracked, nose bleeding, skin dry, scaly, and hanging loosely from the body, lining of stomach dried out causing dry heaves and vomiting, hyperthermia, brain cells dried out causing convulsions) nor will they experience consciously any symptoms (burning of urine, hunger, thirst).

Of related concern is the question of whether such patients experience any pain and suffering. While this has been much debated, it is not difficult to answer. The neurologic substratum for genuine human thinking and emotions and experiencing pain and suffering at a conscious level is the cerebral cortex. The American Academy of Neurology, in its amicus curiae brief filed in the Brophy case, took an unequivocal position on this issue: patients in a persistent vegetative state cannot experience pain and suffering.

No conscious experience of pain and suffering is possible without the integrated functioning of the brainstem and cerebral cortex. Pain and suffering are attributes of consciousness, and PVS patients like Brophy do not experience them. Noxious stimuli may activate peripherally located nerves, but only a brain with the capacity for consciousness can translate that neutral activity into an experience. That part of Brophy's brain is forever lost. [14]

There may be, and often are, facial movements and other signs indicating an apparent manifestation of conscious human suffering, but these actions result from subcortical (structures deep in the cerebral hemispheres that may be relatively undamaged) and brain stem actions of a primitive stereotyped, reflexive nature. In other words, PVS patients may "react" to painful and other noxious stimuli, but they do not "feel" (experience) pain in the sense of conscious discomfort of the kind that physicians would be obligated to treat and of the type that would seriously disturb the family. Families are often quite distressed by these subcortical and brainstem reflex responses, which they mistakenly interpret as a conscious interaction with the environment and an indication that the patient is experiencing distress. The family needs constant reassurance on this matter and, of course, the physician must be extremely confident of the diagnosis.

The cost of maintaining these patients varies substantially by state, type of institution, and support systems. In some states, like Minnesota, daily costs are usually $50 to $70 per day, about $1,500 to $2,000 a month, or approximately $18,000 to $25,000 a year. In Massachusetts, the charges in Paul Brophy's case were approximately $10,000 per month. Extrapolating from a monthly low of $2,000 to a high of $10,000, and assuming there are 5,000 to 10,000 patients in a vegetative state in the United States, the annual national health bill for these patients is from $120 million $1.2 billion. This does not include the extremely high costs of the first year of care after the original injury when the patient may have spent extensive time in an intesive care unit. In cases with which I am personally familiar, costs during the first year (especially in young people) were $200,000 to $250,000. The precise cost will vary depending on how much time is spent in an intensive care unit and at what point the patient is transferred from an acute care hospital to a chronic care facility.

The Need for Clarity, Consistency, and Consensus

The vast majority of termination of treatment cases before the courts in recent years have involved neurologically impaired patients. One major lesson we have learned from these landmark legal cases, and from the thousands of cases occurring regularly in American hospitals today, is the critical need for better understanding of the medical facts and for clarity and consistency in medical terminology.

Physicians should stop using confusing and in many cases inaccurate language. For example, it makes no sense to talk about "comfort measures" or "pain and suffering" in patients in a persistent vegetative state. Physicians should bring to the attention of Congress the fact that the class of patients called "chronically and irreversibly comatose" simply does not exist in any meaningful sense. The term "irreversible coma" should be completely abandoned. Physicians should educate the public that the withdrawal of artificial feeding from patients in persistent vegetative state does not lead to the horrible signs and symptoms attributed to this process by special interest groups; this is misleading rhetoric, not medical reality.

The medical, ethical, and legal issues in the near future will be far more complex and common than those faced thus far. It is time that medical professionals, especially the national medical and neurological specialty societies, undertake a much more active leadership role by developing position papers on the medical aspects of these neurological syndromes, forging a consensus through increased interdisciplinary dialogue, and developing broader guidelines on the appropriate care and management of these patients.

Families, physicians, the public, and the courts can only make informed, humane, and fitting decisions after understanding the relevant and correct medical facts. Once the medical reality of these syndromes is appreciated, I believe that certain logical, moral, and legal conclusions will naturally follow. [15]

References

[1] Ronald E. Cranford and H.L. Smith, "Some Critical Distinctions between Brain Death and the Persistent Vegetative State," Ethics in Science and Medicine 6 (1979), 199-209.

[2] B. Jennett and F. Plum, "Persistent Vegetative State After Brain Damage," The Lancet 1 (April 1972), 734-37.

[3] President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research, Deciding to Forego Life-Sustaining Treatment (Washington, DC: U.S. Government Printing Office, March 1983), 171-92.

[4] Report of the Ad Hoc Committee of the Harvard Medical School to Examine the Definition of Brain Death, "A Definition of Irreversible Coma," Journal of the American Medical Association 205:6 (August 1968), 85-88.

[5] Child Abuse and Neglect Prevention and Treatment, 45 C.F.R. Sections 1340.1-1340.20 (1986).

[6] "New 'Baby Doe' Rules Tested," American Medical News (October 10, 1986), 1, 45.

[7] Consultants to the President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research, "Guidelines for the Determination of Death," Journal of the American Medical Association 246:19 (November 1981), 2184-86.

[8] President's Commission, Deciding to Forego Life-Sustaining Treatment, 179-80.

[9] D. Levy, J. Sidtis, D. Rottenberg, et al., "Positron Emission Tomography in the Diagnosis of the Vegetative State," forthcoming.

[10] In re Quinlan, 70 N.J. 10, 355 A.2d 647, cert denied 429 U.S. 922 (1976); In re Jobes, 108 N.J. 394, 529 A. 2d 434 (1987).

[11] Brophy v. New England Sinai Hospital, Inc., 398 Mass. 417, 497 N.E.2d 626 (1986).

[12] This estimate is based on epidemiological studies from Japan showing approximately 2,000 to 3,000 patients in this condition in that country, and an extrapolation of that data to the United States, taking into account both a doubling in population and our more advanced (and more indiscriminately applied) life-support systems.

[13] Ronald E. Cranford, "Termination of Treatment in the Persistent Vegetative State," Seminars in Neurology 4:1 (March 1984), 36-44.

[14] Brophy v. New England Sinai Hospital, Inc., Amicus Curiae Brief, American Academy of Neurology, Minneapolis, MN (1986).

[15] Ronald E. Cranford, "Consciousness as the Critical Moral (Constitutional) Threshold for Life," presented at the annual General Meeting of the American Society of Law and Medicine, Justice Blackmun, the Supreme Court, and the Limits of Medical Privacy, October 23-24, 1987, Boston, MA.

Ronald E. Cranford is a neurologist at the Hennepin County Medical Center, Minneapolis, MN.
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Publication:The Hastings Center Report
Date:Feb 1, 1988
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