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Persistent vegetative state
CORRESPONDENCE
cardiac surgical units to do the same. Patients and relatives have a right to know that hospitals in which they or their loved ones receive treatment have mechanisms by which the quality of this treatment is monitored and assured. We should continue to lead the way in monitoring performance, to encourage all cardiac surgeons to participate, and to promote the spread of this practice to other surgical and non-surgical specialties. Samer A M Nashef Papworth Hospital, Papworth Everard, Cambridge CB3 8RE, UK 1
2
Lovegrove J, Valencia O, Treasure R, Sherlaw-Johnson C, Gallivan S. Monitoring the results of cardiac surgery by variable life-adjusted display. Lancet 1997; 350: 1128–30. Sergeant P, Meyns B. La critique est aisée mais l’art est difficile. Lancet 1997; 350: 1114–15.
SIR—In cardiovascular surgery, stakes have always been high. Kirklin has been indispensable in promoting performance awareness among cardiac surgeons;1 the nomogram in P Sergeant and B Meyns Oct 18 commentary2 is a pictorial example of Kirklin’s school. Indeed, databases may provide a basis for appropriate indication, efficacy, and effectiveness of treatment. Also, they may compensate for the lack of sound randomised clinical trials and provide a factual basis for the development of clinical guidelines in a cardiac-surgical practice, the application of which may be subject to a medical audit. What matters for the patient are the odds of cure given a particular surgical team in a certain hospital. This information can only be derived from the institute’s mortality and complication database. Implicitly, we all agree that the collection of this information is one of the administrative duties of a cardiac-surgical unit. However, we do not include it in the professional standard for retrieval and communication of risk information. Jocelyn Lovegrove and colleagues3 provide an objective tool to assess suboptimal surgical performance. Differences in performance within a group of surgeons are common, but are they relevant? To avoid disputes, safety targets and suboptimal performance should be defined in advance.4 Second, it takes years to accumulate the retrospectively preventable deaths to discern the outliers in the group. From the patient’s point of view, comparison and cooperation with other institutions may provide quick benchmarks and effective risk management.5 Other effective tools in industrial safety management are based on an analysis of organisation and
144
procedures and reported accidents. The medicolegal difficulty in proving poor performance in general or in a particular case results from the absence of normative minimum standards of performance. Although databases may hold this information, transition to professional standards requires a focus on patients’ interests and professional opinions about the acceptance of risks. The emphasis on how to detect a less capable surgeon may move the attention away from effective riskmanagement interventions from which a patient may benefit immediately. Bas A de Mol Academic Medical Center, University of Amsterdam, Amsterdam, and *Safety Science in Health Care, Delft University of Technology, Delft, Netherlands 1
2
3
4
5
Kirklin JW, Blackstone EH. The discipline of the cardiac surgeon. Thorac Cardiovasc Surg 1986; 34: 211–16. Sergeant P, Meyns B. La critique est aisée mais l’art est difficile. Lancet 1997; 350: 1114–15. Lovegrove J, Valencia O, Treasure T, Sherlaw-Johnson C, Gallivan S. Monitoring the results of cardiac surgery by variable lifeadjusted display. Lancet 1997; 350: 1128–30. Mol de BA, Koornneef F. Are percutaneous transluminal angioplasty and coronary artery bypass grafting safe enough? Int J Risk Safety 1994; 6: 39–45. O’Connor GT, Plume SK, Olmstead EM, et al. A regional intervention to improve the hospital mortality associated with coronary artery bypass graft surgery. JAMA 1996; 275: 841–46.
Persistent vegetative state SIR—T C Britton and Jack Colover (Nov 1, p 1324)1 raise interesting questions about my seminar on the persistent vegetative state (PVS). 2 Britton agrees that “consciousness, in all its aspects, is a matter of degree” but suggests that this undermines the definition of PVS as a stage of “wakefulness without awareness”. I disagree. Patients in PVS continue to display a cycle of sleep and wakefulness, but show no signs of contentful awareness, neither in terms of recognition of their surroundings nor any sign of purposeful activity. I agree with Britton’s implication that it is difficult to establish with certainty whether a patient is unaware, which is underlined by the high rates of misdiagnosis in PVS.3 Colover’s main claims are that the term PVS is emotive and derogatory, that degrees of consciousness cannot be objectively assessed, and that PVS is a concept “mainly of social and legal interest” rather than a genuine
diagnostic category. I have sympathy with the first point, but find it hard to take exception to the word persistent, which implies simply that the condition has been present for some time. The term vegetative, however, does have unwanted connotations; unaware might be more appropriate. But the choice of terminology has no bearing on the more important question: whether PVS—by whatever name—exists. Colover’s second point is that degrees of consciousness cannot be objectively assessed, especially if patients are unable to communicate. However, most of us would agree that, as a rule, careful long-term observation can reveal signs of awareness, if awareness there be. Exciting work on the assessment of awareness under anaesthesia 4 and in different states of consciousness 5 may eventually make it possible to corroborate clinical observation with physiological measurement. Finally, Colover claims that PVS is a social or legal rather than a diagnostic category. It is true that its pathology and clinical presentation are diverse. The same could be said of epilepsy or depression, both important, if imprecise, diagnoses. It is also true that journalists and lawyers, and the public at large, have taken an interest in PVS, but this in itself does not invalidate its credentials as a diagnosis. Brain damage sometimes seems to rise to a state of “wakefulness without awareness”, so far as can be determined. Indeed, recognition of this state is important for patients and their families. Its occurrence is explained by the relative separation of the brain systems that govern arousal from those that supply the content of consciousness. The condition is rare and misdiagnosis all too easy, but this should not deter us from trying to get the diagnosis right. Adam Zeman Department of Clinical Neurosciences, University of Edinburgh, Western General Hospital, Edinburgh EX4 2XU, UK 1 2 3
4
5
Britten TC; Colover J. Persistent vegetative state. Lancet 1997; 350: 1324. Zeman A. Persistent vegetative state. Lancet 1997; 350: 795–99. Andrews K, Murphy L, Munday R, Littlewood C. Misdiagnosis of the persistent vegetative state: retrospective study in a rehabilitation unit. BMJ 1996; 313: 13–16. Jones JG. Perception and memory during general anaesthesia. Br J Anaesth 1994; 73: 31–37. Llinas R, Ribary U. Coherent 40-Hz oscillation characteristics dream state in humans. Proc Natl Acad Sci USA 1993; 90: 2078–81.
THE LANCET • Vol 351 • January 10, 1998
cardiac surgical units to do the same. Patients and relatives have a right to know that hospitals in which they or their loved ones receive treatment have mechanisms by which the quality of this treatment is monitored and assured. We should continue to lead the way in monitoring performance, to encourage all cardiac surgeons to participate, and to promote the spread of this practice to other surgical and non-surgical specialties. Samer A M Nashef Papworth Hospital, Papworth Everard, Cambridge CB3 8RE, UK 1
2
Lovegrove J, Valencia O, Treasure R, Sherlaw-Johnson C, Gallivan S. Monitoring the results of cardiac surgery by variable life-adjusted display. Lancet 1997; 350: 1128–30. Sergeant P, Meyns B. La critique est aisée mais l’art est difficile. Lancet 1997; 350: 1114–15.
SIR—In cardiovascular surgery, stakes have always been high. Kirklin has been indispensable in promoting performance awareness among cardiac surgeons;1 the nomogram in P Sergeant and B Meyns Oct 18 commentary2 is a pictorial example of Kirklin’s school. Indeed, databases may provide a basis for appropriate indication, efficacy, and effectiveness of treatment. Also, they may compensate for the lack of sound randomised clinical trials and provide a factual basis for the development of clinical guidelines in a cardiac-surgical practice, the application of which may be subject to a medical audit. What matters for the patient are the odds of cure given a particular surgical team in a certain hospital. This information can only be derived from the institute’s mortality and complication database. Implicitly, we all agree that the collection of this information is one of the administrative duties of a cardiac-surgical unit. However, we do not include it in the professional standard for retrieval and communication of risk information. Jocelyn Lovegrove and colleagues3 provide an objective tool to assess suboptimal surgical performance. Differences in performance within a group of surgeons are common, but are they relevant? To avoid disputes, safety targets and suboptimal performance should be defined in advance.4 Second, it takes years to accumulate the retrospectively preventable deaths to discern the outliers in the group. From the patient’s point of view, comparison and cooperation with other institutions may provide quick benchmarks and effective risk management.5 Other effective tools in industrial safety management are based on an analysis of organisation and
144
procedures and reported accidents. The medicolegal difficulty in proving poor performance in general or in a particular case results from the absence of normative minimum standards of performance. Although databases may hold this information, transition to professional standards requires a focus on patients’ interests and professional opinions about the acceptance of risks. The emphasis on how to detect a less capable surgeon may move the attention away from effective riskmanagement interventions from which a patient may benefit immediately. Bas A de Mol Academic Medical Center, University of Amsterdam, Amsterdam, and *Safety Science in Health Care, Delft University of Technology, Delft, Netherlands 1
2
3
4
5
Kirklin JW, Blackstone EH. The discipline of the cardiac surgeon. Thorac Cardiovasc Surg 1986; 34: 211–16. Sergeant P, Meyns B. La critique est aisée mais l’art est difficile. Lancet 1997; 350: 1114–15. Lovegrove J, Valencia O, Treasure T, Sherlaw-Johnson C, Gallivan S. Monitoring the results of cardiac surgery by variable lifeadjusted display. Lancet 1997; 350: 1128–30. Mol de BA, Koornneef F. Are percutaneous transluminal angioplasty and coronary artery bypass grafting safe enough? Int J Risk Safety 1994; 6: 39–45. O’Connor GT, Plume SK, Olmstead EM, et al. A regional intervention to improve the hospital mortality associated with coronary artery bypass graft surgery. JAMA 1996; 275: 841–46.
Persistent vegetative state SIR—T C Britton and Jack Colover (Nov 1, p 1324)1 raise interesting questions about my seminar on the persistent vegetative state (PVS). 2 Britton agrees that “consciousness, in all its aspects, is a matter of degree” but suggests that this undermines the definition of PVS as a stage of “wakefulness without awareness”. I disagree. Patients in PVS continue to display a cycle of sleep and wakefulness, but show no signs of contentful awareness, neither in terms of recognition of their surroundings nor any sign of purposeful activity. I agree with Britton’s implication that it is difficult to establish with certainty whether a patient is unaware, which is underlined by the high rates of misdiagnosis in PVS.3 Colover’s main claims are that the term PVS is emotive and derogatory, that degrees of consciousness cannot be objectively assessed, and that PVS is a concept “mainly of social and legal interest” rather than a genuine
diagnostic category. I have sympathy with the first point, but find it hard to take exception to the word persistent, which implies simply that the condition has been present for some time. The term vegetative, however, does have unwanted connotations; unaware might be more appropriate. But the choice of terminology has no bearing on the more important question: whether PVS—by whatever name—exists. Colover’s second point is that degrees of consciousness cannot be objectively assessed, especially if patients are unable to communicate. However, most of us would agree that, as a rule, careful long-term observation can reveal signs of awareness, if awareness there be. Exciting work on the assessment of awareness under anaesthesia 4 and in different states of consciousness 5 may eventually make it possible to corroborate clinical observation with physiological measurement. Finally, Colover claims that PVS is a social or legal rather than a diagnostic category. It is true that its pathology and clinical presentation are diverse. The same could be said of epilepsy or depression, both important, if imprecise, diagnoses. It is also true that journalists and lawyers, and the public at large, have taken an interest in PVS, but this in itself does not invalidate its credentials as a diagnosis. Brain damage sometimes seems to rise to a state of “wakefulness without awareness”, so far as can be determined. Indeed, recognition of this state is important for patients and their families. Its occurrence is explained by the relative separation of the brain systems that govern arousal from those that supply the content of consciousness. The condition is rare and misdiagnosis all too easy, but this should not deter us from trying to get the diagnosis right. Adam Zeman Department of Clinical Neurosciences, University of Edinburgh, Western General Hospital, Edinburgh EX4 2XU, UK 1 2 3
4
5
Britten TC; Colover J. Persistent vegetative state. Lancet 1997; 350: 1324. Zeman A. Persistent vegetative state. Lancet 1997; 350: 795–99. Andrews K, Murphy L, Munday R, Littlewood C. Misdiagnosis of the persistent vegetative state: retrospective study in a rehabilitation unit. BMJ 1996; 313: 13–16. Jones JG. Perception and memory during general anaesthesia. Br J Anaesth 1994; 73: 31–37. Llinas R, Ribary U. Coherent 40-Hz oscillation characteristics dream state in humans. Proc Natl Acad Sci USA 1993; 90: 2078–81.
THE LANCET • Vol 351 • January 10, 1998