New Technology, Old Dilemma — Monitoring EEG Activity during Executions
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《新英格兰医药杂志》
On April 21, 2006, Willie Brown, Jr., was executed by lethal injection in North Carolina for the 1983 killing of a convenience-store clerk. The execution might have received little attention if not for the fact that Brown's electroencephalogram (EEG) was monitored during the procedure. This apparently unprecedented monitoring was a response to concern that some inmates have not been properly anesthetized during executions by lethal injection and may therefore have experienced painful deaths that violated the constitutional ban on cruel and unusual punishment.1,2
The EEG device used during Brown's execution was a bispectral index (BIS) monitor. Made by Aspect Medical Systems of Newton, Massachusetts, it works by means of a proprietary algorithm that converts the raw EEG, which is difficult to interpret in real time, into an index of hypnotic level. The compact device is used in operating rooms and intensive care units as an adjunct to other methods for monitoring the effects of anesthetics and sedatives. Depending on the model, it costs $5,000 or $8,500. A single-use sensor — a four-electrode array that is applied to the forehead to record EEG signals — costs about $17.50.
(Figure)
Although the BIS is a relatively new technology, its use in North Carolina — and potentially in California and elsewhere — merely represents the latest chapter in ongoing debates about what methods should be used for execution and whether physicians should participate.1 Corrections officials, under pressure to prove that their execution methods are humane, are increasingly relying on medical expertise and technology. However, the American Medical Association, the American Society of Anesthesiologists, and others in the medical community consider any physician involvement in executions unethical.
There are various EEG activity monitors.3 The BIS device records the EEG and converts it into a single number, ranging from 0 for a flat-line, or isoelectric, tracing to 100, which is typical for a person who is awake. The target range for a patient under general anesthesia is 40 to 60.
During an execution by means of lethal injection, three agents are usually given: first the anesthetic sodium thiopental, then the paralytic pancuronium bromide, and finally a fatal dose of potassium chloride. The concept behind the monitoring is to confirm that the sodium thiopental has rendered the inmate sufficiently unconscious that he or she will have no awareness of the subsequent injections and their effects. The supposition is that, if necessary, someone other than an anesthesiologist or other physician could rely on the BIS monitor to assess a prisoner's level of consciousness and help to ensure that an execution meets constitutional standards.
Of course, there is no way to be certain that an executed prisoner was unaware, and the concept of a humane execution could be considered an oxymoron. An execution is not a clinical procedure, and capital punishment is not the practice of medicine. Moreover, the role of brain-function monitors in the prevention of intraoperative awareness is controversial.4 A monitor does not replace an anesthesiologist. Monitor readings may be inaccurate, for instance, if the EEG signal is contaminated by artifacts. Although intraoperative awareness is rare — with a reported incidence of 0.1 to 0.2 percent — a task force of the American Society of Anesthesiologists recently concluded that "a specific number may not correlate with a specific depth of anesthesia" and that "the general clinical applicability of these monitors in the prevention of intraoperative awareness has not been established."3 The task force recommended that "intraoperative monitoring of depth of anesthesia, for the purpose of minimizing the occurrence of awareness, should rely on multiple modalities."
Anesthesiologist Scott Kelley, a vice president and the medical director of Aspect, said that the use of the BIS monitor in an execution was inconsistent with its intended use in health care facilities, as well as with his company's mission "to improve people's lives." According to Kelley, there is no assurance that "BIS monitoring alone would prevent an inmate from suffering during the lethal-injection procedure."
Moreover, the broader issue, said Kelley, "is the misapplication of scientific data gathered in surgical patients under the care of an anesthesia professional. It is not appropriate to extrapolate from the addition of brain monitoring as a means to prevent surgical awareness to the isolated use of BIS monitoring as described in North Carolina." He expressed concern "that this may give a medical appearance to an execution by suggesting that it is `performed under anesthesia.' It should not." Although Aspect would like to prevent its monitors from being used in future executions, it is probably powerless to do so, since more than 34,000 monitors have already been installed worldwide and can be resold: in early May, one was for sale on eBay for $1,250.
In 2005, the United States ranked fourth in the world in numbers of executions, behind only China, Iran, and Saudi Arabia. The number of U.S. executions peaked at 98 in 1999. In 2005, there were 60. As of May 24 of this year, there have been 20, all by lethal injection, according to the Death Penalty Information Center. On January 1, 2006, there were 3373 death-row inmates in the United States (see graph).
Numbers of Death-Row Inmates in the United States, as of January 1, 2006.
Some inmates may be listed in more than one state. Data are from the Legal Defense Fund of the National Association for the Advancement of Colored People.
Aspect first became involved in the controversy in February 2006, when a California corrections official sought to evaluate one of its monitors for possible use in the execution of Michael Morales, a convicted murderer who had challenged the state's execution procedures. Aspect refused to sell the official a monitor. "The request did not seem appropriate," Kelley said. After two anesthesiologists who had agreed to take part withdrew, the execution was postponed and remains on hold, with a further hearing scheduled for September 19. It remains uncertain whether California will revise its execution procedures to incorporate the use of an EEG monitoring device.5
Like Morales, Brown had challenged his state's lethal-injection protocol. On April 7, U.S. District Judge Malcolm Howard ruled that his execution in North Carolina could proceed only if there were "execution personnel with sufficient medical training to ensure that Plaintiff is in all respects unconscious prior to and at the time of the administration of any pancuronium bromide or potassium chloride." Subsequently, the protocol was modified to include the BIS monitoring of Brown's level of consciousness. The monitor was to be located in an observation room adjacent to the execution chamber, next to an electrocardiographic monitor, where a licensed physician and a licensed registered nurse could view them. If the BIS reading was 60 or higher after the injection of the initial 3000 mg of sodium thiopental, then the execution team was to continue to administer the agent until the reading fell below 60, and only then were the subsequent injections to be given.
On April 11, a North Carolina corrections official called Aspect's toll-free telephone sales number to purchase a monitor, which was shipped the same day. According to Aspect, the written purchase-order request sent from North Carolina stated, "This equipment is used to monitor vital signs and sedation scales of patients recovering from surgery." After he became aware of the sale, Kelley described it as "a regrettable system failure." According to an affidavit from Kelley, the purchasers "never indicated in any way that they intended to use in connection with the execution of the Plaintiff." A spokesperson for the North Carolina Department of Correction declined to comment.
After Judge Howard accepted the modified protocol, a federal appeals court also accepted it, in a two-to-one decision. In his blistering dissent, Judge M. Blaine Michael wrote that "the clear weight of evidence, however, reveals that the State's use of the BIS monitor will not adequately ensure that Brown will remain unconscious throughout his execution."
Sales of EEG monitors to corrections facilities pose a quandary, since the devices have perfectly acceptable uses in prison hospitals. Since 2000, Aspect has sold about a half-dozen BIS devices to such institutions. The company now requires that, for sales to penitentiaries, an authorized and responsible person employed by the facility must sign and date a statement assuring that sensors and monitors "will not be used on an individual or individuals during or as part of a lethal injection execution procedure." In May, Aspect received another inquiry — this time from a state prison hospital in California. As of early June, Aspect had heard nothing further.
Source Information
Dr. Steinbrook (rsteinbrook@attglobal.net) is a national correspondent for the Journal.
References
Gawande A. When law and ethics collide -- why physicians participate in executions. N Engl J Med 2006;354:1221-1229.
Koniaris LG, Zimmers TA, Lubarsky DA, Sheldon JP. Inadequate anesthesia in lethal injection for execution. Lancet 2005;365:1412-1414.
Practice advisory for intraoperative awareness and brain function monitoring: a report by the American Society of Anesthesiologists Task Force on Intraoperative Awareness. Anesthesiology 2006;104:847-864.
Zimmerman R. How necessary is brain monitor in anesthesia? Wall Street Journal. October 25, 2005:B1.
Weinstein H. Executions unlikely for rest of year. Los Angeles Times. April 28, 2006:B1.(Robert Steinbrook, M.D.)
The EEG device used during Brown's execution was a bispectral index (BIS) monitor. Made by Aspect Medical Systems of Newton, Massachusetts, it works by means of a proprietary algorithm that converts the raw EEG, which is difficult to interpret in real time, into an index of hypnotic level. The compact device is used in operating rooms and intensive care units as an adjunct to other methods for monitoring the effects of anesthetics and sedatives. Depending on the model, it costs $5,000 or $8,500. A single-use sensor — a four-electrode array that is applied to the forehead to record EEG signals — costs about $17.50.
(Figure)
Although the BIS is a relatively new technology, its use in North Carolina — and potentially in California and elsewhere — merely represents the latest chapter in ongoing debates about what methods should be used for execution and whether physicians should participate.1 Corrections officials, under pressure to prove that their execution methods are humane, are increasingly relying on medical expertise and technology. However, the American Medical Association, the American Society of Anesthesiologists, and others in the medical community consider any physician involvement in executions unethical.
There are various EEG activity monitors.3 The BIS device records the EEG and converts it into a single number, ranging from 0 for a flat-line, or isoelectric, tracing to 100, which is typical for a person who is awake. The target range for a patient under general anesthesia is 40 to 60.
During an execution by means of lethal injection, three agents are usually given: first the anesthetic sodium thiopental, then the paralytic pancuronium bromide, and finally a fatal dose of potassium chloride. The concept behind the monitoring is to confirm that the sodium thiopental has rendered the inmate sufficiently unconscious that he or she will have no awareness of the subsequent injections and their effects. The supposition is that, if necessary, someone other than an anesthesiologist or other physician could rely on the BIS monitor to assess a prisoner's level of consciousness and help to ensure that an execution meets constitutional standards.
Of course, there is no way to be certain that an executed prisoner was unaware, and the concept of a humane execution could be considered an oxymoron. An execution is not a clinical procedure, and capital punishment is not the practice of medicine. Moreover, the role of brain-function monitors in the prevention of intraoperative awareness is controversial.4 A monitor does not replace an anesthesiologist. Monitor readings may be inaccurate, for instance, if the EEG signal is contaminated by artifacts. Although intraoperative awareness is rare — with a reported incidence of 0.1 to 0.2 percent — a task force of the American Society of Anesthesiologists recently concluded that "a specific number may not correlate with a specific depth of anesthesia" and that "the general clinical applicability of these monitors in the prevention of intraoperative awareness has not been established."3 The task force recommended that "intraoperative monitoring of depth of anesthesia, for the purpose of minimizing the occurrence of awareness, should rely on multiple modalities."
Anesthesiologist Scott Kelley, a vice president and the medical director of Aspect, said that the use of the BIS monitor in an execution was inconsistent with its intended use in health care facilities, as well as with his company's mission "to improve people's lives." According to Kelley, there is no assurance that "BIS monitoring alone would prevent an inmate from suffering during the lethal-injection procedure."
Moreover, the broader issue, said Kelley, "is the misapplication of scientific data gathered in surgical patients under the care of an anesthesia professional. It is not appropriate to extrapolate from the addition of brain monitoring as a means to prevent surgical awareness to the isolated use of BIS monitoring as described in North Carolina." He expressed concern "that this may give a medical appearance to an execution by suggesting that it is `performed under anesthesia.' It should not." Although Aspect would like to prevent its monitors from being used in future executions, it is probably powerless to do so, since more than 34,000 monitors have already been installed worldwide and can be resold: in early May, one was for sale on eBay for $1,250.
In 2005, the United States ranked fourth in the world in numbers of executions, behind only China, Iran, and Saudi Arabia. The number of U.S. executions peaked at 98 in 1999. In 2005, there were 60. As of May 24 of this year, there have been 20, all by lethal injection, according to the Death Penalty Information Center. On January 1, 2006, there were 3373 death-row inmates in the United States (see graph).
Numbers of Death-Row Inmates in the United States, as of January 1, 2006.
Some inmates may be listed in more than one state. Data are from the Legal Defense Fund of the National Association for the Advancement of Colored People.
Aspect first became involved in the controversy in February 2006, when a California corrections official sought to evaluate one of its monitors for possible use in the execution of Michael Morales, a convicted murderer who had challenged the state's execution procedures. Aspect refused to sell the official a monitor. "The request did not seem appropriate," Kelley said. After two anesthesiologists who had agreed to take part withdrew, the execution was postponed and remains on hold, with a further hearing scheduled for September 19. It remains uncertain whether California will revise its execution procedures to incorporate the use of an EEG monitoring device.5
Like Morales, Brown had challenged his state's lethal-injection protocol. On April 7, U.S. District Judge Malcolm Howard ruled that his execution in North Carolina could proceed only if there were "execution personnel with sufficient medical training to ensure that Plaintiff is in all respects unconscious prior to and at the time of the administration of any pancuronium bromide or potassium chloride." Subsequently, the protocol was modified to include the BIS monitoring of Brown's level of consciousness. The monitor was to be located in an observation room adjacent to the execution chamber, next to an electrocardiographic monitor, where a licensed physician and a licensed registered nurse could view them. If the BIS reading was 60 or higher after the injection of the initial 3000 mg of sodium thiopental, then the execution team was to continue to administer the agent until the reading fell below 60, and only then were the subsequent injections to be given.
On April 11, a North Carolina corrections official called Aspect's toll-free telephone sales number to purchase a monitor, which was shipped the same day. According to Aspect, the written purchase-order request sent from North Carolina stated, "This equipment is used to monitor vital signs and sedation scales of patients recovering from surgery." After he became aware of the sale, Kelley described it as "a regrettable system failure." According to an affidavit from Kelley, the purchasers "never indicated in any way that they intended to use in connection with the execution of the Plaintiff." A spokesperson for the North Carolina Department of Correction declined to comment.
After Judge Howard accepted the modified protocol, a federal appeals court also accepted it, in a two-to-one decision. In his blistering dissent, Judge M. Blaine Michael wrote that "the clear weight of evidence, however, reveals that the State's use of the BIS monitor will not adequately ensure that Brown will remain unconscious throughout his execution."
Sales of EEG monitors to corrections facilities pose a quandary, since the devices have perfectly acceptable uses in prison hospitals. Since 2000, Aspect has sold about a half-dozen BIS devices to such institutions. The company now requires that, for sales to penitentiaries, an authorized and responsible person employed by the facility must sign and date a statement assuring that sensors and monitors "will not be used on an individual or individuals during or as part of a lethal injection execution procedure." In May, Aspect received another inquiry — this time from a state prison hospital in California. As of early June, Aspect had heard nothing further.
Source Information
Dr. Steinbrook (rsteinbrook@attglobal.net) is a national correspondent for the Journal.
References
Gawande A. When law and ethics collide -- why physicians participate in executions. N Engl J Med 2006;354:1221-1229.
Koniaris LG, Zimmers TA, Lubarsky DA, Sheldon JP. Inadequate anesthesia in lethal injection for execution. Lancet 2005;365:1412-1414.
Practice advisory for intraoperative awareness and brain function monitoring: a report by the American Society of Anesthesiologists Task Force on Intraoperative Awareness. Anesthesiology 2006;104:847-864.
Zimmerman R. How necessary is brain monitor in anesthesia? Wall Street Journal. October 25, 2005:B1.
Weinstein H. Executions unlikely for rest of year. Los Angeles Times. April 28, 2006:B1.(Robert Steinbrook, M.D.)