Downloaded from http://spcare.bmj.com/ on September 3, 2015 - Published by group.bmj.com
Case report
Left ventricular assist device withdrawal: an ethical discussion Sarah McLean,1,2 Tara Ni Dhonnchu,3 Niall Mahon,4 Regina McQuillan,1 Bert Gordijn,5 Karen Ryan1,3
1
Palliative Care Service, St Francis Hospice, Dublin, Ireland 2 Milford Care Centre, Castletroy, Limerick, Ireland 3 Department of Cardiothoracic Surgery, Mater Misericordiae University Hospital, Dublin, Ireland 4 Department of Cardiology, Mater Misericordiae University Hospital, Dublin, Ireland 5 Institute of Ethics, Dublin City University, Dublin, Ireland Correspondence to Dr Sarah McLean, SpR in Palliative Medicine, Milford Care Centre, Castletroy, Co. Limerick, Ireland; [email protected] Received 14 August 2012 Revised 27 November 2012 Accepted 06 December 2012 Published Online First 7 January 2013
ABSTRACT Specialist palliative care (SPC) services are increasingly integrated with chronic heart failure (CHF) services. Left ventricular assist devices (LVADs) represent an advance in the management of advanced CHF, but may pose ethical challenges for SPC services providing care to this population. The patient received an LVAD as ‘bridge-toheart-transplant,’ but subsequently experienced multiple cerebral haemorrhages, resulting in neurological deficits, and severe functional impairment. The risk of further cerebral events precluded ongoing anticoagulation, and she was transferred to an SPC inpatient unit for symptom control and end-of-life care. Following discussion within the multi-disciplinary team and with the patient’s family, LVAD support was withdrawn, and the patient died peacefully. This piece reviews the ethical considerations that informed decision-making, in particular, autonomy, informed consent and futility. In addition, the question of the nature of LVADs is debated and how the perceptions of the patient, and others, of the device may influence decision-making around withdrawal of treatment.
INTRODUCTION Specialist palliative care (SPC) services are becoming increasingly integrated with chronic heart failure (CHF) services. Left ventricular assist devices (LVADs), surgically implanted pumps that support cardiac circulation, improve outcomes in patients with advanced CHF awaiting heart transplant and also improve survival and quality-of-life in select transplant-ineligible patients: ‘destination therapy’.1 However, these therapeutic advances may pose ethical challenges for SPC services providing care to this population. To cite: McLean S, Dhonnchu TN, Mahon N, et al. BMJ Supportive & Palliative Care 2014;4: 193–195.
CASE DESCRIPTION The patient, a 53-year-old female, experienced a myocardial infarction followed by severe CHF, which was refractory to
McLean S, et al. BMJ Supportive & Palliative Care 2014;4:193–195. doi:10.1136/bmjspcare-2012-000347
optimal medical therapy. An LVAD (Heartmate II) was inserted. She was commenced on warfarin to prevent thrombus formation within the device (target International Normalised Ratio (INR) of 1.8–2.2), and was discharged home awaiting a heart transplant. Two months later, the patient presented with headaches, secondary to an extensive left-sided parietal haemorrhage (INR of 2.2). Anticoagulation was held, but intravenous heparin was cautiously re-introduced after 2 weeks. On each occasion that anticoagulation was re-introduced, however, further cerebral haemorrhage occurred. The cumulative effects of these events included significant cognitive, verbal and functional impairment; complete visual loss; dysphagia with recurrent aspiration; and headaches. The most common LVAD complications are neurological sequelae, infection, device malfunction and haemorrhage.1 On the basis of the patient’s clinical and radiological characteristics, physicians in cardiology, cardiothoracics, neurology and haematology agreed that continuing anticoagulation would almost certainly lead to further cerebral haemorrhage, with attendant neurological sequelae. In partnership with the patient’s family, it was decided to continue aspirin only, while acknowledging that the LVAD would likely malfunction due to thrombus. SPC referral was made for symptom control and end-of-life care. It was agreed to transfer her to an SPC inpatient unit, with staff expert in the management of patients with impaired cognition and communication. Prior to transfer, SPC staff received LVAD education and training. Following transfer, the patient’s condition continued to deteriorate, despite antibiotics for respiratory sepsis, and she remained symptomatic with headaches and an agitated delirium, despite optimal pharmacological symptom management.
193
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Case report The patient was judged to lack the capacity to engage in decision-making, and had not previously engaged in advance care planning (ACP). Her family advocated that her current quality-of-life would not have been acceptable to her and that she would not have consented to LVAD insertion had she known what might follow. Her care was discussed at length by the multidisciplinary team, and a decision made to withdraw LVAD support. The LVAD was deactivated by a senior physician, and she died with her family present. ETHICAL ANALYSIS From an ethical viewpoint, there are two reasons to withdraw treatment: refusal or medical futility. The patient refuses
If a patient has been appropriately informed, has comprehended the disclosures, acts competently and voluntarily, and refuses treatment, respect for autonomy demands that he or she should not be forced to undergo the intervention. When a patient is not competent, the substituted judgment and the best-interests standards may be considered.2 Underlying the first is respect for autonomy. Following this standard involves the attempt to reconstruct what the patient would have preferred. ACP can be helpful in this endeavour. According to the second standard, based on beneficence, a decision is taken based on what would reasonably considered to be good for the patient.2 In this case, the patient was not competent to participate in decision-making. Although she had no ACP, based on their knowledge of her idiosyncratic values and preferences, her family were able to reconstruct her viewpoint and advocate for her. It was noted by the medical team that even if this information were not available, a best-interests judgment would point in the same direction. Informed consent
Disclosure is a core element of informed consent.2 Full informed consent for LVADs should include the possibility of survival following serious complications, Table 1
and should potentially include ACP. The legal application of ACP varies depending on jurisdiction, but the practice is becoming increasingly widespread, and represents a valid way for competent persons to exercise their autonomy.2 Medical futility
Where there is a goal, and a treatment aimed at achieving this goal, futility implies that the chance that the action will achieve this goal is too low and/or anticipated burdens outweigh benefits. Although often presented as objective, futility judgments are valueladen, but, nevertheless, form an important part of clinicians’ professional activities as they are bound by the principles of beneficence and non-malfeasance. Physicians are not obligated to provide treatments they believe are futile to patients.2 Complicating considerations
Withdrawal of LVAD support may be considered ethically complex, as an LVAD may be perceived as a constitutive intervention, similar to a transplanted organ, or as an external device, separate from the body.3 4 Ontology refers to the subject of existence: ‘the study of categories of things’. In terms of integration into the body, and functionality, an LVAD may be categorised as an ‘internal’ or ‘external’ device.3 The LVAD, once implanted, irreversibly alters the physiological state of the patient in a way that other medical devices do not4 (see table 1). Phenomenology describes the study of how we experience things—therefore, not ‘what is an LVAD’, but ‘how is an LVAD experienced?’—is it ‘perceived as a body part’ (Merleau-Ponty’s ‘blind-man’s cane’) or ‘perceived as an artificial device’?3 Perception becomes relevant when the patients’ autonomy—the autonomy they feel over their body’s functioning or ceasing to function—is considered. The second-person perspective becomes relevant where the patient has lost capacity or where there is a discrepancy. It has been proposed that the ontological categorisation of LVADs should be complemented by a phenomenological approach. The patient’s family’s input was vital
The ontological approach: ‘internality’ versus ‘externality’ theses, modified from Simon and Fischback4 and Kraemer3
The ‘internality’ thesis
The ‘externality’ thesis
The LVAD shares many ethically relevant features with true artificial, or transplanted, organs, for example, a transplanted kidney or porcine valve. Implantation of an LVAD irreversibly alters the natural physiological condition of the heart. As continuous flow LVADs lack valves, deactivating the LVAD can impede any residual heart function, and, if removed, the native heart will cease to function.
Even when inserted as destination therapy, the LVAD acts only as an adjunct to prolonging life by supporting the native heart. Where the LVAD is already implanted, a decision to deactivate the LVAD does not introduce a new pathology in the way that externally administered harmful medications would. Deactivating the LVAD can instead be compared with withdrawing mechanical ventilation while leaving the endotracheal tube in place, thus making spontaneous respiration more difficult. The LVAD requires an external power source, anticoagulation therapy and consistent maintenance in order to function.
Once implanted, the LVAD functions independent of hospital based equipment or medical intervention, and therefore differs from most types of life support, for example, ventilation. LVAD, left ventricular assist device.
194
McLean S, et al. BMJ Supportive & Palliative Care 2014;4:193–195. doi:10.1136/bmjspcare-2012-000347
Downloaded from http://spcare.bmj.com/ on September 3, 2015 - Published by group.bmj.com
Case report in describing how she perceived the LVAD in the time preceding her cerebral events: as a burdensome external device which had adversely affected her quality-of-life. Euthanasia
The distinction between ‘killing’ and ‘letting die’ separates permissible from condemnable practice.2 Letting die is considered acceptable only under conditions of medical futility or valid refusal of treatment.5 It is commonly understood that withholding or withdrawing treatment represents letting die as ‘natural’ death occurs.2 However, damage to the native heart following LVAD insertion irrevocably alters the natural course of events. In addition, the lethal pathophysiology leading to death should be considered.5 Where a patient is imminently dying because of a new lethal pathophysiology unrelated to the functions supported by the LVAD, the LVAD is no longer effective in supporting circulation. Therefore, discontinuing LVAD support may be considered ‘allowing natural death’ in such circumstances.5 CONCLUSIONS Although transplant remains the definitive treatment for end-stage CHF, increasing numbers of LVADs are inserted as destination therapy. Some transplant-eligible LVAD patients will suffer complications, leading to inevitable end-of-life issues. The ‘hybrid’ nature of LVADs is difficult to define. A complementary ontological and phenomenological analysis may assist in medical decision-making. In situations where a patient loses capacity without an ACP, the input of family may facilitate decisionmaking according to the substitute-judgment standard. Consideration of the exact lethal pathophysiology may also be helpful; for example, cerebral haemorrhage and respiratory sepsis, in this patient’s case. Such ethical challenges will become increasingly common as the use of LVADs grows. As SPC and CHF services become increasingly integrated, an
understanding of these issues is essential for SPC services involved in the care of such patients with advanced CHF. Acknowledgements We would like to acknowledge this
patient’s family for their support in the use of the case as a teaching tool, in order to improve the understanding of, and care of, patients with similar challenging ethical issues. Contributors The case report was instigated and written
by the corresponding author, with significant input from KR. RM, TND and NM were senior clinicians involved in the case and provided input on the article and ethical aspects of the case. BG commented on the ethical analysis. SM and KR are responsible for the overall content of the article. Competing interests None. Patient consent Obtained. Provenance and peer review Not commissioned; externally peer reviewed. Data sharing statement Additional data may be obtained by contacting the corresponding author.
REFERENCES 1 Slaughter MS, Rogers JG, Milano CA, et al. Advanced heart failure treated with continuous-flow left ventricular assist device. N Engl J Med 2009;361:2241–51. 2 Beauchamp TL, Childress JF. Principles of biomedical ethics/ Tom L. Beauchamp, James F. Childress. 4th edn. New York: Oxford University Press, 1994. 3 Kraemer F. Ontology or phenomenology? How the Lvad challenges the euthanasia debate. Bioethics Published Online First: 29 Jul 2011. doi:10.1111/j.1467-8519.2011.01900.x 4 Simon JR, Fischback Ruth L. Doctor, can you turn off my LVAD? Hastings Center Report 2008;28:14–15. 5 Rady MY, Verheijde JL. Ethical challenges with deactivation of durable mechanical circulatory support at the end of life: left ventricular assist devices and total artificial hearts. J Intensive Care Med Published Online First: 6 Mar 2012. doi:10.1177/ 0885066611432415
McLean S, et al. BMJ Supportive & Palliative Care 2014;4:193–195. doi:10.1136/bmjspcare-2012-000347
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Downloaded from http://spcare.bmj.com/ on September 3, 2015 - Published by group.bmj.com
Left ventricular assist device withdrawal: an ethical discussion Sarah McLean, Tara Ni Dhonnchu, Niall Mahon, Regina McQuillan, Bert Gordijn and Karen Ryan BMJ Support Palliat Care 2014 4: 193-195 originally published online January 7, 2013
doi: 10.1136/bmjspcare-2012-000347 Updated information and services can be found at: http://spcare.bmj.com/content/4/2/193
These include:
References Email alerting service
This article cites 2 articles, 0 of which you can access for free at: http://spcare.bmj.com/content/4/2/193#BIBL Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article.
Notes
To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions To order reprints go to: http://journals.bmj.com/cgi/reprintform To subscribe to BMJ go to: http://group.bmj.com/subscribe/
Case report
Left ventricular assist device withdrawal: an ethical discussion Sarah McLean,1,2 Tara Ni Dhonnchu,3 Niall Mahon,4 Regina McQuillan,1 Bert Gordijn,5 Karen Ryan1,3
1
Palliative Care Service, St Francis Hospice, Dublin, Ireland 2 Milford Care Centre, Castletroy, Limerick, Ireland 3 Department of Cardiothoracic Surgery, Mater Misericordiae University Hospital, Dublin, Ireland 4 Department of Cardiology, Mater Misericordiae University Hospital, Dublin, Ireland 5 Institute of Ethics, Dublin City University, Dublin, Ireland Correspondence to Dr Sarah McLean, SpR in Palliative Medicine, Milford Care Centre, Castletroy, Co. Limerick, Ireland; [email protected] Received 14 August 2012 Revised 27 November 2012 Accepted 06 December 2012 Published Online First 7 January 2013
ABSTRACT Specialist palliative care (SPC) services are increasingly integrated with chronic heart failure (CHF) services. Left ventricular assist devices (LVADs) represent an advance in the management of advanced CHF, but may pose ethical challenges for SPC services providing care to this population. The patient received an LVAD as ‘bridge-toheart-transplant,’ but subsequently experienced multiple cerebral haemorrhages, resulting in neurological deficits, and severe functional impairment. The risk of further cerebral events precluded ongoing anticoagulation, and she was transferred to an SPC inpatient unit for symptom control and end-of-life care. Following discussion within the multi-disciplinary team and with the patient’s family, LVAD support was withdrawn, and the patient died peacefully. This piece reviews the ethical considerations that informed decision-making, in particular, autonomy, informed consent and futility. In addition, the question of the nature of LVADs is debated and how the perceptions of the patient, and others, of the device may influence decision-making around withdrawal of treatment.
INTRODUCTION Specialist palliative care (SPC) services are becoming increasingly integrated with chronic heart failure (CHF) services. Left ventricular assist devices (LVADs), surgically implanted pumps that support cardiac circulation, improve outcomes in patients with advanced CHF awaiting heart transplant and also improve survival and quality-of-life in select transplant-ineligible patients: ‘destination therapy’.1 However, these therapeutic advances may pose ethical challenges for SPC services providing care to this population. To cite: McLean S, Dhonnchu TN, Mahon N, et al. BMJ Supportive & Palliative Care 2014;4: 193–195.
CASE DESCRIPTION The patient, a 53-year-old female, experienced a myocardial infarction followed by severe CHF, which was refractory to
McLean S, et al. BMJ Supportive & Palliative Care 2014;4:193–195. doi:10.1136/bmjspcare-2012-000347
optimal medical therapy. An LVAD (Heartmate II) was inserted. She was commenced on warfarin to prevent thrombus formation within the device (target International Normalised Ratio (INR) of 1.8–2.2), and was discharged home awaiting a heart transplant. Two months later, the patient presented with headaches, secondary to an extensive left-sided parietal haemorrhage (INR of 2.2). Anticoagulation was held, but intravenous heparin was cautiously re-introduced after 2 weeks. On each occasion that anticoagulation was re-introduced, however, further cerebral haemorrhage occurred. The cumulative effects of these events included significant cognitive, verbal and functional impairment; complete visual loss; dysphagia with recurrent aspiration; and headaches. The most common LVAD complications are neurological sequelae, infection, device malfunction and haemorrhage.1 On the basis of the patient’s clinical and radiological characteristics, physicians in cardiology, cardiothoracics, neurology and haematology agreed that continuing anticoagulation would almost certainly lead to further cerebral haemorrhage, with attendant neurological sequelae. In partnership with the patient’s family, it was decided to continue aspirin only, while acknowledging that the LVAD would likely malfunction due to thrombus. SPC referral was made for symptom control and end-of-life care. It was agreed to transfer her to an SPC inpatient unit, with staff expert in the management of patients with impaired cognition and communication. Prior to transfer, SPC staff received LVAD education and training. Following transfer, the patient’s condition continued to deteriorate, despite antibiotics for respiratory sepsis, and she remained symptomatic with headaches and an agitated delirium, despite optimal pharmacological symptom management.
193
Downloaded from http://spcare.bmj.com/ on September 3, 2015 - Published by group.bmj.com
Case report The patient was judged to lack the capacity to engage in decision-making, and had not previously engaged in advance care planning (ACP). Her family advocated that her current quality-of-life would not have been acceptable to her and that she would not have consented to LVAD insertion had she known what might follow. Her care was discussed at length by the multidisciplinary team, and a decision made to withdraw LVAD support. The LVAD was deactivated by a senior physician, and she died with her family present. ETHICAL ANALYSIS From an ethical viewpoint, there are two reasons to withdraw treatment: refusal or medical futility. The patient refuses
If a patient has been appropriately informed, has comprehended the disclosures, acts competently and voluntarily, and refuses treatment, respect for autonomy demands that he or she should not be forced to undergo the intervention. When a patient is not competent, the substituted judgment and the best-interests standards may be considered.2 Underlying the first is respect for autonomy. Following this standard involves the attempt to reconstruct what the patient would have preferred. ACP can be helpful in this endeavour. According to the second standard, based on beneficence, a decision is taken based on what would reasonably considered to be good for the patient.2 In this case, the patient was not competent to participate in decision-making. Although she had no ACP, based on their knowledge of her idiosyncratic values and preferences, her family were able to reconstruct her viewpoint and advocate for her. It was noted by the medical team that even if this information were not available, a best-interests judgment would point in the same direction. Informed consent
Disclosure is a core element of informed consent.2 Full informed consent for LVADs should include the possibility of survival following serious complications, Table 1
and should potentially include ACP. The legal application of ACP varies depending on jurisdiction, but the practice is becoming increasingly widespread, and represents a valid way for competent persons to exercise their autonomy.2 Medical futility
Where there is a goal, and a treatment aimed at achieving this goal, futility implies that the chance that the action will achieve this goal is too low and/or anticipated burdens outweigh benefits. Although often presented as objective, futility judgments are valueladen, but, nevertheless, form an important part of clinicians’ professional activities as they are bound by the principles of beneficence and non-malfeasance. Physicians are not obligated to provide treatments they believe are futile to patients.2 Complicating considerations
Withdrawal of LVAD support may be considered ethically complex, as an LVAD may be perceived as a constitutive intervention, similar to a transplanted organ, or as an external device, separate from the body.3 4 Ontology refers to the subject of existence: ‘the study of categories of things’. In terms of integration into the body, and functionality, an LVAD may be categorised as an ‘internal’ or ‘external’ device.3 The LVAD, once implanted, irreversibly alters the physiological state of the patient in a way that other medical devices do not4 (see table 1). Phenomenology describes the study of how we experience things—therefore, not ‘what is an LVAD’, but ‘how is an LVAD experienced?’—is it ‘perceived as a body part’ (Merleau-Ponty’s ‘blind-man’s cane’) or ‘perceived as an artificial device’?3 Perception becomes relevant when the patients’ autonomy—the autonomy they feel over their body’s functioning or ceasing to function—is considered. The second-person perspective becomes relevant where the patient has lost capacity or where there is a discrepancy. It has been proposed that the ontological categorisation of LVADs should be complemented by a phenomenological approach. The patient’s family’s input was vital
The ontological approach: ‘internality’ versus ‘externality’ theses, modified from Simon and Fischback4 and Kraemer3
The ‘internality’ thesis
The ‘externality’ thesis
The LVAD shares many ethically relevant features with true artificial, or transplanted, organs, for example, a transplanted kidney or porcine valve. Implantation of an LVAD irreversibly alters the natural physiological condition of the heart. As continuous flow LVADs lack valves, deactivating the LVAD can impede any residual heart function, and, if removed, the native heart will cease to function.
Even when inserted as destination therapy, the LVAD acts only as an adjunct to prolonging life by supporting the native heart. Where the LVAD is already implanted, a decision to deactivate the LVAD does not introduce a new pathology in the way that externally administered harmful medications would. Deactivating the LVAD can instead be compared with withdrawing mechanical ventilation while leaving the endotracheal tube in place, thus making spontaneous respiration more difficult. The LVAD requires an external power source, anticoagulation therapy and consistent maintenance in order to function.
Once implanted, the LVAD functions independent of hospital based equipment or medical intervention, and therefore differs from most types of life support, for example, ventilation. LVAD, left ventricular assist device.
194
McLean S, et al. BMJ Supportive & Palliative Care 2014;4:193–195. doi:10.1136/bmjspcare-2012-000347
Downloaded from http://spcare.bmj.com/ on September 3, 2015 - Published by group.bmj.com
Case report in describing how she perceived the LVAD in the time preceding her cerebral events: as a burdensome external device which had adversely affected her quality-of-life. Euthanasia
The distinction between ‘killing’ and ‘letting die’ separates permissible from condemnable practice.2 Letting die is considered acceptable only under conditions of medical futility or valid refusal of treatment.5 It is commonly understood that withholding or withdrawing treatment represents letting die as ‘natural’ death occurs.2 However, damage to the native heart following LVAD insertion irrevocably alters the natural course of events. In addition, the lethal pathophysiology leading to death should be considered.5 Where a patient is imminently dying because of a new lethal pathophysiology unrelated to the functions supported by the LVAD, the LVAD is no longer effective in supporting circulation. Therefore, discontinuing LVAD support may be considered ‘allowing natural death’ in such circumstances.5 CONCLUSIONS Although transplant remains the definitive treatment for end-stage CHF, increasing numbers of LVADs are inserted as destination therapy. Some transplant-eligible LVAD patients will suffer complications, leading to inevitable end-of-life issues. The ‘hybrid’ nature of LVADs is difficult to define. A complementary ontological and phenomenological analysis may assist in medical decision-making. In situations where a patient loses capacity without an ACP, the input of family may facilitate decisionmaking according to the substitute-judgment standard. Consideration of the exact lethal pathophysiology may also be helpful; for example, cerebral haemorrhage and respiratory sepsis, in this patient’s case. Such ethical challenges will become increasingly common as the use of LVADs grows. As SPC and CHF services become increasingly integrated, an
understanding of these issues is essential for SPC services involved in the care of such patients with advanced CHF. Acknowledgements We would like to acknowledge this
patient’s family for their support in the use of the case as a teaching tool, in order to improve the understanding of, and care of, patients with similar challenging ethical issues. Contributors The case report was instigated and written
by the corresponding author, with significant input from KR. RM, TND and NM were senior clinicians involved in the case and provided input on the article and ethical aspects of the case. BG commented on the ethical analysis. SM and KR are responsible for the overall content of the article. Competing interests None. Patient consent Obtained. Provenance and peer review Not commissioned; externally peer reviewed. Data sharing statement Additional data may be obtained by contacting the corresponding author.
REFERENCES 1 Slaughter MS, Rogers JG, Milano CA, et al. Advanced heart failure treated with continuous-flow left ventricular assist device. N Engl J Med 2009;361:2241–51. 2 Beauchamp TL, Childress JF. Principles of biomedical ethics/ Tom L. Beauchamp, James F. Childress. 4th edn. New York: Oxford University Press, 1994. 3 Kraemer F. Ontology or phenomenology? How the Lvad challenges the euthanasia debate. Bioethics Published Online First: 29 Jul 2011. doi:10.1111/j.1467-8519.2011.01900.x 4 Simon JR, Fischback Ruth L. Doctor, can you turn off my LVAD? Hastings Center Report 2008;28:14–15. 5 Rady MY, Verheijde JL. Ethical challenges with deactivation of durable mechanical circulatory support at the end of life: left ventricular assist devices and total artificial hearts. J Intensive Care Med Published Online First: 6 Mar 2012. doi:10.1177/ 0885066611432415
McLean S, et al. BMJ Supportive & Palliative Care 2014;4:193–195. doi:10.1136/bmjspcare-2012-000347
195
Downloaded from http://spcare.bmj.com/ on September 3, 2015 - Published by group.bmj.com
Left ventricular assist device withdrawal: an ethical discussion Sarah McLean, Tara Ni Dhonnchu, Niall Mahon, Regina McQuillan, Bert Gordijn and Karen Ryan BMJ Support Palliat Care 2014 4: 193-195 originally published online January 7, 2013
doi: 10.1136/bmjspcare-2012-000347 Updated information and services can be found at: http://spcare.bmj.com/content/4/2/193
These include:
References Email alerting service
This article cites 2 articles, 0 of which you can access for free at: http://spcare.bmj.com/content/4/2/193#BIBL Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article.
Notes
To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions To order reprints go to: http://journals.bmj.com/cgi/reprintform To subscribe to BMJ go to: http://group.bmj.com/subscribe/
