Duchenne muscular dystrophy

Study objectives: Although long-term ventilation (LTV) has been shown to extend the lives of individuals with Duchenne muscular dystrophy (DMD), initiating LTV is still considered controversial. The purpose of the study was to describe the LTV-related attitudes and practices of Canadian physicians who follow up patients with DMD.

Design: The study consisted of a mail questionnaire supplemented by face-to-face interviews.

Participants: Forty-five physicians who follow up patients with DMD through Canadian neuromuscular clinics.

Measurements: A mail questionnaire of 66 closed-ended questions related to practice and attitudes was completed by all respondents. Qualitative semistructured interviews were conducted with six volunteer physicians, and were audiotaped and transcribed.

Results: The results indicated that 25.0% of physicians do not discuss LTV with all of their DMD patients. The most frequently cited reason for advising against LTV was poor patient quality of life (52.6%). Three themes emerged from the qualitative data: mentioning and discussing LTV are discrete events with different purposes, nighttime and full-time LTV decisions are approached differently, and physicians modify their discussions to influence outcome.

Conclusions: The study demonstrated considerable agreement among the physicians regarding disclosure practices. Concerns are raised by the number of physicians who do not disclose to all patients and families and the role of quality-of-life judgments in decision making. It is suggested that because of their subjective nature, quality-of-life judgments should not be made without the participation of the patient and family, and that an initial disclosure is the minimum requirement of informed consent/decision making. (CHEST 2001; 119:940-946)

Key words: decision making; mechanical ventilation; neuromuscular diseases; physician-patient relationship

Abbreviations: DMD = Duchenne muscular dystrophy; LTV = long-term ventilation; MIDS = Modified Issues in Disability Scale

Physicians' Beliefs and Practices

Whether or not to offer patients with neuromuscular diseases long-term ventilation (LTV) still remains a subject of controversy.[1,2] In the past, individuals with Duchenne muscular dystrophy (DMD) could expect to survive into their late teens or early 20s. More recently, mechanical ventilation has been shown to prolong the lives of these individuals, but it does not offer a cure. Instead, the ventilator offers the continuation of a life that will grow even more dependent on third-party care and electrical devices. As Gilgoff[1] asks, "The respirator: Is it the tool of the devil, entrapping the helpless patient and keeping him from the peaceful sleep of death, or is it the angel of mercy, saving a stricken young man from the menacing jaws of death?"

The earliest reported use of LTV to prolong the lives of individuals with DMD was in 1973.[3] Since that time, the technology has advanced to include several different types of ventilatory aids. Invasive methods deliver breaths to the patient through a tracheostomy; noninvasive methods deliver breaths by way of a nasal mask or a mouthpiece. LTV may initially only be required on a part-time basis, such as during the night or naps, but will progress to full-time use.

Despite the proven success of mechanical ventilation in extending the lives of individuals with DMD,[2,4] it appears that it is still not routinely offered or discussed with all patients. Bach[5] surveyed American Muscular Dystrophy Association clinic directors in 1992 and found that 33% never discussed ventilatory assistance with their patients, 31% discussed it with "at least a few patients," and only 36% discussed it with all or most patients. The most frequently cited reasons for not offering ventilation were poor patient quality of life, lack of adequate financial resources, inadequate home environment, cognitive deficits, excessive burden on the family, and families uninterested or unwilling to discuss.

This study sought to reexamine these observations in a Canadian context using both quantitative and qualitative methods and was part of a larger normative ethical analysis of the decision-making process (B. Gibson, MSc; unpublished data; 1998). The purpose was to describe the LTV-related attitudes and practices of Canadian physicians who follow up patients with DMD.

MATERIALS AND METHODS

Ethics approval for the study was obtained from the University of Toronto Research Ethics Board. A questionnaire of 67 closed-ended items was sent to all physicians identified through provincial Muscular Dystrophy Association branches as directors, co-directors, or respirologists associated with a Canadian neuromuscular clinic. Administration of the questionnaire occurred between the months of February and April 1997. The questions were developed based on the primary investigator's clinical experience, the relevant literature (notably the study by Bach,[5] previously referred to), and three initial pilot interviews with physicians who follow up patients with DMD. The draft questionnaire was then pilot tested on three additional physicians. A translated French-language version was also produced after the procedures outlined by Guillemin et al.[6] The survey addressed physicians' practice and attitudes regarding LTV for DMD patients and included the Modified Issues in Disability Scale (MIDS), developed and previously validated by Makas,[7,8] which measures attitudes toward disability. The MIDS is a 37-item Likert-type scale, in which subjects are asked to indicate their extent of agreement or disagreement with statements about persons with disabilities. Scores on the MIDS range from 37 (least positive) to 259 (most positive). This scale was chosen because it has been tested for reliability, has strong content validity, and is easy to administer and score. The MIDS is also a unique scale, in which persons with disabilities were actively involved in the scale construction and validation process.

Collection

The survey was administered according to a modified Dillman procedure,[9] which emphasizes a personalized approach followed by multiple mailings. At the initial mailing, each potential respondent was sent a personalized cover letter with the questionnaire along with a stamped envelope for returning the survey. A reminder letter was sent 3 weeks later, followed by a second complete mailing 3 weeks after this. Finally, respondents who had not returned questionnaires were contacted by telephone. An honorarium of $20 (Canadian) was offered to the physicians for completion of the questionnaire.

Because the survey was self-administered, respondents indicated their consent by completing and returning the survey. Respondents were advised that the information they provided would be kept completely confidential.

Further exploration of the physicians' approach to LTV decisions was addressed using qualitative methods. Face-to-face interviews were conducted with six of the respondents after the questionnaires had been returned and analyzed. Interview respondents were chosen from a pool of 16 using selective sampling methods[10] and based on three criteria: the respondents represented a range of geographic locations in Canada, the respondents' demographics approximated the demographic profile of the larger study sample, and the respondents represented a range of attitudes/practices toward ventilation. The physicians were asked to elaborate on the decision-making process they engaged in with patients and families. They were encouraged to describe actual cases as well as their overall philosophy and clinical approach to management of LTV decisions. The interviews allowed for the probing of specific responses, which was not possible on the structured questionnaire, and therefore provide a richer description of the physicians' attitudes and practices. Written informed consent was obtained from all respondents before the interviews.

All interviews were conducted by the principal investigator using open-ended semistructured questions. The interviews were audiotaped and transcribed into a qualitative analysis program (Ethnograph, version 3.0; Qualis Research Associates; Salt Lake City, UT). The data were then analyzed for recurring themes using grounded-theory techniques as described by Strauss and Corbin.[11]

RESULTS

Questionnaire

Eighty-three physicians were initially sent a questionnaire. Of these, 23 physicians were excluded from the study because they were no longer practicing in Canada or they were not following up patients with DMD, leaving a total of 60 physicians from 34 clinics appropriate for the study. Forty-five questionnaires from 29 clinics were returned for a physician-response rate of 75.0% and a clinic-response rate of 85.3%. The mean age of the respondents was 47.0 [+ or -] 8.2 years. The majority of the respondents were male (77.3%) and had been working in a neuromuscular clinic for an average of 11.6 [+ or -] 6.9 years. The sample consisted of 14 respirologists (31.1%), 12 neurologists (26.7%), 10 pediatricians (22.2%), 6 physiatrists/rehabilitation specialists (13.3%), and 3 others (6.7%).

When asked if they informed their DMD patients and families about the option of LTV, of the 44 respondents who answered, 33 respondents (75.0%) said they always inform their patients/families, 10 respondents (22.7%) said they sometimes did not tell patients/families about mechanical ventilation, and 1 respondent (2.3%) never informed patients/families about mechanical ventilation (Fig 1). A trend was identified between attitudes toward disability and disclosure practices. Those physicians who always informed patients of the option of LTV had a higher mean MIDS score (190.3) than those who did not (mean, 175.5; t test, p = 0.06). Female physicians were more likely to inform their patients about the option of ventilation ([chi square], 4.48, p = 0.03; Fisher's Exact Test, p = 0.03).

[Figure 1 ILLUSTRATION OMITTED]

All of the physicians who disclosed information about mechanical ventilation (n = 43) were asked whether or not they recommended mechanical ventilation to their patients. The physicians were asked to quantify, expressed as a percentage, how frequently they recommend, advise against, or were impartial in their discussions. Summaries of the numbers of physicians who always give the same advice and those who give varying advice appear in Table 1. The majority of the physicians (57.1%) reported that they were "always impartial" in their discussions with patients and families.

Table 1--Type of Advice Given to Patients Regarding LTV by Frequency (n = 42)(*)

(*) Data are expressed as No. (%).

Respondents were asked to report the reasons why they might not inform or recommend mechanical ventilation to patients/families. The results are summarized in Table 2. Respondents were allowed to choose as many reasons as might apply to their practice. Nineteen physicians gave a total of 58 responses. The most frequently cited reason for not recommending ventilation was poor patient quality of life. The second most cited reasons were distributed equally between lack of home-care support availability and inadequacy of the home environment.

Table 2--Reasons for Not Offering/Recommending Mechanical Ventilation(*)

(*) Data are presented as No. Respondents could choose multiple responses.

A small number of physicians (n = 3) included "lack of family financial resources" among their reasons for not recommending ventilation. It should be noted that it is unlikely the physicians were referring to the costs of medical equipment such as the ventilator itself, which as a general rule would be supplied under provincial health insurance plans. The physicians were likely referring to the ancillary costs of treatment including the attendant-care costs that, in some communities, are only partially covered.

Interviews

The interviews were conducted between May and July 1997, with six physicians in four different cities and three different provinces in Canada, with representatives from both eastern and western provinces. Table 3 shows the distribution of the respondents' demographic characteristics compared to that of the larger study sample. Analysis of the physicians' accounts revealed three shared major themes that were important to their management of LTV decisions: mentioning and discussing, the nighttime/full-time distinction, and discussion and influence. The following paragraphs highlight the findings within each theme.

1. Mentioning and discussing: Physicians initially mention mechanical ventilation to patients and families as a way of introducing the topic and then proceed to discussion at a later date. For example one physician stated, "I think it's something that should be brought up first of all at the time of diagnosis--just mention it in sort of a broad sense ... over the next several years mention it again ... If the respirologist said to me in the last clinic `I think we're getting close to the time we should talk to his parents about this kind of issue in more detail,' then I see them ..."

2. Nighttime/full-time distinction: While the data indicated that initiating nighttime LTV has become standard practice in the last few years, full-time mechanical ventilation is still not routinely discussed by all physicians with all patients. Quality of life was often referred to when physicians were discussing differences in their management of full-time vs nighttime LTV decisions. Full-time mechanical ventilation is viewed as life extending, but physicians vary in their opinions as to whether or not this represents a benefit or a burden for all or specific patients. One physician expressed his belief that full-time mechanical ventilation results in an unacceptable quality of life: "I guess I'm sort of, I'm sort of still having a bias in terms of ventilatory support for somebody who is, for somebody who has a terminal disease. Um, their quality of life is the pits. Once they get on chronic ventilation, you've now forgotten about quality of life as a positive thing and you're thinking you know, just survival."

In contrast, some physicians manage the full-time decision in the same manner as the nighttime decision, and the full gamut of discussion events occurs with each. The physician in the following quote discusses progression to full-time LTV in relation to the patient's personal choices and needs: "And they often ask, well, themselves, is it full-time or part-time? I say to them, `It's your decision. You start at part-time, and it may go on just overnight for 10 years, or 5 years, or 1 year. You may find you get tired after meals and want to rest for an hour. You may find that eventually you're going to be using it all the time, maybe 20 hours a day or so, but, ah, I'm not going to tell you how much to use it.'"

3. Discussion and influence: Discussion involves an in-depth exploration of the option of mechanical ventilation that can occur over time but usually involves at least one lengthy discussion with one or more team members. The events that trigger these discussions are related to laboratory results or patient symptoms. Discussion events center on the sharing of facts and values, and conveying opinion. Conveying of opinion can be either intentional or unintentional. For example, giving a clear recommendation or urging a patient to "give it a try" are examples of intentional conveying of opinion: "On the nighttime ventilation, I sort of am positive about it and say, `I really believe you might benefit from this. Give it a try.'"

Table 3--Demographic Distribution of Interview Participants(*)

(*) Unless otherwise indicated, data are expressed as mean (range).

Framing information negatively or positively or not initiating further discussion are examples of unintentional conveying of opinion: "Well, it's not that I don't recommend it. I say, `Look, here are the facts, and the care and the length of time and the benefits and the side effects you're going to get from all of this, side effects in terms of time and social structure, costs to your families that are considerable. But hey, you know, it's your decision in the end,' and there you go. So we all tend to sway the families, there's no doubt about that."

Several issues are reflected in this quotation. The physician does not appear to want to give a recommendation, presumably because he does not want to direct the patient/family's behavior. Instead of giving a recommendation, he presents some "facts" and "side effects" of mechanical ventilation that are all negative. He acknowledges this information will sway the patient. Not wanting to give an explicit positive or negative recommendation was common among the interview participants. Another physician had this to say: "We would frame it in such a way as to lean a little bit against it. We don't tell them it's wrong. And we wouldn't refuse to do it. We tell them that in that type of situation. We would make it clear that it would be a challenge and that it's possible that in the long run it might be very hard. If they insisted, we'd do it."

Again the physician indicates he believes the final decision is up to the family, but only if they "insisted." Information is framed in a negative light to make it appear unattractive.

DISCUSSION

Physicians have both an ethical and legal responsibility to disclose available treatment options to their patients.[12-15] Furthermore, assisting patients to make informed choices that are consistent with their own values and preferences requires physicians to engage patients and their families in a process of mutual participation in decision making that requires more than simple disclosure.[16] The survey revealed that 25% of the physicians did not disclose the option of LTV to some of their patients with DMD. These results are an improvement on the 1992 findings of Bach,[5] who found that 36% of physicians never discussed mechanical ventilation with any of their patients. This may be explained by geographic differences in practice, by a general change in practice patterns from 1992, to now, or both. An interesting finding in our interviews was that some of the physicians avoided discussion of progression from nighttime to full-time ventilation, an issue that the study by Bach[5] did not address. Unfortunately, our results are based On a small sample of interviews but warrant further exploration.

Why would physicians not provide information regarding LTV when the benefits of LTV are well documented and the physician has several years from the time of diagnosis to discuss both the benefits and the burdens with the patient and family? Quality-of-life judgments appear to play a significant role in the physicians' approaches to LTV discussions. In this study, the most common reason for not recommending LTV was perceived poor quality of life (Table 2). This is not entirely unexpected, as LTV decisions are by their nature value laden and involve a weighing of benefits and burdens that go beyond physiologic effect. Because the physiologic effects of mechanical ventilation are uncontested, the decision largely rests on considerations of the burdens that the patient and family will have to bear, and whether or not the burdens outweigh the potential benefits. Physicians may have valid concerns about poor patient quality of life and may have serious misgivings about participating in care they feel is ultimately harmful to the patients and families they care for.

Unilateral judgments of quality of life, however, should be avoided when the patient and his or her family are capable of contributing to these deliberations. There is considerable empirical evidence demonstrating that health-care professionals may base treatment decisions on mistaken perceptions of the quality of life of their patients.[17-19] For example, Schneiderman[19] compared (1) patients' preferences for specific lifesaving procedures with physicians' predictions of the patients' preferences, and (2) physician's preferences for themselves if they were in the same situation. They found that physicians often underestimate their patients' perceived quality of life and that physicians' predictions of what lifesaving procedures their patients would want more closely corresponded to their own personal preferences than the patient's actual preferences. In another study, Bach et al[18] compared physicians' estimations of the satisfaction with life of a group of muscular dystrophy patients receiving mechanical ventilation with the patient's own evaluations. Not only did the physicians significantly underestimate the patients' satisfaction with life, the physicians who discouraged ventilator use were more likely to underestimate the life satisfaction of a ventilator user. This is consistent with the findings in the current study that demonstrated a possible association between attitudes toward disability and disclosure practices, with those physicians having the least positive attitudes being less likely to disclose LTV information.

There are obvious problems of intersubjective variability and bias inherent in quality-of-life judgments. Because quality-of-life assessments are, at least in part, value dependent, different physicians will have different determinations of what constitutes an acceptable quality of life. Physicians in this study disagreed on whether or not patients with DMD can enjoy quality lives while dependent on a ventilator, especially if mechanical ventilation is to be on a full-time basis. Nondisclosure based on a determination of quality of life may seem legitimate to one physician and unacceptable to another. Youngner[20] contends that while physicians may be well placed to initiate and guide discussions about prognosis or potential quality of life, these decisions cannot be made unilaterally. For one patient, a life of extreme disability or pain might be quite tolerable; for another, totally unacceptable. Physicians should not have the authority to decide which lives are not worth living because it is possible that they may inadvertently base decisions on their own values or unconsciously discriminate against the severely physically or mentally disabled. Furthermore, whether or not a patient is offered a life-sustaining therapy may depend on who his or her doctor is, rather than the patient's individual circumstances.[21]

What then is the role of the physician in the decision-making process? The majority of the physicians (57.1%) in the study reported that they always present information to patients and families in an impartial manner, rather than recommend or advise against mechanical ventilation. While it may be true that the physicians are attempting to eliminate bias, whether or not they can present information completely impartially is debatable and not necessarily desirable. A questionnaire does not allow for exploration of the personal meaning each physician attaches to the concept of impartiality, and therefore these results taken by themselves need to be interpreted with caution. The interviews offered some clarification. The physicians all voiced a belief that the final decision to accept or reject LTV rested with the patient and family, but admitted to having significant influence on that decision. Most physicians stopped short of giving an explicit recommendation but conveyed opinion to families using a less direct approach. Some forms of influence were overt, such as urging a patient to give it a try. Others were subtler, such as framing information in order to discourage a choice. "Impartiality" therefore did not exclude making a recommendation, however indirect it may be.

Respecting the patient's autonomous decision making does not mean that health-care professionals cannot or should not offer a recommendation.[22] Physicians working with patients with DMD have often known the patient and family for years and know or have known dozens of other families faced with the same decision. The physician has a wealth of knowledge and experience, both medical and nonmedical, that can help the family with their deliberations. Physicians can help patients to hook up with support groups or locate Internet and other resource materials that will help to inform and offer a different viewpoint. Through ongoing dialogue, the physician can assist the individual to make a choice that is most appropriate by fostering the patient's understanding of how the medical information relates to his unique perspective and situation.[23,24] The final decision will then rest with the patient/family.

Some may argue that the power inequities in the patient-physician relationship dictate that physicians should withhold their opinions, as they have too great an influence on their patients. As many have pointed out, power inequalities can hinder autonomous choice.[25,26] There also exists ethnic, class, economic, and value differences between patients and physicians that prevent one from assuming a commonality of interests between the two.[27] The physician may unwittingly impose his or her own values on the patient, and the uncertain patient may too easily accept this imposition. Brody[28] has argued that to address the inequalities, it is important that physicians be explicit in their recommendations and avoid framing information in order to sway a response. Recommendations should be clearly stated as such, and less direct forms of influence should be avoided. Physicians as well as patients do not make decisions based solely on rational or conscious deliberations. While physicians cannot know all the unconscious, internalized forces that guide them, open discussion can serve to identify underlying assumptions that may not be self-evident.[29]

Brody[28] suggests that what is required of the physician is "transparency." Physicians should essentially make transparent the basis on which a proposed treatment has been chosen. The physician thus reveals not only factual information but also the values he or she attaches to each. As an example related to LTV decisions, the physician may reveal that she does not recommend LTV because she does not feel the patient will be able to enjoy a reasonable quality of life. She may add that she feels strongly about this because she is worried that the family will not be able to cope financially or emotionally with caring for the patient at home and that the patient will eventually end up in an institution. The family members then have the opportunity to question the physician's reasoning, to explore their own values to see if they are in agreement, to speak with others and consider alternative viewpoints, and to query or confirm the physician's assumption about their coping abilities or the unacceptability of life in an institution. This seems particularly appropriate for the families of individuals with chronic illnesses facing long-term decisions who have the unique opportunity of having a series of discussions with their doctors over time.

Future Directions

There remain many areas for future research. Because the purpose of the study was to describe practice, a questionnaire was chosen as the appropriate methodology to collect information on practices across the country. However, much information was gained from the qualitative interviews. A qualitative study that involves a larger sample size may provide further understanding of current practice.

Further research is also needed to examine the experiences of patients and families, as well as the contributions and experiences of other members of the health-care team. In addition, this study focused on physicians working with patients with DMD; however, patients with other conditions such as COPD or other neuromuscular diseases face similar choices. Research that compares and contrasts approaches with these different patient groups might provide further insights.

SUMMARY

This study revealed that Canadian physicians vary in their approach to LTV decisions. While the majority of physicians disclose the option of LTV to patients with DMD and their families, 25% said they do not always disclose. Furthermore, the qualitative data showed that different physicians framed information either positively or negatively depending on their own preferences and, despite a desire to be impartial, agreed that they had significant influence over the families' decisions. It is suggested that an initial disclosure is the minimum requirement of informed consent/decision-making. Once disclosure is made, a shared decision-making approach serves to support autonomous choice and determine the course of action that is best for the patient and his family. Such a model will encourage patients and families to explore their own values and question their physician's recommendations while at the same benefiting from their physician's knowledge and experience. To help facilitate these recommendations, ongoing physician education is indicated in both the broad area of shared decision making and in the specific context of long-term ventilation decisions.

ACKNOWLEDGMENT: I thank Dr. Karen Yoshida, Dr. William Harvey, and Dr. Laura Shanner for their support and advice during the research, and Dr. Dina Brooks for her comments on earlier versions of this article. I would also like to thank all the physician participants who generously gave of their time on the study, particularly those who agreed to be interviewed.

REFERENCES

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[2] Bach JR. Pulmonary rehabilitation considerations for Duchenne muscular dystrophy: the prolongation of life by respiratory muscle aids. Crit Rev Phys Rehabil Med 1992; 3:239-269

[3] Alberion G, Alba A, Lee M, et al. Pulmonary care of Duchenne type of dystrophy. NY State J Med 1973; 73:1206-1207

[4] Curran JF, Colbert AP. Ventilator management in Dechenne muscular dystrophy and post poliomyelitis syndrome: twelve years experience. Arch Phys Med Rehabil 1989; 70:180-185

[5] Bach JR. Ventilator use by muscular dystrophy association patients. Arch Phys Med Rehabil 1992; 73:179-183

[6] Guillemin F, Bombardier C, Beaton D. Cross-cultural adaptation of health related quality of life measures: literature review and proposed guidelines. J Clin Epidemiol 1993; 46:1417-1432

[7] Makas E. The MIDS (Modified Issues in Disability Scale). Washington, DC: The George Washington University, 1985

[8] Makas E. In the MIDSt: Modified Issues in Disability Scale testing. In: Kiger G, Hey SC, eds. The social organization of disability experience. Salem, OR: The Society for Disability Studies, 1991; 109-114

[9] Dillman DA. Mail and telephone surveys: the total design method. New York, NY: John Wiley and Sons, 1978

[10] Kuzel AJ. Sampling in qualitative inquiry. In: Crabtree BF, Miller WL, eds. Doing qualitative research. Newbury Park, CA: Sage Publications, 1992; 31-44

[11] Strauss A, Corbin J. Basics of qualitative research: grounded theory procedures and techniques. Newbury Park, CA: Sage Publications, 1990; 57-175

[12] Etchells E, Sharpe G, Walsh P, et al. Bioethics for clinicians: 1. Consent. Can Med Assoc J 1996; 155:177-180

[13] Beauchamp TL, Childress JF. Principles of biomedical ethics. 4th ed. New York, NY: Oxford University Press, 1994; 145

[14] Macklin R. Mortal choices: bioethics in today's world. New York, NY: Pantheon Books, 1987; 36

[15] Somerville MA. Consent to medical care: protection of life series. Ottawa, Canada: Law Reform Commission of Canada, 1980; 11

[16] The President's Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research. Deciding to forego life sustaining treatment: a report on the ethical medical and legal issues in treatment decisions. Washington, DC: US Government Printing Office, 1983

[17] Gerhart KA, Koziol-McLain J, Lowenstein SR, et al. Quality of life after spinal cord injury: knowledge and attitudes of emergency care providers. Ann Emerg Care Med 1994; 23:807-812

[18] Bach JR, Campagnola DI, Hoeman S. Life satisfaction of individuals with Duchenne muscular dystrophy using long term mechanical ventilatory support. Am J Phys Med Rehabil 1991; 70:129-135

[19] Schneiderman LJ. Do physicians' own preferences for life sustaining treatment influence their perceptions of patients' preferences? J Clin Ethics 1993; Spring: 28-33

[20] Youngner SJ. Who defines futility? JAMA 1988; 260:2094-2095

[21] Griener G. The physician's authority to withhold futile treatment. J Med Philos 1995; 20:207-224

[22] Hayry M. Measuring the quality of life: why, how and what? Theor Med 1991; 12:97-116

[23] Katz J. The silent world of doctor and patient. New York, NY: The Free Press, 1984; xvi-xviii

[24] Lidz CW, Applebaum PS, Meisel A. Two models of implementing informed consent. Arch Intern Med 1988; 148:1385-1389

[25] Brody H. The healer's power. New Haven, CT: Yale University Press, 1992

[26] Loewy EH. Textbook of medical ethics. New York, NY: Plenum Publishing Corporation, 1989; 61

[27] Veatch BM. Models for ethical medicine in a revolutionary age. Hastings Cent Rep 1972; 2:5-7

[28] Brody H. Transparency: informed consent in primary care. Hastings Cent Rep 1989; Sept/Oct:5-9

[29] Katz J. The silent world of doctor and patient. New York, NY: The Free Press, 1984; 124

(*) From the Department of Physical Therapy, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.

Performed at the Institute of Medical Sciences, University of Toronto.

Financial support was provided by the Ontario Respiratory Care Society Fellowship.

Correspondence to: Barbara Gibson, MSc, BMR (Physical Therapy), University Health Network, 610 University Ave, RM16-726, Toronto, Ontario, Canada M5G 2M9; e-mail: barbara.gibson@ utoronto.ca

COPYRIGHT 2001 American College of Chest Physicians
COPYRIGHT 2001 Gale Group