Are certainly most reverent Of the principles of epidemiology. Some doctors adore the violin, But statistics becomes, to their chagrin, Not a fun song, But a Schwann song, As it appears to deplete their myelin.
The average doc's cortex appears not to consist Of thought routes possessed by the trained physicist: One seeks image portrayal, T'other numerical detail A qualitative difference, thinks this lyricist. Postscript For those who prefer Change "him" into "her" And for "he", "she", Lest I vex Those for whom sex In words will cause a frown For an inappropriate noun. Frank I. Jackson, MB, ChB Senior radiologist Cross Cancer Institute Edmonton, Alta.
Edinburgh is synonymous with medical history I was very interested to read
burgh, but he was assistant to the famous extramural teacher of anatomy Dr. John Barclay and eventually took charge of Barclay's anatomy school. The article implies that Knox was elected conservator of the university museum; in fact he was appointed the first conservator of the museum of the Royal College of Surgeons of Edinburgh. Knox had not "arranged for the university to take possession of the extensive specimen collection of Charles Bell". This collection was purchased by the Royal College on Knox's recommendation after he and Dr. Alexander Watson had inspected the collection in London. The article states that the cadavers supplied by William Burke and William Hare were particularly valued by Knox because "they provided prime examples of deformities" that "greatly improved the collection of specimens" in the Royal College museum. In fact the collection includes no specimens obtained in this way. The bodies supplied by Burke and Hare were used entirely for teaching purposes. I greatly enjoyed the article, and these comments are made in no carping spirit. As a member of the team responsible for establishing the historical display in the Sir Jules Thorn Hall of the Royal College museum I am delighted to know that Ms. Chouinard was impressed by it.
this article, by Amy Chouinard (Can Med Assoc J 1990; 142: 745-746). I did not have the pleasure of meeting the author when she visited Edinburgh in December 1989, but I know that Ian F. MacLaren, FRCS (Edin) of Surgeons of Edinburgh all the members of staff of the Royal College Royal College of Surgeons of Ed- Edinburgh, Scotland inburgh who met her at that time were distressed by the news of her death in February 1990. I hope it will be considered no disrespect to Universal precautions her memory if I correct certain minor inaccuracies in the article. lthough I welcome the deA tailed cost-accounting for The first is the statement that Dr. Robert Knox was "an assisuniversal precautions protant lecturer in anatomy at the vided by Drs. Susan R. Stock, university". Knox never held a Amiram Gafni and Ralph F. university appointment in Edin- Bloch in their article "Universal 256
CAN MED ASSOC J 1990; 143 (4)
precautions to prevent HIV transmission to health care workers: an
economic analysis" (Can Med Assoc J 1990; 142: 937-946) the authors present a negative conclusion that requires comment. By debating cost effectiveness in terms of the value of a health care worker's life they divert attention from the real reason that a change from a category-specific to an interaction-driven system of hospi-
tal infection control for patient care is long overdue. Infection control personnel have long recognized the hazards inherent in systems of precautions based on known or suspected communicable diseases. Policies such as the sterilization of endoscopes after use in infectious cases but only disinfection after use in all other cases have resulted in many instances of transmission of disease (e.g., salmonellosis, tuberculosis, hepatitis B). Silent carriers outnumber both known and suspected cases. Such policies are illogical and must be abandoned. Most hospitals now process instruments the same way after every instance of use, regardless of the presumptive diagnosis. With the endoscope example, inactivation of the most resistant pathogens (namely Mycobacterium tuberculosis and hepatitis B virus) that may contaminate the instrument must be routinely ensured. The traditional categoryspecific systems of patient care precautions are similarly obsolete. For all types of contact with patients or their substances the strategy for preventing transmission of pathogens to other people (health care workers and patients alike) must be based on the risk associated with the specific type of contact and not the presumptive diagnosis. Prevention of all disease transmission, not just protection from infection with the human immunodeficiency virus and hepatitis B, is the goal. Of the two basic types of interaction-driven
systems, only body substance precautions - and not universal precautions - completes a congruous system of hospital infection control. Clearly, the handling of "sharps" (any clinical item capable of causing a cut or puncture) that are contaminated with blood presents the highest risk. I agree that this problem deserves much more attention. So-called pointof-use disposal systems mounted on walls remote from the bedside have provided an expensive solution that is more apparent than real. Health care resources are inadequate, and we must be cost conscious. However, direct cost benefit must not be the sole criterion used for planning any change. How much of what we accept today as standard medical practice would survive similar cost analysis? Julie Righter, MD, FRCPC Head Division of Microbiology Toronto East General and Orthopaedic Hospital Toronto, Ont.
[The authors respond.]
gowns to prevent body fluids from coming in contact with intact skin. The evidence we reviewed suggests that the occupational risk of HIV infection in health care workers is primarily associated with needlestick and other percutaneous injuries, yet few of the current recommendations are aimed at preventing these. Body substance isolation techniques may well turn out to be effective and efficient at preventing hospital-acquired nosocomial infections among patients. But that was not the rationale given by the US Centers for Disease Control for instituting universal precautions. We are not suggesting that resources be denied for protecting health care workers from HIV infection and believe it would be inappropriate for hospital administrators to conclude so on the basis of our study. As an occupational health physician one of us (S.R.S.) is quite committed to the prevention of occupational disease and believes that health care workers should be provided with effective methods of protection. But implementing measures that are not effective provides health care workers with false assurances. Moreover, our economic analysis demonstrates that we may be paying dearly for such assurances, with money that could instead be devoted to the development and implementation of effective protection. We therefore have suggested that we need to refine the recommendations and devote our resources to better understanding how such exposures occur and to designing equipment and surgical techniques that prevent them more effectively. Although we agree with Righter that cost should not be the sole criterion used for planning health care programs, we do believe there is a role for economic analyses.
Dr. Righter's letter brings out some important issues and some misconceptions that can be drawn from our article. We do not conclude from our study that the universality of universal precautions is problematic, nor are we advocating a return to category-specific precautions. We agree with Righter that there are many situations in which nosocomial infection will occur if precautions are only taken when a communicable disease is known or suspected. Rather, we are questioning the efficacy and appropriateness of several of the specific recommendations that constitute universal precautions to prevent HIV infection in health care workers, The real cost of any program is not such as the use of impermeable the number of dollars appearing in
the budget but, rather, the health outcomes achievable with some other program that were forgone when the resources were committed to the first program. It is this "opportunity cost" that an economic evaluation seeks to estimate and to compare with program benefits.' Susan R. Stock, MD Assistant professor Department of Family Medicine Amiram Gafni, DSc Centre for Health Economics and Policy Analysis Associate professor Department of Clinical Epidemiology and Biostatistics Ralph F. Bloch, MD, PhD, FRCPC Associate professor Department of Medicine McMaster University Hamilton, Ont.
Reference 1. Department of Clinical Epidemiology and Biostatistics, McMaster University Health Sciences Centre: How to read clinical journals: VII. To understand an economic evaluation (part A). Can Med Assoc J 1984; 130: 1428-1432, 1434
Fighting AIDS in francophone African countries I felt sad after reading the fol-
lowing two paragraphs in James Hale's article "The Third World: AIDS finds a comfortable home" (Can Med Assoc J 1990; 142: 869-870). The Canadian International Development Agency (CIDA) provides most of Canada's international AIDS funding. . . . From 1987 to 1995, it is expected to spend more than $60 million . . . training health care workers, producing videos to educate street children and providing epidemiologic surveillance support. Recently, Monique Landry, the minister for external relations, announced that CIDA will fund a 5-year,
$22-million program at Laval University that will help fight AIDS in francophone African countries. CAN MED ASSOC J 1990; 143 (4)
257
The average doc's cortex appears not to consist Of thought routes possessed by the trained physicist: One seeks image portrayal, T'other numerical detail A qualitative difference, thinks this lyricist. Postscript For those who prefer Change "him" into "her" And for "he", "she", Lest I vex Those for whom sex In words will cause a frown For an inappropriate noun. Frank I. Jackson, MB, ChB Senior radiologist Cross Cancer Institute Edmonton, Alta.
Edinburgh is synonymous with medical history I was very interested to read
burgh, but he was assistant to the famous extramural teacher of anatomy Dr. John Barclay and eventually took charge of Barclay's anatomy school. The article implies that Knox was elected conservator of the university museum; in fact he was appointed the first conservator of the museum of the Royal College of Surgeons of Edinburgh. Knox had not "arranged for the university to take possession of the extensive specimen collection of Charles Bell". This collection was purchased by the Royal College on Knox's recommendation after he and Dr. Alexander Watson had inspected the collection in London. The article states that the cadavers supplied by William Burke and William Hare were particularly valued by Knox because "they provided prime examples of deformities" that "greatly improved the collection of specimens" in the Royal College museum. In fact the collection includes no specimens obtained in this way. The bodies supplied by Burke and Hare were used entirely for teaching purposes. I greatly enjoyed the article, and these comments are made in no carping spirit. As a member of the team responsible for establishing the historical display in the Sir Jules Thorn Hall of the Royal College museum I am delighted to know that Ms. Chouinard was impressed by it.
this article, by Amy Chouinard (Can Med Assoc J 1990; 142: 745-746). I did not have the pleasure of meeting the author when she visited Edinburgh in December 1989, but I know that Ian F. MacLaren, FRCS (Edin) of Surgeons of Edinburgh all the members of staff of the Royal College Royal College of Surgeons of Ed- Edinburgh, Scotland inburgh who met her at that time were distressed by the news of her death in February 1990. I hope it will be considered no disrespect to Universal precautions her memory if I correct certain minor inaccuracies in the article. lthough I welcome the deA tailed cost-accounting for The first is the statement that Dr. Robert Knox was "an assisuniversal precautions protant lecturer in anatomy at the vided by Drs. Susan R. Stock, university". Knox never held a Amiram Gafni and Ralph F. university appointment in Edin- Bloch in their article "Universal 256
CAN MED ASSOC J 1990; 143 (4)
precautions to prevent HIV transmission to health care workers: an
economic analysis" (Can Med Assoc J 1990; 142: 937-946) the authors present a negative conclusion that requires comment. By debating cost effectiveness in terms of the value of a health care worker's life they divert attention from the real reason that a change from a category-specific to an interaction-driven system of hospi-
tal infection control for patient care is long overdue. Infection control personnel have long recognized the hazards inherent in systems of precautions based on known or suspected communicable diseases. Policies such as the sterilization of endoscopes after use in infectious cases but only disinfection after use in all other cases have resulted in many instances of transmission of disease (e.g., salmonellosis, tuberculosis, hepatitis B). Silent carriers outnumber both known and suspected cases. Such policies are illogical and must be abandoned. Most hospitals now process instruments the same way after every instance of use, regardless of the presumptive diagnosis. With the endoscope example, inactivation of the most resistant pathogens (namely Mycobacterium tuberculosis and hepatitis B virus) that may contaminate the instrument must be routinely ensured. The traditional categoryspecific systems of patient care precautions are similarly obsolete. For all types of contact with patients or their substances the strategy for preventing transmission of pathogens to other people (health care workers and patients alike) must be based on the risk associated with the specific type of contact and not the presumptive diagnosis. Prevention of all disease transmission, not just protection from infection with the human immunodeficiency virus and hepatitis B, is the goal. Of the two basic types of interaction-driven
systems, only body substance precautions - and not universal precautions - completes a congruous system of hospital infection control. Clearly, the handling of "sharps" (any clinical item capable of causing a cut or puncture) that are contaminated with blood presents the highest risk. I agree that this problem deserves much more attention. So-called pointof-use disposal systems mounted on walls remote from the bedside have provided an expensive solution that is more apparent than real. Health care resources are inadequate, and we must be cost conscious. However, direct cost benefit must not be the sole criterion used for planning any change. How much of what we accept today as standard medical practice would survive similar cost analysis? Julie Righter, MD, FRCPC Head Division of Microbiology Toronto East General and Orthopaedic Hospital Toronto, Ont.
[The authors respond.]
gowns to prevent body fluids from coming in contact with intact skin. The evidence we reviewed suggests that the occupational risk of HIV infection in health care workers is primarily associated with needlestick and other percutaneous injuries, yet few of the current recommendations are aimed at preventing these. Body substance isolation techniques may well turn out to be effective and efficient at preventing hospital-acquired nosocomial infections among patients. But that was not the rationale given by the US Centers for Disease Control for instituting universal precautions. We are not suggesting that resources be denied for protecting health care workers from HIV infection and believe it would be inappropriate for hospital administrators to conclude so on the basis of our study. As an occupational health physician one of us (S.R.S.) is quite committed to the prevention of occupational disease and believes that health care workers should be provided with effective methods of protection. But implementing measures that are not effective provides health care workers with false assurances. Moreover, our economic analysis demonstrates that we may be paying dearly for such assurances, with money that could instead be devoted to the development and implementation of effective protection. We therefore have suggested that we need to refine the recommendations and devote our resources to better understanding how such exposures occur and to designing equipment and surgical techniques that prevent them more effectively. Although we agree with Righter that cost should not be the sole criterion used for planning health care programs, we do believe there is a role for economic analyses.
Dr. Righter's letter brings out some important issues and some misconceptions that can be drawn from our article. We do not conclude from our study that the universality of universal precautions is problematic, nor are we advocating a return to category-specific precautions. We agree with Righter that there are many situations in which nosocomial infection will occur if precautions are only taken when a communicable disease is known or suspected. Rather, we are questioning the efficacy and appropriateness of several of the specific recommendations that constitute universal precautions to prevent HIV infection in health care workers, The real cost of any program is not such as the use of impermeable the number of dollars appearing in
the budget but, rather, the health outcomes achievable with some other program that were forgone when the resources were committed to the first program. It is this "opportunity cost" that an economic evaluation seeks to estimate and to compare with program benefits.' Susan R. Stock, MD Assistant professor Department of Family Medicine Amiram Gafni, DSc Centre for Health Economics and Policy Analysis Associate professor Department of Clinical Epidemiology and Biostatistics Ralph F. Bloch, MD, PhD, FRCPC Associate professor Department of Medicine McMaster University Hamilton, Ont.
Reference 1. Department of Clinical Epidemiology and Biostatistics, McMaster University Health Sciences Centre: How to read clinical journals: VII. To understand an economic evaluation (part A). Can Med Assoc J 1984; 130: 1428-1432, 1434
Fighting AIDS in francophone African countries I felt sad after reading the fol-
lowing two paragraphs in James Hale's article "The Third World: AIDS finds a comfortable home" (Can Med Assoc J 1990; 142: 869-870). The Canadian International Development Agency (CIDA) provides most of Canada's international AIDS funding. . . . From 1987 to 1995, it is expected to spend more than $60 million . . . training health care workers, producing videos to educate street children and providing epidemiologic surveillance support. Recently, Monique Landry, the minister for external relations, announced that CIDA will fund a 5-year,
$22-million program at Laval University that will help fight AIDS in francophone African countries. CAN MED ASSOC J 1990; 143 (4)
257
