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Pressure Sores - A Key Quality Indicator
60
Journal of Tissue Viability 1994 Vol 4 No 2
Pressure Sores - A Key Quality Indicator Nicky Cullum1 and Peter Shakespeare2
Research Fellow, Dept ofNursing, University ofLiverpool Director, Laing Burns Research Laboratory
1
2
A review of the recently published DoH Guide for NHS Purchasers and Providers together with some comments on the supporting Report by Consultants Touche Ross. Pressure Sores - a Key Quality Indicator' was published by the Department ofHealth in December 1993, and was generated by a working group of seventeen members representing a variety ofperspectives in health care. The document is aimed at raising awareness in both purchasers and providers of the need for a coherent pressure sore policy, and is effectively peppered with (apparently) true horror stories from those who have experienced pressure sores at first hand; either personally or in those they care for. Whilst it is hoped that this guide achieves its aim, the fact that it delivers some fairly straightforward messages in a rather verbose and confusing way cannot be ignored. The document usefully provides definitions of the terms 'prevalence' and 'incidence', but unfortunately does not differentiate between them in terms of their usefulness as quality indicators. The introductory paragraph delivers the bald statement that ' ..... the prevalence ofpressure sores is an excellent indicator ofquality of care', however we know that prevalence figures are exceedingly difficult to interpret and use operationally in any meaningful way 1• The point is that prevalence of people with pressure sores in any provider unit is likely to fluctuate over time, for a number of reasons, by at least 5% (the target for annual reduction ofprevalence set by the NHS ME), and whilst quality of care is an important element, the number of people admitted with sores, and the duration of existing sores confuses the picture. The incidence of new sores developing in any care setting however, is a measure which is more meaningful to service providers and can be used to guide to decision-making. Furthermore, whilst it is laudable to convey the message that strenuous efforts must be made to avoid pressure sore development, one must also acknowledge that there are situations in which pressure sore development is unavoidable, or the lesser of two evils. There are (thankfully infrequent) instances where, in terminal care for example, as death seems imminent, peace and comfort are more important than strenuous attempts at pressure relief, and in certain situations in critical care, pressure sores may be unavoidable in the face of other priorities.The findings of the recent Department of Health commissioned Touche Ross report on 'The cost of Pressure sores' are presented briefly in Annex 1 and discussed. I would suggest that the impact ofthe take-home message ofthis section may have been lost somewhat as a result of the variety and the complexity of the economic data presented here. Projected highest and lowest costings for both preventing and treating pressure sores are compared and contrasted for a number of
situations: per patient: for all English hospitals: one typical English hospital: and with and without staff costs etc. Touche Ross concluded that the financial cost of preventing a sore in a particular patient may be similar to the cost of treating one, however if the development of a sore results in successful litigation for the patient then prevention would be cheaper. On a hospital basis, the cost of prevention may be more expensive than treatment, as a much larger number of patients would require active prevention than would develop a sore and require treatment, however if staff costs are removed from the calculation, then prevention is cheaper. Touche Ross also make the vital point that the physical and psychological costs to the individual are hard to place a value on. The usefulness of this guide lies in its distillation of the key issues for those who are not experts in Tissue Viability. A list ofissues to be considered during the development ofprevention and management protocols is comprehensive and probably very helpful. A section on 'Multidisciplinary working and skills mix' illustrates very clearly the range of health care professionals and lay people who can and should be involved in pressure sore prevention, but the recommendation that 'providers of services might wish to consider the benefits to be derived from employing specialist tissue viability nurses' is made rather weakly - it seems likely that a Tissue Viability Specialist is a prerequisite for the provision of a coherent and effective pressure sore prevention and monitoring programme. Mention is made rather briefly of the availability of specialist equipment to aid pressure relief, but no direction is given as to the evidence (or lack of it) for the effectiveness of pressure relieving aids. Laudable though the Medical Devices Directorate's funding of the technical evaluation of support services is, it does not take the place ofprospective randomized controlled trials of clinical effectiveness. Annex 2 comprises a resume of the key messages from the literature in areas such as: the morbidity associated with pressure sores; risk assessment tools; and prevention measures. It is the later area where health care professionals require the maximum, high quality information, and it is precisely where information is lacking. The issues related to prevention are presented here with a broad brush, however what both providers and purchasers (the latter for contracting purposes) urgently require are systematic reviews of the evidence for the effectiveness of pressure sore prevention interventions. Such reviews should be widely and effectively disseminated, and encapsulated into
Journal of Tissue Viability 1994 Vol 4 No 2 clinical guidelines for practice. It is envisaged that the NHS research and development strategy, incorporating the UK Cochrane Centre and the Centre for Reviews and Dissemination, together with the current NHS Management Executive Nursing Directorate Consenus Stratgegy for Mainly Nursing Led Major Clinical Guidelines (which is incorporating pressure sores as an area for guideline development) will achieve this. Annex 3 of the report valuably presents provider units with a step-by-step guide to establishing a pressure sore policy. I suspect that this will be deemed to be one of the most useful sections of the document. The principal recommendations are that provider units institute a local pressure sore group, which in tum establishes a knowledge and policy base. Suggested components of the knowledge base include local incidence/ prevalence data and a review of existing policy, whilst the policy base might include the development of protocols, the allocation of responsibilities and the identification of training needs. The identification oflocal knowledge and policy bases will then direct target setting and the development of an action plan to achieve process and outcome targets. The upbeat message with which the document draws to a close is that exemplary practice is already in existence in many areas. Annex 4 presents six sketches of good practice from North Derbyshire, North Lincolnshire, Epsom, Mersey, Mid-Cheshire and Shrewsbury, together with contact names for further information. It is hoped that these individuals will be able to cope with the inevitable floods of enquiries! Finally, the reader is signposted to further resources; videos on pressure sore prevention and treatment, and a wealth of reading material. In summary, the intentions of this document are laudable; efforts to reduce the incidence of pressure sores must be a good thing. One means of achieving this is by identification of evidence-based practice, and the incorporation of this good practice into clinical guidelines, locally derived protocols, and contracts. The target for an overall annual reduction in the prevalence ofpressure sores however is fairly meaningless, and provider units would be well advised to build into their pressure sore programmes a means ofmeasuring the rate ofdevelopment of new sores within their units (incidence). Finally, it is essential that the development oflocal pressure policies involves staff at all levels of the service, and is endorsed by all. One essential component of any successful programme will be the continuing education ofnursing staff; something which appears to have been almost abandoned by the NHS in recent years. One regularly hears of nurses having not only to pay for their awn attendance at study days and conferences, but having to attend them in their own time. A real commitmemt, at all levels, to a reduction in the incidence of pressure sores must, by definiton, address the need for education as a priority. If this is done, and the other (fairly straightforward) recommendations in this document are followed, then we will succeed! Reference 1. ClarkM, Cullum N. Matching patient need for pressure sore prevention with the supply ofpressure redistributing mattresses. J Adv Nursing, 1992; 17:310-16.
61
Touche Ross Report - The Cost of Pressure Sores The attention of readers is drawn to this report which provides some of the background material for 'Pressure Sores - A Key Quality Indicator'. It contains some interesting data on the relative costs of treatment and prevention of pressure sores. The salient point to be drawn from the report concerns the balance of costs between prevention and treatment. Prevention is obviously a worthwhile activity. It is widely accepted that it is a cost effective process and an humane course of action. However, wherever a prevention exercise is undertaken a series of factors have to be considered. Among these are: 1. What population is the best target for 'prevention'? 2. What is the 'unit cost' of prevention? 3. Is prevention in fact any different from treatment? 4. How can the effects of prevention be measured in terms of disease prevalence and morbidity?
Touche Ross have calculated the 'costs' of treatment and prevention in a single hospital with 600 occupied beds. The results are interesting. For treatment costs the estimated range is £1, 154,000-£644,000. The biggest single item in this is the so-called opportunity costs which estimate the loss to the hospital as a result of blocked beds occupied by pressure sore patients. For prevention costs theestimatedrangeis£2,709,000-£645,000. In both 'high' and 'low' cost options the major element is staff time. A logical interpretation of these data would suggest that, at the extreme, it may actually be more economic to undertake very little prevention and accept that there are inevitable treatment costs. The figures presented by Touche Ross illustrate well the points concerning the assessment ofrisk ofpressure sore development set out for discussion in the January issue of the Joumal. In the report the pressure sore prevalence quoted is 8% (very close to Mr Bond's figures for N Derbyshire set out in the October 93 issue of the Journal), and the prevalence of 'at risk' patients approximately 26% (somewhat lower than the figures reported by Mr Bond). Everyone now has to accept explicitly, as they always have done implicitly, that money talks. Perhaps it is not actual money that is talking, but Accountancy. The report makes some very interesting points about 'prevention' and its cost effectiveness. The general understanding of prevention is often in terms of vaccination or antibiotic prophylaxis, activities which are cheap, effective and need to be undertaken once only. In terms of pressure sore development, 'prevention' is a continuing process and may require similar equipment and staff commitment to the treatment regime used to deal with established sores. Since the costs ofprevention and treatment are therefore similar it is dificult to argue in economic terms that prevention is cost effective - a point which reinforces the necessity for risk assessment to identify those genuinely at risk of developing the condition.
62
Journal of Tissue Viability 1994 Vol 4 No 2
In their conclusion Touche Ross state 'Our estimates for a large DGH (600 occupied beds) suggest that annual costs will be in the following ranges (for a low cost regime):
Equipment Staffing
Prevention Treatment £s £s 94,000 106,000 540,000 185,000
The report continues: 'With ideal data it would be possible to calculate the cost of a variety of preventive regimes. In our view it is unlikely that maximum prevention will be the least costly regime since, ifthe regime was withdrawn for a large number of low risk cases, the additional cost of treatment from the pressure sores that developed would be small.' The report is careful to set the framework for comparison of its prevention and treatment estimates and by its own admission, may be underestimating the cost of treatment. However the essential message is clear. Unless prevention can be shown to be effective in monetary terms it may become discredited at managerial level. In my view this could be to the detriment of all, with patients first on the list.
Two letters to the Editor, relevant to the Report Sir
Scoring the Risk Scores
I was interested in your article in the January edition of the Journal and immediately checked Mr Bond's article (JTV Oct 93) for the table shown in your article (Table 2), I assume that you have extracted this from Table 6 in Mr Bond's article? If this is so, I do have a slight problem inasmuch as the figures given by Mr Bond do not seem to tally with your own. However, this makes only a marginal difference to your subsequent inferences. Nevertheless, I am more concerned that your article implies that Mr Bond's calculations were based on an Incidence survey when, it seems to me, they were based on a Point Prevalence Survey. In other words, the sores found in Mr Bond's survey were not necessarily correlated to an 'Initial' risk score taken before the patients concerned actually developed overt sores. I'm sure you will agree that this is an important consideration if we are to arrive at a true Sensitivity and Specificity for the risk-assessment method used. In the case under consideration, the method used was actually a mixture of various risk scales. I first became aware of the importance of of 'Sensitivity' and 'Specificity' (mentioned in your article) after reading a useful article by Warner and Hall1 which showed me that the Norton Scale has a Sensitivity of 63% with more than 50 patients developing sores, and a Specificity of70% - for patients in acute Care of the Elderly wards. Subsequently, I completed a 3-year study at the Royal National Orthopaedic Hospital, Stanmore, with the aim of similarly validating the PSPS (which I developed
in 1976.) This study was prospective (patients were scored on admission, and only those without overt pressure sores at that time were later included in the data analysis - as was the case with Norton's work2 • My study showed that the PSPS had an 89% Sensitivity and a 76% Specificity3, with more than 50 patients developing sores. To date, I am not aware of any risk assessment scale which has fared better than this - on a valid prospective study. There are, however, some other scales which are very promising4 , and I certainly endorse your view that the TVS should be more involved in furthering validation studies on risk-assessment scales - in a variety of nursing situations. I am enclosing a copy of my PSPS card*, together with a copy of the Category Examples sheet*; the latter being for those trained nurses who wish to be more precise in their scoring, while the former is more suitable for general use. (A knowledge of medical terminology is not assumed.) Yours faithfully Peter Lowthian M.Phil RGN,Clinical Nursing Specialist/Lecturer 134 Villiers Road,Oxhey,Watford WDl 4AJ References 1 Warner U and Hall DJ. Pressure Sores: a policy for prevention. Nurs Times 1986;82 (16) 59-61. 2 Norton D, McLaren R, Exton-Smith AN. An investigation of geriatric nursing problems in hospital. 1962. (Reprinted 1975) Churchill Livingstone London. 3 Lowthian PT. Identifying and protecting patients who may get pressure sores. Nurs Standard. 1989;4 (4) 26-29. 4 Lowthian PT. Acute patient care: pressure areas. Br J Nursing. 1993; 2(9) 449-458. * see pages 62,63 Mr Lowthian is quite correct to take me to task for some of the conceptual errors in my short note on 'Scoring the Risk Scores'. The figures I used were taken from Mr Bond's paper, abstracted from Table 6 in part 3 of the paper, simply by summing the totals in the High Risk and Low Risk categories. I believe these figures to be correct. Mr Lowthian's point about the fact that these are prevalence rather than incidence figures is quite correct and well made. If anything, though, I believe this rather adds weight to the argument that the scores allocate too many patients into the 'at risk' group. If I understand it correctly, a prevalence figure will be influenced both by the intrinsic risk of developing the c.ondition and the duration for which the condition persists. Thus it will be very difficult to assess true risk rates for pressure sore development in view of the extreme variation in the persistence of the sores. In view of the the fact that the problem of pressure sores is urgent and requires action at the present time, I believe we shall be stuck with using prevalence figures for a very long time to come before a true estimate ofrisk is made. It is also arguable whether or not a true assessment of risk is necessary for the evaluation of the risk scores, since the allocation of resources is dependent more on prevalence than on risk, so that, practically, prevalence may be a more useful measure. Editor
Journal of Tissue Viability 1994 Vol 4 No 2
Pressure Sores - A Key Quality Indicator Nicky Cullum1 and Peter Shakespeare2
Research Fellow, Dept ofNursing, University ofLiverpool Director, Laing Burns Research Laboratory
1
2
A review of the recently published DoH Guide for NHS Purchasers and Providers together with some comments on the supporting Report by Consultants Touche Ross. Pressure Sores - a Key Quality Indicator' was published by the Department ofHealth in December 1993, and was generated by a working group of seventeen members representing a variety ofperspectives in health care. The document is aimed at raising awareness in both purchasers and providers of the need for a coherent pressure sore policy, and is effectively peppered with (apparently) true horror stories from those who have experienced pressure sores at first hand; either personally or in those they care for. Whilst it is hoped that this guide achieves its aim, the fact that it delivers some fairly straightforward messages in a rather verbose and confusing way cannot be ignored. The document usefully provides definitions of the terms 'prevalence' and 'incidence', but unfortunately does not differentiate between them in terms of their usefulness as quality indicators. The introductory paragraph delivers the bald statement that ' ..... the prevalence ofpressure sores is an excellent indicator ofquality of care', however we know that prevalence figures are exceedingly difficult to interpret and use operationally in any meaningful way 1• The point is that prevalence of people with pressure sores in any provider unit is likely to fluctuate over time, for a number of reasons, by at least 5% (the target for annual reduction ofprevalence set by the NHS ME), and whilst quality of care is an important element, the number of people admitted with sores, and the duration of existing sores confuses the picture. The incidence of new sores developing in any care setting however, is a measure which is more meaningful to service providers and can be used to guide to decision-making. Furthermore, whilst it is laudable to convey the message that strenuous efforts must be made to avoid pressure sore development, one must also acknowledge that there are situations in which pressure sore development is unavoidable, or the lesser of two evils. There are (thankfully infrequent) instances where, in terminal care for example, as death seems imminent, peace and comfort are more important than strenuous attempts at pressure relief, and in certain situations in critical care, pressure sores may be unavoidable in the face of other priorities.The findings of the recent Department of Health commissioned Touche Ross report on 'The cost of Pressure sores' are presented briefly in Annex 1 and discussed. I would suggest that the impact ofthe take-home message ofthis section may have been lost somewhat as a result of the variety and the complexity of the economic data presented here. Projected highest and lowest costings for both preventing and treating pressure sores are compared and contrasted for a number of
situations: per patient: for all English hospitals: one typical English hospital: and with and without staff costs etc. Touche Ross concluded that the financial cost of preventing a sore in a particular patient may be similar to the cost of treating one, however if the development of a sore results in successful litigation for the patient then prevention would be cheaper. On a hospital basis, the cost of prevention may be more expensive than treatment, as a much larger number of patients would require active prevention than would develop a sore and require treatment, however if staff costs are removed from the calculation, then prevention is cheaper. Touche Ross also make the vital point that the physical and psychological costs to the individual are hard to place a value on. The usefulness of this guide lies in its distillation of the key issues for those who are not experts in Tissue Viability. A list ofissues to be considered during the development ofprevention and management protocols is comprehensive and probably very helpful. A section on 'Multidisciplinary working and skills mix' illustrates very clearly the range of health care professionals and lay people who can and should be involved in pressure sore prevention, but the recommendation that 'providers of services might wish to consider the benefits to be derived from employing specialist tissue viability nurses' is made rather weakly - it seems likely that a Tissue Viability Specialist is a prerequisite for the provision of a coherent and effective pressure sore prevention and monitoring programme. Mention is made rather briefly of the availability of specialist equipment to aid pressure relief, but no direction is given as to the evidence (or lack of it) for the effectiveness of pressure relieving aids. Laudable though the Medical Devices Directorate's funding of the technical evaluation of support services is, it does not take the place ofprospective randomized controlled trials of clinical effectiveness. Annex 2 comprises a resume of the key messages from the literature in areas such as: the morbidity associated with pressure sores; risk assessment tools; and prevention measures. It is the later area where health care professionals require the maximum, high quality information, and it is precisely where information is lacking. The issues related to prevention are presented here with a broad brush, however what both providers and purchasers (the latter for contracting purposes) urgently require are systematic reviews of the evidence for the effectiveness of pressure sore prevention interventions. Such reviews should be widely and effectively disseminated, and encapsulated into
Journal of Tissue Viability 1994 Vol 4 No 2 clinical guidelines for practice. It is envisaged that the NHS research and development strategy, incorporating the UK Cochrane Centre and the Centre for Reviews and Dissemination, together with the current NHS Management Executive Nursing Directorate Consenus Stratgegy for Mainly Nursing Led Major Clinical Guidelines (which is incorporating pressure sores as an area for guideline development) will achieve this. Annex 3 of the report valuably presents provider units with a step-by-step guide to establishing a pressure sore policy. I suspect that this will be deemed to be one of the most useful sections of the document. The principal recommendations are that provider units institute a local pressure sore group, which in tum establishes a knowledge and policy base. Suggested components of the knowledge base include local incidence/ prevalence data and a review of existing policy, whilst the policy base might include the development of protocols, the allocation of responsibilities and the identification of training needs. The identification oflocal knowledge and policy bases will then direct target setting and the development of an action plan to achieve process and outcome targets. The upbeat message with which the document draws to a close is that exemplary practice is already in existence in many areas. Annex 4 presents six sketches of good practice from North Derbyshire, North Lincolnshire, Epsom, Mersey, Mid-Cheshire and Shrewsbury, together with contact names for further information. It is hoped that these individuals will be able to cope with the inevitable floods of enquiries! Finally, the reader is signposted to further resources; videos on pressure sore prevention and treatment, and a wealth of reading material. In summary, the intentions of this document are laudable; efforts to reduce the incidence of pressure sores must be a good thing. One means of achieving this is by identification of evidence-based practice, and the incorporation of this good practice into clinical guidelines, locally derived protocols, and contracts. The target for an overall annual reduction in the prevalence ofpressure sores however is fairly meaningless, and provider units would be well advised to build into their pressure sore programmes a means ofmeasuring the rate ofdevelopment of new sores within their units (incidence). Finally, it is essential that the development oflocal pressure policies involves staff at all levels of the service, and is endorsed by all. One essential component of any successful programme will be the continuing education ofnursing staff; something which appears to have been almost abandoned by the NHS in recent years. One regularly hears of nurses having not only to pay for their awn attendance at study days and conferences, but having to attend them in their own time. A real commitmemt, at all levels, to a reduction in the incidence of pressure sores must, by definiton, address the need for education as a priority. If this is done, and the other (fairly straightforward) recommendations in this document are followed, then we will succeed! Reference 1. ClarkM, Cullum N. Matching patient need for pressure sore prevention with the supply ofpressure redistributing mattresses. J Adv Nursing, 1992; 17:310-16.
61
Touche Ross Report - The Cost of Pressure Sores The attention of readers is drawn to this report which provides some of the background material for 'Pressure Sores - A Key Quality Indicator'. It contains some interesting data on the relative costs of treatment and prevention of pressure sores. The salient point to be drawn from the report concerns the balance of costs between prevention and treatment. Prevention is obviously a worthwhile activity. It is widely accepted that it is a cost effective process and an humane course of action. However, wherever a prevention exercise is undertaken a series of factors have to be considered. Among these are: 1. What population is the best target for 'prevention'? 2. What is the 'unit cost' of prevention? 3. Is prevention in fact any different from treatment? 4. How can the effects of prevention be measured in terms of disease prevalence and morbidity?
Touche Ross have calculated the 'costs' of treatment and prevention in a single hospital with 600 occupied beds. The results are interesting. For treatment costs the estimated range is £1, 154,000-£644,000. The biggest single item in this is the so-called opportunity costs which estimate the loss to the hospital as a result of blocked beds occupied by pressure sore patients. For prevention costs theestimatedrangeis£2,709,000-£645,000. In both 'high' and 'low' cost options the major element is staff time. A logical interpretation of these data would suggest that, at the extreme, it may actually be more economic to undertake very little prevention and accept that there are inevitable treatment costs. The figures presented by Touche Ross illustrate well the points concerning the assessment ofrisk ofpressure sore development set out for discussion in the January issue of the Joumal. In the report the pressure sore prevalence quoted is 8% (very close to Mr Bond's figures for N Derbyshire set out in the October 93 issue of the Journal), and the prevalence of 'at risk' patients approximately 26% (somewhat lower than the figures reported by Mr Bond). Everyone now has to accept explicitly, as they always have done implicitly, that money talks. Perhaps it is not actual money that is talking, but Accountancy. The report makes some very interesting points about 'prevention' and its cost effectiveness. The general understanding of prevention is often in terms of vaccination or antibiotic prophylaxis, activities which are cheap, effective and need to be undertaken once only. In terms of pressure sore development, 'prevention' is a continuing process and may require similar equipment and staff commitment to the treatment regime used to deal with established sores. Since the costs ofprevention and treatment are therefore similar it is dificult to argue in economic terms that prevention is cost effective - a point which reinforces the necessity for risk assessment to identify those genuinely at risk of developing the condition.
62
Journal of Tissue Viability 1994 Vol 4 No 2
In their conclusion Touche Ross state 'Our estimates for a large DGH (600 occupied beds) suggest that annual costs will be in the following ranges (for a low cost regime):
Equipment Staffing
Prevention Treatment £s £s 94,000 106,000 540,000 185,000
The report continues: 'With ideal data it would be possible to calculate the cost of a variety of preventive regimes. In our view it is unlikely that maximum prevention will be the least costly regime since, ifthe regime was withdrawn for a large number of low risk cases, the additional cost of treatment from the pressure sores that developed would be small.' The report is careful to set the framework for comparison of its prevention and treatment estimates and by its own admission, may be underestimating the cost of treatment. However the essential message is clear. Unless prevention can be shown to be effective in monetary terms it may become discredited at managerial level. In my view this could be to the detriment of all, with patients first on the list.
Two letters to the Editor, relevant to the Report Sir
Scoring the Risk Scores
I was interested in your article in the January edition of the Journal and immediately checked Mr Bond's article (JTV Oct 93) for the table shown in your article (Table 2), I assume that you have extracted this from Table 6 in Mr Bond's article? If this is so, I do have a slight problem inasmuch as the figures given by Mr Bond do not seem to tally with your own. However, this makes only a marginal difference to your subsequent inferences. Nevertheless, I am more concerned that your article implies that Mr Bond's calculations were based on an Incidence survey when, it seems to me, they were based on a Point Prevalence Survey. In other words, the sores found in Mr Bond's survey were not necessarily correlated to an 'Initial' risk score taken before the patients concerned actually developed overt sores. I'm sure you will agree that this is an important consideration if we are to arrive at a true Sensitivity and Specificity for the risk-assessment method used. In the case under consideration, the method used was actually a mixture of various risk scales. I first became aware of the importance of of 'Sensitivity' and 'Specificity' (mentioned in your article) after reading a useful article by Warner and Hall1 which showed me that the Norton Scale has a Sensitivity of 63% with more than 50 patients developing sores, and a Specificity of70% - for patients in acute Care of the Elderly wards. Subsequently, I completed a 3-year study at the Royal National Orthopaedic Hospital, Stanmore, with the aim of similarly validating the PSPS (which I developed
in 1976.) This study was prospective (patients were scored on admission, and only those without overt pressure sores at that time were later included in the data analysis - as was the case with Norton's work2 • My study showed that the PSPS had an 89% Sensitivity and a 76% Specificity3, with more than 50 patients developing sores. To date, I am not aware of any risk assessment scale which has fared better than this - on a valid prospective study. There are, however, some other scales which are very promising4 , and I certainly endorse your view that the TVS should be more involved in furthering validation studies on risk-assessment scales - in a variety of nursing situations. I am enclosing a copy of my PSPS card*, together with a copy of the Category Examples sheet*; the latter being for those trained nurses who wish to be more precise in their scoring, while the former is more suitable for general use. (A knowledge of medical terminology is not assumed.) Yours faithfully Peter Lowthian M.Phil RGN,Clinical Nursing Specialist/Lecturer 134 Villiers Road,Oxhey,Watford WDl 4AJ References 1 Warner U and Hall DJ. Pressure Sores: a policy for prevention. Nurs Times 1986;82 (16) 59-61. 2 Norton D, McLaren R, Exton-Smith AN. An investigation of geriatric nursing problems in hospital. 1962. (Reprinted 1975) Churchill Livingstone London. 3 Lowthian PT. Identifying and protecting patients who may get pressure sores. Nurs Standard. 1989;4 (4) 26-29. 4 Lowthian PT. Acute patient care: pressure areas. Br J Nursing. 1993; 2(9) 449-458. * see pages 62,63 Mr Lowthian is quite correct to take me to task for some of the conceptual errors in my short note on 'Scoring the Risk Scores'. The figures I used were taken from Mr Bond's paper, abstracted from Table 6 in part 3 of the paper, simply by summing the totals in the High Risk and Low Risk categories. I believe these figures to be correct. Mr Lowthian's point about the fact that these are prevalence rather than incidence figures is quite correct and well made. If anything, though, I believe this rather adds weight to the argument that the scores allocate too many patients into the 'at risk' group. If I understand it correctly, a prevalence figure will be influenced both by the intrinsic risk of developing the c.ondition and the duration for which the condition persists. Thus it will be very difficult to assess true risk rates for pressure sore development in view of the extreme variation in the persistence of the sores. In view of the the fact that the problem of pressure sores is urgent and requires action at the present time, I believe we shall be stuck with using prevalence figures for a very long time to come before a true estimate ofrisk is made. It is also arguable whether or not a true assessment of risk is necessary for the evaluation of the risk scores, since the allocation of resources is dependent more on prevalence than on risk, so that, practically, prevalence may be a more useful measure. Editor