- Email: [email protected]
Rubbing carbon footprints up the wrong way?
92 * Address: BODE Chemie GmbH & Co. KG, Scientific Affairs, Melanchthonstrasse 27, 22525 Hamburg, Germany. Tel.: þ49 40 54006 0; fax: þ49 40 54006 128.
ª 2008 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jhin.2008.09.021
Rubbing carbon footprints up the wrong way? Madam, Kampf suggests an easy way to reduce National Health Service CO2 emissions by 1400 tonnes and water use by 70 million litres by abandoning the use of water in surgical scrubbing altogether in favour of alcohol-based hand rubs. This is an interesting line of thinking and one which is supported by current evidence indicating the equivalent efficacy of alcohol-based rubbing solutions in preventing surgical site infections.1 However, to quote H.L. Mencken, ‘there is always an easy solution to every human problem e neat, plausible, and wrong’.2 There are several aspects of his suggestion which require more detailed scrutiny before we can accept that alcohol-based rubbing solutions are more environmentally friendly than soap and water. First, isopropyl alcohol is derived from propene, a hydrocarbon and fossil fuel. To suggest that increasing the use of this product will result in a reduction in CO2 emissions may well be erroneous as it could increase fossil fuel use and CO2 emissions. Second, once the isopropyl alcohol has evaporated from the hands it is degraded in the environment both microbially, via acetone, in water under oxidative conditions and photochemically, as vapour in the atmosphere, eventually releasing CO2 and water into the environment. Third, although a great deal of water appears to be saved by this change of practice, a certain amount of water will be embedded in the production process of alcohol gel, meaning its use may not even save that much water.3 The final and perhaps largest difficulty is one of implementation. Translating research findings into practice is notoriously difficult and slow. Semmelweis first made the connection between a lack of hand washing and the spread of infection in the 1840s; today this connection is undisputed but hand washing is still not practised optimally.4 Changing behaviour is a recognised challenge and the results of attempts to alter it can be unexpected.5
Letters to the Editor There are several surgical and infection control measures where tradition, myth and legend as much as evidence of efficacy dictate our actions; the use of face masks in theatre, several orthopaedic techniques and even the ward rounds on which we see patients are just a few examples.6e8 Not all evidence-based changes will result in more environmentally friendly practice but we should continue to strive to find evidence for what we do. In the case of surgical scrubbing we are presented with several options which are equally effective but some are more environmentally friendly, a lucky winewin situation. The strength of the case made for the tap design studied in our paper was the lack of a need for behaviour change by hard wiring the system to favour ‘greener’ behaviour and the indisputable reduction in resource usage. Kampf’s case is well made; however, it requires not only a change in practice but also a more detailed assessment of the environmental impact of alcohol-based rubbing gels before concluding that they are equally efficacious but more environmentally friendly than surgical scrubbing with soap, water and a leg-operated tap.
Acknowledgements I thank Dr M. Jarvis of the Glasgow University Department of Chemistry for his advice on the degradation of isopropyl alcohol in the environment. Conflict of interest statement None declared. Funding sources None.
References 1. Tanner J, Swarbrook S, Stuart J. Surgical hand antisepsis to reduce surgical site infection. Cochrane Database Syst Rev 2008;(1). CD004288. 2. Mencken HL. The divine afflatus. A Mencken chrestomathy (1949). In: Columbia Encyclopedia, 6th ed. New York, NY: Columbia University Press; 2002. p. 443. 3. Hoekstra AY, Chapagain AK. Water footprints of nations: water use by people as a function of their consumption pattern. Water Resour Manag 2007;21:35e48. 4. Zanni GR. Hand hygiene: more than just hands. Consult Pharm 2008;23:438e44. 5. Schultz PW, Nolan JM, Cialdini RB, Goldstein NJ, Griskevicius V. The constructive, destructive, and reconstructive power of social norms. Psychol Sci 2007;18:429e34.
Letters to the Editor 6. Davis PJ, Spady D, Forgie SE. A survey of Alberta physicians’ use of and attitudes toward face masks and face shields in the operating room setting. Am J Infect Control 2007;35: 455e9. 7. Tejwani NC, Immerman I. Myths and legends in orthopaedic practice: are we all guilty? Clin Orthop Relat Res 2008; 466:2861e72. 8. O’Hare JA. Anatomy of the ward round. Eur J Intern Med 2008;19:309e13.
J.E.A. Somner* The Tennent Institute of Ophthalmology, Glasgow, UK E-mail address: [email protected] Available online 28 November 2008 * Address: The Tennent Institute of Ophthalmology, Gartnavel General Hospital, 1053 Great Western Road, Glasgow G120YN, UK. Tel.: þ41 7973708930; fax: þ44 0141 211 2054. ª 2008 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jhin.2008.10.016
RUWA scoring system: a novel predictive tool for the identification of patients at high risk for complications from Clostridium difficile infection We are writing in response to the article by Bishara et al. regarding the mortality of patients with antibiotic-associated diarrhoea. In particular we noted the fact that, on regression analysis, hypoalbuminaemia and elevated serum urea levels were independently associated with mortality.1 One recent study from Israel, for example, has shown that a white cell count >20 103/mm3 (P ¼ 0.009) and an albumin of <2.5 g/dL (P ¼ 0.02) are independently statistically significant risk factors for severe disease.2 Hypoalbuminaemia has been shown to be a risk factor for mortality as well as a risk factor for refractoriness to treatment in previous studies.3,4 We performed a prospective observational study to determine the sensitivity and specificity of the RUWA risk stratification system for predicting which patients would develop severe complications from Clostridium difficile infection (CDI)/C. difficile-associated disease (CDAD) using basic laboratory tests. We devised ‘RUWA’, a novel risk stratification system for CDI, which is an acronym for the Ratio of white cell count on the day of the positive C. difficile toxin test to two days previously, as well as the Urea, White cell count and Albumin on the day of the positive C. difficile toxin
93 test. The score is assessed on the day of the positive C. difficile toxin test (day 1) and is repeated two days later (day 3). As this was an observational study it was not possible to calculate a day 1 and a day 3 score for all patients due to the relevant laboratory tests not having been performed in some cases. The study was carried out in a tertiary referral hospital with ethical approval from the hospital’s Ethics Committee. All patients who had a positive toxin test for C. difficile were included in the study. Patients with repeat positive tests were only included once within a four-week period. A RUWA score was calculated based on results within 24 h of the positive C. difficile toxin test and again two days later using the scoring system in Table I. For example, a patient with a white cell ratio of 2.5, urea of 15 mmol/L, white cell count of 15 109/L and an albumin of 25 g/L would have a score of 5. Cases with a score of 4 were considered to be at risk of severe complications. Patients were also clinically reviewed on day 1 and day 3 as part of an enhanced surveillance system in order to determine which patients had developed severe complications. Severe disease was defined as mortality due to CDI, admission to the intensive care unit, pancolitis on computed tomography imaging or the need for a colectomy due to complications from CDI. Fifty-eight patients had a score compiled for day 1, and 75 patients had a score compiled for day 3. Eighty-one patients had a score for either day 1 or day 3 and 52 patients had scores compiled for both days. In total, eight patients had severe complications. Using a cut-off score of 4, the RUWA risk stratification system had a sensitivity of 80.0% (95% confidence interval: 39.4e96.3) and 62.5% (32.3e 85.6), and a specificity of 77.4% (73.5e78.9) and 82.1% (78.5e84.8) on day 1 and day 3 respectively. For patients stratified on both day 1 and day 3 the sensitivity was 100% (59.2e100) and specificity was 70.2% (65.9e70.2). The positive predictive value on day 1 was 25.0% (12.3e30.1) and on day 3 was 29.4% (15.2e40.3), and the negative predictive value on Table I Score 0 1 2 3
Scoring chart to calculate the RUWA score Ratio
Urea (mmol/L)
0.5e1.5 <10 >1.5e2 10e20 >2e4 >20 >4, or <0.5
WCC (109/L)
Albumin (g/L)
4e10 >10e20 >20e30 <4, >30
>30 24e30 <24
RUWA, ratio of white cell count on the day of the positive C. difficile toxin test to two days previously, as well as the urea, white cell count (WCC) and albumin on the day of the positive C. difficile toxin test.
ª 2008 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jhin.2008.09.021
Rubbing carbon footprints up the wrong way? Madam, Kampf suggests an easy way to reduce National Health Service CO2 emissions by 1400 tonnes and water use by 70 million litres by abandoning the use of water in surgical scrubbing altogether in favour of alcohol-based hand rubs. This is an interesting line of thinking and one which is supported by current evidence indicating the equivalent efficacy of alcohol-based rubbing solutions in preventing surgical site infections.1 However, to quote H.L. Mencken, ‘there is always an easy solution to every human problem e neat, plausible, and wrong’.2 There are several aspects of his suggestion which require more detailed scrutiny before we can accept that alcohol-based rubbing solutions are more environmentally friendly than soap and water. First, isopropyl alcohol is derived from propene, a hydrocarbon and fossil fuel. To suggest that increasing the use of this product will result in a reduction in CO2 emissions may well be erroneous as it could increase fossil fuel use and CO2 emissions. Second, once the isopropyl alcohol has evaporated from the hands it is degraded in the environment both microbially, via acetone, in water under oxidative conditions and photochemically, as vapour in the atmosphere, eventually releasing CO2 and water into the environment. Third, although a great deal of water appears to be saved by this change of practice, a certain amount of water will be embedded in the production process of alcohol gel, meaning its use may not even save that much water.3 The final and perhaps largest difficulty is one of implementation. Translating research findings into practice is notoriously difficult and slow. Semmelweis first made the connection between a lack of hand washing and the spread of infection in the 1840s; today this connection is undisputed but hand washing is still not practised optimally.4 Changing behaviour is a recognised challenge and the results of attempts to alter it can be unexpected.5
Letters to the Editor There are several surgical and infection control measures where tradition, myth and legend as much as evidence of efficacy dictate our actions; the use of face masks in theatre, several orthopaedic techniques and even the ward rounds on which we see patients are just a few examples.6e8 Not all evidence-based changes will result in more environmentally friendly practice but we should continue to strive to find evidence for what we do. In the case of surgical scrubbing we are presented with several options which are equally effective but some are more environmentally friendly, a lucky winewin situation. The strength of the case made for the tap design studied in our paper was the lack of a need for behaviour change by hard wiring the system to favour ‘greener’ behaviour and the indisputable reduction in resource usage. Kampf’s case is well made; however, it requires not only a change in practice but also a more detailed assessment of the environmental impact of alcohol-based rubbing gels before concluding that they are equally efficacious but more environmentally friendly than surgical scrubbing with soap, water and a leg-operated tap.
Acknowledgements I thank Dr M. Jarvis of the Glasgow University Department of Chemistry for his advice on the degradation of isopropyl alcohol in the environment. Conflict of interest statement None declared. Funding sources None.
References 1. Tanner J, Swarbrook S, Stuart J. Surgical hand antisepsis to reduce surgical site infection. Cochrane Database Syst Rev 2008;(1). CD004288. 2. Mencken HL. The divine afflatus. A Mencken chrestomathy (1949). In: Columbia Encyclopedia, 6th ed. New York, NY: Columbia University Press; 2002. p. 443. 3. Hoekstra AY, Chapagain AK. Water footprints of nations: water use by people as a function of their consumption pattern. Water Resour Manag 2007;21:35e48. 4. Zanni GR. Hand hygiene: more than just hands. Consult Pharm 2008;23:438e44. 5. Schultz PW, Nolan JM, Cialdini RB, Goldstein NJ, Griskevicius V. The constructive, destructive, and reconstructive power of social norms. Psychol Sci 2007;18:429e34.
Letters to the Editor 6. Davis PJ, Spady D, Forgie SE. A survey of Alberta physicians’ use of and attitudes toward face masks and face shields in the operating room setting. Am J Infect Control 2007;35: 455e9. 7. Tejwani NC, Immerman I. Myths and legends in orthopaedic practice: are we all guilty? Clin Orthop Relat Res 2008; 466:2861e72. 8. O’Hare JA. Anatomy of the ward round. Eur J Intern Med 2008;19:309e13.
J.E.A. Somner* The Tennent Institute of Ophthalmology, Glasgow, UK E-mail address: [email protected] Available online 28 November 2008 * Address: The Tennent Institute of Ophthalmology, Gartnavel General Hospital, 1053 Great Western Road, Glasgow G120YN, UK. Tel.: þ41 7973708930; fax: þ44 0141 211 2054. ª 2008 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jhin.2008.10.016
RUWA scoring system: a novel predictive tool for the identification of patients at high risk for complications from Clostridium difficile infection We are writing in response to the article by Bishara et al. regarding the mortality of patients with antibiotic-associated diarrhoea. In particular we noted the fact that, on regression analysis, hypoalbuminaemia and elevated serum urea levels were independently associated with mortality.1 One recent study from Israel, for example, has shown that a white cell count >20 103/mm3 (P ¼ 0.009) and an albumin of <2.5 g/dL (P ¼ 0.02) are independently statistically significant risk factors for severe disease.2 Hypoalbuminaemia has been shown to be a risk factor for mortality as well as a risk factor for refractoriness to treatment in previous studies.3,4 We performed a prospective observational study to determine the sensitivity and specificity of the RUWA risk stratification system for predicting which patients would develop severe complications from Clostridium difficile infection (CDI)/C. difficile-associated disease (CDAD) using basic laboratory tests. We devised ‘RUWA’, a novel risk stratification system for CDI, which is an acronym for the Ratio of white cell count on the day of the positive C. difficile toxin test to two days previously, as well as the Urea, White cell count and Albumin on the day of the positive C. difficile toxin
93 test. The score is assessed on the day of the positive C. difficile toxin test (day 1) and is repeated two days later (day 3). As this was an observational study it was not possible to calculate a day 1 and a day 3 score for all patients due to the relevant laboratory tests not having been performed in some cases. The study was carried out in a tertiary referral hospital with ethical approval from the hospital’s Ethics Committee. All patients who had a positive toxin test for C. difficile were included in the study. Patients with repeat positive tests were only included once within a four-week period. A RUWA score was calculated based on results within 24 h of the positive C. difficile toxin test and again two days later using the scoring system in Table I. For example, a patient with a white cell ratio of 2.5, urea of 15 mmol/L, white cell count of 15 109/L and an albumin of 25 g/L would have a score of 5. Cases with a score of 4 were considered to be at risk of severe complications. Patients were also clinically reviewed on day 1 and day 3 as part of an enhanced surveillance system in order to determine which patients had developed severe complications. Severe disease was defined as mortality due to CDI, admission to the intensive care unit, pancolitis on computed tomography imaging or the need for a colectomy due to complications from CDI. Fifty-eight patients had a score compiled for day 1, and 75 patients had a score compiled for day 3. Eighty-one patients had a score for either day 1 or day 3 and 52 patients had scores compiled for both days. In total, eight patients had severe complications. Using a cut-off score of 4, the RUWA risk stratification system had a sensitivity of 80.0% (95% confidence interval: 39.4e96.3) and 62.5% (32.3e 85.6), and a specificity of 77.4% (73.5e78.9) and 82.1% (78.5e84.8) on day 1 and day 3 respectively. For patients stratified on both day 1 and day 3 the sensitivity was 100% (59.2e100) and specificity was 70.2% (65.9e70.2). The positive predictive value on day 1 was 25.0% (12.3e30.1) and on day 3 was 29.4% (15.2e40.3), and the negative predictive value on Table I Score 0 1 2 3
Scoring chart to calculate the RUWA score Ratio
Urea (mmol/L)
0.5e1.5 <10 >1.5e2 10e20 >2e4 >20 >4, or <0.5
WCC (109/L)
Albumin (g/L)
4e10 >10e20 >20e30 <4, >30
>30 24e30 <24
RUWA, ratio of white cell count on the day of the positive C. difficile toxin test to two days previously, as well as the urea, white cell count (WCC) and albumin on the day of the positive C. difficile toxin test.