Occupational Medicine 2014;64:312–316 doi:10.1093/occmed/kqu055
EDITORIALs
The Lewis–Prusik test. Time to say goodbye to an old friend? 2 s [4] and 5 s [7]. These variations in the method of undertaking the test, evaluation of recovery time and the variability in force used to compress the nail bed make inconsistency of outcome inevitable. Lobos and Menon [8] reported inconsistent performance and interpretation of the test in an acute setting, finding that while all participants reported CRT of more than 3 s as abnormal, there was disagreement on the definition of normal CRT. Introduction of the use of CRT in trauma in 1947 is attributed to Beecher and Simeone [9], who classified refilling as normal, definite slowing or very sluggish to indicate severity of traumatic (hypovolaemic) shock. In 1980, the outcome of CRT assessment was introduced as a component of trauma scoring, but the decision to use 2 s as the limit of normality appears to have been arbitrary and without evidence. Reviewing the use of CRT in 2008, Lewin and Maconochie [10] observed ‘that there are scant data on CRT in adults and what evidence there is shows little consensus with established practice’. Its value in trauma is now seen as limited, with assessment of central CRT being a more useful indicator of shock. Finger CRT can be affected by core body temperature, medication, age, gender and other underlying medical conditions as well as ambient temperature. There may be other non-clinical influences, so that lighting conditions may influence interpretation of the outcome, and the use of nail varnish may make the test difficult to undertake. For many years, the Lewis–Prusik test was advocated as part of the clinical assessment of the vascular component of possible HAVS, previously known as vibration white finger. However, logic dictates that the test is unlikely to be of value in those patients with episodic digital vasospasm and no underlying permanent vascular impairment. During an episode of Raynaud’s phenomenon, the impairment of blood flow is already present and will not be influenced by nail-bed compression, and in the absence of digital vasospasm, one would not expect any impairment due to the episodic disease. Yamada et al. [11] suggested that nail-bed compression was of value only when used in conjunction with a cold challenge on subjects with severe (Stage 3) vascular disease, and Okada et al. [12] noted that this test was not useful in distinguishing Raynaud’s subjects from control when done at an ambient room temperature of 20°C but was helpful after 1 min immersion in cold water at 4°C with a room temperature of 6°C. In 1994, the UK Health and Safety Executive (HSE) document HS(G)88 [13] noted that the test ‘is poorly standardized and the result
© The Author 2014. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: [email protected]
Downloaded from http://occmed.oxfordjournals.org/ at Serials Section, Dixson Library on June 3, 2015
Estimation of the capillary refill time (CRT) was originally intended to be part of the assessment of peripheral circulation, either in vascular disease of the upper limbs or in the presence of peripheral shutdown due to systemic cardiovascular shock. The test is undertaken by the examiner putting pressure on the end of the finger nail to compress the nail bed and produce blanching and noting the time taken for normal colour to return following release of the compression. The underlying theory is that reduced capillary pressure, due to local compromise or to reduced systemic blood pressure, will cause slower refilling of the surface vessels allowing a simple visual assessment to quantify peripheral circulation. In occupational health, and particularly relating to assessment of individuals with hand–arm vibration syndrome (HAVS), the test is widely known by its eponym— the Lewis–Prusik test. The eponym refers to Sir Thomas Lewis and Dr Bohumil Prusik. Lewis (1881–1945) [1] is widely regarded as having been a pioneer of the introduction of electrocardiography to clinical practice and the subsequent identification of atrial fibrillation. Having achieved acclaim for his work on ‘the soldiers heart and effort syndrome’, he published a series of useful publications on Raynaud’s phenomenon, including the suggestion that this disorder was caused by a local fault rather than the irritability of the central parts of the (spinal) cord as originally suggested by Raynaud. Prusik (1886– 1964) [2] was a Czechoslovakian physician who demonstrated a wide range of interest and expertise, including anaphylaxis, the treatment of pulmonary tuberculosis by artificial pneumothorax and the relationship between infectious diseases and cancer. In 1920, he produced a dissertation entitled ‘peripheral vasculature and their participation in the circulation of blood’. The eponym has been widely used in occupational medicine textbooks and occasionally misused—occasionally it has been referred to as ‘the Louis Prusik test’. Standard teaching varies regarding the need for this test. Machleder [3] does not refer to use of nail-bed compression as part of the initial clinical examination of upper limb vascular disease but Williams [4] suggests that assessment of CRT is required. Review of other literature also reveals a remarkable lack of standardization for undertaking this test, even in some instances by the same author in different publications. The suggested time for nail-bed compression varies between 5 s [5] and 10 s [6,7]. The end point is marked by recovery of the nail bed to normal colour and is variously defined as between
Editorials 313
Roger Cooke Summers Place, Worcester, UK e-mail: [email protected]
References 1. Hollman A. Sir Thomas Lewis: Pioneer Cardiologist and Clinical Scientist. London: Springer, 1997. ISBN 3540760490.
2. Reinis Z. Bohumil Prusik 1886–1964. Angiologica 1964;1:315–316. 3. Machleder HI. Vascular Disorders of the Upper Extremity. London: Futura, 1998. ISBN 0879934093. 4. Williams ME. Geriatric Physical Diagnosis: A Guide to Observation and Assessment. London: Mcfarland, 2008. ISBN 9780786430093. 5. Pelmear PL. Clinical evaluation of vibration-exposed complainants in field surveys. Scand J Work Environ Health 1987;13:284–285. 6. Faculty of Occupational Medicine. Hand Transmitted Vibration: Clinical Effects and Pathophysiology. Report of a Working Party. London: Royal College of Physicians, 1993. ISBN 1873240511. 7. Pelmear P, Wassermann DE. Hand Arm Vibration. Beverly Farms, MA: OEM Press, 1998. 8. Lobos AT, Menon K. A multidisciplinary survey on capillary refill time: inconsistent performance and interpretation of a common clinical test. Pediatr Crit Care Med 2008;9:386–391. 9. Beecher HK, Simeone FA. The internal state of the severely wounded man on entry to the most forward hospital. Surgery 1947;22:672–711. 10. Lewin J, Maconochie I. Capillary refill time in adults. Emerg Med J 2008;25:325–326. 11. Yamada S, Sakakibara H, Futatsuka M. Vibration dose, disturbance stage, and examination results and subjective symptoms in vibration syndrome. Nagoya J Med Sci 1995;58:1–12. 12. Okada A,Yamashita T, Ideda T. Screening test for Raynaud’s phenomenon of occupational origin. Am Ind Hyg Assoc J 1972;33:476–482. 13. HSE. Hand Arm Vibration HS(g)88. London: HSE, 1994. 14. Faculty of Occupational Medicine of the RCP. HandTransmitted Vibration: Clinical Effects and Pathophysiology. London: RCP, 1993. 15. HSE. The Control of Vibration at Work Regulations. Guidance on Regulations. London: HSE, 2005.
doi:10.1093/occmed/kqu061
Occupational cancer: key challenges and opportunities for change Over 300 000 newly diagnosed cancers occur in the UK each year [1]. Strategies to reduce these require a sound evidence base on which to target priorities. Causes of occupationally related cancers have been investigated over many decades, particularly in countries such as Britain and Italy. Occupational studies have played an important part in the identification of many carcinogens; indeed many of the human carcinogens classified into IARC Group 1 as representing a carcinogenic hazard to humans are based on evidence largely from studies of occupational groups. They have also contributed to the regulation of carcinogens in the workplace and more widely at the lower levels encountered
in the general environment. Occupational carcinogens have been investigated in both industry-based studies and in general population studies using a range of epidemiological methods. Such studies have well-recognized limitations including a potential lack of sensitivity to detect very low risks, difficulty in discriminating between several plausible risk factors in complex situations, the inability to evaluate the impact of recent exposures and uncertainty in interpreting negative studies or inverse relationships [2]. Occupational studies provide a range of measures of the effect of a carcinogen on cancer including relative and absolute risks, estimates of the numbers exposed and
Downloaded from http://occmed.oxfordjournals.org/ at Serials Section, Dixson Library on June 3, 2015
unlikely to be helpful unless it is grossly abnormal’ following an identically worded conclusion of the report of a Royal College of Physicians working group that had been published a year earlier [14]. However, both publications continued to include it as part of the forms they proposed for routine surveillance of vibration exposed workers. Current guidance from the UK HSE [15] does not include this test as part of the recommended protocol for assessment of HAVS, and the health surveillance forms do not require it to be undertaken. Review of the literature demonstrates that the Lewis– Prusik test used as part of health surveillance for HAVS has been poorly standardized, which also applies to its use in trauma. Prusik himself is quoted as saying ‘in medicine axioms are not rigid patterns. Apply today what you have learned, only until advances of science change the basis of opinion on causes, course and treatment of various diseases’. Surely, therefore, he would agree that although the test that shares his name has been tacitly dropped from recent recommendations, the time has come to state clearly that it no longer has a place in the assessment of those exposed to hand-transmitted vibration.
EDITORIALs
The Lewis–Prusik test. Time to say goodbye to an old friend? 2 s [4] and 5 s [7]. These variations in the method of undertaking the test, evaluation of recovery time and the variability in force used to compress the nail bed make inconsistency of outcome inevitable. Lobos and Menon [8] reported inconsistent performance and interpretation of the test in an acute setting, finding that while all participants reported CRT of more than 3 s as abnormal, there was disagreement on the definition of normal CRT. Introduction of the use of CRT in trauma in 1947 is attributed to Beecher and Simeone [9], who classified refilling as normal, definite slowing or very sluggish to indicate severity of traumatic (hypovolaemic) shock. In 1980, the outcome of CRT assessment was introduced as a component of trauma scoring, but the decision to use 2 s as the limit of normality appears to have been arbitrary and without evidence. Reviewing the use of CRT in 2008, Lewin and Maconochie [10] observed ‘that there are scant data on CRT in adults and what evidence there is shows little consensus with established practice’. Its value in trauma is now seen as limited, with assessment of central CRT being a more useful indicator of shock. Finger CRT can be affected by core body temperature, medication, age, gender and other underlying medical conditions as well as ambient temperature. There may be other non-clinical influences, so that lighting conditions may influence interpretation of the outcome, and the use of nail varnish may make the test difficult to undertake. For many years, the Lewis–Prusik test was advocated as part of the clinical assessment of the vascular component of possible HAVS, previously known as vibration white finger. However, logic dictates that the test is unlikely to be of value in those patients with episodic digital vasospasm and no underlying permanent vascular impairment. During an episode of Raynaud’s phenomenon, the impairment of blood flow is already present and will not be influenced by nail-bed compression, and in the absence of digital vasospasm, one would not expect any impairment due to the episodic disease. Yamada et al. [11] suggested that nail-bed compression was of value only when used in conjunction with a cold challenge on subjects with severe (Stage 3) vascular disease, and Okada et al. [12] noted that this test was not useful in distinguishing Raynaud’s subjects from control when done at an ambient room temperature of 20°C but was helpful after 1 min immersion in cold water at 4°C with a room temperature of 6°C. In 1994, the UK Health and Safety Executive (HSE) document HS(G)88 [13] noted that the test ‘is poorly standardized and the result
© The Author 2014. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: [email protected]
Downloaded from http://occmed.oxfordjournals.org/ at Serials Section, Dixson Library on June 3, 2015
Estimation of the capillary refill time (CRT) was originally intended to be part of the assessment of peripheral circulation, either in vascular disease of the upper limbs or in the presence of peripheral shutdown due to systemic cardiovascular shock. The test is undertaken by the examiner putting pressure on the end of the finger nail to compress the nail bed and produce blanching and noting the time taken for normal colour to return following release of the compression. The underlying theory is that reduced capillary pressure, due to local compromise or to reduced systemic blood pressure, will cause slower refilling of the surface vessels allowing a simple visual assessment to quantify peripheral circulation. In occupational health, and particularly relating to assessment of individuals with hand–arm vibration syndrome (HAVS), the test is widely known by its eponym— the Lewis–Prusik test. The eponym refers to Sir Thomas Lewis and Dr Bohumil Prusik. Lewis (1881–1945) [1] is widely regarded as having been a pioneer of the introduction of electrocardiography to clinical practice and the subsequent identification of atrial fibrillation. Having achieved acclaim for his work on ‘the soldiers heart and effort syndrome’, he published a series of useful publications on Raynaud’s phenomenon, including the suggestion that this disorder was caused by a local fault rather than the irritability of the central parts of the (spinal) cord as originally suggested by Raynaud. Prusik (1886– 1964) [2] was a Czechoslovakian physician who demonstrated a wide range of interest and expertise, including anaphylaxis, the treatment of pulmonary tuberculosis by artificial pneumothorax and the relationship between infectious diseases and cancer. In 1920, he produced a dissertation entitled ‘peripheral vasculature and their participation in the circulation of blood’. The eponym has been widely used in occupational medicine textbooks and occasionally misused—occasionally it has been referred to as ‘the Louis Prusik test’. Standard teaching varies regarding the need for this test. Machleder [3] does not refer to use of nail-bed compression as part of the initial clinical examination of upper limb vascular disease but Williams [4] suggests that assessment of CRT is required. Review of other literature also reveals a remarkable lack of standardization for undertaking this test, even in some instances by the same author in different publications. The suggested time for nail-bed compression varies between 5 s [5] and 10 s [6,7]. The end point is marked by recovery of the nail bed to normal colour and is variously defined as between
Editorials 313
Roger Cooke Summers Place, Worcester, UK e-mail: [email protected]
References 1. Hollman A. Sir Thomas Lewis: Pioneer Cardiologist and Clinical Scientist. London: Springer, 1997. ISBN 3540760490.
2. Reinis Z. Bohumil Prusik 1886–1964. Angiologica 1964;1:315–316. 3. Machleder HI. Vascular Disorders of the Upper Extremity. London: Futura, 1998. ISBN 0879934093. 4. Williams ME. Geriatric Physical Diagnosis: A Guide to Observation and Assessment. London: Mcfarland, 2008. ISBN 9780786430093. 5. Pelmear PL. Clinical evaluation of vibration-exposed complainants in field surveys. Scand J Work Environ Health 1987;13:284–285. 6. Faculty of Occupational Medicine. Hand Transmitted Vibration: Clinical Effects and Pathophysiology. Report of a Working Party. London: Royal College of Physicians, 1993. ISBN 1873240511. 7. Pelmear P, Wassermann DE. Hand Arm Vibration. Beverly Farms, MA: OEM Press, 1998. 8. Lobos AT, Menon K. A multidisciplinary survey on capillary refill time: inconsistent performance and interpretation of a common clinical test. Pediatr Crit Care Med 2008;9:386–391. 9. Beecher HK, Simeone FA. The internal state of the severely wounded man on entry to the most forward hospital. Surgery 1947;22:672–711. 10. Lewin J, Maconochie I. Capillary refill time in adults. Emerg Med J 2008;25:325–326. 11. Yamada S, Sakakibara H, Futatsuka M. Vibration dose, disturbance stage, and examination results and subjective symptoms in vibration syndrome. Nagoya J Med Sci 1995;58:1–12. 12. Okada A,Yamashita T, Ideda T. Screening test for Raynaud’s phenomenon of occupational origin. Am Ind Hyg Assoc J 1972;33:476–482. 13. HSE. Hand Arm Vibration HS(g)88. London: HSE, 1994. 14. Faculty of Occupational Medicine of the RCP. HandTransmitted Vibration: Clinical Effects and Pathophysiology. London: RCP, 1993. 15. HSE. The Control of Vibration at Work Regulations. Guidance on Regulations. London: HSE, 2005.
doi:10.1093/occmed/kqu061
Occupational cancer: key challenges and opportunities for change Over 300 000 newly diagnosed cancers occur in the UK each year [1]. Strategies to reduce these require a sound evidence base on which to target priorities. Causes of occupationally related cancers have been investigated over many decades, particularly in countries such as Britain and Italy. Occupational studies have played an important part in the identification of many carcinogens; indeed many of the human carcinogens classified into IARC Group 1 as representing a carcinogenic hazard to humans are based on evidence largely from studies of occupational groups. They have also contributed to the regulation of carcinogens in the workplace and more widely at the lower levels encountered
in the general environment. Occupational carcinogens have been investigated in both industry-based studies and in general population studies using a range of epidemiological methods. Such studies have well-recognized limitations including a potential lack of sensitivity to detect very low risks, difficulty in discriminating between several plausible risk factors in complex situations, the inability to evaluate the impact of recent exposures and uncertainty in interpreting negative studies or inverse relationships [2]. Occupational studies provide a range of measures of the effect of a carcinogen on cancer including relative and absolute risks, estimates of the numbers exposed and
Downloaded from http://occmed.oxfordjournals.org/ at Serials Section, Dixson Library on June 3, 2015
unlikely to be helpful unless it is grossly abnormal’ following an identically worded conclusion of the report of a Royal College of Physicians working group that had been published a year earlier [14]. However, both publications continued to include it as part of the forms they proposed for routine surveillance of vibration exposed workers. Current guidance from the UK HSE [15] does not include this test as part of the recommended protocol for assessment of HAVS, and the health surveillance forms do not require it to be undertaken. Review of the literature demonstrates that the Lewis– Prusik test used as part of health surveillance for HAVS has been poorly standardized, which also applies to its use in trauma. Prusik himself is quoted as saying ‘in medicine axioms are not rigid patterns. Apply today what you have learned, only until advances of science change the basis of opinion on causes, course and treatment of various diseases’. Surely, therefore, he would agree that although the test that shares his name has been tacitly dropped from recent recommendations, the time has come to state clearly that it no longer has a place in the assessment of those exposed to hand-transmitted vibration.
