sequential estimation of enzyme activity to develop a strategy for early diagnosis of acute myocardial infarction. We enrolled 103 patients with suspected myocardial infarction, of whom 43 were confirmed to have had a myocardial infarction based on clinical history, characteristic evolution of electrocardiographic changes over 24-26 hours, and raised activity of creatine kinase and its MB isoenzyme (>5% of total creatine kinase activity over 24 hours. In the light of Dr Mullen's letter we reanalysed our database with specific reference to electrocardiographic changes at time of presentation. Of the 43 patients who were confirmed to have a myocardial infarction, 30 (69%) had electrocardiographic abnormalities suggestive of infarction or ischaemia. Of these electrocardiograms 20 were diagnostic of acute myocardial infarction (ST elevation >1 mm in standard leads or >2 mm in precordial leads), and the remaining 10 showed ST segment depression (seven) or T wave inversion (three). Of the remaining 13 patients, six had electrocardiographic evidence of left bundle branch system block and seven patients had a normal electrocardiogram. We support Dr Timmis's view that the electrocardiography, in conjunction with clinical history, is the earliest and most useful investigation for diagnosing acute myocardial infarction and need for thrombolytic treatment. Timed sequential estimation of enzyme activities, however, do have a role in the diagnosis or exclusion of acute myocardial infarction. Of the 23 patients with non-diagnostic electrocardiograms all had change in activity of the MB isoenzyme of greater than eight units 12 hours after admission. Whether these patients would benefit from thrombolytic treatment is unclear, and we will have to
await the results of ongoing clinical trials that are examining this question. Dr Timmis seems to contradict himself when he states in his article that "at Newham patients with regional ST elevation presenting within 24 hours after the onset of continuous chest pain are given thrombolytic therapy" and then in his reply to Dr Mullen's letter that the benefits of thrombolytic therapy after 12 hours or more are considerably diminished.3 That the benefits of late thrombolysis are diminished is well supported and would equally apply to patients who present late (with electrocardiographic diagnosis) or in whom disease is diagnosed late (with equivocal electrocardiographic changes but diagnostic cardiac enzyme activities). We disagree with Dr Mullen regarding the sensitivity of log slopes of creatine kinase activity, especially if the initial creatine kinase activities are raised, and have recently presented our experience with this method.5 S G VIJAN M W MILLAR-CRAIG Derbyshire Royal Infirmary, Derby DEI 2QY 1 Timmis AD. Early diagnosis of acute myocardial infarction. BMJ3 1990;301:941-2. (27 October.) 2 Mullen PJ. Early diagnosis of acute myocardial infarction. BMJ
1990;301:1213. (24 November.) 3 Timtnis AD. Early diagnosis of acute myocardial infarction. BMJ 1990;301:1214. (24 November.) 4 Gruppo Italiano per lo studio della Streptochinasi nell'infarcto Miocardico. Effectiveness of intravenous thrombolytic treatment in acute myocardial infarction. Lancet 1986;i:397402. 5 Vijan SG, Ingle AR, Hill PG, Millar-Craig MW. Failure of creatine kinase log slope values to reliably predict acute myocardial infarction. In: Proceedings of the Association of Clinical Biochemnists national meeting. London: Association of Clinical Biochemists, 1990:58.
work, and lower productivity? Perhaps this is a subject that would repay attention. RICHARD H AMIS Ripley, Surrey GU23 6AF I Stewart A. Safety and health in the construction industry. BMJ 1990;301: 1100. (10 November.)
HSE's portfolio SIR,-Ms Jane Dawson reported Professor Malcolm Harrington as saying that the Health and Safety Executive should control health and safety at all work places.' This is not only unworkable but undesirable. In house health and safety staff will have local knowledge of processes and people, enabling them to influence key decision makers. This sort of information is known only to insiders and would be hidden from any external enforcing agency.
In the case of doctors operating within industry what is required is better training of occupational physicians and less dabbling by general practitioners who are now finding that they are out of their depth and in a system that is foreign to them. With regards to breaches in health and safety legislation fines should be greater and certainly sufficient to make an impact on the profit sheet. Furthermore, corporate responsibility for enforcing health and safety legislation clearly lies with the main board of directors. Until each director's safety record features in his or her performance appraisal it makes little difference whether health and safety is policed in house or by the Health and Safety Executive. C J M POOLE
Rover,
Safety and health in the construction industry
Birmingham B31 2TB
SIR, - Dr Alastair Stewart is right to draw attention to the appalling, and continuing, high accident rates in the construction and civil engineering industries. But I do not think that his diagnosis is necessarily correct. I was for many years chairman of a medium sized construction company, in which safety was taken seriously; and for six of those years I was chairman of the Confederation of British Industry's health and safety committee. The construction industry workforce is composed largely of unregistered, ununionised, subcontracted gangs. The reason is simple. The building industry is peripatetic-the "factory" moves on after each job-with a proliferation of firms, many of which employ as few as five or six men. As firms can be set up with the minimum of working capital companies may flourish and fade in an accelerated life cycle. Thus there is little continuity of employment, particularly at the smaller end of the scale-a factor that can strongly militate against the inculcation of a "safety culture" in the employee. The large household name companies and, in most cases, the middle sized construction companies have for many years taken a responsible, positive, and active attitude towards health and safety. But the real problem is to instil safety consciousness and positive attitudes to safety among the workforce. Construction has an open air, gung-ho, macho image, and human attitudes are too often formed by the terrible twins customs and practice. The Health and Safety at Work etc Act states (Part I, 7a) that every employee has a duty of care towards himself and to others while at work. This cannot be translated into responsible action until the employee-be he chairman or tea boy-intellectually assents to what he is required to do. Real progress towards using safety helmets-and Alastair Stewart will be aware of the incidence of head injuries in the industry-was not made until
1 Dawson J. Oil and railways added to HSE's portfolio. BMJ 1990;301:1177. (24 November.)
54
the employers and unions agreed, reluctantly, and after many years of fruitless persuasion, that failure to wear a safety helmet as instructed should become a disciplinary offence (there is a parallel here with the wearing of car safety belts). So a greater degree of unionisation would not have resulted in quicker progress towards the end we all desire: a progressive and sustained reduction in fatalities and accidents of all kinds. The key to progress lies in safety training. The HMS Glasgow case in the late 1970s confirmed beyond doubt that a main contractor is responsible for the safety and health compliance of his subcontractors; so that on a multicontractor site the standards of safety training and compliance will be those of the lead or main contractor. I hope that Alastair Stewart and I might usefully join hands in pressing for two immediate objectives: an increase in the number of inspectors that the Health and Safety Executive can deploy in its construction division, and pressure for legislation to increase the upper limit of fines that can be levied on convictions of health and safety offences together with guidelines for judges and magistrates on the appropriate "tariff' for such offences. Employers and trade unions have been sitting round the table together on the Health and Safety Commission and various advisory committees since 1974. Having served on the construction industry advisory committee for two years, I have no doubt that this committee needs an independent chairman of sufficient standing to carry conviction with the top table of the industry. Finally, I hope to see increasing emphasis on industrial health over the current decade. The Control of Substances Hazardous to Health (COSHH) Regulations have taken us a long way, as have the regulations on noise emissions. But what about mental illness in the industrial contextschizophrenia and depression-the latter often referred to as stress, which, if undiagnosed and untreated, leads to lost time, diminished quality of
Too many ethics committees SIR,-Ms Tamzin J Berry and colleagues gave a convincing example of the serious problems presented to multicentre epidemiological studies by the need to secure approval from too many ethics committees.' This problem was first identified in 1982-3 by the interprofessional working group, which was set up by the BMA, under Sir Douglas Black's chairmanship, to advise the Department of Health on the operation of the then impending data protection legislation. The BMA formulated proposals for a national ethics research committee after extensive consultation with all the main relevant professional bodies that were prepared to meet us and with organisations representing patients. These proposals were approved as policy early in 19862 and supported by the General Medical Council. Action is long overdue, and I welcome the increasing recognition of an urgent need. A W MACARA
University of Bristol, Bristol BS8 2PR I Berry TJ, Ades TE, Peckham CS. Too many ethical committees. BMJ 1990;301:1274. (1 December.) 2 Macara AW. Ethical review of multi-centred trials. J Med Ethics 1990;16: 150-2.
Correction Cholestasis associated with cinnarizine A printer's error occurred in this drug point by Dr Steven F Moss and others. The second author was Dr Julian R F Walters and not Walker as published.
BMJ VOLUME 302
5 JANUARY 1991
await the results of ongoing clinical trials that are examining this question. Dr Timmis seems to contradict himself when he states in his article that "at Newham patients with regional ST elevation presenting within 24 hours after the onset of continuous chest pain are given thrombolytic therapy" and then in his reply to Dr Mullen's letter that the benefits of thrombolytic therapy after 12 hours or more are considerably diminished.3 That the benefits of late thrombolysis are diminished is well supported and would equally apply to patients who present late (with electrocardiographic diagnosis) or in whom disease is diagnosed late (with equivocal electrocardiographic changes but diagnostic cardiac enzyme activities). We disagree with Dr Mullen regarding the sensitivity of log slopes of creatine kinase activity, especially if the initial creatine kinase activities are raised, and have recently presented our experience with this method.5 S G VIJAN M W MILLAR-CRAIG Derbyshire Royal Infirmary, Derby DEI 2QY 1 Timmis AD. Early diagnosis of acute myocardial infarction. BMJ3 1990;301:941-2. (27 October.) 2 Mullen PJ. Early diagnosis of acute myocardial infarction. BMJ
1990;301:1213. (24 November.) 3 Timtnis AD. Early diagnosis of acute myocardial infarction. BMJ 1990;301:1214. (24 November.) 4 Gruppo Italiano per lo studio della Streptochinasi nell'infarcto Miocardico. Effectiveness of intravenous thrombolytic treatment in acute myocardial infarction. Lancet 1986;i:397402. 5 Vijan SG, Ingle AR, Hill PG, Millar-Craig MW. Failure of creatine kinase log slope values to reliably predict acute myocardial infarction. In: Proceedings of the Association of Clinical Biochemnists national meeting. London: Association of Clinical Biochemists, 1990:58.
work, and lower productivity? Perhaps this is a subject that would repay attention. RICHARD H AMIS Ripley, Surrey GU23 6AF I Stewart A. Safety and health in the construction industry. BMJ 1990;301: 1100. (10 November.)
HSE's portfolio SIR,-Ms Jane Dawson reported Professor Malcolm Harrington as saying that the Health and Safety Executive should control health and safety at all work places.' This is not only unworkable but undesirable. In house health and safety staff will have local knowledge of processes and people, enabling them to influence key decision makers. This sort of information is known only to insiders and would be hidden from any external enforcing agency.
In the case of doctors operating within industry what is required is better training of occupational physicians and less dabbling by general practitioners who are now finding that they are out of their depth and in a system that is foreign to them. With regards to breaches in health and safety legislation fines should be greater and certainly sufficient to make an impact on the profit sheet. Furthermore, corporate responsibility for enforcing health and safety legislation clearly lies with the main board of directors. Until each director's safety record features in his or her performance appraisal it makes little difference whether health and safety is policed in house or by the Health and Safety Executive. C J M POOLE
Rover,
Safety and health in the construction industry
Birmingham B31 2TB
SIR, - Dr Alastair Stewart is right to draw attention to the appalling, and continuing, high accident rates in the construction and civil engineering industries. But I do not think that his diagnosis is necessarily correct. I was for many years chairman of a medium sized construction company, in which safety was taken seriously; and for six of those years I was chairman of the Confederation of British Industry's health and safety committee. The construction industry workforce is composed largely of unregistered, ununionised, subcontracted gangs. The reason is simple. The building industry is peripatetic-the "factory" moves on after each job-with a proliferation of firms, many of which employ as few as five or six men. As firms can be set up with the minimum of working capital companies may flourish and fade in an accelerated life cycle. Thus there is little continuity of employment, particularly at the smaller end of the scale-a factor that can strongly militate against the inculcation of a "safety culture" in the employee. The large household name companies and, in most cases, the middle sized construction companies have for many years taken a responsible, positive, and active attitude towards health and safety. But the real problem is to instil safety consciousness and positive attitudes to safety among the workforce. Construction has an open air, gung-ho, macho image, and human attitudes are too often formed by the terrible twins customs and practice. The Health and Safety at Work etc Act states (Part I, 7a) that every employee has a duty of care towards himself and to others while at work. This cannot be translated into responsible action until the employee-be he chairman or tea boy-intellectually assents to what he is required to do. Real progress towards using safety helmets-and Alastair Stewart will be aware of the incidence of head injuries in the industry-was not made until
1 Dawson J. Oil and railways added to HSE's portfolio. BMJ 1990;301:1177. (24 November.)
54
the employers and unions agreed, reluctantly, and after many years of fruitless persuasion, that failure to wear a safety helmet as instructed should become a disciplinary offence (there is a parallel here with the wearing of car safety belts). So a greater degree of unionisation would not have resulted in quicker progress towards the end we all desire: a progressive and sustained reduction in fatalities and accidents of all kinds. The key to progress lies in safety training. The HMS Glasgow case in the late 1970s confirmed beyond doubt that a main contractor is responsible for the safety and health compliance of his subcontractors; so that on a multicontractor site the standards of safety training and compliance will be those of the lead or main contractor. I hope that Alastair Stewart and I might usefully join hands in pressing for two immediate objectives: an increase in the number of inspectors that the Health and Safety Executive can deploy in its construction division, and pressure for legislation to increase the upper limit of fines that can be levied on convictions of health and safety offences together with guidelines for judges and magistrates on the appropriate "tariff' for such offences. Employers and trade unions have been sitting round the table together on the Health and Safety Commission and various advisory committees since 1974. Having served on the construction industry advisory committee for two years, I have no doubt that this committee needs an independent chairman of sufficient standing to carry conviction with the top table of the industry. Finally, I hope to see increasing emphasis on industrial health over the current decade. The Control of Substances Hazardous to Health (COSHH) Regulations have taken us a long way, as have the regulations on noise emissions. But what about mental illness in the industrial contextschizophrenia and depression-the latter often referred to as stress, which, if undiagnosed and untreated, leads to lost time, diminished quality of
Too many ethics committees SIR,-Ms Tamzin J Berry and colleagues gave a convincing example of the serious problems presented to multicentre epidemiological studies by the need to secure approval from too many ethics committees.' This problem was first identified in 1982-3 by the interprofessional working group, which was set up by the BMA, under Sir Douglas Black's chairmanship, to advise the Department of Health on the operation of the then impending data protection legislation. The BMA formulated proposals for a national ethics research committee after extensive consultation with all the main relevant professional bodies that were prepared to meet us and with organisations representing patients. These proposals were approved as policy early in 19862 and supported by the General Medical Council. Action is long overdue, and I welcome the increasing recognition of an urgent need. A W MACARA
University of Bristol, Bristol BS8 2PR I Berry TJ, Ades TE, Peckham CS. Too many ethical committees. BMJ 1990;301:1274. (1 December.) 2 Macara AW. Ethical review of multi-centred trials. J Med Ethics 1990;16: 150-2.
Correction Cholestasis associated with cinnarizine A printer's error occurred in this drug point by Dr Steven F Moss and others. The second author was Dr Julian R F Walters and not Walker as published.
BMJ VOLUME 302
5 JANUARY 1991
