Jan 26, 1985 - daily, propranolol 160 mg daily, and nadolol. 80 mg daily), two calcium channel blockers. (verapamil 360 mg daily and nifedipine 60 mg daily) ...
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unlikely cause as symptoms were similarly common (82% and 77%) on three floors ventilated by one system and on two floors ventilated by an unrelated system. Neither system recirculated internal air so that contamination of one system by the other was unlikely. The most probable explanation seemed to be that the symptoms were simply due to inadequate ventilation of the building. This was supported by direct measurements of air entry into both ventilation systems, which was well below that recommended for the size of the building and the number of staff. Also, air movement within the building was restricted by internal partitioning, for which the ventilation system was not designed. The solution involves expansion of the ventilation system with more ducts supplying grids sited in under ventilated areas. MALCOLM LAW Department of Environmental and Preventive Medicine, Medical College of St Bartholomew's Hospital, London EClM 6BQ
K A M GRANT Department of Community Medicine, City and Hackney District Health Authority, London EC1
SIR,-The study by Dr M J Finnegan and others of the sick building syndrome has direct relevance to Jane Smith's article in the same issue (p 1599) on things that go wrong with hospital building. The symptoms prevalent among office workers are also experienced by hospital staff in the new generation of mechanically ventilated' hospitals. Ironically, I first noticed this in Greenwich District Hospital, which is praised as a model of good design in a previous article in your series on hospital building (24 November, p 1437). Ever since it opened there has been a high incidence of complaints of sore throats, nasal congestion, headaches, and lethargy among staff. An important point which did not emerge from the sick building study is that hazards from chemicals used at work (solvents in laboratories, photocopiers, cleaning fluids, etc) may be exacerbated by inadequate mechanical ventilation.' Potential sources of air pollution must be considered in the design of ventilation even in non-industrial workplaces. GENE FEDER Guy's Hospital, London SEI 9RT I Sterling TD, Sterling E, Dimich-Ward H. Buildin illness in the white collar workplace. Int j Health Serv 1983;13:177-285.
,B Blockers after myocardial infarction: have trials changed practice? SIR,-This survey by Dr N S Baber and others of British consultant cardiologists (24 November, p 1431) was carried out to elicit -their current practices when prescribing long term ( blockers after myocardial infarction. Though favourable evidence of clinical trials appears to have been assimilated into hospital practice, it does not appear to have extended into general practice. The authors say that one explanation of this apparent discrepancy might be that cardiologists do not control long term care. For many years I have tried to establish guidelines for general practitioners in the care of survivors of myocardial infarction. The benefits of (3 blockers for long term care do not seem to me to be clearcut for the following
reasons. Firstly, all reported trials have been hospital based. I am not aware of any community based study, yet we know that in some places more than a third of patients are treated by general practitioners at home in the acute phase of the illness, and these patients will not have been included in the surveys. Secondly, all surveys report considerable exclusion from the trials, usually over 50%. Thirdly, the trials have been restricted to people under 70 years of age, which excludes about a quarter of men and half of the women who have had a myocardial infarction. A 25% reduction in fatality is claimed for long term care, a saving of about two lives out of every 100 survivors given treatment, but it is clear that these surveys have been conducted on highly selected patients in the community. General practitioners are not cardiologists and they have a wide remit. Placing patients on 3 blockers firmly establishes "disease" orientation and supervision by doctors. An alternative case, which would have to be proved, of course, would be to encourage "health" orientation. An environmental approach could use the evidence of myocardial infarction as a marker of Western disease, both in the individual and possibly in the family too. Such a lead would provide an opportunity to discuss a wide range of environmental illnesses, a familiar experience for general practitioners. Prescribing ( blockers does not preclude this wider approach, but I suspect that it may alter the emphasis to secondary prevention. There is a danger that doctors and patients will neglect other aspects of their lives. A COLLING
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this property, rather than selectivity, as determining the extent to which these drugs influence glucose control. The lack of effect on HbA,C after atenolol combined with prazosin suggests that a adrenoceptor activity in addition to 3 adrenoceptor activity may play an important part in mediating these effects of , blockers, which cannot be explained by changes in insulin secretion. The lack of effect of the calcium channel blockers is of interest in view of case reports about the effects of nifedipine on diabetics and the theoretical importance of calcium as a mediator of insulin release. I am grateful for advice from N Wilkinson, A Rosethorn, Professor A Breckenridge, J Thomas (statistician), and Professor P Turner.
IAN WHITCROFT Department of Clinical Pharmacology, St Bartholomew's Hospital, London ECIA 7BE
Disaster at the dining table
SIR,-I have been practising martial arts for many years and have been medical attendant to many tournaments, so I feel competent to disagree heartily (or rather vasovagally) with Dr M C Kelly (29 September, p 830). He suggested that a "blow administered with the clenched fist to the solar plexus" would cause a forced expiration and dislodge an obstructing food particle and is easier to perform than the Heimlich manoeuvre. Traditionally the solar plexus is one of the target points to defeat an opponent and it does this well indeed, most likely through a vasovagal reflex. When thus struck a person Stockton on Tees, will not exhale but will look surprised and Cleveland stunned first, then will take one or more gasping deep inspirations (further aspirating a foreign body) before deciding whether or Do antihypertensive drugs precipitate not to collapse. The non-focused, more diabetes? gentle, Heimlich manoeuvre would be my SIR,-The paper by Professor C Bengtsson strong preference. J BALASSA and others (1 December, p 1495) adds to the Marrickville, large and apparently contradictory literature NSW 2204, Australia about the effects of antihypertensive drugs on the glycaemic control of diabetics. I have conducted a 20 month study in Warrington Falls from trees and associated injuries General Hospital, the results of which, to be published in full, appear to support their SIR,-The interesting article by Dr Peter findings. I examined the effects of three (3 Barss and others (22-29 December, p 1717) adrenoceptor antagonists (atenolol 100 mg drew attention to several important problems daily, propranolol 160 mg daily, and nadolol with life in rural areas of the Pacific Isles. 80 mg daily), two calcium channel blockers Reviewing elbow injuries treated at the (verapamil 360 mg daily and nifedipine 60 Shining Hospital in the Pokhara Valley, mg daily), and an a adrenoceptor antagonist situated at the foot of the Annapurna range in (prazosin 3 mg daily alone and in combination Nepal, we came across very similar problems.' with atenolol 100 mg daily) on glycosylated Here one of the major tasks of the young haemoglobin (HbA,c), in non-insulin depen- boys is to collect the cattle fodder, which dent diabetics also found to be suffering from often necessitates climbing cliffs or trees. hypertension or angina pectoris. The only Once the children leave home the task then treatment before the study was diet or falls to the women, who are by then becoming less agile with advancing years and account sulphonylurea drugs. All three ( blockers caused a significant for most injuries in the over 18 age group. increase in glycosylated haemoglobin (HbA,c) The usual injury is therefore sustained by after three and four months' treatment com- falling on to an outstretched arm, which in pared with values on placebo and from non- our series produced mainly elbow injuriesdiabetic controls. The rise after propranolol 46% of 366 arm injuries that underwent x ray was significantly greater than after atenolol examination in 1975 and 1976; only 18-6% of or nadolol. No significant changes were found this group underwent radiography for wrist in serum insulin values. No significant changes injuries. (The apparently small number of in HbAjc concentrations were found after wrist injuries partly reflects the need to prazosin alone or in combination with atenolol, restrict investigations, for which patients pay,2 so that "simple" injuries are often treated on nor after the calcium antagonists. While atenolol is cardioselective, nadolol is the basis of the clinical diagnosis alone.) Over four years 143 out of the total 314 not. Both drugs are, however, less lipophilic than propranolol. It is tempting to implicate elbow injuries seen were supracondylar
