700
BRITISH MEDICAL JOURNAL
sented, with 4 ' overall and none in the 2 pm-10 pm group. This at first sight implies that barbiturates protect against daytime fractures, but this would be ridiculous. Nonbarbiturate hypnotics were under-represented in the nocturnal group and over-represented in the day groups with 216 cases (79 %). If the apparent excess of daytime fractures due to non-barbiturate hypnotics-that is, those over the expected 49-59°, (average 540/) were removed this would amount to 72 cases (25 ,'). There would then be 12 barbiturate cases out of 219 daytime fractures (5 %) It is difficult to explain the extremely low incidence of non-barbiturate hypnotics in the nocturnal fracture group but even more difficult to explain the extremely low barbiturate usage in the daytime groups. The barbiturate group could be explained by a general usage of about 5 ° in the population at risk, with proneness in the users to nocturnal femoral fracture. Similarly the non-barbiturate group could be explained by a low usage giving a low rate in the nocturnal fracture group but increased liability to daytime fractures. These explanations do not carry conviction and would require a pattern of usage extremely divergent from the outpatient referral survey drawn from the same population. The only other explanation that I can see, however, is that the records from which the figures were drawn were incomplete or inaccurate. It would add strength to the warnings of the dangers of barbiturate hypnotics if the authors could provide, for the low barbiturate-user rate in the daytime groups, an explanation which, in my arithmetical simplicity, has escaped me. T B DUNN Geriatric Unit, Chadwell Heath Hospital, Romford, Essex
SIR,-Drs J B and E T Macdonald (20 August, p 483) have described an association between femoral fracture and barbiturate ingestion by elderly people. We should like to draw attention to another problem. Anticonvulsants, including phenobarbitone, may cause osteomalacia and it has been suggested that barbiturate habituation combined with nutritional deficiency of vitamin D may be an unrecognised cause of osteomalacia in the elderly.' In a general practice survey carried out between 1973 and 1974 to screen patients aged 65 years and over 6 % of those screened were taking a barbiturate for indications other than epilepsy.2 Excluding from analysis those known to have metabolic bone disease before the study, patients taking barbiturates had a mean corrected serum calcium concentration lower than those taking a non-barbiturate hypnotic (P < 0001). The difference could not be attributed to differences in age, sex, renal or hepatic dysfunction, or other drug ingestion or to other known
diseases. Patients taking barbiturates also had slightly higher alkaline phosphatase activities and lower phosphate concentrations, although these differences were not significant. The available data were insufficient to assess the clinical importance of the biochemical abnormality, but our findings raise the possibility that therapeutic doses of barbiturate used for reasons other than epilepsy may influence vitamin D metabolism adversely and may promote osteomalacia in the elderly. It is noteworthy that almost one-third of the barbiturate-containing drugs prescribed to the patients surveyed were in combined preparations (see table) and that the barbiturate content of the latter is not obvious from the proprietary name. Doctors who prescribe such drugs should be aware that even the small barbiturate content may not be entirely harmless. R E YOUNG L E RAMSAY T S MURRAY Department of Medicine, Gardiner Institute, Western Infirmary, Glasgow Fraser, H S, et al, British Medical Journal, 1976, 1, 1507. Young, R E, et al, Postgradluate Medical Joutrnal, 1977, 53, 212.
SIR,-The report from Nottingham on the prescribing of barbiturates in the elderly (20 August, p 483) is disquieting on two scores: firstly, because of the statistically significant increase in specific morbidity-that is, nocturnal femoral fracture-and secondly, because of the apparent non-acceptance of the increasingly held opinion that there are better, safer, non-lethal, and less habit-forming alternatives to the barbiturates now available. Whether this is true in the rest of the country is not accurately known, though it is claimed in good faith by CURB that barbiturate prescribing has fallen considerably. What is happening in an East Ariglian district is in direct contrast to what is happening in Nottingham, although the Ipswich district is admittedly only half the size. For some time the numbers of self-poisoned patients attending or admitted to the Ipswich Hospital have been monitored; whereas these figures are roughly constant, the incidence of barbiturate selfpoisoning is falling and is now less than half the incidence of two years ago. Prescribing figures for barbiturates, measured by the number of prescriptions dispensed, are 75 % down on the equivalent quarter four years ago. The number of geriatric patients admitted with a history of recent barbiturate consumption to the geriatric department of the Ipswich Hospital this year does not yet reach 20. Finally, the incidence of barbiturate use preceding femoral fracture is insignificant. In order to put the Nottingham picture in a
Barbiturate-containing preparations used in the barbiturate grouip Preparation (proprietary name)
No of subjects
Tuinal
5
Soneryl
3
Bellergal .3 ,, .. .. Luminal .2 Gardenal .1 Neutradonna Sed .1 Sodium Amytal .1 Aludrox SA .1
Franol.1
..
..
..
3
Barbiturate content per tablet (or other presentation)
Quinalbarbitone Amylobarbitone Butobarbitone Phenobarbitone Phenobarbitone Phenobarbitone Phenobarbitone Amylobarbitone Amylobarbitone Secbutobarbitone Phenobarbitone
50 50 100 20 30 30 30 8 200
mg mg mg mg mg mg mg mg,tg (powder) mg 8 mg/5 ml (suspension) 8 mg
10 SEPTEMBER 1977
comparative light it has been necessary to glean local facts rapidly and these have inevitably been reported in general terms. Nevertheless, from a district where a cooperative policy of reducing the prescribing of outdated and hazardous drugs has been adopted for the past 8± years it is reassuring to find that the alarming situation reported from elsewhere is not necessarily found everywhere. FRANK WELLS Ipswich, Suffolk
Shortage of anaesthetists
SIR,-I read Dr David Freedman's letter (13 August, p 456) advocating a more extensive use of local analgesic technique to cover less major surgery with approbation and great interest. I heartily agree that, in the outpatient department in particular, we sadly neglect the use of local techniques in the United Kingdom today. Just how frequently is general anaesthesia really necessary at all in the casualty department or, indeed, in the dental surgery ? We are one of the few nations who employ it so extensively in these areas. Should not general anaesthesia be accorded the respect it deserves and confined to "day" or at least "session" stay units ? We must confess, if we are honest, that general anaesthesia is often used for more minor surgery as much because it is rapid and convenient for the operator and anaesthetist as for humanitarian reasons. General anaesthesia plunges the patient into an abyss of oblivion, but it has its inherent dangers; local analgesia is safer, but success in its application necessitates a little more time and skill and, above all, a knowledge and appreciation of the patient's psyche and the sensations which he is likely to experience. Questions such as "Can you feel anything?" provoke the mistrust of the patient, and, if he is also permitted to see the knife or needle penetrating the skin, it is small wonder that a numbed sensation no worse than a light touch is quickly translated into psychogenic pain. Some surgeons are psychologically unable to operate under local analgesia and easily transmit their own uneasiness to the patient. Dr Freedman rightly advocates some mild sedation for the nervous patient. He is quite right to do so; local analgesia and general anaesthesia are too often treated as separate issues. One might also mention that the use of small doses of intravenous analgesics, such as pentazocine, or inhalation analgesics, such as controlled concentrations of nitrous oxide or trichlorethylene, can greatly increase the efficiency of local analgesia. Success with local analgesia is attained only with patience and perseverance; the price of failure can be one of the worst situations in anaesthesia-the imposition of a general anaesthetic on an already terrified patient. No one who is old enough to have experienced dental and minor surgery under procaine, which took so long to act that the operator sometimes did not have the patience to wait for its full effect, will deny that the introduction of rapidly acting lignocaine and prilocaine constituted a revolution in the practice of local analgesia. The introduction of long-acting bupivacaine is an equally great step forward. Its use not only permits us to extend the benefits of local analgesia to the much neglected field of postoperative pain control (for example, in haemorrhoidectomy),
BRITISH MEDICAL JOURNAL
10 SEPTEMBER 1977
but for the same reason it gives us justification for teaching our younger colleagues local techniques under general anaesthesia. We would avail ourselves of this opportunity, but surgeons will need to be tolerant of slightly increased delays between cases. As an anaesthetist I thank Dr Freedman, as a surgeon, for his compliment to British anaesthetists in his final paragraph and I applaud his caution in advising that local analgesic techniques be generally confined to less complicated or extensive procedures. I would, however, wish to emphasise that the responsibility of modern physician anaesthetists is often as much that of keeping the patient alive in the face of the twin traumas of pathology and surgery as of the equally important task of relieving pain. It is in the area of life support that "their talents [are often] most required." T B BOULTON Association of Anaesthetists of Great Britain and Ireland, London WC1
SIR,-Dare I suggest that there is no shortage of anaesthetists just as, a few years ago, there was not really a shortage of nurses? The alleged shortage would vanish with realistic payments for additional work-the sort of money which would deter one from playing at decorator, plumber, gardener, or car mechanic to keep going. Paying for this kind of help out of taxed income is prohibitive; why should anaesthetists be cheaper ? The technical books I used to pay £4 50 for now take £14 50 so I can no longer afford them and my educational growth is permanently stunted. We are becoming a nation of amateurs in a world where professionalism keeps you ahead. Thus while I admire Mr A W Fowler's "DIY anaesthesia" (27 August, p 576), I must state that a competent specialist can expect to produce far superior results in terms of convenience, comfort, and full return of consciousness than he can obtain with intravenous diazepam, Cyclimorph, and local anaesthetics. But how difficult it will be for me to substantiate this claim. A S GARDINER Folkestone, Kent
A case of intrinsic asthma
SIR,-Does no one check the accuracy of statements made in your pages, or at least edit the article by adding "in my (the writer's) experience . ." ? In your recent article "A case of intrinsic asthma" (23 July, p 250) Professor M D Rawlins states, "We don't yet know what the dangers of salbutamol are . . ." How long does he want a drug to be used before such statements are no longer necessary? Surely it is recognised that the advantages to the patient from a drug such as salbutamol far outweigh the problems of the disease it is used for ? Professor Rawlins also states that "cromoglycate ... is of no value for intrinsic asthma." However, numerous publications have attested to the value of cromoglycate in intrinsic asthma. The report of the Northern General Hospital/Brompton Hospital/MRC collaborative trial' clearly states, "We have . . . not completely answered the question of whether patients with intrinsic asthma respond less well than those with extrinsic asthma. The results suggest, however, that SCG is almost
701
equally effective in both types of asthma." In a review of cromoglycate Grant2 suggests that the individual patient with intrinsic asthma should not be denied even a one-in-three chance of improvement from it. In general terms articles such as the one I am criticising are read with great interest. General practitioners in particular obtain much valuable information from them, and trying out a drug on the recommendation of such an article can often lead to considerable benefit in a particular patient and save valuable hospital time by not needing a consultant referral. But when such inaccuracies are allowed in print GPs not only fail to prescribe a valuable drug but the patient may remain inadequately treated. P J KINGSLEY
the extrinsic asthmatics allocated to placebo had not been withdrawn by 52 weeks. I do not conclude from this that the individual patient with extrinsic asthma should be given a one-in-three chance of improvement with placebo therapy! M D RAWLINS
Loughborough, Leics
Vision screening in preschool children
l Northern General Hospital/Brompton Hospital,'MRC Collaborative Trial, British Medical J7ournal, 1976, 1, 361. 2 Grant, I W B, Prescribers J'ournal, 1973, 13, 32.
***We sent a copy of this letter to Professor Rawlins, whose reply, together with comments on other letters already published, is printed below.-ED, BM7. SIR,-Your letters about this case (23 July, p 250) have expressed most eloquently the reasons why it should have been published "under the inappropriate and grandiose title of 'Community Clinics in Clinical Pharmacology. '" (Dr I W B Grant, 20 August, p 516). Dr Kingsley seems to have missed the point about salbutamol. I do not dispute its value in the management of asthma and indeed I suggested that this particular patient should continue receiving it. I did, however, wish to convey a word of caution because of the possibility that (like isoprenaline) it might produce "tolerance" to ,-agonists (both exogenous and endogenous). The Medical Research Council trials' 2 your correspondents quote were excellent in many respects. However, they do not demonstrate the value of sodium cromoglycate (SCG) in patients with intrinsic asthma. In the first place Dr David Honeybourne (20 August, p 516) is incorrect when he states that, using the FEV1 as an index of improvement, the second trial showed benefit from SCG in both extrinsic and intrinsic asthma: the published figures relate to FEV1 changes in all the patients studied and the excess of patients with extrinsic asthma treated with SCG (34 patients) could have easily "masked" the response of those patients with intrinsic asthma treated with SCG (10 patients). Secondly, the method used in the trials to define "therapeutic failure" with the drug is subject to major problems when applied to small numbers of patients: the 10 participating physicians withdrew patients from the trial if at any time progress was unsatisfactory, and such withdrawals constituted "therapeutic failure." As the authors of the report clearly state, the influence of the physicians' desire to persist with treatment was likely to have had an influence on the progress of some patients. With 10 physicians treating 10 intrinsic asthmatics with SCG it is not legitimate to draw positive conclusions. The fact that some studies3 with SCG have described individual intrinsic asthmatics who have derived "benefit" from the drug (mainly on subjective rather than objective criteria) is not helpful. The MRC trials showed that nearly one-third of
Department of Pharmacological Sciences, University of Newcastle upon Tyne
2
Brompton Hospital/MRC Collaborative Trial, British Medical Journal, 1972, 4, 383. Northern General Hospital/Brompton Hospital/MRC Collaborative Trial, British Medical Journal, 1976, 1, 361. Brogden, R N, Speight, T M, and Avery, G S, Drugs, 1975, 7, 164.
SIR,-In his excellent letter (27 August, p 577), Dr P A Gardiner reminds us that defects of vision found in children who have already gone to school have in the vast majority of cases been present for some considerable time before the child actually reached school age, and he correctly reiterates the need to examine the visual function of children at as early an age as possible in order to improve the chances of obtaining benefit from treatment. Speaking of the problems of examining all children in this age group he makes the point that if the children who have a parental or sibling history of visual defect are examined, then probably the majority of children with such a defect can be identified. This of course is perfectly true, but the problems of examining all children in the preschool age group are not as great as might be supposed. In a feasibility study conducted in Ayrshire during 1975 and 1976 some 500 children aged 31! years were examined with a view to identifying those who had defects of visual function. The examinations were carried out by an orthoptist who took a history and a family history. She then assessed visual acuity, examined ocular movements, and performed a cover test and a prism reflex test. The primary objective of this exercise was to determine what the staffing requirements would be if such testing were to be adopted as a routine measure and also to discover whether the administration could organise such a screening procedure. As a result of the studies it was discovered that an orthoptist could handle four children an hour and that to examine all the children in Ayrshire, with a population of some 300 000, it would be necessary to have seven or at the most eight additional orthoptic sessions. The main problem experienced by the administration was that of discovering where the children lived, and indeed in the initial list of children drawn up some 39 % had no known address, although this percentage was halved as the result of the efforts of the health visitors in the area. The final turnout was in the region of 70 %, which is a not unusual figure for screening procedures, and probably this figure could be improved upon with more attention to public relations. It is proposed to initiate a routine visual screening procedure for 3 --year-old children in South Ayrshire, commencing in January 1978. As the preschool screening procedure develops, so the ophthalmic unit's commitment to the traditional school eye clinics will be reduced and ultimately these clinics will disappear. Preschool children who have been found to have a defect will be referred to the hospital ophthalmic clinic, and once the pro-
BRITISH MEDICAL JOURNAL
sented, with 4 ' overall and none in the 2 pm-10 pm group. This at first sight implies that barbiturates protect against daytime fractures, but this would be ridiculous. Nonbarbiturate hypnotics were under-represented in the nocturnal group and over-represented in the day groups with 216 cases (79 %). If the apparent excess of daytime fractures due to non-barbiturate hypnotics-that is, those over the expected 49-59°, (average 540/) were removed this would amount to 72 cases (25 ,'). There would then be 12 barbiturate cases out of 219 daytime fractures (5 %) It is difficult to explain the extremely low incidence of non-barbiturate hypnotics in the nocturnal fracture group but even more difficult to explain the extremely low barbiturate usage in the daytime groups. The barbiturate group could be explained by a general usage of about 5 ° in the population at risk, with proneness in the users to nocturnal femoral fracture. Similarly the non-barbiturate group could be explained by a low usage giving a low rate in the nocturnal fracture group but increased liability to daytime fractures. These explanations do not carry conviction and would require a pattern of usage extremely divergent from the outpatient referral survey drawn from the same population. The only other explanation that I can see, however, is that the records from which the figures were drawn were incomplete or inaccurate. It would add strength to the warnings of the dangers of barbiturate hypnotics if the authors could provide, for the low barbiturate-user rate in the daytime groups, an explanation which, in my arithmetical simplicity, has escaped me. T B DUNN Geriatric Unit, Chadwell Heath Hospital, Romford, Essex
SIR,-Drs J B and E T Macdonald (20 August, p 483) have described an association between femoral fracture and barbiturate ingestion by elderly people. We should like to draw attention to another problem. Anticonvulsants, including phenobarbitone, may cause osteomalacia and it has been suggested that barbiturate habituation combined with nutritional deficiency of vitamin D may be an unrecognised cause of osteomalacia in the elderly.' In a general practice survey carried out between 1973 and 1974 to screen patients aged 65 years and over 6 % of those screened were taking a barbiturate for indications other than epilepsy.2 Excluding from analysis those known to have metabolic bone disease before the study, patients taking barbiturates had a mean corrected serum calcium concentration lower than those taking a non-barbiturate hypnotic (P < 0001). The difference could not be attributed to differences in age, sex, renal or hepatic dysfunction, or other drug ingestion or to other known
diseases. Patients taking barbiturates also had slightly higher alkaline phosphatase activities and lower phosphate concentrations, although these differences were not significant. The available data were insufficient to assess the clinical importance of the biochemical abnormality, but our findings raise the possibility that therapeutic doses of barbiturate used for reasons other than epilepsy may influence vitamin D metabolism adversely and may promote osteomalacia in the elderly. It is noteworthy that almost one-third of the barbiturate-containing drugs prescribed to the patients surveyed were in combined preparations (see table) and that the barbiturate content of the latter is not obvious from the proprietary name. Doctors who prescribe such drugs should be aware that even the small barbiturate content may not be entirely harmless. R E YOUNG L E RAMSAY T S MURRAY Department of Medicine, Gardiner Institute, Western Infirmary, Glasgow Fraser, H S, et al, British Medical Journal, 1976, 1, 1507. Young, R E, et al, Postgradluate Medical Joutrnal, 1977, 53, 212.
SIR,-The report from Nottingham on the prescribing of barbiturates in the elderly (20 August, p 483) is disquieting on two scores: firstly, because of the statistically significant increase in specific morbidity-that is, nocturnal femoral fracture-and secondly, because of the apparent non-acceptance of the increasingly held opinion that there are better, safer, non-lethal, and less habit-forming alternatives to the barbiturates now available. Whether this is true in the rest of the country is not accurately known, though it is claimed in good faith by CURB that barbiturate prescribing has fallen considerably. What is happening in an East Ariglian district is in direct contrast to what is happening in Nottingham, although the Ipswich district is admittedly only half the size. For some time the numbers of self-poisoned patients attending or admitted to the Ipswich Hospital have been monitored; whereas these figures are roughly constant, the incidence of barbiturate selfpoisoning is falling and is now less than half the incidence of two years ago. Prescribing figures for barbiturates, measured by the number of prescriptions dispensed, are 75 % down on the equivalent quarter four years ago. The number of geriatric patients admitted with a history of recent barbiturate consumption to the geriatric department of the Ipswich Hospital this year does not yet reach 20. Finally, the incidence of barbiturate use preceding femoral fracture is insignificant. In order to put the Nottingham picture in a
Barbiturate-containing preparations used in the barbiturate grouip Preparation (proprietary name)
No of subjects
Tuinal
5
Soneryl
3
Bellergal .3 ,, .. .. Luminal .2 Gardenal .1 Neutradonna Sed .1 Sodium Amytal .1 Aludrox SA .1
Franol.1
..
..
..
3
Barbiturate content per tablet (or other presentation)
Quinalbarbitone Amylobarbitone Butobarbitone Phenobarbitone Phenobarbitone Phenobarbitone Phenobarbitone Amylobarbitone Amylobarbitone Secbutobarbitone Phenobarbitone
50 50 100 20 30 30 30 8 200
mg mg mg mg mg mg mg mg,tg (powder) mg 8 mg/5 ml (suspension) 8 mg
10 SEPTEMBER 1977
comparative light it has been necessary to glean local facts rapidly and these have inevitably been reported in general terms. Nevertheless, from a district where a cooperative policy of reducing the prescribing of outdated and hazardous drugs has been adopted for the past 8± years it is reassuring to find that the alarming situation reported from elsewhere is not necessarily found everywhere. FRANK WELLS Ipswich, Suffolk
Shortage of anaesthetists
SIR,-I read Dr David Freedman's letter (13 August, p 456) advocating a more extensive use of local analgesic technique to cover less major surgery with approbation and great interest. I heartily agree that, in the outpatient department in particular, we sadly neglect the use of local techniques in the United Kingdom today. Just how frequently is general anaesthesia really necessary at all in the casualty department or, indeed, in the dental surgery ? We are one of the few nations who employ it so extensively in these areas. Should not general anaesthesia be accorded the respect it deserves and confined to "day" or at least "session" stay units ? We must confess, if we are honest, that general anaesthesia is often used for more minor surgery as much because it is rapid and convenient for the operator and anaesthetist as for humanitarian reasons. General anaesthesia plunges the patient into an abyss of oblivion, but it has its inherent dangers; local analgesia is safer, but success in its application necessitates a little more time and skill and, above all, a knowledge and appreciation of the patient's psyche and the sensations which he is likely to experience. Questions such as "Can you feel anything?" provoke the mistrust of the patient, and, if he is also permitted to see the knife or needle penetrating the skin, it is small wonder that a numbed sensation no worse than a light touch is quickly translated into psychogenic pain. Some surgeons are psychologically unable to operate under local analgesia and easily transmit their own uneasiness to the patient. Dr Freedman rightly advocates some mild sedation for the nervous patient. He is quite right to do so; local analgesia and general anaesthesia are too often treated as separate issues. One might also mention that the use of small doses of intravenous analgesics, such as pentazocine, or inhalation analgesics, such as controlled concentrations of nitrous oxide or trichlorethylene, can greatly increase the efficiency of local analgesia. Success with local analgesia is attained only with patience and perseverance; the price of failure can be one of the worst situations in anaesthesia-the imposition of a general anaesthetic on an already terrified patient. No one who is old enough to have experienced dental and minor surgery under procaine, which took so long to act that the operator sometimes did not have the patience to wait for its full effect, will deny that the introduction of rapidly acting lignocaine and prilocaine constituted a revolution in the practice of local analgesia. The introduction of long-acting bupivacaine is an equally great step forward. Its use not only permits us to extend the benefits of local analgesia to the much neglected field of postoperative pain control (for example, in haemorrhoidectomy),
BRITISH MEDICAL JOURNAL
10 SEPTEMBER 1977
but for the same reason it gives us justification for teaching our younger colleagues local techniques under general anaesthesia. We would avail ourselves of this opportunity, but surgeons will need to be tolerant of slightly increased delays between cases. As an anaesthetist I thank Dr Freedman, as a surgeon, for his compliment to British anaesthetists in his final paragraph and I applaud his caution in advising that local analgesic techniques be generally confined to less complicated or extensive procedures. I would, however, wish to emphasise that the responsibility of modern physician anaesthetists is often as much that of keeping the patient alive in the face of the twin traumas of pathology and surgery as of the equally important task of relieving pain. It is in the area of life support that "their talents [are often] most required." T B BOULTON Association of Anaesthetists of Great Britain and Ireland, London WC1
SIR,-Dare I suggest that there is no shortage of anaesthetists just as, a few years ago, there was not really a shortage of nurses? The alleged shortage would vanish with realistic payments for additional work-the sort of money which would deter one from playing at decorator, plumber, gardener, or car mechanic to keep going. Paying for this kind of help out of taxed income is prohibitive; why should anaesthetists be cheaper ? The technical books I used to pay £4 50 for now take £14 50 so I can no longer afford them and my educational growth is permanently stunted. We are becoming a nation of amateurs in a world where professionalism keeps you ahead. Thus while I admire Mr A W Fowler's "DIY anaesthesia" (27 August, p 576), I must state that a competent specialist can expect to produce far superior results in terms of convenience, comfort, and full return of consciousness than he can obtain with intravenous diazepam, Cyclimorph, and local anaesthetics. But how difficult it will be for me to substantiate this claim. A S GARDINER Folkestone, Kent
A case of intrinsic asthma
SIR,-Does no one check the accuracy of statements made in your pages, or at least edit the article by adding "in my (the writer's) experience . ." ? In your recent article "A case of intrinsic asthma" (23 July, p 250) Professor M D Rawlins states, "We don't yet know what the dangers of salbutamol are . . ." How long does he want a drug to be used before such statements are no longer necessary? Surely it is recognised that the advantages to the patient from a drug such as salbutamol far outweigh the problems of the disease it is used for ? Professor Rawlins also states that "cromoglycate ... is of no value for intrinsic asthma." However, numerous publications have attested to the value of cromoglycate in intrinsic asthma. The report of the Northern General Hospital/Brompton Hospital/MRC collaborative trial' clearly states, "We have . . . not completely answered the question of whether patients with intrinsic asthma respond less well than those with extrinsic asthma. The results suggest, however, that SCG is almost
701
equally effective in both types of asthma." In a review of cromoglycate Grant2 suggests that the individual patient with intrinsic asthma should not be denied even a one-in-three chance of improvement from it. In general terms articles such as the one I am criticising are read with great interest. General practitioners in particular obtain much valuable information from them, and trying out a drug on the recommendation of such an article can often lead to considerable benefit in a particular patient and save valuable hospital time by not needing a consultant referral. But when such inaccuracies are allowed in print GPs not only fail to prescribe a valuable drug but the patient may remain inadequately treated. P J KINGSLEY
the extrinsic asthmatics allocated to placebo had not been withdrawn by 52 weeks. I do not conclude from this that the individual patient with extrinsic asthma should be given a one-in-three chance of improvement with placebo therapy! M D RAWLINS
Loughborough, Leics
Vision screening in preschool children
l Northern General Hospital/Brompton Hospital,'MRC Collaborative Trial, British Medical J7ournal, 1976, 1, 361. 2 Grant, I W B, Prescribers J'ournal, 1973, 13, 32.
***We sent a copy of this letter to Professor Rawlins, whose reply, together with comments on other letters already published, is printed below.-ED, BM7. SIR,-Your letters about this case (23 July, p 250) have expressed most eloquently the reasons why it should have been published "under the inappropriate and grandiose title of 'Community Clinics in Clinical Pharmacology. '" (Dr I W B Grant, 20 August, p 516). Dr Kingsley seems to have missed the point about salbutamol. I do not dispute its value in the management of asthma and indeed I suggested that this particular patient should continue receiving it. I did, however, wish to convey a word of caution because of the possibility that (like isoprenaline) it might produce "tolerance" to ,-agonists (both exogenous and endogenous). The Medical Research Council trials' 2 your correspondents quote were excellent in many respects. However, they do not demonstrate the value of sodium cromoglycate (SCG) in patients with intrinsic asthma. In the first place Dr David Honeybourne (20 August, p 516) is incorrect when he states that, using the FEV1 as an index of improvement, the second trial showed benefit from SCG in both extrinsic and intrinsic asthma: the published figures relate to FEV1 changes in all the patients studied and the excess of patients with extrinsic asthma treated with SCG (34 patients) could have easily "masked" the response of those patients with intrinsic asthma treated with SCG (10 patients). Secondly, the method used in the trials to define "therapeutic failure" with the drug is subject to major problems when applied to small numbers of patients: the 10 participating physicians withdrew patients from the trial if at any time progress was unsatisfactory, and such withdrawals constituted "therapeutic failure." As the authors of the report clearly state, the influence of the physicians' desire to persist with treatment was likely to have had an influence on the progress of some patients. With 10 physicians treating 10 intrinsic asthmatics with SCG it is not legitimate to draw positive conclusions. The fact that some studies3 with SCG have described individual intrinsic asthmatics who have derived "benefit" from the drug (mainly on subjective rather than objective criteria) is not helpful. The MRC trials showed that nearly one-third of
Department of Pharmacological Sciences, University of Newcastle upon Tyne
2
Brompton Hospital/MRC Collaborative Trial, British Medical Journal, 1972, 4, 383. Northern General Hospital/Brompton Hospital/MRC Collaborative Trial, British Medical Journal, 1976, 1, 361. Brogden, R N, Speight, T M, and Avery, G S, Drugs, 1975, 7, 164.
SIR,-In his excellent letter (27 August, p 577), Dr P A Gardiner reminds us that defects of vision found in children who have already gone to school have in the vast majority of cases been present for some considerable time before the child actually reached school age, and he correctly reiterates the need to examine the visual function of children at as early an age as possible in order to improve the chances of obtaining benefit from treatment. Speaking of the problems of examining all children in this age group he makes the point that if the children who have a parental or sibling history of visual defect are examined, then probably the majority of children with such a defect can be identified. This of course is perfectly true, but the problems of examining all children in the preschool age group are not as great as might be supposed. In a feasibility study conducted in Ayrshire during 1975 and 1976 some 500 children aged 31! years were examined with a view to identifying those who had defects of visual function. The examinations were carried out by an orthoptist who took a history and a family history. She then assessed visual acuity, examined ocular movements, and performed a cover test and a prism reflex test. The primary objective of this exercise was to determine what the staffing requirements would be if such testing were to be adopted as a routine measure and also to discover whether the administration could organise such a screening procedure. As a result of the studies it was discovered that an orthoptist could handle four children an hour and that to examine all the children in Ayrshire, with a population of some 300 000, it would be necessary to have seven or at the most eight additional orthoptic sessions. The main problem experienced by the administration was that of discovering where the children lived, and indeed in the initial list of children drawn up some 39 % had no known address, although this percentage was halved as the result of the efforts of the health visitors in the area. The final turnout was in the region of 70 %, which is a not unusual figure for screening procedures, and probably this figure could be improved upon with more attention to public relations. It is proposed to initiate a routine visual screening procedure for 3 --year-old children in South Ayrshire, commencing in January 1978. As the preschool screening procedure develops, so the ophthalmic unit's commitment to the traditional school eye clinics will be reduced and ultimately these clinics will disappear. Preschool children who have been found to have a defect will be referred to the hospital ophthalmic clinic, and once the pro-
