- Email: [email protected]
PRIVIES ON TRUNK ROADS
342 the Canterbury Post-graduate Centre, attended by 120 health visitors and school medical officers, and some general practitioners. We feel that continued publicity of this kind must mean better results in the future, and less unnecessary loss of sight at an early age. I am grateful to permission to cite
the medical officer of health for Canterbury for the above figures, and particularly for his help
and interest. Kent and
Canterbury Hospital.
R. A. r D. CRAWFORD. r
A
CHADWICK AND HIS REPORT SIR,-In your article in Before Our Time (July 31) you say that after Chadwick submitted his report " the Home Secretary havered, and it was- not until a year later that something was done ". The word " haver " is a Scotticism, and it means "to talk nonsense". It does not mean to " dither " or " procrastinate ". Department of Bacteriology, Welsh National School of Medicine, T HOMSON. SCOTT THOMSON. Cardiff.
larger losses, incurred more rapidly, changes in the plasma concentration. of
to
produce significant
We agree with Dr. Tashima that the alkalosis which developed in the two patients receiving 400 mg. hydrocortisone per day may have increased both the degree of hypokalxmia and the urinary loss of potassium. Aklalosis did not occur in the other subjects; so that alkalosis cannot be considered essential for the production of the hypokalaemia. It would also have been inappropriate to have emphasised the role of a low total body-potassium, since the exchangeable potassium was normal in two of the three subjects in whom this was measured. Dr. Ross suggested that there may be increased loss of potassium in the facces during hydrocortisone administration, but we did not find this. The faecal-potassium values of the four subjects whose daily fsecal potassium loss was measured in our study are given in the accompanying table. K. D. BAGSHAWE Department of Medicine, Charing Cross Hospital Medical School School, J. " R. CURTIS Fulham Hospital, ,,’ -. E. S. GARNETT. W.6. London,
PRIVIES ON TRUNK ROADS HYDROCORTISONE AND PLASMA-POTASSIUM SIR,-We wish to reply to the comments of Dr. Ross/ Dr. Tashimaand Dr. Gantt3 on our article.4Dr. Gantt’s point was that the potassium losses of the sub-
jects receiving hydrocortisone could account for the hypokal2emia which occurred, and Dr. Ross observed that a loss of only 23 mEq. of potassium from the extracellular fluid of an average-sized individual would produce a fall of 1-9 mEq. per litre in plasma-potassium concentration. The assumption that external losses of potassium of any magnitude are necessarily reflected in a fall in the plasmapotassium concentration is not justified. For instance, early morning plasma-potassium concentrations are not systematically lower than those of the previous evening, despite an uncompensated overnight urinary loss of 20-40 mEq. in normal subjects. It is well known that where potassium intake is severely curtailed renal conservation of potassium does not occur promptly. Normal subjects have been observed to lose from 47 to 67 mEq. potassium during 24 hours’ complete fasting, and triplicate determinations of their plasma-potassium concentration on samples taken hourly in this period showed no significant fall. Reimer et al.induced negative potassium
SIR,-At the instigation of a general practitioner in my constituency, I have for some time been endeavouring to persuade the Government to make a grant towards the provision of public lavatories on trunk roads, because of the extremely insanitary conditions which arise en route to holiday areas in gardens and fields adjoining trunk routes. From the Attorney-General and the Home Office I learn that the police have no powers to prosecute people who relieve themselves on private property, however openly, unless it can be proved that the objective in so doing is to insult " another person, rather than to achieve personal relief. I am advised by the Parliamentary Secretary to the Ministry of Health " that there is no evidence so far that typhoid can be spread in this way ". I have yet to meet a single medical practitioner who agrees with this view. "
House of
Commons, S.W. l. London, S.W.1.
.
,,
ROBIN MAXWELL-HYSLOP.
balances of up
DE BONO WHISTLE AS TEST OF LUNG FUNCTION Sir,- should like to make some comments on the article by Dr. Colley and Dr. Holland (July 31) on the use of a whistle as a screening test of lung function. The article deals mainly with four prototype whistles. Only these four were ever made because they contained basic manufacturing errors. Furthermore, the grade 4 which they assessed has been eliminated from the production models because I found it to be insufficiently discriminatory. If this grade is omitted from the results obtained in the miners tested the picture alters considerably. Further, the article points out that there " seems to be a difference between whistles manufactured at different times "-this is hardly surprising. No evidence is offered that changes in one-second forced expiratory volume (r.E.v.i.o) should be reflected by changes in peak expiratory flow-rate (P.E.F.R.). This rate is much more effort-dependent, and it is probable that over a six-month interval the patient’s effort changed more than the state of his
out
lungs.
F&CAL-POTASSIUM
VALUES IN FOUR
SUBJECTS
to 241 mEq. in 12 days, by dietary means, withsignificant change in the plasma-potassium concentration. Moore et al. found no change in plasma-potassium in subjects who lost three times their total extracellular-fluid potassium at a rate of 40 mEq. per day. The loss of potassium in all but one of our subjects, calculated on Dr. Gantt’s basis, was less than 200 mEq., and was incurred over periods of up to 17 days. If the hypokalsemia observed in these subjects is attributed to this loss of potassium, an explanation is required for the failure 1. Ross, E. J. Lancet, 1965, i, 215. 2. Tashima, C. K. ibid. p. 866. 3. Gantt, C. L. ibid. p. 1167. 4. Bagshawe, K. D., Curtis, J. R., Garnett, E. S. ibid. p. 18. 5. Pollard, A. C., Bagshawe, K. D., Clarkson, E. M. Communication to Medical Research Society. Oct. 18, 1963. 6. Reimer, A., Schock, H. K., Newburgh, L. H. J. Am. diet. Ass. 1951, 29, 1042. 7. Moore, F. D., Boling, E. A., Ditmore, H. B., Sicular, A., Teterick, J. E., Ellison, A. E., Hoye, S. J., Ball, M. R. Metabolism, 1955, 4, 379.
>
The fact that the whistle-grades mostly fell suggests that either the patient’s effort or the investigator’s experience altered. A fault in the whistle ought to have given a random distribution of changes in grade. Where grades with a sharp limit are used it is fallacious to use the number of patients changing grade as an index. It can be shown that with a whistle-error of only 5 % (plus 5 % patienteffort variability and 5% observer error) as many as 72-5% of patients could have changed grades. Finally, from some of their phrases I suspect that Dr. Colley and Dr. Holland were straining their ears " in deciding if a whistle has been produced ". This is not the correct way to use the instrument-having no moving parts or inertia it can respond to much shorter blasts of high flow-rate than can the
the medical officer of health for Canterbury for the above figures, and particularly for his help
and interest. Kent and
Canterbury Hospital.
R. A. r D. CRAWFORD. r
A
CHADWICK AND HIS REPORT SIR,-In your article in Before Our Time (July 31) you say that after Chadwick submitted his report " the Home Secretary havered, and it was- not until a year later that something was done ". The word " haver " is a Scotticism, and it means "to talk nonsense". It does not mean to " dither " or " procrastinate ". Department of Bacteriology, Welsh National School of Medicine, T HOMSON. SCOTT THOMSON. Cardiff.
larger losses, incurred more rapidly, changes in the plasma concentration. of
to
produce significant
We agree with Dr. Tashima that the alkalosis which developed in the two patients receiving 400 mg. hydrocortisone per day may have increased both the degree of hypokalxmia and the urinary loss of potassium. Aklalosis did not occur in the other subjects; so that alkalosis cannot be considered essential for the production of the hypokalaemia. It would also have been inappropriate to have emphasised the role of a low total body-potassium, since the exchangeable potassium was normal in two of the three subjects in whom this was measured. Dr. Ross suggested that there may be increased loss of potassium in the facces during hydrocortisone administration, but we did not find this. The faecal-potassium values of the four subjects whose daily fsecal potassium loss was measured in our study are given in the accompanying table. K. D. BAGSHAWE Department of Medicine, Charing Cross Hospital Medical School School, J. " R. CURTIS Fulham Hospital, ,,’ -. E. S. GARNETT. W.6. London,
PRIVIES ON TRUNK ROADS HYDROCORTISONE AND PLASMA-POTASSIUM SIR,-We wish to reply to the comments of Dr. Ross/ Dr. Tashimaand Dr. Gantt3 on our article.4Dr. Gantt’s point was that the potassium losses of the sub-
jects receiving hydrocortisone could account for the hypokal2emia which occurred, and Dr. Ross observed that a loss of only 23 mEq. of potassium from the extracellular fluid of an average-sized individual would produce a fall of 1-9 mEq. per litre in plasma-potassium concentration. The assumption that external losses of potassium of any magnitude are necessarily reflected in a fall in the plasmapotassium concentration is not justified. For instance, early morning plasma-potassium concentrations are not systematically lower than those of the previous evening, despite an uncompensated overnight urinary loss of 20-40 mEq. in normal subjects. It is well known that where potassium intake is severely curtailed renal conservation of potassium does not occur promptly. Normal subjects have been observed to lose from 47 to 67 mEq. potassium during 24 hours’ complete fasting, and triplicate determinations of their plasma-potassium concentration on samples taken hourly in this period showed no significant fall. Reimer et al.induced negative potassium
SIR,-At the instigation of a general practitioner in my constituency, I have for some time been endeavouring to persuade the Government to make a grant towards the provision of public lavatories on trunk roads, because of the extremely insanitary conditions which arise en route to holiday areas in gardens and fields adjoining trunk routes. From the Attorney-General and the Home Office I learn that the police have no powers to prosecute people who relieve themselves on private property, however openly, unless it can be proved that the objective in so doing is to insult " another person, rather than to achieve personal relief. I am advised by the Parliamentary Secretary to the Ministry of Health " that there is no evidence so far that typhoid can be spread in this way ". I have yet to meet a single medical practitioner who agrees with this view. "
House of
Commons, S.W. l. London, S.W.1.
.
,,
ROBIN MAXWELL-HYSLOP.
balances of up
DE BONO WHISTLE AS TEST OF LUNG FUNCTION Sir,- should like to make some comments on the article by Dr. Colley and Dr. Holland (July 31) on the use of a whistle as a screening test of lung function. The article deals mainly with four prototype whistles. Only these four were ever made because they contained basic manufacturing errors. Furthermore, the grade 4 which they assessed has been eliminated from the production models because I found it to be insufficiently discriminatory. If this grade is omitted from the results obtained in the miners tested the picture alters considerably. Further, the article points out that there " seems to be a difference between whistles manufactured at different times "-this is hardly surprising. No evidence is offered that changes in one-second forced expiratory volume (r.E.v.i.o) should be reflected by changes in peak expiratory flow-rate (P.E.F.R.). This rate is much more effort-dependent, and it is probable that over a six-month interval the patient’s effort changed more than the state of his
out
lungs.
F&CAL-POTASSIUM
VALUES IN FOUR
SUBJECTS
to 241 mEq. in 12 days, by dietary means, withsignificant change in the plasma-potassium concentration. Moore et al. found no change in plasma-potassium in subjects who lost three times their total extracellular-fluid potassium at a rate of 40 mEq. per day. The loss of potassium in all but one of our subjects, calculated on Dr. Gantt’s basis, was less than 200 mEq., and was incurred over periods of up to 17 days. If the hypokalsemia observed in these subjects is attributed to this loss of potassium, an explanation is required for the failure 1. Ross, E. J. Lancet, 1965, i, 215. 2. Tashima, C. K. ibid. p. 866. 3. Gantt, C. L. ibid. p. 1167. 4. Bagshawe, K. D., Curtis, J. R., Garnett, E. S. ibid. p. 18. 5. Pollard, A. C., Bagshawe, K. D., Clarkson, E. M. Communication to Medical Research Society. Oct. 18, 1963. 6. Reimer, A., Schock, H. K., Newburgh, L. H. J. Am. diet. Ass. 1951, 29, 1042. 7. Moore, F. D., Boling, E. A., Ditmore, H. B., Sicular, A., Teterick, J. E., Ellison, A. E., Hoye, S. J., Ball, M. R. Metabolism, 1955, 4, 379.
>
The fact that the whistle-grades mostly fell suggests that either the patient’s effort or the investigator’s experience altered. A fault in the whistle ought to have given a random distribution of changes in grade. Where grades with a sharp limit are used it is fallacious to use the number of patients changing grade as an index. It can be shown that with a whistle-error of only 5 % (plus 5 % patienteffort variability and 5% observer error) as many as 72-5% of patients could have changed grades. Finally, from some of their phrases I suspect that Dr. Colley and Dr. Holland were straining their ears " in deciding if a whistle has been produced ". This is not the correct way to use the instrument-having no moving parts or inertia it can respond to much shorter blasts of high flow-rate than can the