other aspects of government policy at present the emphasis is on movement from centralisation towards control by market forces. Bearing in mind the relative sizes of the two services (about 600 forensic scientists compared with about 40 Home Office pathologists), the working party, representing a minority interest, could not be expected to have gone any distance down the road suggested by Dr Havard, desirable though that might be. Rather than being criticised, I believe that the members of the working party should be applauded for having at least made some important progress at a very difficult time when, for instance, financial pressures have just compelled the closure of the department of forensic medicine at Leeds, one of the largest in the country. The recommendations should, with luck, prevent any further such losses; and the formation of the policy advisory board at least provides a focus that could initiate future developments such as those envisaged by Dr Havard. But this will require a much more fundamental reappraisal of scientific support for the system of criminal justice than that embodied in the remit of the working party. D J GEE
Only four hyperbaric facilities exist within the National Health Setvice in England, requiring many patients to be referred from NHS hospitals to private diving and Ministry of Defence or Home Office establishments. Such facilities have difficulty in obtaining reimbursement from the NHS for these treatments. Our unit receives referrals from the four Thames regions, often through the New Cross Hospital Poisons Unit. It is time that this problem was recognised and suitable facilities provided for its treatment. MARTIN R HAMILTON-FARRELL MICHAEL NATHANSON
Whipps Cross Hospital, London El lNR 1 Crawford R, Campbell DGD, RossJ. Carbon monoxide poisoning in the home: recognition and treatment. BMJ7 1990;301:977-9. (27 October.) 2 Anonymous. Treatment of carbon monoxide poisoning. Drug TherBull 1988;26:78-9. 3 Smith JS, Brandon S. Morbidity from acute carbon monoxide poisoning at three year follow-up. BMJ 1973;i:318-21. 4 Goulon M, Barios A, Rapin M, Nouilhat F, Grobuis S, Labrousse J. Carbon monoxide poisoning and acute anoxia due to breathing coal gas and hydrocarbons. Journal of Hyperbanrc Medicine 1986;1:23-41.
University of Leeds, Leeds LS2 9JT 1 Havard JDJ. Forensic pathology: a blinkered report. BMJ7 1990;301:943-4. (27 October.) 2 Home Affairs Committee. The forensic science service. London: HMSO, 1989. (HC26-1 and 2.)
Carbon monoxide poisoning in the home SIR,-Mr Rudy Crawford and colleagues must be congratulated on drawing attention to an underdiagnosed and sometimes ill treated condition, carbon monoxide poisoning. ' Unfortunately, it is a popular method of attempting suicide, by using the exhaust gas of motor vehicles. Our hyperbaric unit treated 27 patients with carbon monoxide poisoning in 1989, and has so far treated 28 patients this year. About half of the cases referred to this unit are attempted suicides and half are due to domestic heating accidents. Mr Crawford and colleagues suggest that carbon monoxide poisoning tends to occur during bad weather, but it is our experience that the autumn, when heating systems are switched on, is a period of high risk. The authors recommend that hyperbaric oxygen treatment should be used where appropriate but do not specify their referral criteria. These criteria were outlined in 1988.2 By agreement with the New Cross Hospital Poisons Unit, our unit accepts cases if the patient is or was at some time unconscious; has had neurological symptoms other than a simple headache; has had, at any stage, a carboxyhaemoglobin concentration >20%; has had cardiac complications; or is pregnant. Unfortunately, because our facility consists of two chambers for one person we are unable to treat patients with cardiovascular instability and patients who cannot maintain their own airway. We recommend artificial ventilation with 100% oxygen for 6-12 hours for these patients, thus also preventing a potentially dangerous transfer to another hospital. The authors made no mention of the late sequelae of carbon monoxide poisoning, which can result in neuropsychiatric disability up to three years after exposure.' Published reports strongly suggest that such late sequelae are minimised by early treatment with hyperbaric oxygen.4 Mr Crawford and colleagues say that their patients all made a complete recovery but do not describe the follow up. Follow up for four to six weeks is recommended.2
BMJ VOLUME 301
17 NOVEMBER 1990
SIR, -The lesson of the week by Mr Rudy Crawford and others reminds me of a visit to a health centre in a Korean town.' One unusual item of equipment was a hyperbaric oxygen chamber kept for resuscitating patients with carbon monoxide poisoning, a fairly common occurrence in the winter owing to the ancient Korean central heating systems, known as "ondol," which transmit hot gases from wood or coal burners through underfloor ducts. The coal was in the form of dust compacted into a cube with holes in it to allow for easy burning. Until about 10 years ago traditionally constructed houses had mud floors so that any cracks in the floor allowed the combustion gases to escape into the room. Modern floors are more likely to be made of concrete.
Two of these six patients had abnormal results on the sustained handgrip test and orthostatic hypotension was measured in one. Diabetes in this group was diagnosed by laboratory screening. Long lasting unrecognised metabolic disorders are the most probable causes of autonomic neuropathy in these newly diagnosed diabetic patients. Early diagnosis of diabetes can prevent or delay the autonomic function disturbances. Evaluation of cardiovascular reflexes is desirable in newly diagnosed diabetic patients. As these tests are, however, time consuming, we have recently elaborated a rational diagnostic model for screening purposes.5 Briefly, as a first step, heart rate response to deep breathing and standing up are measured. If both of these give normal results no further test is needed. If one or both are abnormal, the heart rate response to the Valsalva manoeuvre and blood pressure response to sustained handgrip should be examined. Blood pressure response to standing has to be tested only in those patients with abnormal results on the handgrip test. This procedure gave a correct diagnosis of autonomic neuropathy in all the 35 diabetic patients, thus, the Valsalva manoeuvre and sustained handgrip tests could have been omitted in 26 and assessment of blood pressure response to standing in 33 patients. Alcoholic diabetic patients have more serious autonomic neuropathy, and it occurs earlier in the course of their diabetes.6 Chronic liver disease is also an independent risk factor for autonomic failure.78 We examined another five newly diagnosed diabetic patients who had chronic alcoholic liver disease. Each of these patients had autonomic neuropathy, two of them exhibiting not less than four abnormal variables. Chronic alcoholism, liver diseases, and other aetiological factors should be taken into consideration as well as diabetes when autonomic neuropathy is assessed in a newly diagnosed diabetic patient. P KEMPLER A VARADI F SZALAY
F L WHALLEY
Lee on the Solent, Hampshire PO13 9NL 1 Crawford R, Campbell DGD, Ross J. Carbon monoxide poisoning in the home: recognition and treatment. BM7 1990;301:977-9. (27 October.)
Diabetic autonomic neuropathy SIR, -Dr R W Bilous' quotes a study by Zeigler et al as evidence that cardiovascular reflexes are impaired in insulin dependent patients after two years of poor diabetic control.2 Autonomic failure may be present, however, even at the time of diagnosis of diabetes. Fraser et al reported on six patients with autonomic neuropathy found among 10 newly diagnosed diabetic men.3 We studied 35 newly diagnosed non-alcoholic diabetic patients; 21 of them (mean age 23 (range 14-36) years) were insulin dependent and 14 (47-1 (37-63) years) were non-insulin dependent. We evaluated the heart rate responses to deep breathing (beat to beat variation), Valsalva manoeuvre, and standing up, and blood pressure responses to standing up and sustained handgrip.4 Among the insulin dependent patients one had an abnormal response to deep breathing, one had an abnormal heart rate response to standing up, and another had abnormal results in both these tests. In these three patients the interval between the onset of the symptoms (polyuria, polydipsia, weight loss) and the diagnosis of diabetes was longer than three months, rising to one and a half years. Two of the non-insulin dependent patients had an abnormal heart rate response to standing up and four an abnormal response to deep breathing.
GY TAMAS Semmelweis University Medical School,
Budapest, Hungary H-1083 1 Bilous RW. Diabetic autonomic neuropathy. BMJ 1990;301: 565-6. (22 September.) 2 Ziegler D, Cicmir I, Mayer P, Wiefels K, Gries FA. The natural course of peripheral and autonomic neural function during the first two years of type 1 diabetes. Klin Wochenschr 1988;66: 1085-92. 3 Fraser DM, Campbell IW, Ewing DJ, Murray A, Neilson JMM, Clarke BF. Peripheral and autonomic neuropathy in newly diagnosed diabetes mellitus. Diabetes 1977;26:546-50. 4 Ewing DJ, Clarke BF. Diagnosis and management of diabetic autonomic neuropathy. BMJ 1982;285:916-8. 5 Kempler P, Varadi A, Tamas Gy. Which battery of cardiovascular autonomic function tests-suggestion for a rational diagnostic
model. Diabetologia 1990;33:640. 6 Kempler P, Varadi A, Regos E, Veszter B, Oravecz L, Kiss E. Cardiovascular autonomic neuropathy in diabetes mellitus, in chronic alcoholism and in patients suffering from diabetes and
alcoholism simultaneously. Diabetologia 1987;30:538A. 7 Thulurath PJ, Triger DR. Autonomic neuropathy in chronic liver disease. QJ Med 1989;72:737-47. 8 Kempler P, Varadi A, Szalay F. Autonomic neuropathy in liver disease. Lancet 1989;ii:1332.
Ultrasonography and renal obstruction SIR,-I must take issue with Dr Judith Webb over the supposed diagnostic value of ultrasonography in suspected urinary obstruction in the presence of infection.' Ultrasonography can be highly misleading in this situation and can lead to management errors. An infected kidney that becomes obstructed can lose function rapidly and consequently fail to produce enough urine to cause pelvicaliceal dilatation. This seems particularly likely in diabetic patients with an infected upper 1161
Only four hyperbaric facilities exist within the National Health Setvice in England, requiring many patients to be referred from NHS hospitals to private diving and Ministry of Defence or Home Office establishments. Such facilities have difficulty in obtaining reimbursement from the NHS for these treatments. Our unit receives referrals from the four Thames regions, often through the New Cross Hospital Poisons Unit. It is time that this problem was recognised and suitable facilities provided for its treatment. MARTIN R HAMILTON-FARRELL MICHAEL NATHANSON
Whipps Cross Hospital, London El lNR 1 Crawford R, Campbell DGD, RossJ. Carbon monoxide poisoning in the home: recognition and treatment. BMJ7 1990;301:977-9. (27 October.) 2 Anonymous. Treatment of carbon monoxide poisoning. Drug TherBull 1988;26:78-9. 3 Smith JS, Brandon S. Morbidity from acute carbon monoxide poisoning at three year follow-up. BMJ 1973;i:318-21. 4 Goulon M, Barios A, Rapin M, Nouilhat F, Grobuis S, Labrousse J. Carbon monoxide poisoning and acute anoxia due to breathing coal gas and hydrocarbons. Journal of Hyperbanrc Medicine 1986;1:23-41.
University of Leeds, Leeds LS2 9JT 1 Havard JDJ. Forensic pathology: a blinkered report. BMJ7 1990;301:943-4. (27 October.) 2 Home Affairs Committee. The forensic science service. London: HMSO, 1989. (HC26-1 and 2.)
Carbon monoxide poisoning in the home SIR,-Mr Rudy Crawford and colleagues must be congratulated on drawing attention to an underdiagnosed and sometimes ill treated condition, carbon monoxide poisoning. ' Unfortunately, it is a popular method of attempting suicide, by using the exhaust gas of motor vehicles. Our hyperbaric unit treated 27 patients with carbon monoxide poisoning in 1989, and has so far treated 28 patients this year. About half of the cases referred to this unit are attempted suicides and half are due to domestic heating accidents. Mr Crawford and colleagues suggest that carbon monoxide poisoning tends to occur during bad weather, but it is our experience that the autumn, when heating systems are switched on, is a period of high risk. The authors recommend that hyperbaric oxygen treatment should be used where appropriate but do not specify their referral criteria. These criteria were outlined in 1988.2 By agreement with the New Cross Hospital Poisons Unit, our unit accepts cases if the patient is or was at some time unconscious; has had neurological symptoms other than a simple headache; has had, at any stage, a carboxyhaemoglobin concentration >20%; has had cardiac complications; or is pregnant. Unfortunately, because our facility consists of two chambers for one person we are unable to treat patients with cardiovascular instability and patients who cannot maintain their own airway. We recommend artificial ventilation with 100% oxygen for 6-12 hours for these patients, thus also preventing a potentially dangerous transfer to another hospital. The authors made no mention of the late sequelae of carbon monoxide poisoning, which can result in neuropsychiatric disability up to three years after exposure.' Published reports strongly suggest that such late sequelae are minimised by early treatment with hyperbaric oxygen.4 Mr Crawford and colleagues say that their patients all made a complete recovery but do not describe the follow up. Follow up for four to six weeks is recommended.2
BMJ VOLUME 301
17 NOVEMBER 1990
SIR, -The lesson of the week by Mr Rudy Crawford and others reminds me of a visit to a health centre in a Korean town.' One unusual item of equipment was a hyperbaric oxygen chamber kept for resuscitating patients with carbon monoxide poisoning, a fairly common occurrence in the winter owing to the ancient Korean central heating systems, known as "ondol," which transmit hot gases from wood or coal burners through underfloor ducts. The coal was in the form of dust compacted into a cube with holes in it to allow for easy burning. Until about 10 years ago traditionally constructed houses had mud floors so that any cracks in the floor allowed the combustion gases to escape into the room. Modern floors are more likely to be made of concrete.
Two of these six patients had abnormal results on the sustained handgrip test and orthostatic hypotension was measured in one. Diabetes in this group was diagnosed by laboratory screening. Long lasting unrecognised metabolic disorders are the most probable causes of autonomic neuropathy in these newly diagnosed diabetic patients. Early diagnosis of diabetes can prevent or delay the autonomic function disturbances. Evaluation of cardiovascular reflexes is desirable in newly diagnosed diabetic patients. As these tests are, however, time consuming, we have recently elaborated a rational diagnostic model for screening purposes.5 Briefly, as a first step, heart rate response to deep breathing and standing up are measured. If both of these give normal results no further test is needed. If one or both are abnormal, the heart rate response to the Valsalva manoeuvre and blood pressure response to sustained handgrip should be examined. Blood pressure response to standing has to be tested only in those patients with abnormal results on the handgrip test. This procedure gave a correct diagnosis of autonomic neuropathy in all the 35 diabetic patients, thus, the Valsalva manoeuvre and sustained handgrip tests could have been omitted in 26 and assessment of blood pressure response to standing in 33 patients. Alcoholic diabetic patients have more serious autonomic neuropathy, and it occurs earlier in the course of their diabetes.6 Chronic liver disease is also an independent risk factor for autonomic failure.78 We examined another five newly diagnosed diabetic patients who had chronic alcoholic liver disease. Each of these patients had autonomic neuropathy, two of them exhibiting not less than four abnormal variables. Chronic alcoholism, liver diseases, and other aetiological factors should be taken into consideration as well as diabetes when autonomic neuropathy is assessed in a newly diagnosed diabetic patient. P KEMPLER A VARADI F SZALAY
F L WHALLEY
Lee on the Solent, Hampshire PO13 9NL 1 Crawford R, Campbell DGD, Ross J. Carbon monoxide poisoning in the home: recognition and treatment. BM7 1990;301:977-9. (27 October.)
Diabetic autonomic neuropathy SIR, -Dr R W Bilous' quotes a study by Zeigler et al as evidence that cardiovascular reflexes are impaired in insulin dependent patients after two years of poor diabetic control.2 Autonomic failure may be present, however, even at the time of diagnosis of diabetes. Fraser et al reported on six patients with autonomic neuropathy found among 10 newly diagnosed diabetic men.3 We studied 35 newly diagnosed non-alcoholic diabetic patients; 21 of them (mean age 23 (range 14-36) years) were insulin dependent and 14 (47-1 (37-63) years) were non-insulin dependent. We evaluated the heart rate responses to deep breathing (beat to beat variation), Valsalva manoeuvre, and standing up, and blood pressure responses to standing up and sustained handgrip.4 Among the insulin dependent patients one had an abnormal response to deep breathing, one had an abnormal heart rate response to standing up, and another had abnormal results in both these tests. In these three patients the interval between the onset of the symptoms (polyuria, polydipsia, weight loss) and the diagnosis of diabetes was longer than three months, rising to one and a half years. Two of the non-insulin dependent patients had an abnormal heart rate response to standing up and four an abnormal response to deep breathing.
GY TAMAS Semmelweis University Medical School,
Budapest, Hungary H-1083 1 Bilous RW. Diabetic autonomic neuropathy. BMJ 1990;301: 565-6. (22 September.) 2 Ziegler D, Cicmir I, Mayer P, Wiefels K, Gries FA. The natural course of peripheral and autonomic neural function during the first two years of type 1 diabetes. Klin Wochenschr 1988;66: 1085-92. 3 Fraser DM, Campbell IW, Ewing DJ, Murray A, Neilson JMM, Clarke BF. Peripheral and autonomic neuropathy in newly diagnosed diabetes mellitus. Diabetes 1977;26:546-50. 4 Ewing DJ, Clarke BF. Diagnosis and management of diabetic autonomic neuropathy. BMJ 1982;285:916-8. 5 Kempler P, Varadi A, Tamas Gy. Which battery of cardiovascular autonomic function tests-suggestion for a rational diagnostic
model. Diabetologia 1990;33:640. 6 Kempler P, Varadi A, Regos E, Veszter B, Oravecz L, Kiss E. Cardiovascular autonomic neuropathy in diabetes mellitus, in chronic alcoholism and in patients suffering from diabetes and
alcoholism simultaneously. Diabetologia 1987;30:538A. 7 Thulurath PJ, Triger DR. Autonomic neuropathy in chronic liver disease. QJ Med 1989;72:737-47. 8 Kempler P, Varadi A, Szalay F. Autonomic neuropathy in liver disease. Lancet 1989;ii:1332.
Ultrasonography and renal obstruction SIR,-I must take issue with Dr Judith Webb over the supposed diagnostic value of ultrasonography in suspected urinary obstruction in the presence of infection.' Ultrasonography can be highly misleading in this situation and can lead to management errors. An infected kidney that becomes obstructed can lose function rapidly and consequently fail to produce enough urine to cause pelvicaliceal dilatation. This seems particularly likely in diabetic patients with an infected upper 1161
