pressure= cardiac output x peripheral resistance. The importance of this statement.is that preservation of arterial blood pressure in a supine pregnant subject does not indicate that the supine position is not detrimental to the mother and fetus; cardiac output is nevertheless likely to be reduced considerably. A preferable term to "supine hypotension syndrome" is "aortocaval compression syndrome." ROBERT W JOHNSON
Bristol Maternity Hospital, Bristol BS2 8EG 1 Nash P, Driscoll P. Trauma in pregnancy. BMJ 1990;301:974-6. (27 October.)
AUTHORS' REPLY,-We agree that despite preservation of arterial blood pressure in the supine, pregnant patient the cardiac output may be sufficiently reduced to be detrimental to both mother and fetus. The article on hypovolaemic shock in the ABC of Major Trauma series clarifies grading of shock and emphasises that hypotension is a late sign reached when class III shock has occurred.'
different treatments, treatment in different centres, or treatment in different specialties. Overall figures may conceal groups of patients who could be treated far more efficiently. For example, it may be that much of the benefit gained from the treatment of head injury was from relatively simple and cheap treatments that would not require a regional neurosurgical centre, whereas the figures suggest that no benefit is gained from the treatment of "diffuse and unspecified" head injury. When the benefits of treatment are small or uncertain the confidence intervals of cost-benefit become huge, and conventional controlled trials are required to quantify benefits accurately. The use of cost-benefit analysis needs careful examination and standardisation if it is to be used for comparisons between specialties, and several difficult ethical issues must be examined. In the present climate there must be a fear that such data will be used not to determine where extra funds should be channelled but where further cutbacks can be made. JONATHAN MICHAELS Royal Berkshire Hospital, Reading RGl 5AN
PAMELA NASH
Hillingdon Hospital, Uxbridge, Middlesex UB8 3NN PETER DRISCOLL
1 Pickard JD, Bailey S, Sanderson H, Rees M, Garfield JS. Steps toward cost-benefit analysis of regional neurosurgical care. BMJ 1990;301:629-34. (29 September.) 2 Weinstein MC, Fineberg HV, Elstein AS, ei al. Clinical decision analysis. Philadelphia: W B Saunders, 1980.
St Bartholomew's Hospital, London ECIA 7BE
PJF. Management of hypovolaemic shock. BMJ 1990;300:1453-7. (2 June.)
I Baskett
Cost-benefit analysis of regional neurosurgical care SIR,-Dr J D Pickard and colleagues provide information that is becoming more important with the current emphasis on resource management. There are, however, several problems that need to be studied before reasonable decisions can be based on such data. The authors used two measures of outcome with quite different results. "Cost per bad outcome averted" may be a suitable measure for crude comparisons when outcomes are similar, but it would be difficult to extend such methods to other cases. "Cost per quality adjusted life year" is more universally acceptable, but its application needs to be consistent. Variation in the age and life expectancy of the patient group may have a large effect on such a measure. Is it really valid to equate a 60 year extension of life in a child with an extension of five years for each of 12 middle aged people? There is evidence that patients and doctors consider that the saving of a year of life is more valuable if it is the next year rather than many years in the future.2 Perhaps some method of discounting future years should be used to take account of this. Comparisons are even more complex if subtle measures of quality of life are considered rather than broad groupings of outcome. It is important to decide which costs are to be included in the calculations. The authors use only hospital costs and ignore the costs of rehabilitation and continuing care. They also show, however, that the cost of continuing care for a single patient who is severely disabled after a head injury is over three times the hospital's expenditure on head injuries in a year. To take such a limited view biases decisions towards more expensive options. If a broader view is taken it becomes evident that more expensive treatment can be justified by even a small reduction in serious disability. In practice, non-treatment with zero cost is rarely an alternative. The choice is usually between
BMJ
VOLUME 301
17 NOVEMBER 1990
How easy is it to contact the duty doctor responsible for admissions? SIR,-Dr S W Davies reports a 19% failure rate in his attempts to contact general practitioners by telephone between the hours of 9 30 am and 5 30 pm. ' His experience does not surprise me, but I believe that the percentage of abortive calls could be at least halved by using a simple technique. The normal "office" hours in general practice are not the same as those in the hospital service. Despite the growth of modern group practices professional life in general practice retains a strong morning and evening pattern. The figure shows the estimated probability of a telephone call made on a weekday coinciding with a scheduled surgery in an average general practice, based on a recent listing of the surgery times of 92 principals in general practice in Islington. Clearly the chance of a call made between 1130 and 1630 coinciding with a scheduled surgery is low. During this time doctors are often doing home visits, clinical assistantships, teaching, etc. In our haematology department we generally need to contact at least one general practitioner each day. From experience I would suggest the following procedure for contacting general practitioners. Make the first call as normal, but if this fails consult the circulated listings of general practitioners and their surgery times (copies
are usually held by accident and emergency departments and pathology laboratories). A call made during surgery hours will usually be successful in contacting the general practitioner or at least a responsible partner. If high standards of patient care are to be offered then this extra effort must be made. In return a minority of general practitioners ought to improve their off duty arrangements for dealing with urgent messages that do not arise from patients seeking the attention of a deputising service. CHRISTOPHER MATTOCK Whittington Hospital, London N19 5NF I Davies SW. How easy is it to contact the duty doctor responsible for admissions? BMJ7 1990;301:817. (6 October.)
Extracorporeal membrane oxygenation SIR, -Dr Stephen J Rose raised several interesting issues in his response' to our recent editorial.2 We fully accept that it is essential not to commence a trial before an adequate level of expertise with the technique has been acquired. For us this point is rapidly approaching. The technique and the problems related to it have been precisely described. The learning curve, therefore, is shorter than it used to be. Indeed, in seven cases we have not encountered any complications relating to the technique that would have contributed to the clinical outcome. We do not accept that there is clear evidence to suggest that the differences in obstetric care will reduce the need for an extracorporeal membrane oxygenation service in the United Kingdom. These data are simply not available at present. Similarly, comments about the role of extracorporeal membrane oxygenation in specific conditions, such as congenital diaphragmatic hernia, can be answered only by a trial, although diaphragmatic hernia remains the second commonest primary diagnosis as an indication for extracorporeal membrane oxygenation according to the registry of the Extra Corporeal Life Support Organisation. Furthermore, persistent fetal circulation often coexists with diaphragmatic hernia, and this element of hypoxia is potentially reversible with extracorporeal membrane oxygenation. Finally, Dr Rose questions whether it is advisable to provide a new neonatal treatment when funds for conventional neonatal treatments are in short supply. Extracorporeal membrane oxygenation is extremely labour intensive and requires highly skilled staff from different specialties. The cost of the treatment is high, but no more so than maximal conventional therapy. In the United States it is covered by all insurance companies as a standard treatment. We agree that the use of this technique in the United Kingdom must be well justified, but, again, this can be done only by a trial. A W SOSNOWSKI S J BONSER
100. University of Leicester,
__80-
Leicester LEI 7RH T R GRAHAM R K FIRMIN
~.60-
Groby Road Hospital,
.oCZ0 40-
Leicester LE3 9QE
0 900
D J FIELD
4
20 1100
1300
Leicester Royal Infirmary, Leicester LEI SWW
1500
1700
1900
Time of day (h) Probability of telephone call coinciding with scheduled surgery hours in Islington general practices
1 Rose JR. Extracorporeal membrane oxygenation.
BMJ
1990;301:609. (22 September.) 2 Sosnowski AW, Bonser SJ, Field DJ, Graham TR, Firmin RK. Extracorporeal membrane oxygenation. BMJ 1990;301:303-4.
(11 August.)
1163
Bristol Maternity Hospital, Bristol BS2 8EG 1 Nash P, Driscoll P. Trauma in pregnancy. BMJ 1990;301:974-6. (27 October.)
AUTHORS' REPLY,-We agree that despite preservation of arterial blood pressure in the supine, pregnant patient the cardiac output may be sufficiently reduced to be detrimental to both mother and fetus. The article on hypovolaemic shock in the ABC of Major Trauma series clarifies grading of shock and emphasises that hypotension is a late sign reached when class III shock has occurred.'
different treatments, treatment in different centres, or treatment in different specialties. Overall figures may conceal groups of patients who could be treated far more efficiently. For example, it may be that much of the benefit gained from the treatment of head injury was from relatively simple and cheap treatments that would not require a regional neurosurgical centre, whereas the figures suggest that no benefit is gained from the treatment of "diffuse and unspecified" head injury. When the benefits of treatment are small or uncertain the confidence intervals of cost-benefit become huge, and conventional controlled trials are required to quantify benefits accurately. The use of cost-benefit analysis needs careful examination and standardisation if it is to be used for comparisons between specialties, and several difficult ethical issues must be examined. In the present climate there must be a fear that such data will be used not to determine where extra funds should be channelled but where further cutbacks can be made. JONATHAN MICHAELS Royal Berkshire Hospital, Reading RGl 5AN
PAMELA NASH
Hillingdon Hospital, Uxbridge, Middlesex UB8 3NN PETER DRISCOLL
1 Pickard JD, Bailey S, Sanderson H, Rees M, Garfield JS. Steps toward cost-benefit analysis of regional neurosurgical care. BMJ 1990;301:629-34. (29 September.) 2 Weinstein MC, Fineberg HV, Elstein AS, ei al. Clinical decision analysis. Philadelphia: W B Saunders, 1980.
St Bartholomew's Hospital, London ECIA 7BE
PJF. Management of hypovolaemic shock. BMJ 1990;300:1453-7. (2 June.)
I Baskett
Cost-benefit analysis of regional neurosurgical care SIR,-Dr J D Pickard and colleagues provide information that is becoming more important with the current emphasis on resource management. There are, however, several problems that need to be studied before reasonable decisions can be based on such data. The authors used two measures of outcome with quite different results. "Cost per bad outcome averted" may be a suitable measure for crude comparisons when outcomes are similar, but it would be difficult to extend such methods to other cases. "Cost per quality adjusted life year" is more universally acceptable, but its application needs to be consistent. Variation in the age and life expectancy of the patient group may have a large effect on such a measure. Is it really valid to equate a 60 year extension of life in a child with an extension of five years for each of 12 middle aged people? There is evidence that patients and doctors consider that the saving of a year of life is more valuable if it is the next year rather than many years in the future.2 Perhaps some method of discounting future years should be used to take account of this. Comparisons are even more complex if subtle measures of quality of life are considered rather than broad groupings of outcome. It is important to decide which costs are to be included in the calculations. The authors use only hospital costs and ignore the costs of rehabilitation and continuing care. They also show, however, that the cost of continuing care for a single patient who is severely disabled after a head injury is over three times the hospital's expenditure on head injuries in a year. To take such a limited view biases decisions towards more expensive options. If a broader view is taken it becomes evident that more expensive treatment can be justified by even a small reduction in serious disability. In practice, non-treatment with zero cost is rarely an alternative. The choice is usually between
BMJ
VOLUME 301
17 NOVEMBER 1990
How easy is it to contact the duty doctor responsible for admissions? SIR,-Dr S W Davies reports a 19% failure rate in his attempts to contact general practitioners by telephone between the hours of 9 30 am and 5 30 pm. ' His experience does not surprise me, but I believe that the percentage of abortive calls could be at least halved by using a simple technique. The normal "office" hours in general practice are not the same as those in the hospital service. Despite the growth of modern group practices professional life in general practice retains a strong morning and evening pattern. The figure shows the estimated probability of a telephone call made on a weekday coinciding with a scheduled surgery in an average general practice, based on a recent listing of the surgery times of 92 principals in general practice in Islington. Clearly the chance of a call made between 1130 and 1630 coinciding with a scheduled surgery is low. During this time doctors are often doing home visits, clinical assistantships, teaching, etc. In our haematology department we generally need to contact at least one general practitioner each day. From experience I would suggest the following procedure for contacting general practitioners. Make the first call as normal, but if this fails consult the circulated listings of general practitioners and their surgery times (copies
are usually held by accident and emergency departments and pathology laboratories). A call made during surgery hours will usually be successful in contacting the general practitioner or at least a responsible partner. If high standards of patient care are to be offered then this extra effort must be made. In return a minority of general practitioners ought to improve their off duty arrangements for dealing with urgent messages that do not arise from patients seeking the attention of a deputising service. CHRISTOPHER MATTOCK Whittington Hospital, London N19 5NF I Davies SW. How easy is it to contact the duty doctor responsible for admissions? BMJ7 1990;301:817. (6 October.)
Extracorporeal membrane oxygenation SIR, -Dr Stephen J Rose raised several interesting issues in his response' to our recent editorial.2 We fully accept that it is essential not to commence a trial before an adequate level of expertise with the technique has been acquired. For us this point is rapidly approaching. The technique and the problems related to it have been precisely described. The learning curve, therefore, is shorter than it used to be. Indeed, in seven cases we have not encountered any complications relating to the technique that would have contributed to the clinical outcome. We do not accept that there is clear evidence to suggest that the differences in obstetric care will reduce the need for an extracorporeal membrane oxygenation service in the United Kingdom. These data are simply not available at present. Similarly, comments about the role of extracorporeal membrane oxygenation in specific conditions, such as congenital diaphragmatic hernia, can be answered only by a trial, although diaphragmatic hernia remains the second commonest primary diagnosis as an indication for extracorporeal membrane oxygenation according to the registry of the Extra Corporeal Life Support Organisation. Furthermore, persistent fetal circulation often coexists with diaphragmatic hernia, and this element of hypoxia is potentially reversible with extracorporeal membrane oxygenation. Finally, Dr Rose questions whether it is advisable to provide a new neonatal treatment when funds for conventional neonatal treatments are in short supply. Extracorporeal membrane oxygenation is extremely labour intensive and requires highly skilled staff from different specialties. The cost of the treatment is high, but no more so than maximal conventional therapy. In the United States it is covered by all insurance companies as a standard treatment. We agree that the use of this technique in the United Kingdom must be well justified, but, again, this can be done only by a trial. A W SOSNOWSKI S J BONSER
100. University of Leicester,
__80-
Leicester LEI 7RH T R GRAHAM R K FIRMIN
~.60-
Groby Road Hospital,
.oCZ0 40-
Leicester LE3 9QE
0 900
D J FIELD
4
20 1100
1300
Leicester Royal Infirmary, Leicester LEI SWW
1500
1700
1900
Time of day (h) Probability of telephone call coinciding with scheduled surgery hours in Islington general practices
1 Rose JR. Extracorporeal membrane oxygenation.
BMJ
1990;301:609. (22 September.) 2 Sosnowski AW, Bonser SJ, Field DJ, Graham TR, Firmin RK. Extracorporeal membrane oxygenation. BMJ 1990;301:303-4.
(11 August.)
1163
