372
argument. More fundamental considerations should be addressed first. These patients are not dead. The physician’s responsibility should be primarily to his patient. Obtaining "decisions" and "permission" from relatives about patients who are not dead seems wrong: surely the relatives should be asked to indicate what they believe the patient might have wanted. The use of artificial ventilation in intensive care units has allowed two rare conditions to become recognised: one, the more common, is brain death, which can result in the fortunate "byproduct" of organs for donation; and the other is a persistent vegetative state, which is far less fortunate. When a seriously ill patient is about to be admitted to intensive care for artificial ventilation should relatives be told that a vegetative state is a possible outcome? The way that information is given can greatly influence decisions. In the data presented, one out of eleven patients did not die as predicted. Do Feest et al propose that relatives are told that there is this level of probability that death is not inevitable, but that the patient may survive in a severely damaged state? Three patients were intubated and ventilated in the emergency department before discussion with a consultant or the relatives. This seems to be presenting the relatives with a fait accompli, and may well force a decision that might not otherwise have been reached. The proposed protocol moves away from the well-defined condition of "brain death" to one of "expected death on a ventilator", which is far less well characterised, and is possibly a dangerous concept. Department of Anaesthetics, Royal Infirmary, Edinburgh EH3 9YW, 1 Schneiderman
G. B. DRUMMOND
UK
LJ, Spragg RG Ethical decisions J Med 1988; 318: 984-88
m
discontinuing
mechanical
ventilation. N Engl
Clinical significance of antenatal calyceal dilatation detected by ultrasound SiR,—The role of ultrasound in the prenatal detection of renal tract anomalies is well established’ but the significance of the findings and the most rational use of confirmatory investigations remain unclear. At the Birmingham Maternity Hospital we have been evaluating antenatal ultrasound screening since 1986. Once an abnormality is detected ultrasound scans are repeated during pregnancy, in the immediate postnatal period, and at six weeks after birth. Investigations and management decisions are planned at monthly meetings of the perinatal renal group at the Birmingham Children’s Hospital. Over the two years January, 1988, to December, 1989, 110 infants were live-born after detection of fetal urological abnormalities; significant lesions were demonstrated in 42%:
All scans showed pelvic dilatation; they were according to the worst appearance antenatally, after delivery, or at 6 weeks. The presence of additional calyceal dilatation was closely associated with the subsequent demonstration of renal lesion, whereas no abnormalities were found in any of the 13 infants with isolated dilatation of the renal pelvis:
cystourethrogram. then classified
These data raise two important issues. The true incidence of VUR in childhood is unknown. However, on the assumption that all VUR is congenital, and given that urinary-tract infection develops in 1% of infants and that one-quarter of these have significant reflux, a conservative estimate of the incidence of VUR would be 2per 1000. If some infants with reflux do not proceed to infection then the incidence would be greater. Since we studied well over 10 000 pregnancies it seems likely that antenatal ultrasound screening does not always identify VUR. Our results also suggest that calyceal dilatation found at any time is an indication for action, including cystourethrogram-but is this investigation justifiable in infants with dilatation confined to the renal pelvis? Our limited data suggest that VUR occurs in less than 25 % of these infants. To explore the issue further we calculated how large a study would be necessary to provide a 90% chance of allowing us to infer, with 95% confidence, the frequency of VUR m this group. If the frequency in infants with isolated pelvic dilatation is assumed to be 10-20%, a further 20 infants are required; if it is 5-10%, 100 infants are needed. An assumed frequency of less than 5% would require a large number of infants and would not justify the widespread use of cystourethrography in clinical practice. These important questions can be answered only by collaborative studies and we would welcome the comments of others involved in programmes to detect fetal renal anomalies. We thank Dr R. L.
Holder, department of
statistics,
University of
Birmingham. Departments of Paediatrics and Radiology, Birmingham Maternity Hospital, Birmingham B15 2TG, UK
S. J. NEWELL M. E. I. MORGAN J. M. MCHUGO R. H. R. WHITE C. M. TAYLOR S. CHAPMAN
Departments of Nephrology. Radiology, and Surgery, Children’s Hospital, Birmingham 1
K. J. SHAH P. GORNALL J. J. CORKERY
Tudor J, Whitaker RH Detection and management of the dilated fetal urinary tract
Clin Radiol 1989, 40: 229-30. 2 White RHR Fetal uropathy Br Med J 1989; 298: 1408-09. 3 Reuter KL, Lebowitz RL. Massive vesico-ureteric reflux
mimicking posterior
urethral valves in a fetus. J Clin Ultrasound 1985; 13: 584-87 4. Rolleston GL, Shannon FT, Utley WLE Relationship of infantile reflux to renal damage Br Med J 1970, i 460-64.
vesicoureteric
Bicarbonate and cytoplasmic pH
One aim of screening is to detect asymptomatic vesicoureteric reflux (VUR), in an attempt to prevent reflux nephropathy.2 We have analysed our data with special reference to the detection of VUR by cystourethrography in infants with antenatal renal tract dilatation .3 In 41 infants investigations included a cystourethrogram because of pelvicalyceal dilatation. 9 infants had grade4 III VUR and 2 had grade II. A further infant showed bladder outlet obstruction and another a ureterocoele. In 10 the cystourethrogram was normal but other investigations showed renal tract lesions. In 18 infants no significant lesions was found on cystourethrography or other investigations. A cystourethrogram is an invasive investigation so we looked at the ultrasound scans to see if they were predictive of an abnormal
SIR,-We would like to respond to points raised by correspondents (June 30, p 1586-88) about our paper on effects of bicarbonate on cytoplasmic pH (May 26, p 1243). We argued that the finding that an abrupt increase in bicarbonate concentration can cause cytoplasmic acidification undermines the logic of using bicarbonate in severe acidaemia, especially in cardiopulmonary arrest, and adds to the evidence that such treatment may be dangerous. Dr Buckler and Dr Gasser argue that the mechanism of acidification may not be exclusively permeation of CO, followed by hydration and dissociation, and we agree that we cannot exclude additional mechanisms. Dr Unwin makes the point that platelets may not be a good general model of cell acid-base regulation. However, platelets are prepared fresh from blood, whereas many cells require culture and/or dispersal methods that may influence acid-base responses, especially if these depend on carbonic anhydrase on the outer
argument. More fundamental considerations should be addressed first. These patients are not dead. The physician’s responsibility should be primarily to his patient. Obtaining "decisions" and "permission" from relatives about patients who are not dead seems wrong: surely the relatives should be asked to indicate what they believe the patient might have wanted. The use of artificial ventilation in intensive care units has allowed two rare conditions to become recognised: one, the more common, is brain death, which can result in the fortunate "byproduct" of organs for donation; and the other is a persistent vegetative state, which is far less fortunate. When a seriously ill patient is about to be admitted to intensive care for artificial ventilation should relatives be told that a vegetative state is a possible outcome? The way that information is given can greatly influence decisions. In the data presented, one out of eleven patients did not die as predicted. Do Feest et al propose that relatives are told that there is this level of probability that death is not inevitable, but that the patient may survive in a severely damaged state? Three patients were intubated and ventilated in the emergency department before discussion with a consultant or the relatives. This seems to be presenting the relatives with a fait accompli, and may well force a decision that might not otherwise have been reached. The proposed protocol moves away from the well-defined condition of "brain death" to one of "expected death on a ventilator", which is far less well characterised, and is possibly a dangerous concept. Department of Anaesthetics, Royal Infirmary, Edinburgh EH3 9YW, 1 Schneiderman
G. B. DRUMMOND
UK
LJ, Spragg RG Ethical decisions J Med 1988; 318: 984-88
m
discontinuing
mechanical
ventilation. N Engl
Clinical significance of antenatal calyceal dilatation detected by ultrasound SiR,—The role of ultrasound in the prenatal detection of renal tract anomalies is well established’ but the significance of the findings and the most rational use of confirmatory investigations remain unclear. At the Birmingham Maternity Hospital we have been evaluating antenatal ultrasound screening since 1986. Once an abnormality is detected ultrasound scans are repeated during pregnancy, in the immediate postnatal period, and at six weeks after birth. Investigations and management decisions are planned at monthly meetings of the perinatal renal group at the Birmingham Children’s Hospital. Over the two years January, 1988, to December, 1989, 110 infants were live-born after detection of fetal urological abnormalities; significant lesions were demonstrated in 42%:
All scans showed pelvic dilatation; they were according to the worst appearance antenatally, after delivery, or at 6 weeks. The presence of additional calyceal dilatation was closely associated with the subsequent demonstration of renal lesion, whereas no abnormalities were found in any of the 13 infants with isolated dilatation of the renal pelvis:
cystourethrogram. then classified
These data raise two important issues. The true incidence of VUR in childhood is unknown. However, on the assumption that all VUR is congenital, and given that urinary-tract infection develops in 1% of infants and that one-quarter of these have significant reflux, a conservative estimate of the incidence of VUR would be 2per 1000. If some infants with reflux do not proceed to infection then the incidence would be greater. Since we studied well over 10 000 pregnancies it seems likely that antenatal ultrasound screening does not always identify VUR. Our results also suggest that calyceal dilatation found at any time is an indication for action, including cystourethrogram-but is this investigation justifiable in infants with dilatation confined to the renal pelvis? Our limited data suggest that VUR occurs in less than 25 % of these infants. To explore the issue further we calculated how large a study would be necessary to provide a 90% chance of allowing us to infer, with 95% confidence, the frequency of VUR m this group. If the frequency in infants with isolated pelvic dilatation is assumed to be 10-20%, a further 20 infants are required; if it is 5-10%, 100 infants are needed. An assumed frequency of less than 5% would require a large number of infants and would not justify the widespread use of cystourethrography in clinical practice. These important questions can be answered only by collaborative studies and we would welcome the comments of others involved in programmes to detect fetal renal anomalies. We thank Dr R. L.
Holder, department of
statistics,
University of
Birmingham. Departments of Paediatrics and Radiology, Birmingham Maternity Hospital, Birmingham B15 2TG, UK
S. J. NEWELL M. E. I. MORGAN J. M. MCHUGO R. H. R. WHITE C. M. TAYLOR S. CHAPMAN
Departments of Nephrology. Radiology, and Surgery, Children’s Hospital, Birmingham 1
K. J. SHAH P. GORNALL J. J. CORKERY
Tudor J, Whitaker RH Detection and management of the dilated fetal urinary tract
Clin Radiol 1989, 40: 229-30. 2 White RHR Fetal uropathy Br Med J 1989; 298: 1408-09. 3 Reuter KL, Lebowitz RL. Massive vesico-ureteric reflux
mimicking posterior
urethral valves in a fetus. J Clin Ultrasound 1985; 13: 584-87 4. Rolleston GL, Shannon FT, Utley WLE Relationship of infantile reflux to renal damage Br Med J 1970, i 460-64.
vesicoureteric
Bicarbonate and cytoplasmic pH
One aim of screening is to detect asymptomatic vesicoureteric reflux (VUR), in an attempt to prevent reflux nephropathy.2 We have analysed our data with special reference to the detection of VUR by cystourethrography in infants with antenatal renal tract dilatation .3 In 41 infants investigations included a cystourethrogram because of pelvicalyceal dilatation. 9 infants had grade4 III VUR and 2 had grade II. A further infant showed bladder outlet obstruction and another a ureterocoele. In 10 the cystourethrogram was normal but other investigations showed renal tract lesions. In 18 infants no significant lesions was found on cystourethrography or other investigations. A cystourethrogram is an invasive investigation so we looked at the ultrasound scans to see if they were predictive of an abnormal
SIR,-We would like to respond to points raised by correspondents (June 30, p 1586-88) about our paper on effects of bicarbonate on cytoplasmic pH (May 26, p 1243). We argued that the finding that an abrupt increase in bicarbonate concentration can cause cytoplasmic acidification undermines the logic of using bicarbonate in severe acidaemia, especially in cardiopulmonary arrest, and adds to the evidence that such treatment may be dangerous. Dr Buckler and Dr Gasser argue that the mechanism of acidification may not be exclusively permeation of CO, followed by hydration and dissociation, and we agree that we cannot exclude additional mechanisms. Dr Unwin makes the point that platelets may not be a good general model of cell acid-base regulation. However, platelets are prepared fresh from blood, whereas many cells require culture and/or dispersal methods that may influence acid-base responses, especially if these depend on carbonic anhydrase on the outer
