1028
BRITISH MEDICAL JOURNAL
by advancing the needle into the liver paren- obtained a mean length of 298 cm with a chyma by only 1 cm instead of the usual 2 cm. standard deviation of 30 cm. If this is a reliable estimate of small-bowel length, then the D LEBREC average length of jejunum and ileum in the B RUEFF adult human should average 120 cm and 180 J-P BENHAMOU cm respectively as measured at the time of surgery. Unite de Recherches de Physiopathologie Hepatique (INSERM), These observations stress the real need to H6pital Beaujon, avoid, whenever possible, ileal excisions or Clichy, France bypass in excess of 150-160 cm. There must indeed be a critical length of residual ileum below which gross decompensation occurs, and SI units and acidity a review of the literature clearly shows that the majority of patients who have died after SIR,-Dr P J Tomlin's letter (24 September, intestinal bypass for morbid obesity have been p 833) illustrates very well the difficulties those patients in whom less than 20 cm of which arise when doctors are unaware of the terminal ileum was retained for absorptive real nature of the data they use and apply purposes. inappropriate arithmetical procedures to them. The procedure recommended by Dr He correctly points out the difficulty in using Maxwell and his colleagues of increasing the means and standard deviations to indicate the amount of residual ileum at the expense of the normal range when the true mean is unknown jejunum in bypass procedures for morbid and the frequency distribution is not Gaussian. obesity has also been advocated by Scott' and But in such circumstances it is surely im- is the most sensible contribution that has been possible to make any rational decision on the made on the subject. It is certainly corroborbasis of such data. To put it bluntly, how can ated by our own experience. one decide what is abnormal when one does A CUSCHIERI not know what is normal? Department of Surgery, To ask clinicians to remember all the details Ninewells Hospital and Medical School, of every test they use is to impose an absurd Dundee and unnecessary burden on them. For them to use constantly a book of tables is little better. Scott, H W. Jourtnal of the Royal College of Surgeons of Edinburgh, 1977, 22, 241. The same information is available perfectly simply by establishing the means and the nature of the frequency distribution, changing the latter to Gaussian form so that the standard Oxytocin induction and neonatal deviation now has some real meaning, hyperbilirubinaemia and then giving the results in standard units of T-score form. This would be additional to the SIR,-The report by Mr W C Chew (10 actual values of the measurements. I have September, p 679) has prompted us to comadvocated this procedure for many years on municate our preliminary observations regardthe grounds that such a single unit, which ing the pathogenetic role of oxytocin infusion, would apply to all tests, present and future, given for induction or augmentation of labour, would make for a tremendous simplification of in neonatal hyperbilirubinaemia. the clinician's task. The association between maternal infusion M HAMILTON of oxytocin during labour and neonatal hyperbilirubinaemia is generally accepted.' 8 HowDepartment of Psychiatry, University of Leeds ever, the exact mechanism of production of hyperbilirubinaemia by oxytocin is still a matter of speculation. It is conceivable that the Modified jejunoileal bypass for obesity oxytocin may cause water retention owing to its antidiuretic-hormone-like effect, resulting SIR,-We agree with the findings of the report in hyponatremia and hyposmolality in the by Dr J D Maxwell and others (17 September, maternal blood. These alterations would be p 726) on the modified jejunoileal bypass for reflected in the fetal blood.l The hyposmolality morbid obesity and would like to make the in the newborn would result in swelling of the following comments. red blood cells, thus making them more fragile There is still considerable confusion regard- and vulnerable to haemolysis. The jaundice ing the extent of small-bowel resection or may therefore appear earlier and serum bilibypass which will result in serious intestinal rubin levels are likely to exceed physiological decompensation. Estimates of the mean length limits in these neonates. of small intestine removed from its mesentery We have attempted to test the above hypoat necropsy have varied from 300 to 990 cm thesis by undertaking a prospective evaluation and have often been used in formulating state- of 49 full-term, vertex-presenting, vaginally ments on the effects of small-bowel excision in delivered newborn babies with feto-maternal the human. These post-mortem estimates do blood group compatibility. Seventeen infants not reflect the length of the small intestine in were delivered after oxytocin infusion and 32 vivo, and as most clinical observations should were born spontaneously. Cord blood was relate to the length of the small intestine collected for estimation of serum osmolality measured at operation it is surprising that this (by Fiske osmometer) and sodium concentrainformation is so scanty and confused. Indeed, tion. The age at onset of jaundice and serum accurate measurements of small-intestine bilirubin at the age of 4 days + 12 h was length at operation are difficult to obtain be- assessed. Serum osmolality and sodium concause of the changing state of the coils of small centration were significantly lower in the bowel consequent on peristaltic activity, babies delivered after oxytocin infusion than in handling, and exposure. In 30 adult patients the control group (see table). Jaundice requiring elective abdominal surgery we have appeared within 24 h of birth in four neonates measured the small-bowel length from the belonging to the oxytocin group, the serum duodenojejunal flexure to the ileocaecal valve bilirubin concentration exceeding 170 ,umol/l after a preliminary exploratory laparotomy and (10 mg/100 ml) in two of these. None of the
15 OCTOBER 1977
Serumiii osmnolality and sodiumi concenitration in infants born spontaneously and after oxytocin inftusion Serum osmolality (mmnol 1)
Control group (32) Oxytocin group (17)
306 14
5 16
290 10
3 60 J
Sodium (mmol 1) 136-46- 508
* 127 95
1
t
5 98 )
*t = 12 70, P
BRITISH MEDICAL JOURNAL
by advancing the needle into the liver paren- obtained a mean length of 298 cm with a chyma by only 1 cm instead of the usual 2 cm. standard deviation of 30 cm. If this is a reliable estimate of small-bowel length, then the D LEBREC average length of jejunum and ileum in the B RUEFF adult human should average 120 cm and 180 J-P BENHAMOU cm respectively as measured at the time of surgery. Unite de Recherches de Physiopathologie Hepatique (INSERM), These observations stress the real need to H6pital Beaujon, avoid, whenever possible, ileal excisions or Clichy, France bypass in excess of 150-160 cm. There must indeed be a critical length of residual ileum below which gross decompensation occurs, and SI units and acidity a review of the literature clearly shows that the majority of patients who have died after SIR,-Dr P J Tomlin's letter (24 September, intestinal bypass for morbid obesity have been p 833) illustrates very well the difficulties those patients in whom less than 20 cm of which arise when doctors are unaware of the terminal ileum was retained for absorptive real nature of the data they use and apply purposes. inappropriate arithmetical procedures to them. The procedure recommended by Dr He correctly points out the difficulty in using Maxwell and his colleagues of increasing the means and standard deviations to indicate the amount of residual ileum at the expense of the normal range when the true mean is unknown jejunum in bypass procedures for morbid and the frequency distribution is not Gaussian. obesity has also been advocated by Scott' and But in such circumstances it is surely im- is the most sensible contribution that has been possible to make any rational decision on the made on the subject. It is certainly corroborbasis of such data. To put it bluntly, how can ated by our own experience. one decide what is abnormal when one does A CUSCHIERI not know what is normal? Department of Surgery, To ask clinicians to remember all the details Ninewells Hospital and Medical School, of every test they use is to impose an absurd Dundee and unnecessary burden on them. For them to use constantly a book of tables is little better. Scott, H W. Jourtnal of the Royal College of Surgeons of Edinburgh, 1977, 22, 241. The same information is available perfectly simply by establishing the means and the nature of the frequency distribution, changing the latter to Gaussian form so that the standard Oxytocin induction and neonatal deviation now has some real meaning, hyperbilirubinaemia and then giving the results in standard units of T-score form. This would be additional to the SIR,-The report by Mr W C Chew (10 actual values of the measurements. I have September, p 679) has prompted us to comadvocated this procedure for many years on municate our preliminary observations regardthe grounds that such a single unit, which ing the pathogenetic role of oxytocin infusion, would apply to all tests, present and future, given for induction or augmentation of labour, would make for a tremendous simplification of in neonatal hyperbilirubinaemia. the clinician's task. The association between maternal infusion M HAMILTON of oxytocin during labour and neonatal hyperbilirubinaemia is generally accepted.' 8 HowDepartment of Psychiatry, University of Leeds ever, the exact mechanism of production of hyperbilirubinaemia by oxytocin is still a matter of speculation. It is conceivable that the Modified jejunoileal bypass for obesity oxytocin may cause water retention owing to its antidiuretic-hormone-like effect, resulting SIR,-We agree with the findings of the report in hyponatremia and hyposmolality in the by Dr J D Maxwell and others (17 September, maternal blood. These alterations would be p 726) on the modified jejunoileal bypass for reflected in the fetal blood.l The hyposmolality morbid obesity and would like to make the in the newborn would result in swelling of the following comments. red blood cells, thus making them more fragile There is still considerable confusion regard- and vulnerable to haemolysis. The jaundice ing the extent of small-bowel resection or may therefore appear earlier and serum bilibypass which will result in serious intestinal rubin levels are likely to exceed physiological decompensation. Estimates of the mean length limits in these neonates. of small intestine removed from its mesentery We have attempted to test the above hypoat necropsy have varied from 300 to 990 cm thesis by undertaking a prospective evaluation and have often been used in formulating state- of 49 full-term, vertex-presenting, vaginally ments on the effects of small-bowel excision in delivered newborn babies with feto-maternal the human. These post-mortem estimates do blood group compatibility. Seventeen infants not reflect the length of the small intestine in were delivered after oxytocin infusion and 32 vivo, and as most clinical observations should were born spontaneously. Cord blood was relate to the length of the small intestine collected for estimation of serum osmolality measured at operation it is surprising that this (by Fiske osmometer) and sodium concentrainformation is so scanty and confused. Indeed, tion. The age at onset of jaundice and serum accurate measurements of small-intestine bilirubin at the age of 4 days + 12 h was length at operation are difficult to obtain be- assessed. Serum osmolality and sodium concause of the changing state of the coils of small centration were significantly lower in the bowel consequent on peristaltic activity, babies delivered after oxytocin infusion than in handling, and exposure. In 30 adult patients the control group (see table). Jaundice requiring elective abdominal surgery we have appeared within 24 h of birth in four neonates measured the small-bowel length from the belonging to the oxytocin group, the serum duodenojejunal flexure to the ileocaecal valve bilirubin concentration exceeding 170 ,umol/l after a preliminary exploratory laparotomy and (10 mg/100 ml) in two of these. None of the
15 OCTOBER 1977
Serumiii osmnolality and sodiumi concenitration in infants born spontaneously and after oxytocin inftusion Serum osmolality (mmnol 1)
Control group (32) Oxytocin group (17)
306 14
5 16
290 10
3 60 J
Sodium (mmol 1) 136-46- 508
* 127 95
1
t
5 98 )
*t = 12 70, P
