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LIPID DEPOSITION IN PARENTERAL INFUSION LINES
701 LIPID DEPOSITION IN PARENTERAL INFUSION LINES
SIR,-Beau and Matuchanskyl have described white deposits in catheter lines during cyclic infusions for total parenteral nutrition (TPN) with lipid emulsions. We may have the answer. Over the past two months, we have been troubled by similar deposits in the infusion lines of children on TPN composed of the following products (KabiVitrum): ’Intralipid’; an aminoacid mixture with glucose and electrolytes (’Vamin 9 Glucose’); and supplementary electrolytes and trace elements (’Ped-El’). Heparin and vitamins were also included. In 24 h this TPN regimen provided, for example, a one-year-old undernourished child (6 kg) with 60 ml of 20% intralipid, 220 ml vamin 9 glucose, and 17 ml ped-el in a total volume of 680 ml. The calcium content of this mixture was 2-8 mmol at a final concentration of 4 j.Il11ol(ml of the whole infusion. These doses are in accordance with the manufacturers rcommendations. We have used a simple test (figure) to reproduce the separation (creaming) of the lipid emulsion by mixing the components of the TPN mixture in plastic test tubes and allowing them to stand at room temperature. This allowed us to predict which feed mixtures were likely to cream. Our investigations were extended to attempt to identify which components in the feed were responsible for creaming. Tubes were set up in each of which one component of the feed was omitted, and it became apparent that both ped-el and heparin had to be present for creaming to occur (figure). Further experiments showed that calcium ions, at their concentration in ped-el, caused creaming in the presence of heparin. It made no difference whether the calcium was present as chloride or gluconate. Creaming of the intralipid was likely at final concentrations of heparin above 1 unit/ml combined with a calcium concentration greater than 1 umol/ml.
P, Matuchansky C. Lipid delivery and catheter obstruction during cyclic total parenteral nutrition. Lancet 1987; ii: 1095-96. 2. du Plessis J, Van Wyk CJ, Ackermann C. The stability of parenteral fat emulsions in nutrition mixtures. J Clin Pharm Ther 1987; 12: 307-18. 3. Taylor CJ, Rangecroft NJ. In: Grant A, Todd E, eds. Enteral and parenteral nutrition. Oxford: Blackwell Scientific, 1987. 1. Beau
GROWTH DURING EARLY TEENAGE PREGNANCIES
SIR,-Are pregnant early teenagers physiologically mature?l,2 Continued linear growth during pregnancy would be an indicator that they are not, but although several studies have inferred growth between successive adolescent pregnancies3° linear growth during the pregnancy itself has not been documented, primarily because existing instruments are not precise enough to measure short-term growth and because of the reliance on changes in stature during pregnancy may be influenced by postural changes, weight gain, and compression of intervertebral discs. To overcome these methodological difficulties, we began using the knee height measuring device (KHMD)5 to monitor the growth of the lower leg during adolescent pregnancy. The KHMD, a smaller variant of the Valk devicedetects small amounts of linear growth over short periods. Recent repots have estimated reliability for the KHMD to be 0-5 nirn.1 Between July, 1987, and the present, we measured 21
primigravidae at ages 12-15 years, 24 multigravidae at ages 15-18 years (with a first pregnancy at age 12-15), and 9 mature controls aged 18-29, twice during pregnancy. The two measurements covered the second and third trimesters, with an average interval of 14 weeks. During pregnancy, young primigravidae gained an average of 1.68 mm, young multigravidae 1-00 mm, and mature controls only 0-10 mm (table). The 99% confidence interval (CI) on the main increment included zero for the controls, but not for the adolescents. With the upper limit of 99 % CI of the mature women as the cut-off for measurement error, 67 % of the young primigravid teenagers and 50% of the multigravid teenagers had larger increments (ie, greater than 0-9 mm) and thus appeared to be
growing. SHORT-TERM GROWTH DURING ADOLESCENT PREGNANCY
Creaming experiments. Intralipid (0-5 ml) was mixed
with vamin 9 glucose (20 ml). A TPN omitted from each numbered tube as follows: (1) potassium dihydrogen phosphate, (2) potassium chloride, (3) zinc sulphate, (4) heparin, (5) magnesium sulphate, (6) ped-el, (7) none, (8) all. The four right-hand tubes contained (besides intralipid and vamin 9 glucose): (9) no additives,
additive
*p < 0-05
vs
zero;
tp <
0 005
M
controls, tp <
0 05
vs
controls-
was
(10) heparin, (11) ped-el, (12) ped-el plus heparin. Several factors including the concentrations of divalent and monovalent cations, pH, and the presence of aminoacid or glucose solutions, affect the particle size and stability of TPN lipid emulsions2 but an effect of heparin has not previously been reported. We are puzzled that lipid deposition in TPN has only lately been identified when the mixtures for infusion have been in use for several years.3 We have investigated more than one batch of intralipid from different distributors and have stored it overnight at temperatures between 4°C and 37°C and obtained the same results. The manufacturers have been unable to explain the creaming. These deposits not only waste expensive TPN equipment and solutions but also, and more seriously, their passage into a patient, particularly a young child, could result in fat embolism. For the moment, we avoid the use of heparin with TPN solutions containing calcium concentrations greater than 1 J.Ullol/ml even though this increases the risks of line occlusion and sepsis.
Sheffield S10 2TH
Departments of Obstetrics and Gynecology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, and School of Osteopathic Medicine, Camden, New Jersey 08103, USA
THERESA O. SCHOLL MARY L. HEDIGER ISADORE G. ANCES
Division of Gastroenterology and
Children’s
Nutrition, Hospital of Philadelphia
CHRISTINE E. CRONK
1. Forbes GB.
Departments of Chemical Pathology, Paediatrics, and Pharmacy, Childrens Hospital,
These data support the hypothesis that linear growth continues during adolescent pregnancy and that some pregnant adolescents may not be completely physiologically mature. To our knowledge, this is the first demonstration that teenagers may continue to grow throughout pregnancy. Continuing maternal growth has implications for the well-being of the mother and fetus and may be one source of the complications associated with young maternal age.8 We do not know if the amount of growth detected is different from that of same-aged non-pregnant subjects, or if the postulated competition9 between mother and fetus for nutrients occurs. Studies are underway to confirm and extend these preliminary results.
J. M. RATTENBURY C. J. TAYLOR S. GANAPATHY
Pregnancy in the teenager biologic aspects. In: McAnamey ER, Stickle G, eds. Pregnancy and childbearing during adolescence New York McGraw-Hill, 1981: 85-90.
2. Frisancho AR, Matos J, Flegel P. Maternal nuritional outcome.
Am J Clin Nutr 1983; 38: 739-46.
status
and adolescent pregnancy
SIR,-Beau and Matuchanskyl have described white deposits in catheter lines during cyclic infusions for total parenteral nutrition (TPN) with lipid emulsions. We may have the answer. Over the past two months, we have been troubled by similar deposits in the infusion lines of children on TPN composed of the following products (KabiVitrum): ’Intralipid’; an aminoacid mixture with glucose and electrolytes (’Vamin 9 Glucose’); and supplementary electrolytes and trace elements (’Ped-El’). Heparin and vitamins were also included. In 24 h this TPN regimen provided, for example, a one-year-old undernourished child (6 kg) with 60 ml of 20% intralipid, 220 ml vamin 9 glucose, and 17 ml ped-el in a total volume of 680 ml. The calcium content of this mixture was 2-8 mmol at a final concentration of 4 j.Il11ol(ml of the whole infusion. These doses are in accordance with the manufacturers rcommendations. We have used a simple test (figure) to reproduce the separation (creaming) of the lipid emulsion by mixing the components of the TPN mixture in plastic test tubes and allowing them to stand at room temperature. This allowed us to predict which feed mixtures were likely to cream. Our investigations were extended to attempt to identify which components in the feed were responsible for creaming. Tubes were set up in each of which one component of the feed was omitted, and it became apparent that both ped-el and heparin had to be present for creaming to occur (figure). Further experiments showed that calcium ions, at their concentration in ped-el, caused creaming in the presence of heparin. It made no difference whether the calcium was present as chloride or gluconate. Creaming of the intralipid was likely at final concentrations of heparin above 1 unit/ml combined with a calcium concentration greater than 1 umol/ml.
P, Matuchansky C. Lipid delivery and catheter obstruction during cyclic total parenteral nutrition. Lancet 1987; ii: 1095-96. 2. du Plessis J, Van Wyk CJ, Ackermann C. The stability of parenteral fat emulsions in nutrition mixtures. J Clin Pharm Ther 1987; 12: 307-18. 3. Taylor CJ, Rangecroft NJ. In: Grant A, Todd E, eds. Enteral and parenteral nutrition. Oxford: Blackwell Scientific, 1987. 1. Beau
GROWTH DURING EARLY TEENAGE PREGNANCIES
SIR,-Are pregnant early teenagers physiologically mature?l,2 Continued linear growth during pregnancy would be an indicator that they are not, but although several studies have inferred growth between successive adolescent pregnancies3° linear growth during the pregnancy itself has not been documented, primarily because existing instruments are not precise enough to measure short-term growth and because of the reliance on changes in stature during pregnancy may be influenced by postural changes, weight gain, and compression of intervertebral discs. To overcome these methodological difficulties, we began using the knee height measuring device (KHMD)5 to monitor the growth of the lower leg during adolescent pregnancy. The KHMD, a smaller variant of the Valk devicedetects small amounts of linear growth over short periods. Recent repots have estimated reliability for the KHMD to be 0-5 nirn.1 Between July, 1987, and the present, we measured 21
primigravidae at ages 12-15 years, 24 multigravidae at ages 15-18 years (with a first pregnancy at age 12-15), and 9 mature controls aged 18-29, twice during pregnancy. The two measurements covered the second and third trimesters, with an average interval of 14 weeks. During pregnancy, young primigravidae gained an average of 1.68 mm, young multigravidae 1-00 mm, and mature controls only 0-10 mm (table). The 99% confidence interval (CI) on the main increment included zero for the controls, but not for the adolescents. With the upper limit of 99 % CI of the mature women as the cut-off for measurement error, 67 % of the young primigravid teenagers and 50% of the multigravid teenagers had larger increments (ie, greater than 0-9 mm) and thus appeared to be
growing. SHORT-TERM GROWTH DURING ADOLESCENT PREGNANCY
Creaming experiments. Intralipid (0-5 ml) was mixed
with vamin 9 glucose (20 ml). A TPN omitted from each numbered tube as follows: (1) potassium dihydrogen phosphate, (2) potassium chloride, (3) zinc sulphate, (4) heparin, (5) magnesium sulphate, (6) ped-el, (7) none, (8) all. The four right-hand tubes contained (besides intralipid and vamin 9 glucose): (9) no additives,
additive
*p < 0-05
vs
zero;
tp <
0 005
M
controls, tp <
0 05
vs
controls-
was
(10) heparin, (11) ped-el, (12) ped-el plus heparin. Several factors including the concentrations of divalent and monovalent cations, pH, and the presence of aminoacid or glucose solutions, affect the particle size and stability of TPN lipid emulsions2 but an effect of heparin has not previously been reported. We are puzzled that lipid deposition in TPN has only lately been identified when the mixtures for infusion have been in use for several years.3 We have investigated more than one batch of intralipid from different distributors and have stored it overnight at temperatures between 4°C and 37°C and obtained the same results. The manufacturers have been unable to explain the creaming. These deposits not only waste expensive TPN equipment and solutions but also, and more seriously, their passage into a patient, particularly a young child, could result in fat embolism. For the moment, we avoid the use of heparin with TPN solutions containing calcium concentrations greater than 1 J.Ullol/ml even though this increases the risks of line occlusion and sepsis.
Sheffield S10 2TH
Departments of Obstetrics and Gynecology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, and School of Osteopathic Medicine, Camden, New Jersey 08103, USA
THERESA O. SCHOLL MARY L. HEDIGER ISADORE G. ANCES
Division of Gastroenterology and
Children’s
Nutrition, Hospital of Philadelphia
CHRISTINE E. CRONK
1. Forbes GB.
Departments of Chemical Pathology, Paediatrics, and Pharmacy, Childrens Hospital,
These data support the hypothesis that linear growth continues during adolescent pregnancy and that some pregnant adolescents may not be completely physiologically mature. To our knowledge, this is the first demonstration that teenagers may continue to grow throughout pregnancy. Continuing maternal growth has implications for the well-being of the mother and fetus and may be one source of the complications associated with young maternal age.8 We do not know if the amount of growth detected is different from that of same-aged non-pregnant subjects, or if the postulated competition9 between mother and fetus for nutrients occurs. Studies are underway to confirm and extend these preliminary results.
J. M. RATTENBURY C. J. TAYLOR S. GANAPATHY
Pregnancy in the teenager biologic aspects. In: McAnamey ER, Stickle G, eds. Pregnancy and childbearing during adolescence New York McGraw-Hill, 1981: 85-90.
2. Frisancho AR, Matos J, Flegel P. Maternal nuritional outcome.
Am J Clin Nutr 1983; 38: 739-46.
status
and adolescent pregnancy