An assessment of published pediatric dosage guidelines for enoxaparin: a retrospective review

OBJECTIVE: To evaluate the ability of published dosage guidelines for enoxaparin to achieve therapeutic anticoagulation and to determine whether the routine monitoring of anti-Xa levels is still necessary at a tertiary care pediatric institution. METHODS: Consecutive charts and laboratory records were reviewed for all patients receiving treatment doses of enoxaparin for thrombosis in the authors institution over a 4-year period (1998-2002). RESULTS: Sixty-six percent (25/38) of the anti-Xa levels were within the recommended therapeutic range (0.5-1.0 [+/- 10%] U/mL) after two doses. The success rates of achieving therapeutic levels were 1/6, 2/3, 6/9, 10/11, and 6/9, for patients 2 months or younger, more than 2 months to 1 year, more than 1 year to 6 years, more than 6 years to 12 years, and more than 12 years of age, respectively. Patients with cardiac or renal disease were more likely to achieve high anti-Xa levels. Thirty-seven percent of patients reported adverse effects. The most common effects were injection site-related bruising and minor bleeding. One patient experienced a major bleed that was not life-threatening. CONCLUSIONS: Most patients achieved therapeutic anticoagulation when dosed according to the published guidelines. Children with cardiac conditions or renal insufficiency or those younger than 2 months were more likely to require dosage adjustments to achieve the therapeutic range. Routine monitoring of anti-Xa levels is still necessary in these patient populations, particularly when the early establishment of therapeutic anticoagulation may be critical. Enoxaparin appears to be well tolerated in the authors' patient population.     

The low molecular weight heparin dalteparin for prophylaxis and therapy of thrombosis in childhood: a report on 48 cases

We investigated the efficacy, safety and relation of dose to plasma anti-Xa activity of the low molecular weight heparin (LMWH) dalteparin in prophylaxis and therapy of arterial and venous thrombosis in pediatric patients. A total of 48 children were enrolled: 10 received dalteparin for prophylaxis (group I), 8 for reocclusion prophylaxis following successful thrombolysis (group II), 5 following failed thrombolysis (group III) and 23 for primary antithrombotic therapy (group IV). Two children were treated with dalteparin for pulmonary veno-occlusive disease (PVOD) and for primary pulmonary hypertension (PPH), respectively. Outcome: In group I no thrombo-embolic event occurred. In group II recanalization was maintained or improved, in group III vascular occlusion persisted under dalteparin. In group IV we saw complete recanalization in 7/23 (30%), partial recanalization in 7/23 (30%) and no recanalization in 9/23 (40%) cases. The child with PVOD had recanalization proven by lung biopsy; the clinical condition of the child with PPH also improved. Minor bleeding occurred in 2/48 (4%) children. For prophylaxis 95 - 52 (mean and SD) anti-Xa IU/kg BW, for therapy 129 - 43 (mean and SD) anti-Xa IU/kg BW proved effective. For both prophylaxis and therapy the required dose per kg BW was inversely related with age (r² = 0.64, P = 0.017; r² = 0.13, P = 0.013). Conclusion Dalteparin proved to be an effective and well tolerated drug for prophylaxis and therapy of thrombosis in pediatric patients. Dose requirement for effective treatment was higher in younger children and decreased with age.     

Thrombolysis with rt-PA in children with arterial and venous thromboses--a new therapy concept

Thrombolytic therapy usually used for thrombosis in the adult has been administered as a therapeutic regiment in pediatric patients (parental consent was sought prior to the treatment with rt-PA). We report our experience with rt-PA in 17 children and adolescents suffering from arterial (n = 4) or venous thrombosis (n = 13) due to local rhabdomyosarcoma, acute lymphoblastic leukemia, chronic myeloblastosis, sickle cell anaemia, parenteral nutrition, haemolytic uremic syndrome, central arterial and venous catheters and septicemia Thrombotic diseases have been diagnosed by Doppler ultrasound, computed tomography, angiography and phlebography. Rt-PA therapy was started immediately after diagnostic procedures had been performed. Rt-PA dose varied from 0.2 mg as a single dose to 0.8 mg/kg bw/d over a three day period in children local thrombolysis was performed. In patients requiring systemic thrombolytic therapy rt-PA was administered from 0.8 mg/kg bw/d in three days to 2.0 mg/kg bw/d over a whole period of three weeks in both groups during thrombolysis low dose heparin was added. When rt-PA infusion was terminated heparin (70 IU - 400 IU/kg bw/d) was administered for 7 to 14 days in order to prevent reocclusion. Later prophylaxis with coumarin derivatives in venous thrombosis and antiplatelet agents in arterial occlusive diseases was performed. In no patient did we see a decrease of fibrinogen and plasminogen during rt-PA therapy.(ABSTRACT TRUNCATED AT 250 WORDS)     

A cross-sectional international survey of continuous subcutaneous insulin infusion in 377 children and adolescents with type 1 diabetes mellitus from 10 countries

OBJECTIVE: To document current practices using continuous subcutaneous insulin infusion (CSII) by downloading electronically the 90-d pump data held within the pump memory and relating that to clinical data from children and adolescents in different pediatric diabetes centers from Europe and Israel. METHODS: Data of patients (1-18 yr) treated with CSII in 23 centers from nine European countries and Israel were recorded with the encapture software (PEC International, Frankfurt, Germany). The number of patients who participated was 377 (48% female; mean diabetes duration +/- SD: 6.8 +/- 3.7 yr; age: 12.9 +/- 3.8 yr, preschool n = 33; prepubertal n = 95; adolescent n = 249; CSII duration: 1.6 +/- 1.2 yr; local HbA1c: 8.1 +/- 1.2%). RESULTS: The total insulin dose was lower than previously reported for injection therapy (0.79 +/- 0.20 U/kg/d). Covariance coefficient of daily total insulin was high in all age groups (adolescents 19 +/- 9%, prepubertal 18 +/- 8 and preschool 17 +/- 8). The distribution of basal insulin infusion rates over 24 hr (48 +/- 12% of total dose) varied significantly between centers and age groups. The number of boluses per day (7 +/- 3) was not significantly different between the age groups (average daily bolus amount: 0.42 +/- 0.16 U/kg). The rate of severe hypoglycemia (coma/convulsions) was 12.4 episodes per 100 patient-years and the number of diabetes-related hospital days was 124 per 100 patient-years. DISCUSSION: Pediatric CSII patients show a high variability in their insulin therapy. This relates both to age-dependent differences in the distribution of basal insulin as to the age-independent day-to-day variation in prandial insulin.     

Analysis of circulating T gamma/delta lymphocytes and CD16/56 cell populations in children and adolescents with Graves' disease

The aim of the present study was to determine the proportion of gamma/delta T-lymphocytes and CD16/CD56 (CD3- and CD3+) cells in the peripheral blood of children and adolescents with Graves' disease (GD; n = 27; mean age, 15.5 +/- 5.1 y) and nontoxic nodular goiter (NTNG; n = 25; mean age, 15.2 +/- 5.7 y), in comparison with sex- and age-matched healthy control subjects (n = 25; mean age, 15.9 +/- 2.4 y). In addition, in patients with GD, we investigated the effect of methimazole therapy on the proportion of these cells. We also looked for associations among the parameters investigated. The percentages of gamma/delta TCR+CD3+ lymphocytes and CD3+, CD16/56+CD3+, and natural killer (NK) cells were analyzed by the three-color flow cytometry using a Coulter EPICS XL cytometer. In patients with untreated GD, we observed a significant decrease in gamma/delta T (CD3+) (p < 0.002), CD16/56(CD3+) (p < 0.001), and NK (p < 0.001) cells in comparison with the healthy control subjects. After 2-6 mo of methimazole therapy, the percentages of gamma/delta TCR+CD3+ and CD16/56(CD3+) cells in peripheral blood of hyperthyroid patients returned to the normal values, whereas the percentages of NK cells normalized after 18-24 mo of therapy. These abnormalities were absent in children and adolescents with NTNG. Furthermore, there was no difference in the percentage of CD3+ lymphocytes in all of the groups. In the patients with untreated GD, we found a negative correlation between free thyroxine concentration in blood serum and the percentages of CD16/56 (CD3-) and gamma delta T cells (r = -0.5, p < 0.035; r = -0.4, p < 0.02). No such correlation was detected in patients with NTNG. We conclude that the abnormal distribution of CD16/CD56 (CD3- and CD3+) cells and gamma/delta T lymphocytes in the peripheral blood in children and adolescents with untreated GD suggests their role in the development of autoimmunity.     

Increased enoxaparin dosing is required for obese children

Weight-based dosing for enoxaparin is recommended in the 2008 American College of Chest Physicians (ACCP) guidelines for venous thromboembolism (VTE) prophylaxis. Enoxaparin 0.5 mg/kg per dose administered subcutaneously every 12 hours is recommended for this indication in children. There is no established upper dosing limit of enoxaparin for prophylaxis in children, and the US Food and Drug Administration-approved enoxaparin dose for adults for VTE prophylaxis is 30 mg subcutaneously every 12 hours or 40 mg subcutaneously daily. Therefore, we assumed that the upper limit for children is 40 mg subcutaneously daily. We reviewed 3 cases of obese adolescent boys who required large doses of enoxaparin to achieve the ACCP-recommended anti-factor Xa range of 0.1 to 0.3 IU/mL for the prevention of VTE. All 3 patients required doses of enoxaparin that are higher than that recommended for adults for VTE prophylaxis: patient A (BMI: 105.9) required >0.28 mg/kg per dose, patient B (BMI: 95.7) required 0.15 mg/kg per dose, and patient C (BMI: 29.9) required 0.49 mg/kg per dose. The desired anti-factor Xa range was achieved when enoxaparin was administered every 12 hours in each patient with no reported episodes of VTE. One patient had minor bruising, but no other adverse events were noted. Because of the variability in dose requirements and unpredictability in patient responses demonstrated in our 3 adolescents, prospective studies are needed to provide definitive recommendations on dosing of enoxaparin for VTE prophylaxis in this subset of obese pediatric patients.     

Low-molecular-weight heparin in thrombotic disease in children and adolescents

PURPOSE: The use of unfractionated heparin (UFH) in children is problematic. In adults, subcutaneous low-molecular-weight heparin (LMWH) is as effective as UFH in the treatment of thrombosis. Because pediatric data are limited, the authors studied the use of enoxaparin in children. PATIENTS AND METHODS: Nineteen children (ages 18 days to 19 years; median age, 40 months) with indications for thrombosis treatment or prophylaxis were studied. Six patients (median age, 33 months), treated on a protocol that included pharmacokinetic studies, initially received enoxaparin 1 mg/kg subcutaneously every 12 hours; doses then were adjusted until target plasma levels of 0.5 to 1.2 anti-Xa U/mL were achieved. The records of 13 additional patients treated with enoxaparin off study were reviewed. RESULTS: In the first six patients, enoxaparin pharmacokinetics was found to be similar to that in adults; once targeted levels were achieved, these remained stable. Among all 19 subjects, 14 had treatment of active thrombosis and 5 underwent thrombosis prophylaxis. For treatment of thrombosis, enoxaparin 1 mg/kg initially was administered subcutaneously every 12 hours. Target anti-Xa levels were achieved with 0.55 to 1.5 mg/kg every 12 hours (mean, 0.98 mg/kg; median, 1.0 mg/kg) in 1 to 7 days (median, 1 day). All patients in the treatment group had clinical improvement within 2 to 5 days, and 12 had follow-up radiological studies that confirmed this. For prophylaxis, enoxaparin was given at 1 mg/kg subcutaneously every 24 hours. No new thrombi were clinically evident in this group. There was no major bleeding with enoxaparin; one patient had transient mild mucosal oozing. CONCLUSION: In this limited population, enoxaparin seems to be a safe, effective, and convenient alternative to UFH in children and adolescents. The adult therapeutic target range of 0.5 to 1.2 anti-Xa U/mL is readily achievable with a starting dose of 1 mg/kg every 12 hours in most children. Initial close monitoring with plasma anti-Xa activity should be done and doses adjusted to achieve target range, particularly in neonates. In the population of this study, enoxaparin seems as effective as UFH in the period immediately thrombotic episode. These results should be confirmed in the ongoing randomized trial comparing LMWH with UFH in children.     

Growth hormone treatment in 35 prepubertal children with achondroplasia: a five-year dose-response trial

BACKGROUND: Achondroplasia is a skeletal dysplasia with extreme, disproportionate, short stature. AIM: In a 5-y growth hormone (GH) treatment study including 1 y without treatment, we investigated growth and body proportion response in 35 children with achondroplasia. METHODS: Patients were randomized to either 0.1 IU/kg (n = 18) or 0.2 IU/kg (n = 17) per day. GH treatment was interrupted for 12 mo after 2 y of treatment in prepubertal patients to study catch-down growth. Mean height SDS (HSDS) at start was -5.6 and -5.2 for the low- and high-dose groups, respectively, and mean age 7.3 and 6.6 y. RESULTS: Mean growth velocity (baseline 4.5/4.6 cm/y for the groups) increased significantly by 1.9/3.6 cm/y during the first year and by 0.5/1.5 cm/y during the second year. During the third year, a decrease of growth velocity was observed at 1.9/1.3 cm/y below baseline values. HSDS increased significantly by 0.6/0.8 during the first year of treatment and in total by 1.3/1.6 during the 5 y of study. Sitting height SDS improved significantly from -2.1/-1.7 to -0.8/0.2 during the study. Body proportion (sitting height/total height) or arm span did not show any significant change. CONCLUSION: GH treatment of children with achondroplasia improves height during 4 y of therapy without adverse effect on trunk-leg disproportion. The short-term effect is comparable to that reported in Turner and Noonan syndrome and in idiopathic short stature.     

Leucine kinetics during simultaneously administered insulin and dexamethasone in preterm infants with severe lung disease

The objective of this study was to determine whether insulin administration would prevent the well-documented catabolic effect of dexamethasone given to preterm infants with chronic lung disease. We studied leucine metabolism in 11 very-low-birth-weight infants before dexamethasone treatment and on d 2, 4, and 7 thereafter. During the first 4 d of dexamethasone, insulin was administered i.v. at a dose of 0.5 (n = 7) or 1.0 (n = 5) IU/kg/d. Leucine turnover was not significantly different between d 0 (337 +/- 41.3 micromol leucine/kg/h), d 2 (288 +/- 27.2 micromol leucine/kg/h), d 4 (302 +/- 22.1 micromol leucine/kg/h), and d 7 (321 +/- 21.2 micromol leucine/kg/h), and neither was leucine breakdown (272 +/- 21.9 micromol leucine/kg/h on d 0, 225 +/- 21.5 micromol leucine/kg/h on d 2, 231 +/- 21 micromol leucine/kg/h on d 4, and 242 +/- 17.6 micromol leucine/kg/h on d 7). Weight gain rates were significantly lower during the first week of dexamethasone treatment compared with the week before treatment or the second and third week. We conclude that during insulin and corticosteroid administration in very-low-birth-weight infants, no changes were observed in leucine kinetics in contrast to previous studies. The decrease in weight gain was not reversed.     

d-Alpha-tocopheryl polyethylene glycol-1000 succinate enhances the absorption of vitamin D in chronic cholestatic liver disease of infancy and childhood.

Rickets and osteopenia, common problems in chronic childhood cholestasis, have been attributed to vitamin D malabsorption leading to reduced serum levels of 25(OH)-vitamin D. d-alpha-Tocopheryl polyethylene glycol-1000 succinate (TPGS), a water-soluble form of vitamin E, forms micelles at low concentration. We evaluated the potential role of TPGS in enhancing vitamin D absorption in eight children (aged 5 mo to 19 y) with severe chronic cholestasis (three extrahepatic biliary atresia, three nonsyndromic intrahepatic cholestasis, and two Alagille syndrome). To evaluate vitamin D absorption, the subjects received vitamin D3 1000 IU/kg (maximum dose of 50,000 IU); they then received the same dose of vitamin D3 mixed with TPGS (25 IU/kg). Serial serum vitamin D3 levels and areas under the curve were measured. All patients had enhanced absorption of vitamin D when it was administered in a mixture with TPGS. Mean area under the curve for serum vitamin D3 was 403.0 +/- 83.1 nmol x h/L (155.6 +/- 32.1 ng x h/mL), with a mean rise above baseline of 13.5 +/- 1.8 nmol/L (5.2 +/- 0.7 ng/mL) with vitamin D/TPGS compared with no rise when vitamin D was given alone (both p less than 0.001). Seven patients have been followed for at least 3 mo while receiving the vitamin D/TPGS combination. Those with initially low serum 25(OH)-vitamin D levels (less than 37.5 nmol/L or 15 ng/mL) had normalization (range 37.5-146 nmol/L) within 1 mo, whereas those with initially normal levels remained normal. While the patients were receiving vitamin D/TPGS, serum vitamin E to total lipid ratio either normalized or remained normal.(ABSTRACT TRUNCATED AT 250 WORDS)     

Portal vein thrombosis in a patient with severe haemophilia A and F V G1691A mutation during continuous infusion of F VIII after intramural jejunal bleeding - Successful thrombolysis under heparin therapy

We report on a 14-year-old boy with severe haemophilia A who developed a portal vein thrombosis during continuous infusion of F VIII. For treatment of a posttraumatic intramural jejunal haematoma with extension into the mesenterium the patient received continuous infusion (CI) of a high purity F VIII concentrate, starting with an initial bolus injection of 100 IU F VIII/kg bw and followed by 4-5 IU F VIII/kg bw/h i.v. F VIII plasma activity ranged between 47 and 88%. Resorption of the haematoma was proven by abdominal ultrasonic follow-ups. After 3 weeks of CI a thrombus formation in the portal vein was detected by ultrasound and confirmed by duplex ultrasound. Subsequent to diagnosis the patient was heparinised with unfractionated heparin (UFH 300-450 IU/kg/d i.v.). In order to induce further resorption of the haematoma, F VIII concentrate was given concomitantly (50 IU/kg bw twice daily) during the initial phase of treatment. After 14 days of anticoagulant therapy with UFH, the regimen was changed to low molecular weight heparin (LMWH; Fraxiparin 0.3™; 2850 IU anti-X activity/d s.c.; bw 60 kg). F VIII dosage was gradually reduced with advanced resorption of the haematoma and thereafter switched to prophylaxis (40 IU/kg bw 3 times weekly). Complete lysis of the thrombus was observed after 6 months of treatment with UFH and LMWH respectively without any further complications. Thereafter LMWH was discontinued. Thrombophilic screening revealed no abnormalities except heterozygous F V G1691A. Conclusion The coexistence of a common prothrombotic risk factor and haemophilia may cause severe complications, in particular if the bleeding disorder has to be corrected temporarily by administration of the concerning deficient agent.     

Amphotericin B lipid complex in pediatric patients with invasive fungal infections.

BACKGROUND: Lipid formulations of amphotericin B have been recently introduced for treatment of invasive fungal infections. However, little is known about their role in pediatric populations. METHODS: We studied the safety and antifungal efficacy of amphotericin B lipid complex (ABLC, Abelcet) in 111 treatment episodes in pediatric patients through an open label, emergency use multicenter study. Patients with invasive fungal infections were enrolled if they had mycoses refractory to conventional antifungal therapy, if they were intolerant of previous systemic antifungal agents or concomitant nephrotoxic drugs or if they had preexisting renal disease. RESULTS: All 111 treatment episodes were evaluable for safety and 54 were evaluable for efficacy. The mean serum creatinine for the study population did not significantly change between baseline (1.23 +/- 0.11 mg/dl) and cessation of ABLC therapy (1.32 +/- 0.12 mg/dl) during 6 weeks. There were no significant differences observed between initial and end-of-therapy levels of serum potassium, magnesium, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and hemoglobin. However, there was an increase in mean total bilirubin (3.66 +/- 0.73 to 5.31 +/- 1.09 mg/dl) at the end of therapy (P = 0.054). Among 54 cases fulfilling criteria for evaluation of antifungal efficacy, a complete or partial therapeutic response was obtained in 38 patients (70%) after ABLC therapy. Complete or partial therapeutic response was documented in 56% of cases with aspergillosis (n = 25) and in 81% (n = 27) with candidiasis. Among premature infants (n = 8) and allogeneic marrow recipients (n = 14), response rates were 88 and 57%, respectively. Response was similar in those patients enrolled because of intolerance to previous antifungal therapy or because of progressive infection. CONCLUSIONS: These data support the use of ABLC for treatment of invasive fungal infections in pediatric patients who are intolerant of or refractory to conventional antifungal therapy.     

Experience with intravenous enoxaparin in critically ill infants and children

OBJECTIVE: Subcutaneous administration of enoxaparin is often difficult in special populations, such as premature infants and critically ill children with severe edema. The difficulty achieving adequate anticoagulation in these patients has led to the employment of intravenous enoxaparin in some cases. However, little pharmacodynamic data are available for determining the appropriate dosing and monitoring (by anti-Factor Xa levels) of intravenous enoxaparin. The objective of this study is to report our experience with the use of intravenous enoxaparin in pediatric patients in the intensive care unit. DESIGN: Retrospective review of medical records. SETTING: Single institution pediatric intensive care unit. PATIENTS: All pediatric patients receiving intravenous enoxaparin in the pediatric intensive care unit at Children's Medical Center Dallas between April 1, 2005 and March 31, 2006 were identified using hospital pharmacy records. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Seven patients were identified as having received intravenous enoxaparin while in the intensive care unit. Higher anti-Xa levels were found at 1-2 hrs after administration of intravenous enoxaparin rather than at the 4-6 hrs documented with subcutaneous administration and these levels decreased substantially 6-8 hrs after an intravenous dose. Mean therapeutic dose for children <1 yr of age was 2.40 mg/kg/dose (+/-sd 0.58). For children > or =1 yr of age, the mean therapeutic dose was 1.11 mg/kg/dose (+/-sd 0.13). The mean prophylactic dose for the two children was 0.93 mg/kg/dose (+/-sd 0.43). CONCLUSIONS: Our data show that the pharmacodynamics of intravenous administration is different from subcutaneous administration and deserves further study.     

Use of Low-Dose Ketamine and/or Midazolam for Pediatric Cardiac Catheterization

Ketamine and midazolam are commonly used in children undergoing cardiac catheterization. However, there is controversy regarding the safety of administering these agents in the absence of an anesthesiologist. We retrospectively reviewed pediatric cardiac catheterization procedures at our institution between 1996 and 1997. A total of 154 patients (0.3-192 months) underwent a total of 205 procedures. They received ketamine (n = 79, 1.05 +/- 0.88 mg/kg/hr), midazolam (n = 35, 0.14 +/- 0.09 mg/kg/hr), or both (n = 91; ketamine, 1.13 +/- 0.84 mg/kg/hr; midazolam, 1.57 +/- 1.03 mg/kg//hr). In 18.5% of patients there were complex cardiac lesions. Mean procedure time was 79 +/- 36.2 minutes. Pre- and postprocedure systolic and diastolic mean blood procedure 72 +/- 14 and 68 +/- 12 mmHg, respectively. Pre- and postprocedure O2 saturation was 93.19 +/- 8.72 and 93.63 +/- 8.3, respectively. One patient required intubation, and 15% required oxygen therapy. The mortality rate was zero. The anesthesiologist's assistance was requested by the cardiologist in 21 procedures (group A) and not requested in 184 procedures (group B). The two groups were not different in relation to the drug used (p = 0.283) or the complexity of the cardiac lesions (p = 0.051). However, there was significant difference between the two regarding the need for supporting drugs (3/21 vs 3/184, p = 0.02) or oxygen treatment (7/21 vs 26/184, p = 0.014). No patients in group B required intubation, whereas 14% and 1.6% required oxygen therapy and supporting drugs, respectively. We conclude that low-dose ketamine and midazolam can be administered safely to most pediatric patients by the cardiologist, who can safely predict the need for an anesthesiologist.     

Birth weight rather than maternal nutrition influences glucose tolerance,blood pressure,and IGF-I levels in sheep

Both small size at birth in humans and maternal undernutrition in experimental animals are associated with impaired glucose tolerance and increased blood pressure in the adult offspring. However it is not clear whether maternal undernutrition in late gestation can influence postnatal phenotype, and whether this might occur independent of size at birth. We severely undernourished pregnant ewes for 10 d (UN10) or 20 d (UN20) from 105 d gestation (term = 146 d) and studied the offspring in comparison to those born to ad libitum fed ewes (AL20). Glucose tolerance tests and blood pressure recordings were performed at 5 mo of age and repeated at 30 mo together with insulin tolerance tests and GH challenges. UN20 lambs were lighter at birth (UN20, 4.9 +/- 0.1 kg, n = 23; UN10, 5.3 +/- 0.1 kg, n = 26; AL20, 5.6 +/- 0.2 kg, n = 26) but not from weaning onward. Plasma glucose area under the curve at 5 mo and plasma insulin at 30 mo increased with current weight and decreased with increasing birth weight. Blood pressure also increased with current weight and decreased with increasing birth weight at 5 but not 30 mo. Plasma IGF-I concentrations increased with current weight at all ages and decreased with increasing birth weight at 30 mo. Plasma insulin response to GH challenge increased with current weight. Nutrition group was not related to any of the outcomes measured when birth weight and current weight were taken into account. These data suggest that size at birth is more closely related to processes that determine postnatal phenotype than is maternal nutrition in late gestation.     

Single dose pharmacokinetics of linezolid in infants and children

BACKGROUND: Linezolid is an oxazolidinone antibiotic with excellent in vitro activity against a number of Gram-positive organisms including antibiotic-resistant isolates. The safety and pharmacokinetics of intravenously administered linezolid were evaluated in children and adolescents to examine the potential for developmental dependence on its disposition characteristics. METHODS: Fifty-eight children (3 months to 16 years old) participated in this study; 44 received a single 1.5-mg/kg dose and 14 received a single 10-mg/kg dose of linezolid administered by intravenous infusion. Repeated blood samples (n = 10 in children > or = 12 months; n = 8 in children 3 to 12 months) were obtained during 24 h after drug administration, and linezolid was quantitated from plasma by high performance liquid chromatography with mass spectrometry detection. Plasma concentration vs. time data were evaluated with a model independent approach. RESULTS: Linezolid was well-tolerated by all subjects. The disposition of linezolid appears to be age-dependent. A significant although weak correlation between age and total body clearance was observed. The mean (+/- SD) values for elimination half-life, total clearance and apparent volume of distribution were 3.0 +/- 1.1 h, 0.34 +/- 0.15 liter/h/kg and 0.73 +/- 0.18 liter/kg, respectively. Estimates of total body clearance and volume of distribution were significantly greater in children than historical values of adult data. As such maximum achievable linezolid plasma concentrations were slightly lower in children, and concentrations 12 h after a single 10-mg/kg dose were below the MIC90 for selected pathogens with in vitro susceptibility to the drug. CONCLUSION: Based on these data a linezolid dose of 10 mg/kg given two to three times daily would appear appropriate for use in pediatric therapeutic clinical trials of this agent.     

Comparison of polyclonal induction agents in pediatric renal transplantation

Collective pediatric data suggest that anti-T-cell induction therapy with polyclonal antibodies improves the outcome of both short- and long-term renal allograft survival. Polyclonal agents, including thymoglobulin (Thy), a rabbit anti-thymocyte globulin; Minnesota (horse) anti-lymphoblast globulin (ALG); and ATGAM, a horse anti-thymocyte globulin (ATG), all suppress B and T cells. While no specific T-cell subset marker exists to measure the adequacy of immunosuppression with polyclonal induction, flow cytometric analysis has been used to evaluate the suppression of CD3, CD4, and CD8 cells. Thy is currently undergoing pediatric trials at our center, and we have utilized ATG and ALG in previous pediatric induction protocols. ALG (20 mg/kg/day) and ATG (15 mg/kg/day) were administered over 10 days, whereas Thy (2 mg/kg/day) was given over 5 days. All inductions were accompanied by preoperative intravenous solumedrol (10 mg/kg) followed by oral prednisone (2 mg/kg/day) with taper. Preoperative (1.5 mg/kg/day) and post-operative (2 mg/kg/day) azathioprine was administered to patients receiving ALG or ATG. Mycophenolate mofetil (MMF) (1200 mg/m2/day) was given to the patients receiving Thy. Post-operative cyclosporin A (CsA) (14 mg/kg/day) was started (for all groups) once renal function permitted (creatinine < 50% of baseline with brisk urine output) (trough goal 150-250 ng/mL via HPLC). Values for CD3, CD4, and CD8 T cells were determined by flow cytometry in 2-18-yr-old renal transplant recipients, comparing the polyclonal induction agent utilized [Thy (n = 8), mean age 9.7 +/- 2.3 yr; ATG (n = 13), mean age 10.1 +/- 4.1 yr; and ALG (n = 9), mean age 9.3 +/- 3.7 yr] over days 2-10 post-induction. Data were expressed as the average percentage of cells remaining relative to the baseline T-cell subsets (day 1 = 100%), because of the large age variation present in basal T-cell subset values. The flow cytometric data suggest that 5 days of Thy appears to give an equal or greater peripheral blood T-cell suppression by day 10 than a 10-day course of either ATG or ALG.     

胶囊内镜在青少年患儿中的应用

目的评估胶囊内镜对疑似患有小肠疾病的儿童患者检查的安全性和有效性。方法2002年8月至2005年5月,连续选择我院15例疑似小肠疾病的儿童和青少年患儿(18岁以下)进行胶囊内镜检查。年龄3～18岁,其中5例患儿年龄小于10岁;体重17～83 kg;身高49～176 cm。检查适应证包括不明原因消化道出血(12例)和腹痛(3例)。本组患儿胶囊内镜检查前胃镜和大肠镜检查结果均阴性。检查结束后分别记录胶囊内镜的置入方法、胃内通过时间、小肠通过时间、胶囊平均排出体外时间、诊断结果和并发症发生的情况。结果除3例最年幼者外,所有患儿均能顺利吞服胶囊。该3例患儿最后经胃镜辅助顺利将胶囊送至胃内。检查期间无1例出现胶囊滞留等并发症。胶囊内镜平均检查时间为(464±40)min。15例中共5例至检查结束胶囊尚未到达回盲瓣。胶囊内镜平均胃内通过时间为(85±90)min,平均小肠通过时间为(283±106)min,平均排出时间为(34.3±21.8)h。胶囊内镜的病变检出率为80%。结论对于儿童患者,胶囊内镜检查(吞服或经胃镜送入)安全可行,其较高的病变检出率与成人患者相似。     

Energy substrate utilization in infants receiving total parenteral nutrition with different glucose to fat ratios

As the fate of glucose and lipids infused during total parenteral nutrition is not well known in infants, we assessed energy substrate oxidation in 36 patients (mean age: 5.8 +/- 3.6 mo) on continuous total parenteral nutrition. The infants received isocaloric feeding regimens with nonprotein energy intakes either based on glucose alone (group 1) or on glucose-lipid mixtures providing 15% (group 2), 35% (group 3), 50% (group 4), or 70% (group 5) energy as fat for at least 6 d before glucose and fat oxidation rates were measured by open-circuit indirect calorimetry. Oxidative glucose disposal reached a maximal rate of 12.6 +/- 1.2 mg/kg.min (17.9 +/- 1.7 g/kg.d) in patients with the higher glucose infusion rates. Glucose infused in excess of maximal oxidative disposal was stored, mainly as fat. The increase in glucose infusion rate was paralleled by an increase in energy expenditure amounting to 16% of the energy value of infused glucose. Net fat oxidation was only observed in group 3 (1.6 +/- 0.7 g/kg.d), 4 (3.4 +/- 0.6 g/kg.d), and 5 (3.9 +/- 0.4 g/kg.d) patients, with glucose infusion rates lower than 18.3 g/kg.d. However, there was no further increase in fat oxidation in group 5 as compared to group 4 patients, despite a further increase in fat intake, which only resulted in increasing fat deposition. Thus, fat infusion aiming at a significant contribution to coverage of energy expenditure requires that glucose oxidation be equal to or lower than maximal oxidative glucose disposal, hence that glucose infusion rates be lower than 18 g/kg.d.(ABSTRACT TRUNCATED AT 250 WORDS)     

Omeprozole therapy in pediatric patients after liver and intestinal transplantation

BACKGROUND: Proton pump inhibitors such as omeprazole are increasingly used to prevent stress-related gastric bleeding in critically ill patients. In this investigation, the acid-suppressive potency of omeprazole was assessed in one at-risk group, pediatric patients undergoing liver or intestinal transplantation, or both. METHODS: Twenty-two patients ranging in age from 0.9 to 108 months (23.8 +/- 6.5) underwent isolated liver (n = 10) or intestinal (11 with composite liver allografts) transplantation. Omeprazole was delivered in bicarbonate suspension through a nasogastric tube. Therapy was started after surgery at 0.5 mg/kg every 12 hours. Gastric pH monitoring was performed approximately 2 days later. RESULTS: For the entire group, mean gastric pH equaled 6.1 +/- 0.3, the same in recipients of isolated liver and intestinal allografts. Twelve of the 22 patients demonstrated a discontinuous omeprazole effect, that is, dissipation of acid reduction before the next dose. Five of the 12 patients with discontinuous omeprazole effect had mean gastric pH of less than 5 (3.9 +/- 0.4). In 4 of these 5, the omeprazole dosing interval was shortened to every 8 or every 6 hours, resulting in an increase in mean pH to 6.6 +/- 0.2 ( P < 0.01). In the remaining 10 of 22 patients, acid suppression was uninterrupted until the next dose. No patient experienced bleeding attributable to gastric erosion. CONCLUSION: Omeprazole suspended in sodium bicarbonate is an effective acid-suppressing agent in pediatric recipients of liver or intestinal transplant, or both. A dosage of 0.5 mg/kg every 12 hours is sufficient for most patients, but dosing every 6 to 8 hours is required to assure maximal acid suppression in all.