Minimum effective dose of midazolam for sedation of mechanically ventilated neonates.

OBJECTIVE: To determine the minimal effective dose (MED) of intravenous midazolam, required for appropriate sedation in 95% of patients, 1 h after drug administration. METHODS: A double-blind dose-finding study using the continual reassessment method, a Bayesian sequential design. Twenty-three newborn infants hospitalized in intensive care unit participated. Inclusion criteria were: (i) post-natal age <28 days, (ii) gestational age >33 weeks, (iii) intubation and ventilatory support required for respiratory distress syndrome, (iv) need for sedation (i.e. one of the six following criteria: agitation or grimacing or crying facial expression before tracheal suctioning, agitation or grimacing or crying facial expression during tracheal suctioning). Each neonate was allocated to a loading dose, ranging from 75 to 200 microg/kg, and a maintenance dose ranging from 37.5 to 100 microg/kg/h. RESULTS: The primary endpoint was the level of sedation 1 h after the onset of infusion. The sedation procedure was classified as a success if all the following clinical criteria were met: no agitation, no grimacing and no crying facial expression before as well as during tracheal suctioning. Based on the 23 patients, the final estimated probability of success was 76.9% (95% credibility interval: 56.6-91.4%) for the 200 microg/kg loading dose. no significant adverse effect was observed. CONCLUSIONS: Continual reassessment is a new approach, suitable for dose-finding study in neonates. this method overcomes some of the ethical, statistical and practical problems associated with this population. Using this method, the MED was estimated to be the 200 mug/kg loading dose of midazolam.

[Use of a polyethylene bag: a way to improve the thermal environment of the premature newborn at the delivery room]. / Utilisation d'un sac en polyéthylène: un moyen d'améliorer l'environnement thermique du prématuré en salle de naissance.

BACKGROUND: Early interventions, such as occlusive wrapping of very low birth weight infants at delivery reduce postnatal temperature fall. This new intervention was implemented in our hospital on January 2000. The aim of this study was to investigate retrospectively the effect of polyethylene wrap, applied immediately at birth, on thermoregulation. PATIENTS AND METHODS: Matched pair analysis was conducted for 60 infants delivered inborn at less than 33 weeks' gestation and 60 premature infants who were born during the second half of 1999 fulfilling the same criteria. The only difference in the management (medical and environmental) was wrapping with a polyethylene bag in the delivery room. Rectal temperature and other vital parameters were taken, after removal of wraps, on admission to NICU. RESULTS: The perinatal characteristics of both groups were comparable. Use of wrapping resulted in a significantly higher admission rectal temperature (difference in means = 0.8 degree C, p < 0.0001), this difference was also significant in infants < 30 weeks. The incidence of hypothermia (< 35.5 degrees C) was less frequent in infants enclosed in plastic bags (8.3% vs 55%). No side effects (skin burns, infection or hyperthermia) were attributable to the intervention. The heart rate was higher in the wrapping group (163 +/- 16 vs 150 +/- 17 b/min, p < 0.01), as well as the capillary glycemia (62 +/- 26 vs 45 +/- 30 mg/dl, p < 0.01). There was no significant difference on arterial pressure. CONCLUSION: Occlusive wrapping with a polyethylene bag at birth prevented low rectal temperature in premature infants in the immediate postnatal period. This method is easy, practical and effective, and does not interfere with current practice for resuscitation.

Combined nutritional support and continuous extracorporeal removal therapy in the severe acute phase of maple syrup urine disease.

OBJECTIVE: The authors assessed the efficiency, tolerance and outcome of neonates and children with maple syrup urine disease (MSUD) in acute decompensation managed by endogenous and extracorporeal removal of accumulated MSUD metabolites. DESIGN: Single center cohort study. SETTING: Pediatric and neonatal intensive care unit in a tertiary care hospital. PATIENTS: Between January, 1991, and June, 1999, six neonates and six children in acute decompensation of MSUD were included in the study. Each of them had two of the three following criteria: comatose state, gastrointestinal intolerance, leucine plasma levels over 1700 micromol/l. INTERVENTIONS: Patients were treated by combined nutrition manipulation and continuous venovenous extracorporeal removal therapies (CECRT) including hemofiltration, hemodialysis or hemodiafiltration. A clinical and biological evaluation was performed before, during and following the treatment. RESULTS: Eleven out of the 12 patients survived. One child had two acute episodes at 6.5 and 9 years old. Eight patients recovered a normal cerebral performance category score. In all cases, plasma leucine level decreased according to a logarithmic mode within 11-24 h hemodiafiltration combined with nutritional support whereas, with nutrition alone after stopping CECRT, the decrease in leucine plasma levels was slower, following a linear mode. Eight patients were supplemented with valine and isoleucine for mean plasma values of 177+/-92 and 68+/-66, respectively. CONCLUSION: In severe acute decompensation of MSUD, CECRT combined with nutritional support limit central nervous system damage, by dramatically decreasing branched chain amino and keto acid levels.

Continuous venovenous hemodialysis in a neonate model: a two-pump system.

OBJECTIVE: To evaluate the efficiency and tolerance of venovenous hemofiltration, hemodiafiltration, and hemodialysis with a two-pump system in a neonatal animal model of acute renal failure. DESIGN: Prospective trial. SETTING: Animal laboratory at a large university-affiliated medical center. SUBJECTS: New Zealand white rabbits, weighing 3325 +/- 380 g. INTERVENTIONS: Venovenous hemofiltration, hemodiafiltration, and hemodialysis were performed in anesthetized rabbits with previous bilateral ureteral ligation. MEASUREMENTS AND MAIN RESULTS: At a blood flow rate of 19 +/- 0.5 mL/min, we determined hematocrit, urea, creatinine, and electrolyte values in blood, at the inlet and outlet of the hemofilter, and in ultrafiltrate at the start and after 15, 30, 60, 90, 120, and 180 mins of hemofiltration (ultrafiltrate flow rate of 1.9 +/- 0.2 mL/min), hemodiafiltration (dialysate plus ultrafiltrate flow rate of 16.9 +/- 0.8 mL/min), and hemodialysis (dialysate flow rate of 15.7 +/- 1.1 mL/min). Arterial blood pressure, heart rate, and body temperature were monitored during the procedures. Urea and creatinine instantaneous clearances were higher with hemodiafiltration (8.0 +/- 0.7 and 6.2 +/- 0.7, respectively, n = 29) and hemodialysis (6.8 +/- 1.1 and 4.8 +/- 0.9, respectively, n = 31) than with hemofiltration (1.8 +/- 0.6 and 1.9 +/- 0.4, respectively, n = 16). Initial and final weights, temperatures, and hematocrit, sodium, and protein blood concentrations of each 180-min procedure were similar. CONCLUSIONS: Hemodiafiltration had a higher urea removal rate than hemodialysis but the management of hemodiafiltration was more cumbersome and time consuming in the absence of a flow equalizer device. As a result, we recommend continuous venovenous hemodialysis as the therapy of choice.

[Unusual localization of an olfactory esthesioneuroma]. / Localisation exceptionnelle d'un esthésioneurome olfactif.

Olfactory neuroblastoma, a nerve tumour arising in the olfactory mucosa, is a relatively easy diagnosis in the case of a mass centered around the cribriform plate. It is more difficult to diagnose in its exceptional ectopic forms (maxillary sinus) in the absence of any cytological and histochemical arguments (fibrils, olfactory rosettes). Its local malignancy is variable with a 42% 5-year survival for stage C and metastases in 30% of cases (principally cervical nodes, bone and liver). The role of imaging is to define the criteria of a mass syndrome and to perform the preoperative staging in a case of apparently simple sinus obstruction.

[Magnetic resonance imaging of neurofibromatoses]. / Imagerie par résonance magnétique des neurofibromatoses.

Neurofibromatosis is classified into two types. Type 1, NF1 or von Recklinghausen's disease, consists of skin and bone lesions as well as central nervous system tumours arising at the expense of glial tissue: optic tract gliomas, glioblastomas, astrocytomas and "hamartomas". Type 2 consists almost exclusively of CNS tumours arising at the expense of nerve envelopes: Schwannomas, meningiomas.