The use of midazolam in diagnostic and short surgical procedures in children.

A new technique of sedation for children is described, in which midazolam (0.2 mg.kg-1) was administered topically by the nasal route, followed by ketamine (9.0 mg.kg-1) administered rectally in 32 patients breathing air spontaneously. Sedation was good in 23, seven required further ketamine (1.0 mg.kg-1 i.v.), and in two, halothane was introduced. There was no evidence of severe respiratory depression except during oesophagoscopy. Cardiovascular stability was excellent. Of 21 patients over 5 years old, 19 developed complete and two partial anterograde amnesia for the administration of ketamine and surgery. The major complications were nausea and vomiting (five patients) and salivation (eight patients). The mean recovery time was 40 min (s.d. 33 min). It provided a relatively safe, adaptable, non-invasive method of inducing sedation in children.

[Hormonal changes induced by etomidate in children during the first 24 postoperative hours]. / Modifications hormonales induites par l'étomidate chez l'enfant pendant les 24 premières heures postopératoires.

The hormonal effects of an etomidate infusion were assessed postoperatively in children undergoing hypospadias or clubfoot repair. The study was carried out in 12 children, aged between 9 and 70 months, randomly assigned to two equal groups. The anaesthetic protocol was identical for all the children, consisting in a light general anaesthesia (halothane induction, intubation after 60 to 80 micrograms.kg-1 vecuronium) combined with lumbar epidural anaesthesia (initial dose of 0.75 ml.kg-1 bupivacaine with adrenaline, with repeat injections of half the previous dose when there was a change in the haemodynamic parameters suggesting inadequate analgesia). Anaesthetic maintenance was different in both groups: 1 to 1.5 vol% enflurane in a nitrous oxide-oxygen mixture (1/1 v/v) in the control group, and 16.8 +/- 3.0 mg.kg-1.min-1 etomidate infusion in the etomidate group. Venous blood samples were collected after induction of anesthesia (before starting the epidural anaesthesia and the etomidate infusion), at the end of surgery (H0), at the 3rd (H3), 6th (H6), 12th (H12) and 24th h (H24) following surgery. The following hormonal blood concentrations were measured: cortisol, 11 beta-desoxycortisol, aldosterone, 11 beta-desoxycorticosterone, dehydroepiandrosterone (DHA) and DHA sulphate (DHA-S). In the control group, cortisol and DHA-S concentrations decreased significantly at H0, aldosterone levels also being significantly lower at H24. In the etomidate group, cortisol concentrations remained significantly lower at H0, H3 and H6; aldosterone concentrations were also significantly lower than control values throughout the study period. There was an important prolonged rise in the concentrations of their precursors. DHA and DHA-S concentrations did not change in the etomidate group.(ABSTRACT TRUNCATED AT 250 WORDS)

Bupivacaine pharmacokinetics during epidural anaesthesia in children.

Blood concentrations and pharmacokinetic parameters of bupivacaine were measured after epidural injection in children aged from 1 to 7 years. The children were allocated to two groups. In Group 1 (five children), pharmacokinetic parameters were measured after a single bolus injection of bupivacaine 0.25% with adrenaline 1:200,000. In Group 2 (eight children), pharmacokinetic parameters were measured after the initial injection and the second injection. The same local anaesthetic was used. The volume of the second injection was half of the initial volume. In children of Group 1, maximum mean concentration (CPmax) was 0.64 +/- 0.05 microgram ml-1, time to maximum concentration (Tmax) 19.2 +/- 3.9 min, vascular absorption (T1/2 abs) 4.3 +/- 1.5 min, terminal half-life (T1/2 beta) 227 +/- 37.7 min, volume of distribution (Vd) 3.4 +/- 0.51 kg-1, and total body clearance (Clt) 11.0 +/- 2.0 ml min-1 kg-1. When compared to an adult's pharmacokinetic parameters, both Vd and Clt were increased, so that T1/2 beta remained essentially unchanged. In children of Group 2, the first repeat injection was performed at 110 +/- 6.9 min. Mean CPmax increased significantly (20% after the second injection), whereas the values of the pharmacokinetic parameters measured did not differ significantly from those measured in children in Group 1. The results obtained in the present study demonstrate that the pharmacokinetic parameters of bupivacaine in children do not differ markedly from those reported in adults and that in the recommended dosage, the mean maximum concentrations, even after the second injection, are less than the presumed toxic levels.

Continuous extradural anaesthesia in children. Clinical and haemodynamic implications.

This study reports the experience of a department of paediatric anaesthesia with 234 continuous extradural anaesthetics performed in 229 children over a 15-month period. Fifty-nine of the children were aged 0-2 yr, 71 were aged 2-8 yr and 104 were older than 8 yr. The surgical procedures lasted more than 60 min (mean 150 +/- 10.6 min); all were carried out under light general anaesthesia. Technical procedure and difficulties are reported. The only local anaesthetic agent used was bupivacaine with or without adrenaline. Mean initial dosage was 0.75 ml kg-1 for children weighing less than 20 kg and 1 ml/10 cm of height for children taller than 100 cm. Using 0.25% bupivacaine mean times until a further injection were 92.0 +/- 2.0 min for bupivacaine with adrenaline and 71.0 +/- 2.5 min for bupivacaine without adrenaline (P less than 0.001). A much longer duration of analgesia was found for younger children using the solution with adrenaline. A haemodynamic study was performed in 74 unpremedicated children (ASA I; aged 0-2 yr (n = 15), 2-8 yr (n = 26) and older than 8 yr (n = 35). Before induction of anaesthesia, heart rate (HR) was significantly increased in the youngest children, but no significant change was found for systolic arterial pressure (SAP). After extradural anaesthesia with 0.25% bupivacaine with adrenaline 1:200000, minimal changes in HR or SAP occurred in children younger than 8 yr; in those older than 8 yr a significant decrease in both HR and SAP was observed. Changes in SAP were at their maximum 25 min after the extradural block and changes in HR were not statistically significant before the 25th min following injection of local anaesthetic. The catheter remained in place in 155 children for postoperative analgesia, mainly for the first 48 h.

Continuous epidural anaesthesia for major abdominal surgery in young children.

The benefits of epidural anaesthesia combined with general anaesthesia were studied in young children scheduled for major abdominal surgical procedure (pull-through for Hirschsprung's disease). Two groups of nine children were studied receiving, respectively, general anaesthesia or general anaesthesia plus epidural anaesthesia. In the group receiving both general and regional anaesthesia, a polyurethane 24 G catheter was inserted via a Tuohy needle 19 G into the lumbar epidural space after induction of anaesthesia and intubation and bupivacaine, 0.25%, was injected epidurally (mean initial volume 0.71 +/- 0.04 ml kg-1). No opiates were needed during operation on the children in this group. After epidural anaesthesia, heart rate decreased significantly but systolic blood pressure remained unchanged. During surgery mean values of both heart rate and systolic blood pressure were significantly lower in the regional analgesia group compared to the general anaesthesia group. The need for blood replacement was also significantly lower, whereas pre- and post-operative haematocrit values were not significantly different. Administration of fluid and electrolytes during operation was also similar in both groups. A combination of epidural and general anaesthesia avoids the use of opiates during surgery, provides excellent per- and post-operative analgesia, allows a rapid and safe recovery, and facilitates the nursing of young children.

[Severe neonatal myasthenia with arthrogryposis]. / Myasthénie néo-natale sévère avec arthrogrypose.

Two children born to myasthenic mothers presented at birth with severe arthrogryposis, hypotonia and respiratory distress which followed a favourable course. A family history in one of these two cases and in another case reported in the literature raises the problem of a possible recurrence.

Clinical pharmacology of vecuronium in children. Studies during nitrous oxide and halothane in oxygen anaesthesia.

Forty-seven children (ASA I or II) were studied during nitrous oxide-oxygen, halothane anaesthesia. The dose-response curve for vecuronium was determined after the injection of a single bolus (40, 55 or 70 micrograms kg-1) to 33 patients. The ED50 and ED95 were 31 and 64 micrograms kg-1 respectively. Fourteen children received a larger dose (100 micrograms kg-1); good intubating conditions were obtained in all of these within 2 min. After a single bolus (100 micrograms kg-1) the duration of action was 36.5 min and the recovery index was 9.3 min. In patients who received small maintenance doses (25 micrograms kg-1) after a single bolus (100 micrograms kg-1) the recovery index after the last maintenance dose was not increased. There were no significant changes in heart rate or arterial pressure. In children, vecuronium has a short duration of action and lacks cumulative or cardiovascular side affects.

[Controlled hypotension during posterior vertebral arthrodesis; value of an isoflurane-nitroglycerin combination]. / Hypotension contrôlée dans les arthrodèses vertébrales par voie postérieure, intérêt de l'association isoflurane-trinitrine.

Eighteen young patients (mean age +/- SD 15.9 +/- 3.3) scheduled for operative treatment of idiopathic scoliosis (posterior spine fusion) were studied during surgery. Deliberate hypotension (MAP less than 60 mm Hg) of long duration (greater than 2 hours) was induced using isoflurane and nitroglycerin. Hypotension was effective in less than 15 min in all patients. The mean inspiratory fraction of isoflurane employed was 2.04 +/- 0.19% for the first operative hour, and 1.36 +/- 0.20% for the second operative hour. The difference between these inspiratory fractions is highly significant (p less than 0.001), while the rate of nitroglycerin infusion was unchanged (3 micrograms X kg-1 X min-1). Heart rate increases significantly at H1 and H2 when compared to preinduction values and the product of heart rate X systolic blood pressure decreases significantly with a mean of 30% versus preinduction values. A satisfactory operative field was obtained in all cases. Blood loss was dependent of the duration of surgery, of the total blood volume of the patient, of the length of spine fusion. For each patient, a slope of blood loss was established. The mean slope was 3.74 +/- 0.39 ml X kg-1 X h-1. The determination of the slope at the end of the first operative hour allows us to predict the total blood loss during surgery. Intra operative awakening was obtained 22.8 +/- 3.7 min after isoflurane was discontinued. Isoflurane and nitroglycerin produce a stable and safe hypotension with no major hemodynamic disturbances. Isoflurane has to be discontinued 20 min before the wake-up test.

Changes in ventilatory patterns during halothane anaesthesia in children.

Changes in ventilatory variables (VE, VE, f, Tl/Ttot, VT/Tl, PE'CO2) were studied in 12 unpremedicated children, weighing between 10 and 20 kg, during halothane anaesthesia. At an inspired concentration of 0.5% halothane, respiratory rate increased, VT decreased, and VE did not change markedly. When the inspired halothane concentration increased further, there was a significant decrease in VE, mainly as a result of a marked decrease in VT. PE'CO2 increased significantly and inspiratory duty cycle decreased at high inspired halothane concentrations. On return to baseline (0.5% halothane), there was a significant decrease in inspiratory timing and a significant increase in PE'CO2. The relations between these changes and the effect of halothane on inspiratory muscles are discussed.

[Continuous peridural anesthesia in children less than 2 years old]. / Anesthésie péridurale continue chez l'enfant de moins de deux ans.

Continuous epidural anaesthesia was carried out in 23 children (age 13.9 +/- 6 months, weight 9.09 +/- 2.5 kg) scheduled for long surgical procedure (soft tissue release for club-foot, "pull-through" for Hirschsprung disease, various genito-urinary procedures). The lumbar epidural space was punctured under general anaesthesia with a 19 G Tuohy needle. A graduated 24 G polyurethane catheter was then inserted and fixed. The local anaesthetic used was bupivacaine 0.25% (0.71 +/- 0.02 ml X kg-1), with or without 1:200,000 adrenaline. Five and 10 min after injection of bupivacaine, heart rate was significantly decreased (p less than 0.05) when compared with pre-induction values, but systolic blood pressure did not change. No other haemodynamic changes occurred. Analgesia was sufficient in all but two cases at incision. Mean duration of surgical procedure was 143 +/- 9.2 min. The time of the first reinjection was significantly longer if bupivacaine with adrenaline was used (116 +/- 2.34 min), when compared with bupivacaine without adrenaline (68.9 +/- 3.92 min) (p less than 0.001). No systemic analgesic was needed during the surgical procedure and anaesthesia was maintained either with halothane (inspiratory fraction less than 0.5%) or enflurane (inspiratory fraction less than 0.8%). All children were extubated at the end of the surgical procedure. The catheter was maintained in 16 children for postoperative analgesia. The first postoperative injection was given 7.1 +/- 0.45 h later. The catheter remained in situ 26.7 +/- 4.1 h. No complication was observed. Thus, during surgery, the need for systemic analgesia was avoided and a rapid and safe postoperative recovery was obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

[High frequency ventilation during the surgical treatment of esophageal atresia]. / Ventilation à haute fréquence durant la cure chirurgicale de l'atrésie de l'oesophage.

The preliminary results of the use of high frequency positive pressure ventilation (HFPPV) in six newborn infants presenting a type III oesophageal atresia during the thoracic stage of surgical repair are reported. HFPPV allowed correct gas exchange during the surgical procedure. In the six cases, a significant decrease in PaCO2 (p less than 0.05) was observed, whereas the effects on PaO2 were variable. The technical problems, mechanism of gas transport during HFPPV and clinical interest of HFPPV in thoracic surgery are discussed.

[Anesthesia of the newborn weighing less than 2000 g, 100 cases (author's transl)]. / Anesthésie de l'enfant de moins de 2 000 g. Cent cas.

We gave special attention to these very fragile newborns in whom associated pathology was often present. We were faced above all by respiratory and hemodynamic problems. Pre-operative care is essential and must be adapted to the degree of emergency. The newborn must reach the operating room in normothermia, normoxia and in adequate metabolic status. The anaesthesia technique used was always simple with few anaesthesics and ventilation controlled manually and mechanically after intubation. Scrupulous monitoring was always the case. Principal anaesthesic incidents included hypothermia and tachycardia. A precise cause was linked to the 13 accidents encountered. In 8 cases slow decurarisation was noted. Special comments must be made about the premature infant's possibilities versus pharmacocinetic of anesthesics, hemodynamic modification, hyperbi lirubinemia hepatic and renal enzymatic immaturity. Thus we think the anesthesiologist must be specifically trained for the care of these patients.