Kelly A. Hummer

A comparison of three doses of a commercially prepared oral midazolam syrup in children.

Midazolam is widely used as a preanesthetic medication for children. Prior studies have used extemporaneous formulations to disguise the bitter taste of IV midazolam and to improve patient acceptance, but with unknown bioavailability. In this prospective, randomized, double-blinded study we examined the efficacy, safety, and taste acceptability of three doses (0.25, 0.5, and 1.0 mg/kg, up to a maximum of 20 mg) of commercially prepared Versed® syrup (midazolam HCl) in children stratified by age (6 mo to <2 yr, 2 to <6 yr, and 6 to <16 yr). All children were ASA class I–III scheduled for elective surgery. Subjects were continuously observed and monitored with pulse oximetry. Ninety-five percent of patients accepted the syrup, and 97% demonstrated satisfactory sedation before induction. There was an apparent relationship between dose and onset of sedation and anxiolysis (P < 0.01). Eight-eight percent had satisfactory anxiety ratings at the time of attempted separation from parents, and 86% had satisfactory anxiety ratings at face mask application. The youngest age group recovered earlier than the two older age groups (P < 0.001). There was no relationship between midazolam dose and duration of postanesthesia care unit stay. Before induction, there were no episodes of desaturation, but there were two episodes of nausea and three episodes of emesis. At the time of induction, during anesthesia, and in the postanesthesia care unit, there were several adverse respiratory events. Oral midazolam syrup is effective for producing sedation and anxiolysis at a dose of 0.25 mg/kg, with minimal effects on respiration and oxygen saturation even when administered at doses as large as 1.0 mg/kg (maximum, 20 mg) as the sole sedating medication to healthy children in a supervised clinical setting.

The Effect of Intranasal Fentanyl on the Emergence Characteristics After Sevoflurane Anesthesia in Children Undergoing Surgery for Bilateral Myringotomy Tube Placement

Children undergoing placement of bilateral myringotomy tubes (BMT) often exhibit pain-related behavior (agitation) in the postanesthesia care unit. We compared the emergence and recovery profiles of pediatric patients who received sevoflurane with or without supplementary intranasal fentanyl for BMT surgery. By using a prospective, double-blinded design, 150 children 6 mo to 5 yr of age, scheduled for routine BMT surgery, were anesthetized with sevoflurane (2%–3%) in a 60% N2O/O2 gas mixture. Patients were randomized to receive equal volumes of intranasal saline (Control), 1 &mgr;g/kg fentanyl or 2 &mgr;g/kg fentanyl. A blinded observer evaluated each patient using a previously described 4-point agitation scale and the Steward recovery scale. Response to parental presence was observed after a score of six (full recovery) was achieved on the Steward recovery scale. There were no significant differences among the three groups regarding age, weight, surgeon, duration of anesthesia, or ear condition. Recovery times and emergence characteristic scores were not statistically different. Agitation scores were significantly reduced in the 2-&mgr;g/kg Fentanyl group as compared with the Control group (P = 0.012). Fentanyl 2 &mgr;g/kg is recommended to reduce the incidence of agitation seen in these patients.

The effect of fentanyl on the emergence characteristics after desflurane or sevoflurane anesthesia in children.

Desflurane and sevoflurane anesthesia are associated with emergence agitation in children. In this study, we examined the effect of a single intraoperative dose of fentanyl on emergence characteristics in children undergoing adenoidectomy. One hundred children, 2–7 yr old, were randomly assigned to receive desflurane or sevoflurane for maintenance of general anesthesia after an inhaled induction with sevoflurane and a 2.5 &mgr;g/kg dose of fentanyl. An observer blind-ed to the anesthetic technique assessed the times to achieve emergence, extubation and recovery criteria, as well as emergence behaviors. The results showed a similar incidence of severe emergence agitation after general anesthesia with desflurane (24%) and sevoflurane (18%). Times to achieve extubation and postanesthesia care unit discharge criteria were shorter with desflurane than with sevoflurane. With this technique, desflurane allows for a more rapid emergence and recovery than sevoflurane. In children receiving desflurane or sevoflurane, the concurrent use of fentanyl in a dose of 2.5 &mgr;g/kg results in a small incidence of emergence agitation.

The incidence of emergence agitation associated with desflurane anesthesia in children is reduced by fentanyl

The rapid emergence and recovery from general anesthesia provided by desflurane is associated with a frequent incidence of emergence agitation in children. We sought to determine the mean effective dose of fentanyl that would significantly reduce the incidence of emergence agitation while preserving rapid recovery. Thirty-two children undergoing adenoidectomy received general anesthesia with desflurane and a dose of fentanyl (1.25, 1.87, 2.8, and 4.2 &mgr;g/kg) determined by the classic up-down method. Recovery characteristics, including time to extubation, recovery, hospital discharge, agitation, pain, and vomiting, were recorded. Demographics and recovery features were assessed by analysis of variance and Kruskal-Wallis tests. The mean effective dose of fentanyl to reduce agitation was calculated with the Dixon-Massey method to be 2.5 ± 6.2 &mgr;g. There were no significant differences when treatment groups were compared for recovery criteria. Postoperative emesis occurred in 75% of patients. The results of this study demonstrate that a dose of 2.5 &mgr;g/kg of fentanyl is sufficient to prevent emergence agitation while preserving the rapid recovery associated with desflurane anesthesia in children undergoing adenoidectomy.

The Effect of Intranasal Administration of Remifentanil on Intubating Conditions and Airway Response After Sevoflurane Induction of Anesthesia in Children

BACKGROUND: Intubation without the use of muscle relaxants in children is frequently done before IV access is secured. In this randomized controlled trial, we compared intubating conditions and airway response to intubation (coughing and/or movement) after sevoflurane induction in children at 2 and 3 min after the administration of intranasal remifentanil (4 mcg/kg) or saline. METHODS: One hundred eighty-eight children, 1–7-yr old, were studied. Nasal remifentanil (4 mcg/kg) or saline was administered 1 min after an 8% sevoflurane N2O induction. The sevoflurane concentration was then reduced to 5% in oxygen, and ventilation assisted/controlled. An anesthesiologist blinded to treatment assignment used a validated score to evaluate the conditions for laryngoscopy and response to intubation. Blood samples for determination of remifentanil blood concentrations were collected from 17 children at baseline, 2, 3, 4, and 10 min after nasal administration of remifentanil. RESULTS: Good or excellent intubating conditions were achieved at 2 min (after the remifentanil bolus) in 68.2% and at 3 min in 91.7% of the children who received intranasal remifentanil versus 37% and 23% in children who received placebo (P < 0.01). The mean remifentanil plasma concentrations (±sd) at 2, 3, 4, and 10 min were 1.0 (0.60), 1.47 (0.52), 1.70 (0.46), and 1.16 (0.36) ng/mL, respectively. Peak plasma concentration was observed at 3.47 min. There were no complications associated with the use of nasal remifentanil. CONCLUSIONS: Nasal administration of remifentanil produces good-to-excellent intubating conditions in 2–3 min after sevoflurane induction of anesthesia.

Intramuscular Rocuronium in Infants and Children A Multicenter Study To Evaluate Tracheal Intubating Conditions, Onset, and Duration of Action

BACKGROUND This multicenter, assessor-blinded, randomized study was done to confirm and extend a pilot study showing that intramuscular rocuronium can provide adequate tracheal intubating conditions in infants (2.5 min) and children (3 min) during halothane anesthesia. METHODS Thirty-eight infants (age range, 3-12 months) and 38 children (age range, 1 to 5 yr) classified as American Society of Anesthesiologists physical status 1 and 2 were evaluated at four investigational sites. Anesthesia was maintained with halothane and oxygen (1% end-tidal concentration if <2.5 yr; 0.80% end-tidal concentration if >2.5 yr) for 5 min. One half of the patients received 0.45 mg/kg intravenous rocuronium. The others received 1 mg/kg (infants) or 1.8 mg/kg (children) of intramuscular rocuronium into the deltoid muscle. Intubating conditions and mechanomyographic responses to ulnar nerve stimulation were assessed. RESULTS The conditions for tracheal intubation at 2.5 and 3 min in infants and children, respectively, were inadequate in a high percentage of patients in the intramuscular group. Nine of 16 infants and 10 of 17 children had adequate or better intubating conditions at 3.5 and 4 min, respectively, after intramuscular rocuronium. Better-than-adequate intubating conditions were achieved in 14 of 15 infants and 16 of 17 children given intravenous rocuronium. Intramuscular rocuronium provided > or =98% blockade in 7.4+/-3.4 min (in infants) and 8+/-6.3 min (in children). Twenty-five percent recovery occurred in 79+/-26 min (in infants) and in 86+/-22 min (in children). CONCLUSIONS Intramuscular rocuronium, in the doses and conditions tested, does not consistently provide satisfactory tracheal intubating conditions in infants and children and is not an adequate alternative to intramuscular succinylcholine when rapid intubation is necessary.