Intramuscular rapacuronium in infants and children: a comparative multicenter study to confirm the efficacy and safety of the age-related tracheal intubating doses of intramuscular rapacuronium (ORG 9487) in two groups of pediatric subjects.

BACKGROUND: This multicenter, assessor, blinded, randomized study was conducted to confirm and extend a pilot study in which intramuscular rapacuronium was given to infants and children to confirm efficacy and to evaluate tracheal intubating conditions. METHODS: Ninety-six pediatric patients were studied in two groups: infants aged 1 to 12 months (n = 46) and children aged 1 to 3 yr (n = 50). Infants received 2.8 mg/kg and children 4.8 mg/kg of intramuscular rapacuronium during 1 minimum alveolar concentration halothane anesthesia. These two groups were studied in three subgroups, depending on the time (1.5, 3, or 4 min) at which tracheal intubation was attempted after the administration of intramuscular rapacuronium into the deltoid muscle. Neuromuscular data collected included onset time, duration of action, and recovery data during train-of-four stimulation at 0.1 Hz. Data were analyzed by the Cochran-Mantel-Haenszel procedure. RESULTS: The tracheal intubating conditions were deemed acceptable in 17, 36, and 64% of infants and 20, 47, and 71% of children at 1.5, 3, or 4 min, respectively. The mean values for % of control twitch height (T1) 2 min after rapacuronium in both groups were similar. The mean (SD) time required to achieve more than or equal to 95% twitch depression in infants was 6.0 (3.7) versus 5.5 (3.8) min in children. CONCLUSIONS: Only 27% of patients achieved clinically acceptable tracheal intubating conditions at 1.5 or 3 min after administration of 2.8 mg/kg and 4.8 mg/kg rapacuronium during 1 minimum alveolar concentration halothane anesthesia. Tracheal intubation conditions at 4 min were acceptable in 69% of subjects. The duration of action of 4.8 mg/kg of rapacuronium in children was longer than 2.8 mg/kg of rapacuronium in infants.

Pediatric evaluation of the bispectral index (BIS) monitor and correlation of BIS with end-tidal sevoflurane concentration in infants and children.

UNLABELLED: The bispectral index (BIS) has been developed in adults and correlates well with clinical hypnotic effects of anesthetics. We investigated whether BIS reflects clinical markers of hypnosis and demonstrates agent dose-responsiveness in infants and children. In an observational arm of this study, BIS values in children undergoing general anesthesia were observed and compared with similar data collected previously in a study of adults. In a second arm of the study, a range of steady-state end-tidal concentrations of sevoflurane was administered and corresponding BIS documented. Data were examined for differences between infants (0-2 yr) and children (2-12 yr). No difference was seen in BIS values in children before induction, during maintenance, and on emergence compared with adult values. There was no difference in BIS between infants and children at similar clinical levels of anesthesia. In children and infants, BIS was inversely proportional to the end-tidal concentration of sevoflurane. The sevoflurane concentration for a BIS = 50 (95% confidence interval) was significantly different: 1. 55% (1.40-1.70) for infants versus 1.25% (1.12-1.37) for children. Although validation with specific behavioral end points was not possible, BIS correlated with clinical indicators of anesthesia in children as it did in adults: as depth of anesthesia increased, BIS diminished. BIS correlated with sevoflurane concentration in infants and children. The concentration-response difference between infants and children was consistent with data showing that minimum alveolar concentration is higher in children less than 1 yr of age. IMPLICATIONS: The use of bispectral index (BIS) during general anesthesia improves the titration of anesthetics in adults. The data from this study suggest that the same equipment and method of electroencephalogram analysis may be applied to infants and children.

A comparison of the intubation conditions between mivacurium and rocuronium during balanced anesthesia.

BACKGROUND: Comparisons of the intubation conditions with mivacurium and rocuronium from previous reports are confounded by the use of varied induction regimens. The authors compared intubation conditions of mivacurium, rocuronium, and a placebo at 90 s and their recovery profiles during anesthesia with nitrous oxide, oxygen, and propofol. METHODS: After induction with midazolam, fentanyl, and propofol in a randomized blinded study, 100 patients received one of the following treatments: 0.25 mg/kg mivacurium in divided doses (0.15 mg/kg followed by 0.1 mg/kg 30 s later); 0.45, 0.6, 0.9, or 1.2 mg/kg rocuronium; or placebo. Evoked thumb adduction was measured throughout. Intubation was attempted 90 s after the initial dose of mivacurium and other treatment doses by a "blinded" physician. Intubating conditions were graded as excellent, good, poor, or not possible. Spontaneous recovery was studied until a 25% initial twitch height was reached. Mean arterial blood pressure and heart rate changes between groups were determined before induction through 6 min after administration of the study drugs. RESULTS: There were no important changes or intergroup differences in mean arterial blood pressure and heart rate. Intubation conditions were good or excellent for both mivacurium and rocuronium at the 0.9 mg/kg dose (93%) and at the 1.2 mg/kg dose (100%). Rocuronium at the 0.6 mg/kg dose was excellent in 27% of patients, whereas rocuronium at the 0.45 mg/kg dose had the least number of excellent conditions and the most poor or not possible assessments. Patients given placebo could not be intubated. Times to maximum blockade for 0.9 and 1.2 mg/kg rocuronium were the shortest. The times to 25% recovery for 0.6 mg/kg rocuronium (mean +/- SD = 27 +/- 8.6 min), 0.9 mg/kg (43.1 +/- 10.8), and 1.2 mg/kg (62.3 +/- 17.4 min) were significantly longer than were those for mivacurium (17.4 +/- 6.2 min). CONCLUSIONS: Mivacurium in a 0.25 mg/kg divided dose and rocuronium at 0.9 mg/kg and 1.2 mg/kg provide good or excellent intubation conditions at 90 s in most patients. Rocuronium was faster in onset at the higher doses (0.9 and 1.2 mg/kg) but had more prolonged recovery times to 25% single twitch height.

Pulsed laser treatment in children and the use of anesthesia.

BACKGROUND: The rationale for choosing certain anesthetic options in children when they are being treated with pulsed lasers is unclear. OBJECTIVE: Our purpose was to assess the safety and side effects of general anesthesia in the treatment of vascular lesions and to compare this to treatment outcome in the office setting. METHODS: We carried out a retrospective chart review of 179 patients, with an age range of 5 weeks to 18 years, who received laser treatment and underwent different anesthetic modalities. The age of the patient and the size, location, and severity of the vascular lesion were also noted. RESULTS: The factors determining the type of anesthesia to use included (1) the age of the patient, (2) the number of treatments, and (3) the size and location of the lesion. Our data showed minimal risk and sequelae of general anesthesia in the treatment of vascular lesions in children. CONCLUSION: Proper selection of anesthesia is a key factor in dealing with children. Office surgery can be performed safely when small lesions are treated. The use of general anesthesia in the treatment of port-wine stains in children does not appear to be accompanied by increased risk.

Comparison of neuromuscular, cardiovascular, and histamine-releasing properties of doxacurium and pipecuronium.

STUDY OBJECTIVES: To determine the neuromuscular, cardiovascular, and histamine releasing properties of doxacurium and pipecuronium at three times effective ED95 doses (3XFD95). DESIGN: Prospective, randomized clinical trial of adult patients. SETTING: University teaching hospital. PATIENTS: 20 ASA status I and II adult patients. INTERVENTIONS: Subjects were anesthetized with thiopental sodium, fentanyl, and nitrous oxide and oxygen (N2O:O2). Plasma samples were taken preoperatively, after thiopental, and 2 and 5 minutes after doxacurium 75 micrograms/kg or pipecuronium 123 micrograms/kg were given for the determination of histamine levels. The ulnar nerve was stimulated via surface electrodes using train-of-four stimulation at 0.1 Hz. The force of contraction of adductor pollicis was recorded using a mechanomyograph. Recovery of the twitch response was followed and, if necessary, neuromuscular block was antagonized with neostigmine and glycopyrrolate. MEASUREMENTS AND MAIN RESULTS: Three patients in the doxacurrium group and one patient in the pipecuronium group exhibited a marked increase in plasma histamine levels. In both groups statistically significant changes were seen in heart rate (HR) measurements (p < 0.02). Doxacurium had a slower onset than pipecuronium [3.1 +/- 0.2 min vs. 1.8 +/- 0.1 min (p < 0.0003)] and a more rapid recovery [72 +/- 8 min vs. 123 +/- 9 min (p < 0.01)]. CONCLUSION: Neither drug caused a clinically significant change in HR or histamine release. In the doses chosen for this study, the rate of onset of block is slower with doxacurium while recovery is more rapid. Histamine release in three patients was caused by thiopental, while in a fourth patient it may have been due to doxacurium.

Oral diamorphine: lack of effect on dyspnoea and exercise tolerance in the "pink puffer" syndrome.

The aim of this study was to assess the effects of diamorphine on breathlessness and exercise tolerance in patients with severe chronic airflow obstruction and normal arterial carbon dioxide tension (PCO2) levels ("pink puffer" syndrome). In this double-blind, cross-over, randomized study we examined both acute and chronic effects of single and multiple doses of oral diamorphine in 14 "pink puffer" patients. Their mean resting forced expiratory volume in one second (FEV1) was 36% predicted normal, mean arterial oxygen tension (PaO2) was 9.2 kPa and mean PaCO2 was 5.2 kPa. Ten patients took either diamorphine 2.5 or 5 mg or placebo elixir 6 hourly for 2 weeks, recording on a diary card dyspnoea, sleepiness and well-being on a visual analogue scale (VAS). The final treatment was given 30 min before measuring spirometry, arterial blood gases, plasma morphine levels, 6 min walking distances, time walked on treadmill and self-assessment of dyspnoea on a VAS scale after exercise. On two further days, eight patients took two doses, 4 h apart, of either diamorphine 7.5 mg or placebo elixir. Spirometry, 6 min walking distance with a VAS score for dyspnoea were measured before and at 1 h after each dose. Morphine levels and blood gases were also measured. Whether given in single or repeated doses, oral diamorphine had no significant effect on exercise tolerance and breathlessness when compared with placebo. Diamorphine 2.5-7.5 mg produced neither sleepiness nor a deterioration in blood gases. However, plasma levels associated with analgesic efficacy were not achieved with these doses. Thus, as given in this study, oral diamorphine is unlikely to have therapeutic potential in the treatment of dyspnoea in the "pink puffer" syndrome.

The Fenem CO2 detector device. An apparatus to prevent unnoticed oesophageal intubation.

A new oesophageal intubation detector device, the Fenem CO2 detector, was used in 100 patients intubated during anaesthesia for elective surgery. This new device was 100% accurate in the differentiation between tracheal and oesophageal placement of a tube.

Comparison of oscillation with three other methods for measuring nasal airways resistance.

In this study we have compared the sensitivity and reproducibility of nasal airways resistance measurements made using an oscillometer, with those made by passive anterior, active anterior and active posterior rhinomanometry. Nasal airways resistance values were compared in 12 patients with rhinitis and 15 normal subjects, of whom ten had additional measurements after a vasoconstrictor spray, oxymetazoline. The coefficients of variation of 6-8 technically satisfactory measurements were 9-19%. The decongestant effect of oxymetazoline was detected by all methods, with no decrease in reproducibility. Post vasoconstrictor nasal airways resistance fell by 28% (passive anterior), 35% (active anterior), 36% (active posterior) and 58% (oscillometry). In conclusion, the oscillation method for deriving nasal airways resistance is a useful, new, simple and noninvasive way of assessing nasal airways patency. Results compare favourably with other, more established techniques.