Tetsu Uejima

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.

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.

BackgroundThis 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. MethodsNinety-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. ResultsThe 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. ConclusionsOnly 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.

Ommaya and McComb reservoir placement in infants: can this be done with regional anesthesia?

1 Uitto J, Pulkkinen L. Heritable diseases affecting the elastic tissue: cutis laxa, pseudoxanthoma elasticum and related disorders. In: Rimoin’s DL, Connor JM, Pyeritz RE, Korf BR, eds. Emery 7 Rimoin’s Principles and Practices of Medical Genetics, 4th edn. New York: Churchill Livingstone, 2002: 4044–4068. 2 Koklu E, Gunes T, Ozturk MA et al. Cutis laxa associated with central hypothyroidism owing to isolated thyrotropin deficiency in a newborn. Pediatr Dermatol 2007; 24: 525–528. 3 Rybojad M, Baumann C, Godeau G et al. Congenital generalized cutis laxa: 5 cases. Ann Dermatol Venereol 1999; 126: 317–319. 4 Guia Torrent JM, Castro Gracia F, Cuenca Gornez M et al. Cardiovascular changes in the cutis laxa congenital syndrome. Rev Esp Cardiol 1999; 52: 204–206. 5 Rigg JR, Jamrozik K, Myles PS et al. Epidural anaesthesia and analgesia and outcome of major surgery: a randomized trial. Lancet 2002; 359: 1276–1282. 6 Carli F, Trudal JL, Belliveau P. The effect of intraoperative thoracic epidural anaesthesia and postoperative analgesia on bowel function after colorectal surgery; a prospective, randomized trial. Dis Colon Rectum 2001; 44: 1083–1089. 7 Ballantyne JC, Carr DB, deFerranti S et al. The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analysis of randomized, controlled trials. Anesth Analg 1998; 86: 598–612.

Evaluation of a new operating room ventilator with volume-controlled ventilation : The Ohmeda 7900

UNLABELLED Changes in fresh gas flow (FGF) during volume-controlled ventilation with the circle system have clinically important effects on the ventilatory variables of children. Current operating room ventilators allow a portion of the FGF to be added to the delivered tidal volume. The Ohmeda 7900 (Madison, WI) ventilator was designed to compensate for changes in FGF. We compared this ventilator with a standard ventilator, the Ohmeda 7000. Twenty patients (13-56 kg) undergoing dental or lower extremity surgery were studied. A side-by-side comparison of the two ventilators was performed using each patient as his or her own control. Beginning with the 7900 ventilator, FGF was set at 3.0 L/min, and the inspiratory to expiratory ratio was set at 1:2. Respiratory rate and tidal volume were adjusted to achieve an ETCO2 of 30-40 mm Hg. After a 10-min period of stabilization, inspired minute ventilation (VI), expired minute ventilation (VE), and ETCO2 were measured. FGF was then increased to 6.0 L/min, and the measurements were repeated after 10 min; FGF was then decreased to 1.5 L/min, and measurements were repeated after 10 min. The patient was then ventilated with an Ohmeda 7000 ventilator, and the sequence was repeated. The Ohmeda 7000 ventilator demonstrated significant changes in VI, VE, plateau pressure, and ETCO2, with changes in FGF (P = 0.0039-0.0001). The Ohmeda 7900 ventilator demonstrated compensation for changes in FGF; there were no significant changes in VI, VE, and ETCO2. We conclude that the Ohmeda 7900 ventilator provides stable ventilatory variables regardless of alterations in FGF (1.5-6.0 L/min). IMPLICATIONS In this study, we compared the effects of changing fresh gas flow on volume-controlled ventilation using two operating room ventilators (Ohmeda 7000 and Ohmeda 7900). The Ohmeda 7900, but not the Ohmeda 7000, provided stable ventilatory variables with fresh gas flows between 1.5 and 6.0 L/min.

Is 0.375% bupivacaine safe in caudal anesthesia in neonates and young infants?

Cucchicaro et al. (1) recently reported single-dose caudal anesthesia in high-risk infants using 0.375% bupivacaine. We are concerned about their use of a relatively large dose of bupivacaine (3.75 mg/ kg) in their caudal solutions, which exceeds previously published guidelines (2,3) of 2.5 mg/kg in infants. The authors justify this dose by citing studies demonstrating serum levels below the reported toxic level of 4 g/mL using comparable doses (4,5). These studies were performed in children, not in neonates or young infants. Berde (3) has stated that convulsions can occur with serum concentrations as low as 2 g/mL. Mazoit et al. (6) reported that neonates and young infants have a significantly higher free fraction of caudally injected bupivacaine. This free fraction correlated inversely with low levels of -1 acid glycoprotein. None of these patients were tracheally intubated or mechanically ventilated. No episodes of hypoxemia were reported, but no mention was made of ETco2. The prematurity and medical conditions of these patients, coupled with surgical retraction, would make them prone to intraoperative hypercarbia, which could precipitate local anesthetic induced seizures should serum levels approach toxic levels. On the basis of these concerns, we caution readers to be judicious in their doses of bupivacaine for caudal blocks, especially in neonates.

Sevoflurane interferes with inhaled nitric oxide (INO) delivery from the INOmax DS machine

SIR—Inhaled nitric oxide (INO) is often administered to pediatric patients with congenital heart disease and pulmonary hypertension in the perioperative period. We have encountered problems with INO delivery from the INOmax DS which should be of interest to all readers who use INO in their practices. On a recent occasion, a child was brought to the operating room (OR) who was already on INO in the pediatric intensive care unit (PICU). The INOmax DS system had been functioning well for an extended period of time. In the OR, INO was administered through the anesthesia circuit. The patient was given air ⁄ oxygen and sevoflurane. A few minutes later, the nitric oxide (NO), nitrogen dioxide (NO2) and oxygen (O2) sensors began to fluctuate in spite of adequate flows through the anesthesia machine. The readings continued to fluctuate from 20% to 60% of previous values. Finally, the NO2 value exceeded 10 ppm and became nonfunctional and the O2 sensor was reading 117%. All of the sensors were recalibrated at which time they appeared to be functioning normally. We took both the INOmax DS and the anesthesia machine out of service and neither machine were reported to be malfunctioning. Since then, we have encountered this problem on a few other occasions prompting us to contact the manufacturer. The instruction manual for the INOmax DS has a section entitled ‘Connection to a Circle Anesthesia System’ (1). The first warning mentions that gas flow rates less than the patient’s minute ventilation may result in higher NO2, higher NO and lower O2 values. A caution section mentions that N2O will affect delivered INO. A 50 ⁄ 50 mixture of O2 ⁄ N2O will result in an approximately 7% reduction of INO compared with delivery with 100% O2. It goes on to state that delivery of 2% isoflurane will result in a 3% error in INO delivery. The last sentence mentions that ‘sudden changes in anesthetic agent concentration may cause brief transient changes in the measured NO and NO2 values.’ The manufacturer has since informed us that there is tremendous cross sensitivity of sevoflurane to the sensors and that this may result in the monitored NO value to go down and the monitored NO2 value to go up (2). The result is that the true amount of delivered NO will not be known if sevoflurane is used. This is apparently because of the increased density of sevoflurane in comparison to isoflurane or desflurane (3). There also appears to be a dose-dependent cross-sensitivity to sevoflurane i.e. higher concentrations of sevoflurane (7–8%) will cause more error than lower concentrations. We have found that the sensors often become completely inoperable at higher concentrations. There is, unfortunately, no solution other than to use the older version of the machine or to avoid the use of sevoflurane when INO is being delivered. It should be noted that the NO2 sensors on both the newer INOmax TM