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A Luks

Publications and source records attributed to A Luks.

At least 19 recordsLinked to original sources
PubMed1997

Improving the design of muscle relaxant studies. Stabilization period and tetanic recruitment.

BACKGROUND: The results from studies of muscle relaxants show wide variations among institutions. The authors hypothesized that some of this variability could be explained by differences in duration of nerve stimulation before drug administration (stabilization period). METHODS: Train-of-four stimulation was applied every 12 s to both ulnar nerves and adductor pollicis twitch tension was measured in anesthetized participants given 30 micrograms/kg vecuronium. In phase 1, the stabilization period was > 30 min for both extremities. In phase 2-4, stabilization period was 20 min for one extremity and 2 min for the other. In addition, in phase 3, a 2-s 50-Hz tetanus initiated the 2-min stimulation period; in phase 4, duration of tetanus was 5 s. Twitch recovery was recorded until stable for more than 15 min. Time to 25% recovery (clinical duration) was calculated based on two indices: predrug and final (recovery) twitch tension. Values for onset and clinical duration were compared by paired parametric and nonparametric tests. RESULTS: In phase 1, predrug and recovery twitch tension were similar in each extremity, and onset and clinical duration did not differ between extremities, permitting paired comparisons in remaining studies. In phase 2, onset was more rapid with 20-min of prestimulation. With 20-min prestimulation, predrug and recovery twitch tension were similar; with 2-min prestimulation, recovery twitch tension exceeded predrug values. When referenced to predrug twitch tension, clinical duration was shorter with 2-min, that with 20-min prestimulation. Initiating stimulation with 2-s or 5-s 50-Hz tetani (phases 3, 4) abolished differences between extremities in onset and recovery. CONCLUSIONS: With only train-of-four stimulation (no tetani), onset and clinical duration vary with duration of prestimulation, suggesting that a brief period of predrug stimulation is inadequate. However, lengthy prestimulation may be impractical in clinical studies. Tetanic stimulation for 2 or 5 s obviates the need for prolonged stabilization during studies of muscle relaxants.

Adult↗
PubMed1997

Bioavailability of intramuscular rocuronium in infants and children.

BACKGROUND: Intramuscular rocuronium, in doses of 1,000 microg/kg in infants and 1,800 microg/kg in children, produces complete twitch depression in 5-6 min. To determine the rate and extent of absorption of rocuronium after intramuscular administration, blood was sampled at various intervals after rocuronium administration by both intramuscular and intravenous routes to determine plasma concentrations (Cp) of rocuronium. METHODS: Twenty-nine pediatric patients ages 3 months to 5 yr were anesthetized with N2O and halothane. The trachea was intubated, ventilation was controlled, and adductor pollicis twitch tension was measured. When anesthetic conditions were stable, rocuronium (1,000 microg/kg for infants and 1,800 microg/kg for children) was injected either intramuscularly (in the deltoid muscle) or intravenously. Four venous plasma samples were obtained from each child 2-240 min after rocuronium administration. A mixed-effects population pharmacokinetic analysis was applied to these values to determine bioavailability, absorption rate constant, and time to peak Cp with intramuscular administration. RESULTS: With intramuscular administration, rocuronium's bioavailability averaged 82.6% and its absorption rate constant was 0.105 min(-1). Simulation indicated that Cp peaked 13 min after rocuronium was given intramuscularly, and that 30 min after intramuscular administration, less than 4% of the administered dose remained to be absorbed from the intramuscular depot. CONCLUSIONS: After rocuronium is administered into the deltoid muscle, plasma concentrations peak at 13 min, and approximately 80% of the administered drug is absorbed systemically.

Androstanols↗
PubMed1996

Intramuscular rocuronium in infants and children. Dose-ranging and tracheal intubating conditions.

BACKGROUND: Rocuronium's rapid onset and intermediate duration of action with intravenous administration suggests that intramuscular administration might facilitate tracheal intubation without producing prolonged paralysis. Accordingly, in infants and children, the authors measured onset at the adductor pollicis and respiratory muscles to determine the optimal dose (phase I), then gave this optimal dose to determine the optimal time for tracheal intubation (phase II). METHODS: The authors studied 45 unpremedicated patients aged 3 months to 5 yr. In phase I, 25 patients were anesthetized with nitrous oxide and halothane and breathed spontaneously; twitch tension and minute ventilation were measured. Rocuronium (800-2,400 micrograms/kg) was injected into the quadriceps or deltoid muscle; doses varied, using an "up-down" technique, the goal being to bracket the dose depressing twitch 75-90% within 5 min. In phase II, deltoid injections of the optimal dose from phase I (infants: 1,000 micrograms/kg; children: 1,800 micrograms/kg) were given to 20 patients anesthetized with 0.82-1.0% halothane. Tracheal intubation was attempted 1.5-3.0 min later; time to tracheal intubation was varied, using an "up-down" technique. RESULTS: In phase I, 5 of 7 patients given quadriceps injections (1,200-2,200 micrograms/kg) had slow onset of twitch and ventilatory depression. With deltoid injections (800-2,400 micrograms/kg), all patients developed complete twitch depression; median time to 50% depression of minute ventilation was 3.2 min in infants and 2.8 min in children. In phase II, intubating conditions were consistently adequate or good-excellent at 2.5 min in infants and 3.0 min in children. Initial twitch recovery was at 57 +/- 13 min (mean +/- SD) in infants and 70 +/- 23 min in children. CONCLUSIONS: Deltoid injections of rocuronium, 1,000 micrograms/kg in infants and 1,800 micrograms/kg in children, rapidly permit tracheal intubation in infants and children, despite a light plane of anesthesia. Duration of action of these large doses might limit clinical utility.

Androstanols↗
PubMed1992

An evaluation of parental assessment of the Big Brothers/Big Sisters program in New York City.

This study used a self-report survey to assess parents' impressions of the impact of the Big Brothers/Big Sisters program on their children. Parents rated program success on each of seven outcome variables (school attendance, grades, getting along with family members, getting along with friends, self-esteem, staying out of trouble, and being more responsible), and two program variables (frequency of contact and length of time in program). While children were rated by their parents as benefiting significantly from the program, children's frequency of contact did not have a significant effect on the outcome measures. However, a trend of increased success with greater time spent in the program was found. Frequency of contact between parents and Big Brothers/Big Sisters was positively correlated with reported success.

Adult↗