Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2002
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of neuromuscular effects, tracheal intubating conditions, and reversibility of rapacuronium versus mivacurium in female patients.
Rapacuronium is a new, rapid-onset, short-duration, nondepolarizing neuromuscular blocking drug. We evaluated the intubating conditions at maximum block after the administration of rapacuronium or mivacurium in female patients undergoing laparoscopy. We also evaluated the neostigmine-induced reversibility of neuromuscular block after this single dose of rapacuronium or mivacurium.
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Anesthesia and analgesia · Apr 2002
Randomized Controlled Trial Comparative Study Clinical TrialPostoperative pain relief in children undergoing tympanomastoid surgery: is a regional block better than opioids?
Peripheral nerve blocks of the surgical site can reduce the need for perioperative opioids thereby decreasing their unwanted adverse effects, such as postoperative nausea and vomiting. In this prospective, randomized, double-blinded study, we examined the efficacy of a great auricular nerve (GAN) block compared with IV morphine sulfate in children undergoing tympanomastoid surgery. After the induction of general anesthesia, children were randomized to receive either a GAN block with 2 mL of 0.25% bupivacaine with epinephrine (1:200,000) and a sham IV injection of 2 mL of saline solution or a sham GAN block with 2 mL of saline solution with an IV injection of 0.1 mg/kg morphine sulfate diluted to 2 mL. Patients' objective pain scores were assessed by a blinded observer and the incidence of vomiting was recorded. The GAN-Block patients as a group required more pain rescue in the postanesthesia care unit; this difference was not statistically different from the IV-morphine group (P = 0.084). Nine GAN-Block patients never received opioid or other analgesics at any time in the first 24 h after surgery. The group that received the GAN block also had a less frequent incidence of vomiting requiring intervention (7 versus 19) during their entire hospitalization or at home (P = 0.027). The GAN-Block group also had more patients who never experienced vomiting (13 of 20 versus 5 of 20, P = 0.026). In this cohort, a peripheral nerve block decreased the overall incidence of postoperative vomiting thereby reducing associated costs. ⋯ We prospectively compared the use of a great auricular nerve block versus IV morphine sulfate in a randomized double-blinded study in children undergoing tympanomastoid surgery. Analgesia was comparable between groups but nearly half the Block group never required additional analgesics and the number of vomiting events was nearly 66% less.
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Anesthesia and analgesia · Apr 2002
Randomized Controlled Trial Clinical TrialIntubating laryngeal mask airway size selection: a randomized triple crossover study in paralyzed, anesthetized male and female adult patients.
We determined the optimal size of intubating laryngeal mask airway (ILM) for ventilation and blind tracheal intubation in men and women. We also determined the distance the tracheal tube needs to protrude beyond the distal aperture to ensure that the cuff is through the vocal cords. Fifty male and 50 female anesthetized, paralyzed patients (ASA physical status I or II, aged 18-80 yr) were studied. Three operators (A, B, and C) were involved for the purposes of blinding. The size 3, 4, or 5 ILM was inserted into each patient in random order by Operator A, and the quality of ventilation was scored (adequate, suboptimal, or failed) by Operator B. The fiberoptic position (correct, too shallow, or too deep) and the distance between the distal aperture and the vocal cords was determined by Operator B. A single attempt at blind intubation was made by Operator C. Operators B and C were blinded to the size of the ILM. Operator C was also blinded to the information recorded by Operator B. All ILMs were inserted into the laryngopharynx at the first attempt. For men and women, the ventilation score was smaller for the Size 3 than the Size 4 or 5 (all: P < 0.002). For men, correct positioning was less common with the Size 3 than the Size 4 or 5 (both: P < 0.02). For women, correct positioning was similar among sizes. For men, tracheal intubation was successful less frequently with the Size 3 (84%) than the Size 4 (100%) or 5 (98%) (both: P < or = 0.01). For women, tracheal intubation success was similar among sizes (Size 3, 4, and 5: 86%, 96%, and 92%, respectively). Intubation was always successful if the ILM was correctly positioned and always failed if it was too shallow or deep. In both male and female patients, the distance between the distal aperture and the vocal cords increased with increasing ILM size (all: P < 0.04) and patient height (P < 0.0001) and was always longer for men (all: P < 0.0001). The overall mean distance (95% confidence interval) that the tracheal tube needed to protrude was 10-12 cm (8-13 cm) in men and 8-11 cm (8-12 cm) in women. We conclude that for men, the Size 4 and 5 ILMs are better than the Size 3 for ventilation and blind intubation. For women, the Size 4 and 5 ILMs are better than the Size 3 for ventilation, but there is no difference among sizes for blind intubation. The length the tracheal tube must protrude from the distal aperture to ensure that the cuff is completely through the vocal cords is 8-13 cm, depending on ILM size, the tracheal tube size, and the sex and height of the patient. ⋯ For men, the Size 4 and 5 intubating laryngeal mask airways are better than the Size 3 for ventilation and blind tracheal intubation. For women, the Size 4 and 5 are better than the Size 3 for ventilation, but there is no difference among sizes for blind intubation. The length the tracheal tube must protrude from the distal aperture of the intubating laryngeal mask airway to ensure that the cuff is completely through the vocal cords is 8-13 cm, depending on the size of the mask and tracheal tube and on the sex and height of the patient.
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Anesthesia and analgesia · Apr 2002
Randomized Controlled Trial Clinical TrialThe reduction in minimum alveolar concentration for tracheal extubation after clonidine premedication in children.
The effects of clonidine on minimum alveolar concentration for tracheal extubation (MAC-ex) have not been elucidated. Clonidine may lead to prolonged emergence from anesthesia. We investigated the effects of oral clonidine premedication on MAC-ex and examined the emergence properties of sevoflurane in children. Sixty ASA physical status I pediatric patients, aged from 2 to 9 yr, were randomly divided into one of three groups and received placebo, clonidine 2 microg/kg, or clonidine 4 microg/kg (n = 20 each) orally, 100 min before the induction of anesthesia. The induction of anesthesia, tracheal intubation, and maintenance of anesthesia were performed with sevoflurane in air and oxygen. MAC-ex was defined according to the modification of Dixon's up-and-down method, with 0.25% as a step size. In addition, in the Control and 4 microg/kg groups, the time from tracheal extubation to spontaneous eye opening (eye-opening time) and the time from tracheal extubation to leaving the operating room (awakening time) were recorded. MAC-ex for sevoflurane (mean +/- SD) was 1.63% +/- 0.13%, 1.04% +/- 0.26%, and 0.66% +/- 0.09% respectively in the Control group, 2 microg/kg group, and 4 microg/kg group. Significant differences were observed among the three groups. The eye-opening times were 5.7 +/- 3.5 min in the Control group and 5.1 +/- 1.0 min in the 4 microg/kg group. The awakening times were 9.7 +/- 3.7 min in the Control group and 9.2 +/- 3.8 min in the 4 microg/kg group. No significant differences were observed among the groups. ⋯ Oral clonidine premedication decreased MAC for tracheal extubation for sevoflurane dose dependency and did not prolong emergence from anesthesia.
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Anesthesia and analgesia · Apr 2002
Randomized Controlled Trial Clinical TrialThe interaction between propofol and clonidine for loss of consciousness.
Clonidine premedication reduces the intraoperative requirement for opioids and volatile anesthetics. Clonidine also reduces the induction dose of IV anesthetics. There is no information, however, regarding the effect of oral clonidine premedication on the propofol blood concentrations required for loss of consciousness, and the interaction between propofol and clonidine. We randomly administered target effect-site concentrations of propofol ranging from 0.5 to 5. 0 microg/mL by using computer-assisted target-controlled infusion to 3 groups of healthy male patients: Control (n = 35), 2.5 microg/kg Clonidine (n = 36), and 5.0 microg/kg Clonidine (n = 36) groups. Nothing was administered to the Control group. Clonidine (2.5 or 5.0 microg/kg) was administered orally 90 min before the induction of anesthesia in the Clonidine groups. After equilibration between the blood and effect-site for 15 min, a verbal command to open their eyes was given two times to the patients. Arterial blood samples for analysis of the serum propofol and clonidine concentrations were taken immediately before verbal commands were given. Measured serum propofol concentrations in equilibrium with the effect-site at which 50% of the patients did not respond to verbal commands (EC50 for loss of consciousness) were determined by logistic regression. The EC50 +/- SE values in the Control, 2.5 microg/kg Clonidine, and 5.0 microg/kg Clonidine groups were 2.67 +/- 0.18, 1.31 +/- 0.12, and 0.91 +/- 0.13 microg/mL, respectively. The EC50 in the 2.5 and 5.0 microg/kg clonidine groups was significantly smaller than that in the Control group (P < 0.001). The use of a response surface modeling analysis indicated that there was an additive interaction between measured arterial propofol and clonidine concentrations in relation to loss of consciousness. These results indicate that propofol and clonidine act additively for loss of consciousness. ⋯ Oral clonidine 2.5 and 5.0 microg/kg premedication decreases the propofol concentration required for loss of consciousness.