Anesthesiology
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Randomized Controlled Trial Comparative Study Clinical Trial
Lack of analgesic activity of morphine-6-glucuronide after short-term intravenous administration in healthy volunteers.
The analgesic activity of morphine-6-glucuronide (M-6-G) is well recognized for its contribution to the effects of morphine and its possible use as an opioid analgesic with a wider therapeutic range than morphine. The present study attempted to quantify the relative contribution of M-6-G to analgesia observed after systemic administration of morphine. ⋯ After short-term intravenous administration at doses that produce plasma concentrations of M-6-G similar to those seen after administration of morphine, M-6-G had no analgesic effects in the present placebo-controlled study in healthy volunteers.
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Randomized Controlled Trial Clinical Trial
Sympathovagal effects of spinal anesthesia assessed by the spontaneous cardiac baroreflex.
The changes in sympathovagal balance induced by spinal anesthesia remain controversial. The spontaneous baroreflex method allows the continuous assessment of the spontaneous engagement of the cardiac baroreflex, giving an index of sympathovagal balance. The purpose of this study was to follow the effects of spinal anesthesia on spontaneous baroreflex sensitivity. ⋯ Using a noninvasive, continuous technique to estimate cardiac sympathovagal balance, no significant variation in autonomic balance induced by spinal anesthesia was observed. However, untoward episodes of bradycardia and hypotension occurred in three patients, who could not be prospectively identified by the parameters studied.
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Comparative Study
The intubation difficulty scale (IDS): proposal and evaluation of a new score characterizing the complexity of endotracheal intubation.
A quantitative scale of intubation difficulty would be useful for objectively comparing the complexity of endotracheal intubations. The authors have developed a quantitative score that can be used to evaluate intubating conditions and techniques with the aim of determining the relative values of predictive factors of intubation difficulty and of the techniques used to decrease such difficulties. ⋯ The IDS correlates with but is less subjective than the VAS and categorical classification. IDS correlates with time to intubation, but it offers details regarding the difficulty encountered that time alone does not. This score may not only aid in evaluation of factors linked to difficult intubations, but it may provide a uniform approach to comparing studies related to this subject.
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Clinical Trial Controlled Clinical Trial
Oral clonidine premedication reduces minimum alveolar concentration of sevoflurane for tracheal intubation in children.
Sevoflurane is a useful anesthetic for inhalational induction in children because of its low solubility in blood and relatively nonpungent odor. Clonidine has sedative and anxiolytic properties and reduces the requirement for inhalation agents. Nitrous oxide (N2O) also decreases the requirement of inhaled anesthetics, but the effect is variable. The minimum alveolar concentration for tracheal intubation (MAC(TI)) of sevoflurane was assessed with and without N2O and clonidine premedication. ⋯ Oral clonidine premedication decreased the MAC(TI) of sevoflurane. Nitrous oxide also decreased the MAC(TI). The combination of clonidine and N2O lessened the MAC(TI) of sevoflurane more than did either drug alone.
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Comparative Study Clinical Trial
Systemic absorption and block after epidural injection of ropivacaine in healthy volunteers.
For local anesthetics, the process of removal from the site of administration influences the duration of anesthesia and the risk for systemic toxicity to develop. The systemic absorption of epidural ropivacaine and the time profile of sensory and motor block were studied in healthy volunteers. ⋯ As much as 50% differences were seen in the arteriovenous plasma concentrations of ropivacaine during the first hour, which has implications for the interpretation of systemic toxic plasma concentrations. The absorption into the general circulation was biphasic, with a correlation between the sensory block and the slower absorption half-life. A faster onset and a longer duration of sensory compared with motor block was seen.