Anesthesia and analgesia
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Anesthesia and analgesia · Jul 2006
Randomized Controlled TrialFunctional magnetic resonance imaging measures of the effects of morphine on central nervous system circuitry in opioid-naive healthy volunteers.
In this pilot study, we used functional magnetic resonance imaging (fMRI) to study the effects of morphine in 8 healthy, opioid-naïve volunteers. Intravenous small-dose morphine (4 mg/70 kg) or saline was administered to volunteers undergoing a fMRI scan. Infusion of morphine, but not saline, elicited mild euphoria without aversive symptoms and resulted in positive signal changes in reward structures including the nucleus accumbens, sublenticular extended amygdala, orbitofrontal cortex, and hippocampus. ⋯ The pattern of activation in reward circuitry was similar to that reported for euphoric drugs of abuse, providing a model to evaluate the initial effects of morphine on the central nervous system components of the circuitry involved in addiction. The segregation of fMRI response that was observed in cortical versus subcortical regions suggests a dissociation of reward from sensory-motor and cognitive functions. Activation patterns were opposite to those previously observed for the mu antagonist, naloxone.
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Anesthesia and analgesia · Jul 2006
Dexmedetomidine for pediatric sedation for computed tomography imaging studies.
Dexmedetomidine is a sedative with limited experience in the pediatric population. This is the first study that prospectively evaluates the sedation profile of a dexmedetomidine pilot program for pediatric sedation for radiological imaging studies. In March 2005, our hospital sedation committee approved the replacement of IV pentobarbital with dexmedetomidine as the standard of care for CT imaging. ⋯ No significant changes were observed in respiratory rate or end-tidal CO2. Mean recovery time was 32 +/- 18 minutes. Based on our pilot results, dexmedetomidine may provide a reliable and effective method of providing sedation.
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Anesthesia and analgesia · Jul 2006
Randomized Controlled Trial Multicenter StudyLevobupivacaine-sufentanil with or without epinephrine during epidural labor analgesia.
In a prospective, randomized, double-blind study, we investigated whether epinephrine increased the efficacy of levobupivacaine and sufentanil during epidural labor analgesia. Seventy term parturients received an epidural injection of levobupivacaine 0.125% and sufentanil 0.75 microg/mL with or without 1:800,000 epinephrine. After an initial dose of 10 mL, a patient-controlled analgesia pump was started. ⋯ Hourly drug consumption, rescue dosing, and pain scores at 15 min and 20 min were lower in the epinephrine group. The incidence of motor block and duration of the second stage of labor tended to be higher in the epinephrine group and were associated with lower Apgar scores at 1 and 5 min. These findings suggest that the addition of epinephrine intensifies the effects of epidural levobupivacaine and sufentanil but may cause more motor block.
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Anesthesia and analgesia · Jul 2006
Randomized Controlled Trial Comparative StudyA prospective, randomized comparison between the popliteal and subgluteal approaches for continuous sciatic nerve block with stimulating catheters.
In this prospective, blinded study, we randomized 56 patients undergoing hallux valgus repair to receive continuous sciatic nerve block using a subgluteal (n = 28) or a posterior popliteal approach (n = 28) with a perineural stimulating catheter. Postoperatively, the stimulating catheter was connected to a patient-controlled analgesia pump with 0.0625% levobupivacaine (basal infusion rate of 3 mL/h, patient-controlled bolus dose of 3 mL, and lockout time of 20 min). Both approaches provided similar postoperative analgesia; however, local anesthetic consumption was larger in the popliteal group (4.9 +/- 1.4 mL/h) compared with the subgluteal group (3.8 +/- 1.1 mL/h; P < 0.05). We conclude continuous postoperative analgesia using stimulating catheters was effective at both injection sites; however, a subgluteal approach reduced the overall amount of local anesthetic.
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Anesthesia and analgesia · Jul 2006
Randomized Controlled TrialMelatonin does not reduce anxiety more than placebo in the elderly undergoing surgery.
Melatonin has been reported to reduce preoperative anxiety. We performed this study to compare preoperative anxiety in elderly patients receiving melatonin (M) or placebo (P). ⋯ The median (quartiles) anxiety level was 5 (2-8) before and 3 (1-7) 90 min after premedication in group M and 5 (3-6) and 3 (1-5) in group P, respectively. M and P reduce anxiety in elderly patients to a similar degree.