Anesthesia and analgesia
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Anesthesia and analgesia · Sep 2003
Case ReportsContinuous paravertebral catheter and outpatient infusion for breast surgery.
Paravertebral somatic nerve block (PVB) provides improved analgesia and decreased side effects compared with general anesthesia for breast surgery. The analgesia is limited with single injection PVB to the duration of the local anesthetic. ⋯ We describe the successful use of continuous paravertebral anesthesia in two patients undergoing major breast surgery. A novel needle system for paravertebral catheter insertion is also presented.
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Anesthesia and analgesia · Sep 2003
Clinical TrialCan quantitative sensory testing predict the outcome of epidural steroid injections in sciatica? A preliminary study.
Quantitative Sensory Testing (QST) is a psycho-physiological test used to identify dysfunction of individual nerve fiber types. In the present study, we investigated whether selective nerve fiber dysfunction, as assessed by QST, correlates with the effectiveness of epidural steroid injections (ESI) in patients with lumbar radiculopathy. Twenty patients with unilateral painful sciatica caused by disc herniation participated in this open study. ⋯ The increase in touch and vibration thresholds (Abeta-fiber dysfunction) was found to be inversely correlated with the improvement in NPS. No correlation was found between heat sensation thresholds (C fibers) and any of the outcome measures. These results suggest that QST has the potential to be an important tool in the selection of the appropriate treatment (e.g., ESI versus surgery) for patients with sciatica and may assist in identifying the mechanisms of pain generation in these patients.
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Anesthesia and analgesia · Sep 2003
Doxapram produces a dose-dependent reduction in the shivering threshold in rabbits.
Dopamine is a thermoregulatory neurotransmitter that provokes hypothermia when injected in or near the hypothalamus. Doxapram stimulates release of dopamine from carotid bodies, but is known to have central effects that are probably, at least in part, similarly mediated. We thus tested the hypothesis that doxapram produces a substantial, dose-dependent reduction in the shivering threshold in rabbits. ⋯ The control rabbits shivered at 36.3 degrees +/- 0.3 degrees C, those given 0.25 mg x kg(-1) x h(-1) doxapram shivered at 34.8 degrees +/- 0.5 degrees C, and those given 0.50 mg x kg(-1) x h(-1) shivered at 33.7 degrees +/- 0.6 degrees C. All the shivering thresholds significantly (P < 0.001) differed from one another. The magnitude of this inhibition, if similar in humans, would be clinically important.
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Anesthesia and analgesia · Sep 2003
The effect of lidocaine on the globule size distribution of propofol emulsions.
In this study, we sought to determine the globule size distribution of a propofol/lidocaine mixture as a function of lidocaine concentration and time elapsed after mixing in a standard formulation of propofol emulsion (Diprivan) and in a new formulation containing L-lysine to improve stability. The globule size was measured with a laser diffraction technique. The median diameter of the globule size in 20 mL of Diprivan immediately after the addition of 0, 10, 20, 30, 40, and 50 mg of lidocaine was similar to that of chylomicrons, ranging from 0.28 +/- 0.01 micro m to 0.30 +/- 0.02 micro m, over the whole range of lidocaine concentration. ⋯ The maximum globule diameter in the propofol emulsion to which L-lysine was added as a stabilizer did not exceed 3.0 micro m even when the largest amount of lidocaine was added. This study demonstrated that when 30 mg of lidocaine was added to 20 mL of Diprivan and the solution was left for a period of time, the globule size increased. Its increase was minimized by the addition of L-lysine to the propofol emulsion.
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Anesthesia and analgesia · Sep 2003
Comparative StudyThe hypnotic and analgesic effects of 2-bromomelatonin.
2-bromomelatonin is an analog of melatonin with a higher melatonin receptor affinity. We tested the hypnotic and analgesic properties of 2-bromomelatonin and compared them with those of propofol. Sprague-Dawley rats were assigned to receive 2-bromomelatonin or propofol IV, or morphine intraperitoneally. ⋯ Intraperitoneal 30 mg/kg morphine did not affect the righting reflex, but resulted in loss of response to tail clamping in all animals. 2-bromomelatonin can exert hypnotic and antinocifensive effects similar to that observed with propofol. Unlike propofol, the reduced nocifensive behavior persisted after the animals had regained their righting reflex. This study provides evidence that 2-bromomelatonin has properties that are desirable in anesthetics or anesthetic adjuvants.