Anesthesia and analgesia
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Anesthesia and analgesia · Nov 2003
The cardioprotective effect of sevoflurane depends on protein kinase C activation, opening of mitochondrial K(+)(ATP) channels, and the production of reactive oxygen species.
Several studies suggest that the cardioprotective effect of sevoflurane depends on protein kinase C (PKC) activation, mitochondrial K(+)(ATP) channel (mitoK(+)(ATP)) opening, and reactive oxygen species (ROS). However, evidence for their involvement was obtained in separate experimental models. Here, we studied the relative roles of PKC, mitoK(+)(ATP), and ROS in sevoflurane-induced cardioprotection in one model. Rat trabeculae were subjected to simulated ischemia by applying metabolic inhibition (MI) through buffer containing NaCN, followed by 60-min reperfusion. Recovery of active force (F(a)) was assessed as percentage of pre-MI force. In time controls, F(a) amounted 60% +/- 5% at the end of the experiment. The recovery of F(a) after MI was reduced to 28% +/- 5% (P = 0.045 versus time control), whereas sevoflurane reversed the detrimental effect of MI (F(a) recovery, 67% +/- 8%; P = 0.01 versus MI). The PKC inhibitor chelerythrine, the mitoK(+)(ATP) inhibitor 5-hydroxy decanoic, and the ROS scavenger N-(2-mercaptopropionyl)-glycine all completely abolished the protective effect of sevoflurane (recovery of F(a), 31% +/- 8%, 33% +/- 8%, and 24% +/- 9% for chelerythrine, 5-hydroxy decanoic, and N-(2-mercaptopropionyl)-glycine, respectively). In conclusion, PKC activation, mitoK(+)(ATP) channel opening, and ROS production are all essential for sevoflurane-induced cardioprotection. These signaling events are arranged in series within a common signaling pathway, rather than in parallel cascades. Our findings implicate that the perioperative use of sevoflurane preserves cardiac function by preventing ischemia-reperfusion injury. ⋯ Protein kinase C, mitochondrial K(+)(ATP) channels and reactive oxygen species act within one downstream signaling pathway in mediating the cardioprotective effect of sevoflurane.
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Anesthesia and analgesia · Nov 2003
Randomized Controlled Trial Comparative Study Clinical TrialSpinal mechanisms contribute to analgesia produced by epidural sufentanil combined with bupivacaine for postoperative analgesia.
When used alone, lipid-soluble epidural opioids are thought to produce analgesia supraspinally via systemic absorption. However, spinal opioids and local anesthetics have been shown to act synergistically at the spinal level in animal studies. We, therefore, tested the hypothesis that sufentanil requirements will be less when given epidurally than IV in patients simultaneously given epidural bupivacaine after major abdominal surgery. Forty patients were anesthetized with isoflurane and epidural bupivacaine for major abdominal surgery. After surgery, each was given a continuous epidural infusion of bupivacaine at a rate of 5 mg/h and sufentanil patient-controlled analgesia (PCA). In a randomized, double-blinded fashion, the sufentanil was given either epidurally or IV. PCA settings were the same in each group. For 60 hrs after surgery, the following variables were measured: pain scores at rest, during mobilization, and during coughing; extension of sensory block; side effects; and sufentanil consumption. Pain scores, extension of sensory block, and the incidence of side effects did not differ between the two groups. Consumption of sufentanil in the epidural group was half that of the IV group (48 h after surgery: 107 +/- 57 microg versus 207 +/- 100 microg for the epidural and IV groups, respectively; P < 0.05). We conclude that spinal mechanisms contribute to the analgesia produced by epidural sufentanil in combination with a local anesthetic. ⋯ When combined with epidural bupivacaine, the sufentanil requirement was 50% less when given epidurally than IV. Epidural sufentanil thus appears to have a spinal mechanism of action.
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Anesthesia and analgesia · Nov 2003
Randomized Controlled Trial Comparative Study Clinical TrialElectrical stimulation of auricular acupuncture points is more effective than conventional manual auricular acupuncture in chronic cervical pain: a pilot study.
In this prospective, randomized, double-blinded, controlled study, we tested the hypothesis that auricular electroacupuncture relieves pain more effectively than conventional manual auricular acupuncture. We studied 21 chronic cervical pain patients without radicular symptoms with insufficient pain relief (visual analogue scale >5) treated with standardized analgesic therapy. All patients received disposable acupuncture needles on the dominant side on the following acupuncture points: cervical spine, shen men, and cushion. In 10 patients, needles were continuously stimulated (2-mA constant current, 1 Hz monophasic) by using the electrical point stimulation device P-STIM. In 11 control patients, no electrical stimulation was administered. All needles were withdrawn 48 h after insertion. Acupuncture was performed once a week for 6 wk. Patients had to complete a questionnaire assessing pain intensity, psychological well-being, activity, sleep, and demand for rescue medication (lornoxicam and tramadol). The reduction in pain scores was significant in the electrical acupuncture group. Similarly, psychological well-being, activity, and sleep were significantly improved in patients receiving electrical acupuncture, and consumption of rescue medication was significantly less. These results demonstrate that continuous electrical stimulation of auricular acupuncture points by using the new point stimulation device P-STIM improves the treatment of chronic cervical pain in an outpatient population. ⋯ Continuous electrical stimulation of auricular acupuncture points by using the new point stimulation device P-STIM significantly decreases pain intensity and significantly improves psychological well-being, activity, and sleep in chronic cervical pain patients.