Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2003
The effect of systemic zonisamide (Zonegran) on thermal hyperalgesia and mechanical allodynia in rats with an experimental mononeuropathy.
We studied the ability of zonisamide (Zonegran) to relieve thermal hyperalgesia and/or mechanical allodynia in the chronic constriction injury model of neuropathic pain. Zonisamide (25, 50, or 100 mg/kg) or saline was administered in a blinded, randomized manner by intraperitoneal injection on postoperative days (PODs) 4, 5, and 6. Paw withdrawal latency (PWL) to heat, paw withdrawal response to von Frey monofilaments, and pain scores based on weight-bearing were tested: before surgery; before and after zonisamide or saline (PODs 4, 5, and 6); and on POD 9. Systemic zonisamide relieved thermal hyperalgesia in a dose-dependent manner. All PWLs were significantly increased after zonisamide administration compared with pre-zonisamide measurements, except with the 100 mg/kg dose on POD 5. After zonisamide 100 mg/kg administration, there was a sustained increase in PWL on PODs 5 and 9, with significant carryover effect from the previous dose. However, zonisamide had little effect on mechanical allodynia, except at the 100 mg/kg dose, which was sedating in the rat. At the 100 mg/kg dose, paw withdrawal response was increased on PODs 4 and 5, whereas pain scores were reduced on PODs 4, 5, and 6. Pain scores were inconsistently reduced after 50 mg/kg or 25 mg/kg doses. ⋯ Zonisamide causes a dose-related decrease in heat sensitivity in a rat model of neuropathic pain, but relieves mechanical sensitivity only in a dose that is sedating to the rat. Zonisamide may be useful in the treatment of some types of neuropathic pain.
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Anesthesia and analgesia · Jun 2003
Randomized Controlled Trial Comparative Study Clinical TrialResistive-heating and forced-air warming are comparably effective.
Serious adverse outcomes from perioperative hypothermia are well documented. Consequently, intraoperative warming has become routine. We thus evaluated the efficacy of a novel, nondisposable carbon-fiber resistive-heating system. Twenty-four patients undergoing open abdominal surgery lasting approximately 4 h were randomly assigned to warming with 1) a full-length circulating water mattress set at 42 degrees C, 2) a lower-body forced-air cover with the blower set on high, or 3) a three-extremity carbon-fiber resistive-heating blanket set to 42 degrees C. Patients were anesthetized with a combination of continuous epidural and general anesthesia. All fluids were warmed to 37 degrees C, and ambient temperature was kept near 22 degrees C. Core (tympanic membrane) temperature changes among the groups were compared by using factorial analysis of variance and Scheffé F tests; results are presented as means +/- SD. Potential confounding factors did not differ significantly among the groups. In the first 2 h of surgery, core temperature decreased by 1.9 degrees C +/- 0.5 degrees C in the circulating-water group, 1.0 degrees C +/- 0.6 degrees C in the forced-air group, and 0.8 degrees C +/- 0.2 degrees C in the resistive-heating group. At the end of surgery, the decreases were 2.0 degrees C +/- 0.8 degrees C in the circulating-water group, 0.6 degrees C +/- 1.0 degrees C in the forced-air group, and 0.5 degrees C +/- 0.4 degrees C in the resistive-heating group. Core temperature decreases were significantly greater in the circulating-water group at all times after 150 elapsed minutes; however, temperature changes in the forced-air and resistive-heating groups never differed significantly. Even during major abdominal surgery, resistive heating maintains core temperature as effectively as forced air. ⋯ Efficacy was similar for forced-air and resistive heating, and both maintained intraoperative core temperature far better than circulating-water mattresses. We thus conclude that even during major abdominal surgery, resistive heating maintains core temperature as effectively as forced air.
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Anesthesia and analgesia · Jun 2003
Randomized Controlled Trial Clinical TrialThe effect of dexamethasone on side effects after coronary revascularization procedures.
Corticosteroids decrease side effects after noncardiac elective surgery. We designed this randomized, double-blinded, placebo-controlled study to test the hypothesis that standard doses of dexamethasone (4 mg x2) would reduce postoperative nausea, vomiting, and pain, decrease the incidence of atrial fibrillation (AF), and improve appetite after cardiac surgery, thereby facilitating the recovery process. A total of 300 patients undergoing coronary revascularization surgery were enrolled in this clinical study. The anesthetic management was standardized in all patients. Dexamethasone (4 mg/mL) or saline (1 mL) was administered after the induction of anesthesia and a second dose of the same study drug was given on the morning after surgery. The incidence of AF was determined by analyzing the first 72 h of continuously recorded electrocardiogram records after cardiac surgery. The patients were assessed at 24- and 48-h intervals after surgery, as well as at the time of hospital discharge, to determine the incidence and severity of postoperative side effects (e.g., nausea, vomiting, pain) and patient satisfaction scores. Dexamethasone significantly reduced the need for antiemetic rescue medication on the first postoperative day (30% versus 42%), and the incidences of nausea (15% versus 26%) and vomiting (5% versus 16%) on the second postoperative day (P < 0.05). In addition, dexamethasone significantly reduced the percentage of patients with a depressed appetite on the second postoperative day. However, the corticosteroid failed to decrease the incidence of AF (27% versus 32%) or the total dosage of opioid analgesic medication administered in the postoperative period. We conclude that dexamethasone (8 mg in divided doses) was beneficial in reducing emetic symptoms and improving appetite after cardiac surgery. However, this dose of the corticosteroid does not seem to have antiarrhythmic or analgesic-sparing properties. ⋯ Dexamethasone (8 mg IV) was beneficial in reducing emetic symptoms and increasing appetite after cardiac surgery. However, this dose of the corticosteroid failed to decrease postoperative pain or the incidence of new-onset atrial fibrillation.