Anesthesia and analgesia
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Intraoperative blood salvage (IBS) devices are used as adjuncts to blood conservation in spinal surgical procedures of increasing duration, complexity, and total blood loss. We applied existing information about the performance and efficiency of IBS devices together with existing information regarding the distribution of crystalloids and colloids to provide clinicians with guidelines for the prediction of the total blood loss implications of a given volume of IBS return. ⋯ When replacement is undertaken with colloids or crystalloids, the appropriate replacement volume will be approximately 2.5 and 8.0 (respectively) times the volume of the IBS recovery. These volumes may be larger than have been appreciated by some clinicians.
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Anesthesia and analgesia · Mar 2005
Dexmedetomidine decreases the convulsive potency of bupivacaine and levobupivacaine in rats: involvement of alpha2-adrenoceptor for controlling convulsions.
Dexmedetomidine, a highly selective alpha(2)-adrenoceptor agonist, is used in combination with local anesthetics for sedation and analgesia. We tested the hypothesis that dexmedetomidine used for sedation alters the convulsive potency of racemic bupivacaine and levobupivacaine in awake, spontaneously breathing rats. In the first experiments, male Sprague-Dawley rats were randomly divided into six groups: bupivacaine with no dexmedetomidine (bupivacaine control; BC), bupivacaine with small-dose dexmedetomidine (BS), bupivacaine with large-dose dexmedetomidine (BL), levobupivacaine with no dexmedetomidine (levobupivacaine control; LC), levobupivacaine with small-dose dexmedetomidine (LS), and levobupivacaine with large-dose dexmedetomidine (LL) (n = 10 for each group). ⋯ Convulsive doses and plasma and brain concentrations of bupivacaine and levobupivacaine at the onset of convulsions in rats receiving yohimbine and dexmedetomidine were significantly smaller than in those receiving only dexmedetomidine (P < 0.05 for all) and were similar to those without dexmedetomidine or yohimbine. We conclude that dexmedetomidine used for sedation decreases the convulsive potency of both bupivacaine and levobupivacaine in rats. Alpha(2)-adrenoceptor agonism may be involved in this anticonvulsant potency.
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Anesthesia and analgesia · Mar 2005
Randomized Controlled Trial Clinical TrialAdding clonidine to the induction bolus and postoperative infusion during continuous femoral nerve block delays recovery of motor function after total knee arthroplasty.
We evaluated the effects of adding clonidine for continuous peripheral nerve infusions. Sixty patients undergoing total knee arthroplasty under combined single-injection sciatic block and continuous femoral infusion were randomly allocated to three groups: block induction with 0.75% ropivacaine followed by 0.2% ropivacaine (group control; n = 20); block induction with 0.75% ropivacaine and 1 microg/kg clonidine followed by 0.2% ropivacaine (group cloni-bolus; n = 20), and block induction with 0.75% ropivacaine and 1 microg/kg clonidine followed by 0.2% ropivacaine with 1 microg/mL clonidine (group cloni-infusion; n = 20). After surgery, continuous femoral infusion was provided with a patient-controlled infusion pump (basal infusion rate, 6 mL/h; incremental dose, 2 mL; lockout time, 15 min). ⋯ Hemodynamic profiles and sedation were similar in the three groups. Motor function impairment after 48 h of infusion was observed in 27% of cloni-infusion patients but in only 6% of both the control and cloni-bolus groups (P = 0.05). We conclude that adding clonidine 1 microg/mL to local anesthetic for continuous femoral nerve block does not improve the quality of pain relief but has the potential for delaying recovery of motor function.
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Anesthesia and analgesia · Mar 2005
Randomized Controlled Trial Clinical TrialIntravenous but not perineural clonidine prolongs postoperative analgesia after psoas compartment block with 0.5% levobupivacaine for hip fracture surgery.
We evaluated the systemic and local effects of clonidine as an analgesic adjunct to psoas compartment block (PCB) with levobupivacaine. In a randomized, prospective, double-blind trial, 36 patients requiring hip fracture surgery received PCB and general anesthesia. Patients were randomized into three groups. ⋯ The groups were similar in terms of 24 h cumulative morphine and acetaminophen consumption. There were no significant differences among groups regarding postoperative adverse effects (bradycardia, hypotension, sedation, and nausea). We conclude that IV but not perineural clonidine (1 microg/kg) prolongs analgesia after PCB without increasing the incidence of adverse effects.
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Anesthesia and analgesia · Mar 2005
Randomized Controlled Trial Clinical TrialThe short-acting beta1-adrenoceptor antagonists esmolol and landiolol suppress the bispectral index response to tracheal intubation during sevoflurane anesthesia.
In this randomized, double-blind, controlled study, we tested the hypothesis that the short-acting beta(1)-adrenoceptor antagonists esmolol and landiolol suppress hemodynamic changes and bispectral index (BIS) increases, both of which are induced by tracheal intubation under general anesthesia with sevoflurane alone. Forty-five patients were randomly assigned to the control, esmolol, and landiolol groups (n = 15 each). Anesthesia was induced with sevoflurane in oxygen, with an end-tidal concentration maintained at 1 minimum alveolar anesthetic concentration (MAC). ⋯ There were no differences in BIS among the three groups before laryngoscopy (39 +/- 5, 39 +/- 5, and 38 +/- 4 in the control, esmolol, and landiolol groups, respectively). BIS increased significantly in the control group (54 +/- 10; P < 0.05) 1 min after intubation, whereas it remained unchanged in the esmolol and landiolol groups (45 +/- 10 and 41 +/- 6, respectively). In conclusion, the increase in both heart rate and BIS after tracheal intubation under 1 MAC sevoflurane anesthesia was suppressed by the concomitant administration of either esmolol or landiolol.