Anesthesia and analgesia
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Anesthesia and analgesia · Nov 2003
Comparative Study Clinical TrialWomen experience more pain and require more morphine than men to achieve a similar degree of analgesia.
Sex differences in pain perception and in response to opioids have been described, but the findings are inconsistent. We sought to determine the effect of sex on pain perception, morphine consumption, and morphine analgesia after surgery. We designed a prospective cohort study and included 423 women and 277 men who emerged from general anesthesia after surgical procedures and who reported pain intensity of >or=5 on the 0-10 numeric rating scale (NRS). We administered 2.5 mg of morphine IV every 10 min until the pain intensity was
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Anesthesia and analgesia · Nov 2003
Clinical TrialUltrasound-guided supraclavicular brachial plexus block.
In this study, we evaluated state-of-the-art ultrasound technology for supraclavicular brachial plexus blocks in 40 outpatients. Ultrasound imaging was used to identify the brachial plexus before the block, guide the block needle to reach target nerves, and visualize the pattern of local anesthetic spread. Needle position was further confirmed by nerve stimulation before injection. The block technique we describe aligned the needle path with the ultrasound beam. The block was successful after one attempt in 95% of the cases, with one failure attributable to subcutaneous injection and one to partial intravascular injection. Pneumothorax did not occur. Our preliminary data suggest that a high-resolution ultrasound probe can reliably identify the brachial plexus and its neighboring structures in the supraclavicular region. The technique of real-time guidance during needle advancement can quickly localize nerves. Distinct patterns of local anesthetic spread observed on ultrasound can further confirm accurate needle location. ⋯ Real-time ultrasound imaging during supraclavicular brachial plexus blocks can facilitate nerve localization and needle placement and examine the pattern of local anesthetic spread.
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Anesthesia and analgesia · Nov 2003
Case ReportsIntrathecal clonidine and severe hypotension after cardiopulmonary bypass.
The use of intrathecal clonidine as an adjunct for the management of chronic pain, intra- and postoperative analgesia is gaining an increase in popularity. However, antinociceptive doses of intrathecal clonidine may produce pronounced hemodynamic side effects, including hypotension and bradycardia. ⋯ We postulate that the intrathecally administered alpha 2-agonist clonidine reduced our patient's ability to tolerate the hemodynamic lability that is present during the separation from cardiopulmonary bypass by potentially inhibiting sympathetic nervous system activity, renin-angiotensin system, or vasopressin release. The authors report a case of severe hypotension after cardiopulmonary bypass in a patient receiving intrathecal clonidine infusion for chronic neuropathic pain.
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Anesthesia and analgesia · Nov 2003
Clinical TrialPossible overestimation of indocyanine green-derived plasma volume early after induction of anesthesia with propofol/fentanyl.
Apparently large plasma volumes derived by indocyanine green (PV-ICG) have been determined in the initial period after induction of anesthesia. We tested the hypothesis that possible overestimation of PV-ICG occurs shortly after anesthetic induction. Anesthesia was induced in 13 patients with fentanyl bolus 2 microg/kg and propofol infusion 0.5 mg x kg(-1) x min(-1) IV until patients lost consciousness and was then maintained with a propofol infusion. PV-ICG and the initial distribution volume of glucose (IDVG) were assessed at 15 min before and at 15 min after anesthetic induction. Plasma ICG and glucose concentrations were measured from serial blood samples taken before and through 7 min after injection of ICG 25 mg and glucose 5 g. PV-ICG and IDVG were calculated using a one-compartment model. PV-ICG was significantly increased by an average of 15.3% after induction, from 2.29 +/- 0.38 (SD) L to 2.64 +/- 0.31 L (P < 0.001). The mean hematocrit (Hct), concentrations of hemoglobin (Hb), and total plasma proteins at postinduction decreased compared with those at preinduction by 2.9%, 2.2%, and 2.3%, respectively (P < 0.05). Percentile increase in plasma volume calculated from Hb and Hct before and after induction was 4%. Consequently, an 11% overestimation in PV-ICG was observed. IDVG remained unchanged. Therefore, the ratio of PV-ICG/IDVG increased from 0.40 +/- 0.05 before induction to 0.48 +/- 0.06 after induction (P < 0.01). These results validate the hypothesis that possible overestimation of PV-ICG occurs during a definable period of time after propofol anesthetic induction. The present results also support the PV-ICG/IDVG ratio as a measure of possible overestimation of PV-ICG or fluid redistribution from the central to the peripheral tissues. ⋯ An approximate 11% overestimation in indocyanine green derived plasma volume was observed after induction of anesthesia using propofol and fentanyl. Simultaneous measurement of the initial distribution volume of glucose may help investigate the presence of overestimation in indocyanine green derived plasma volume.
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Anesthesia and analgesia · Nov 2003
Case ReportsSciatic nerve block in a child: a sonographic approach.
Ultrasound technology can facilitate peripheral nerve blocks in clinical practice. In this case report, ultrasound imaging was used to identify the sciatic nerve and guide local anesthetic injection in the subgluteal region of a child undergoing Achilles tendon lengthening. Sonographic guidance may be especially useful for peripheral nerve blocks in children because the neural imaging is often excellent and reference landmarks are variable. ⋯ In this case report, ultrasound was used to identify the sciatic nerve and guide local anesthetic injection in the subgluteal region of a child. Sonographic guidance may be especially useful for peripheral nerve blocks in children because the neural imaging is often excellent and reference landmarks are variable.