Anesthesia and analgesia
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Anesthesia and analgesia · Mar 2006
The effects of stimulation pattern and sevoflurane concentration on intraoperative motor-evoked potentials.
The usefulness of intraoperative monitoring of motor-evoked potentials (MEPs) during inhaled anesthesia is limited by the suppressive effects of volatile anesthetics on MEP signals. We investigated the effects of different stimulation patterns and end-tidal concentrations of sevoflurane on intraoperative transcranial electrical MEPs. In 12 patients undergoing craniotomy, stimulation patterns (300-500 V, 100-1000 Hz, 1-5 stimuli) and multiples (0.5, 0.75, and 1.0) of minimum alveolar concentration (MAC) of sevoflurane were varied randomly while remifentanil was administered at a constant rate of 0.2 microg x kg(-1) x min(-1). ⋯ A significant main effect of sevoflurane concentration (0.5 versus 0.75 and 1 MAC multiple) on MEP amplitude was observed at the thenar recording site only (P < 0.05). In conclusion, MEP characteristics varied significantly with changes in stimulation pattern and less so with changes in sevoflurane concentration. The results suggest that high frequency repetitive stimulation allows intraoperative use of MEP monitoring during up to 1 MAC multiple of sevoflurane and constant infusion of remifentanil up to 0.2 microg x kg(-1) x min(-1).
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Anesthesia and analgesia · Jan 2006
Randomized Controlled Trial Comparative StudyThe sitting versus right lateral position during combined spinal-epidural anesthesia for cesarean delivery: block characteristics and severity of hypotension.
In the present study we evaluated whether the sitting position during initiation of small-dose combined spinal-epidural anesthesia (CSE) would induce less hypotension as compared with the lateral position. Sixty women undergoing elective cesarean delivery were randomly assigned to receive a spinal injection consisting of 6.6 mg hyperbaric bupivacaine with sufentanil 3.3 microg in either the lateral or the sitting position. After securing the epidural catheter, patients were turned to a 15 degrees left lateral supine position. ⋯ In the lateral group, blocks extended more cephalad than with the sitting position (P = 0.014). Apgar scores did not differ, but umbilical artery pH values were significantly higher in patients of the sitting group (7.31 +/- 0.04 versus 7.26 +/- 0.03; P = 0.02). We conclude that performing a CSE technique for cesarean delivery in the sitting position was technically easier and induced less severe hypotension.
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Anesthesia and analgesia · Oct 2006
Meta Analysis Comparative StudyA comparison of neuraxial block versus general anesthesia for elective total hip replacement: a meta-analysis.
A recent meta-analysis showed that compared with general anesthesia (GA), neuraxial block reduced many serious complications in patients undergoing various types of surgeries. It is not known whether this finding from studying heterogeneous patient groups is applicable to a particular surgical patient population. We performed the present meta-analysis to determine whether anesthesia choice affected the outcome after elective total hip replacement (THR). ⋯ Patients undergoing elective THR under neuraxial anesthesia seem to have better outcomes than those under GA.
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Anesthesia and analgesia · Jan 2006
Randomized Controlled Trial Comparative StudyContinuous positive airway pressure breathing increases the spread of sensory blockade after low-thoracic epidural injection of lidocaine.
Factors affecting the distribution of sensory blockade after epidural injection of local anesthetics remain incompletely clarified. To evaluate if increasing intrathoracic pressure affects the spread of thoracic epidural anesthesia, we randomized 20 patients who received an epidural catheter at the T7-8 or T8-9 intervertebral space into 2 groups. The control group (n = 10) received an epidural test dose of 4 mL lidocaine 2% during spontaneous breathing at ambient pressure. ⋯ The total number of segments blocked was 7 (median, interquartile range 2.25) in the control group and 11 (interquartile range 3.5) in the continuous positive airway pressure group (P = 0.004). The number of segments blocked caudad to the injection site was 3 (median, interquartile range 3.5) in the control group and 6 (interquartile range 2.25) in the continuous positive airway pressure group (P = 0.005). We conclude that continuous positive airway pressure increases the spread of sensory blockade in thoracic epidural anesthesia, primarily by a more caudad extension of sensory blockade.
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Anesthesia and analgesia · Jan 2006
Randomized Controlled Trial Comparative StudyPatient satisfaction with awake craniotomy for tumor surgery: a comparison of remifentanil and fentanyl in conjunction with propofol.
In this study we compared the effectiveness of the use of remifentanil to fentanyl in conjunction with propofol in providing conscious sedation for awake craniotomy for tumor surgery and to assess patient satisfaction with both techniques. The ability to maintain appropriate levels of sedation, adequate analgesia, and hemodynamic stability was assessed in 50 patients randomized to receive either fentanyl or remifentanil. All complications were documented. ⋯ Respiratory complications occurred in 9 (18%) patients (fentanyl 6, remifentanil 3). The recall and satisfaction scores were not different; 93% of all patients were completely satisfied at all interview times. The use of remifentanil infusion in conjunction with propofol is a good alternative to fentanyl and propofol for conscious sedation for the awake craniotomy and these techniques are both well accepted by the patient.