British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Spinal anaesthesia for Caesarean section: effect of Sprotte needle orientation.
We induced spinal anaesthesia in 100 women presenting for elective Caesarean section with the mother in the right lateral position. Patients were allocated randomly to have the side eye of the 24-gauge Sprotte spinal needle pointing in one of four directions: group A, cephalad; group B, right lateral; group C, left lateral; group D, caudad. ⋯ Onset of sensory block to T4 was significantly faster in group A (P = 0.001). There were no differences in final block height, incidence of hypotension, nausea and vomiting or ephedrine requirements.
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Comparative Study
Quantitative EEG in assessment of anaesthetic depth: comparative study of methodology.
Methodology for assessment of depth of anaesthesia based on analysis of the electroencephalogram (EEG) is controversial. Techniques range from display of single measures, for example median value of the frequency spectrum, to dedicated pattern recognition systems based on measures of several EEG features. We have compared the performance of four techniques using tape-recorded data from 23 patients anaesthetized with either halothane or isoflurane using standardized regimens. ⋯ Dose-response curves are presented for stepwise increases in stable end-tidal concentrations of each agent. Results indicated considerable inter-patient variability and the limitations of single EEG measures, particularly with deeper anaesthesia producing a burst suppression pattern in the EEG. Pattern recognition techniques reduced these difficulties and appeared to be promising over a wide range of anaesthetic levels.
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To clarify pregnancy-induced changes in soft tissue anatomy within the vertebral canal, we have studied magnetic resonance (MR) images of the lumbar spine in three women. In each subject, T2-weighted axial MR images were obtained both before pregnancy and at 32 weeks' gestation, and the paired images were compared. ⋯ In addition, the engorged extradural venous plexus displaced the dura away from the wall of the vertebral canal in a posterior direction, which resulted in a decrease in the volume of the cerebrospinal fluid in the dural sac. These findings confirmed the long-held concept that the engorged extradural venous plexus in supine parturients decreases the effective capacity of the extradural and subarachnoid spaces.
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Randomized Controlled Trial Comparative Study Clinical Trial
Alfentanil-mediated analgesia during propofol injection: no evidence for a peripheral action.
We have investigated if alfentanil acts via peripheral opioid receptors to relieve the pain which occurs on injection of propofol. Thirty seconds before induction of anaesthesia and immediately after a tourniquet at 50 mm Hg greater than systolic pressure was inflated on the upper arm, patients were given either placebo (n = 22), alfentanil 1 mg (n = 22) or lignocaine 40 mg (n = 22) via an i.v. cannula in the dorsum of the hand. ⋯ We found a significant reduction in pain after lignocaine compared with the two other groups (P < 0.001), but there was no difference between the placebo and alfentanil groups. We conclude that alfentanil does not relieve pain on injection with propofol via an action on peripheral opioid receptors when alfentanil is limited to the forearm for 30 s before induction of anaesthesia.
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Randomized Controlled Trial Comparative Study Clinical Trial
Spinal anaesthesia with 0.25% hyperbaric bupivacaine for Caesarean section: effects of volume.
To investigate the safety and efficacy of 0.25% hyperbaric bupivacaine for spinal anaesthesia in Caesarean section, we studied 60 parturients allocated randomly to one of three groups. According to the patient's height, groups 1, 2 and 3 received 3.2-3.6 ml (8-9 mg), 3.6-4.0 ml (9-10 mg) and 4.0-4.4 ml (10-11 mg) of 0.25% bupivacaine in 5% glucose, respectively. Subarachnoid injection was performed in the right lateral decubitus position, and parturients were then turned immediately supine with left uterine displacement. ⋯ The incidence of patients requiring analgesics during operation was significantly lower in groups 2 (25%) and 3 (10%) than in group 1 (70%). There was no difference in neonatal condition between the three groups. Spinal anaesthesia with 3.6-4.0 ml of 0.25% bupivacaine in 5% glucose was satisfactory for Caesarean section.