British journal of anaesthesia
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A 19-yr-old woman developed a paraplegia with a T10 sensory level at 22 weeks' gestation. The spinal injury was caused by spontaneous bleed of a presumed arteriovenous malformation in the spinal cord. She presented for Caesarean section at term because of the breech position of her fetus. The successful use of a combined spinal epidural-regional anaesthetic is described and the risks of general and regional anaesthesia are discussed.
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The evoked electromyogram often decreases during anaesthesia in the absence of neuromuscular block. We have measured the electromyogram of the first dorsal interosseous muscle evoked by train-of-four stimulation of the ulnar nerve in 63 patients undergoing anaesthesia for minor surgery. We used Medicotest P-00-S electrodes, a Datex Relaxograph and a current sink in the stimulating leads in parallel with the current path through the patient. ⋯ In the remaining 50 patients, the response decreased to 78.4% (SD 27.1%, range 7.5-95.0%) of baseline values over the first 20 min of anaesthesia. In 22 of these patients, the electromyographic response increased from 71.4 (SD 22.6)% to 92.3 (9.5)% of baseline responses when the stimulus current was increased by 12.3 (2.4) mA, while in the remaining 28 patients the response decreased to 83.7 (10.6)% and did not increase with increasing stimulus current. These results suggest that loss of supramaximal stimulation is partly responsible for the observed changes in the evoked electromyogram during anaesthesia.