Unintended subdural anesthesia and subdural air bubbles after attempted epidural anesthesia in a patient undergoing cesarean section.

BACKGROUND: Unintended subdural anesthesia accompanied by air bubbles compressing the cauda after attempting epidural anesthesia is rare. CASES: A 41-year-old pregnant woman was scheduled to undergo epidural anesthesia for cesarean section. After attempting epidural anesthesia, she experienced prolonged hypotension and recovery time, especially in the right extremity. Through magnetic resonance imaging we found subdural air bubbles compressing the right side of the cauda equina in the L3 region. Thus, we considered unintended subdural anesthesia and performed conservative management with close observation. Her symptoms completely resolved within 24 h. CONCLUSIONS: Here, we report a case with various features of subdural anesthesia and subdural air bubbles compressing the cauda.

Comparison of Contralateral Acceleromyography and Electromyography for Posttetanic Count Measurement.

BACKGROUND: Electromyography has advantages over mechanomyography and acceleromyography. Previously, agreement of the train-of-four counts between acceleromyography and electromyography was found to be fair. The objective of this study was to assess the agreement of posttetanic count including agreement of neuromuscular blockade status (intense block, posttetanic count equal to 0; or deep block, posttetanic count 1 or greater and train-of-four count equal to 0) between acceleromyography and electromyography. METHODS: Thirty-six patients, aged 20 to 65 yr, participated in this study. A dose of 0.6 mg/kg rocuronium, with additional dose of 0.3 mg/kg if required, was administered to the patients. The train-of-four and posttetanic counts were monitored in the contralateral arm using electromyography at the first dorsal interosseus or adductor pollicis, and acceleromyography at the adductor pollicis. Posttetanic count measurements were performed at 6-min intervals; the responses were recorded until the train-of-four count reached 1. The authors evaluated the agreement of degree of neuromuscular blockade (intense or deep block) and that of posttetanic count between acceleromyography and electromyography. RESULTS: The authors analyzed 226 pairs of measurements. The percentage agreement indicating the same neuromuscular blockade status (intense or deep block) between acceleromyography and electromyography was 73%. Cohen's kappa coefficient value was 0.26. After excluding data with acceleromyography-posttetanic counts greater than 15, a total of 184 pairs of posttetanic counts were used to evaluate the agreement between the two monitoring methods. For acceleromyography-posttetanic count, 42 (23%) pairs had the same electromyography-posttetanic count, and 93 (50%) pairs had more than the electromyography-posttetanic count. The mean posttetanic count on electromyography was 38% (95% CI, 20 to 51%) lower than that on acceleromyography (P = 0.0002). CONCLUSIONS: Acceleromyography frequently counted more twitches than electromyography in posttetanic count monitoring. Acceleromyography- and electromyography-posttetanic counts cannot be used interchangeably to assess the degree of neuromuscular blockade.