Comparing Neuromuscular Blockade Measurement Between Upper Arm (TOF Cuff®) and Eyelid (TOF Scan®) Using Mivacurium during General Anesthesia.

BACKGROUND Mivacurium is a non-depolarizing neuromuscular blocking agent. TOF-Cuff® is a device that monitors intraoperative neuromuscular blockade and blood pressure. TOF-Scan® measures muscle relaxation status of an anaesthetized patient. This study included 36 patients aged 18 to 75 years presenting for elective surgery, to compare neuromuscular blockade measured using the TOF-Cuff of the upper arm and the TOF-Scan of the facial corrugator supercilii muscle during general anesthesia and following administration of mivacurium. MATERIAL AND METHODS Train-of-four (TOF) values were obtained every 30 s before intubation and successively every 5 min until extubation. RESULTS The median onset time for TOF-Cuff was longer than for TOF-Scan (210 s vs 90 s, P<0.00001). Multiplying the time to relaxation (according to TOF-Scan) by 1 to 8, respectively, provided concordance with the TOF-Cuff result for the following cumulative percentages of patients: 5.5%, 38.9%, 58.3%, 77.8%, 83.3%, 86.1%, 88.9%, and 91.7%. Analogue values for time to recovery from the last dose were 11.1%, 63.9%, 83.3%, 86.1%, 86.1%, 88.9%, 88.9%, and 91.7%. The proportion of patients who still had TOFratio=0 in the assessment performed at min 15 did not differ significantly between these 2 methods (P=0.088). Both TOF-Scan and TOF-Cuff showed a false-negative result in patients with clinical symptoms of preterm recovery; the numerical difference favored TOF-Cuff (1.6% vs 2.1%) but without statistical significance (P=0.2235). CONCLUSIONS When measurement on the limb is not possible, TOF-Scan on the eyelid can be an alternative for TOF-Cuff on the upper arm, if the time to relaxation is multiplied by at least 8, which is enough for 90% of patients.

Comparison of Relaxometry Between Ulnar Nerve and Posterior Tibial Nerve After Cisatracurium Administration Using Electromyography.

Background: Electromyography can be used for quantitative neuromuscular monitoring during general anesthesia, mostly using the stimulation train-of-four (TOF) pattern. Relaxometry measures the muscular response of the adductor pollicis muscle to electrical stimulation of the ulnar nerve, which is routinely used in clinical practices for monitoring the neuromuscular block. However, when it is not always possible to be used for all patients, the posterior tibial nerve is a suitable alternative. Objectives: Using electromyography, we compared the neuromuscular block between the ulnar and the posterior tibial nerves. Methods: In this study, the participants were 110 patients who met inclusion criteria and submitted their written consent. Following the administration of cisatracurium intravenously, the patients had relaxometry performed simultaneously on the ulnar and the posterior tibial nerves using electromyography. Results: Eighty-seven patients were included in the final analysis. The onset time was 296 ± 99 s at the ulnar nerve and 346 ± 146 s at the tibial nerve, with a mean difference of -50 s and a standard deviation of 164 s. The 95% limits of agreement ranged from -372 s to 272 s. The relaxation time was 105 ± 26 min at the ulnar nerve and 87 ± 25 min at the tibial nerve, with a mean difference of 18 min and a standard deviation of 20 min. Conclusions: Using electromyography, no statistically significant difference was noticed between the ulnar and the posterior tibial nerve during the neuromuscular block. The onset time and the relaxation time assessed with an electromyogram to compare the stimulation of the ulnar and posterior tibial nerves showed large limits of agreement.