Intraoperative assessment of atracurium-induced neuromuscular block using double burst stimulation

Paired train-of-four (TOF) and double burst stimuli (DBS) were administered to the ulnar nerve at the wrist in 25 patients (group 1) paralysed with atracurium 0.5 mg kg-1; responses were measured mechanically (except every third DBS response which was manually evaluated). Another 30 patients (group 2) received a DBS every 60 s. A post-tetanic count (PTC) was performed when the first response (D1) was palpated. There was a significant correlation between the twitch heights of the first TOF response (T1) and D1 and likewise between the twitch heights of both second responses (r = 0.9; P less than 0.001), but there was a significant difference in regression coefficients of these two correlations (P less than 0.001). D1 was palpable first with a median PTC of 7. Our results showed that palpation of a single response implied a satisfactory level of paralysis. DBS may be useful for intraoperative clinical monitoring of neuromuscular block.