DOUBLE BURST STIMULATION WITH SUBMAXIMAL CURRENT

The present study evaluated responses to double burst stimulation (DBS ) at supramaximal and submaximal currents in 30 adult patients. Usuall y, DBS is applied with supramaximal stimulation, but this may be quite uncomfortable for the awake patient. Therefore, the authors investiga ted whether it is possible to obtain an accurate assessment of signifi cant residual neuromuscular blockade if the stimulus current is reduce d to 30 mA. In all patients, neuromuscular response to DBS three three (DBS3.3), DBS three two (DBS3.2) and train-of-four (TOF) stimulation at supramaximal and/or submaximal currents was recorded using a mechan omyograph, and the ratios of the fourth to the first twitch (T4/T1) in duced by TOF stimulation at supramaximal current, and the height of th e second response to the first (D2/D1) induced by DBS at 30 mA and sup ramaximal current were calculated. The relations between control T4/T1 ratios determined by supramaximal TOF stimulation and D2/D1 ratios de termined by supramaximal DBS3.3 and submaximal DBS3.3 were Y = 0.99X 0.08 and Y = 1.01X + 0.04, respectively, and there was no statistical difference between the two regression lines. The same relation betwee n T4/T1 ratios and D2/D1 ratios by DBS3.2 were Y = 0.69X + 0.05 and Y = 0.72X + 0.02, respectively, and there was no significant difference. It is concluded that evaluation of the response to DBS at 30 mA has t he same reliability as evaluation with supramaximal current.