COMPARISON OF TACTILE AND MECHANOMYO-GRAPHICAL ASSESSMENT OF RESPONSETO DOUBLE BURST AND TRAIN-OF-4 STIMULATION DURING MODERATE AND PROFOUND NEUROMUSCULAR BLOCKADE

It is common clinical practice to estimate the degree of neuromuscular blockade hv tactile evaluation of twitch responses. The aim of the pr esent study was to evaluate the use of tactile responses of adductor p ollicis to double-burst stimulation (DBS) and train-of-four (TOF) peri pheral nerve stimulation for monitoring moderate and profound levels o f neuromuscular blockade. The study comprised 44 women scheduled for g ynaecological laparotomy and anaesthetised with midazolam, fentanyl, t hiopentone, halothane, nitrous oxide and atracurium. The tactile respo nses of the adductor pollicis were compared with mechanomyographical m easurements in the contra lateral arm during recovery from neuromuscul ar blockade. The observers (anaesthetic nurses) of the tactile respons es were blinded with regard to the stimulation pattern and the mechano myographical measurements. The time from injection of the initial dose of atracurium until tactile reappearance of the first twitch in DBS ( D-1), was 24.6 (0-39.8) min, median (range). This was more rapid than the time until tactile reappearance of the first twitch in TOF (T-1) 3 2.8 (18.2-43.4) min (P < 0.05). The median time from tactile reappeara nce of D-1 until T-1 recovered to 15% of the control twitch height was longer than the median time from tactile reappearance of T-1 (14.6 ve rsus 10.5 min) (P < 0.05). One or two responses to DBS or TOF were oft en felt before any responses had been detected mechanomyographically i n the contralateral arm. When three or four responses to TOF were felt , responses were always detected mechanomyographically. IT is conclude d that tactile evaluation of responses to DBS stimulation can estimate deeper levels of blockade than tactile evaluation of responses to TOF .