Premium
Motor blockade and EMG recordings in epidural anaesthesia. A comparison between mepivacaine 2%, bupivacaine 0.5 % and etidocaine 1.5%
Author(s) -
Nydahl P.A.,
Axelsson K.,
Philipson L.,
Leissner P.,
Larsson P. G.
Publication year - 1989
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/j.1399-6576.1989.tb02974.x
Subject(s) - mepivacaine , medicine , isometric exercise , bupivacaine , anesthesia , blockade , electromyography , neuromuscular blockade , physical medicine and rehabilitation , receptor
In a double‐blind study young volunteers randomly received 20 ml of mepivacaine 2%, bupivacaine 0.5% or etidocaine 1.5% epidurally, all solutions with adrenaline. The mean cephalad spread of pin‐prick analgesia was equal (T10) in the groups, but the duration was longest for bupivacaine and etidocaine. The motor blockade of the rectus abdominis muscles was assessed quantitatively by rectified integrated electromyographic recordings (RIEMG) and as number of turns in EMG recordings [changes in the direction (rise/fall) of the EMG; TURNS] from three different segmental levels, T7, T9 and T11. The motor blockade of the quadriceps muscles was estimated by EMG recordings simultaneously with muscle force measurements at maximal isometric knee extension. Motor blockade was also evaluated by the Bromage scale. There was good correlation (correlation coefficient 0.91) between RIEMG values and muscle force in knee extension during epidural anaesthesia. TURNS showed a non‐linear relationship to isometric force during epidural anaesthesia and added no further information. At the lower parts of the abdomen (T11), etidocaine gave more profound and longer motor blockade than mepivacaine. For quadriceps muscle function, motor blockade was almost complete with all three local anaesthetics; the duration of maximum motor blockade was short (45–60 min) for mepivacaine, but about 5 h with etidocaine. At the time when the Bromage scale indicated complete regression of motor blockade, the muscle force of knee extension was only 30% and the quadriceps RIEMG 35% of control values and 1–3 h remained until the time of mobilization. The difference between the segmental level of maximal mean pin‐prick analgesia and that of motor blockade was roughly 4 segments with mepivacaine and bupivacaine and 2.5 segments with etidocaine. The time of complete regression of analgesia and the time of complete regression of motor blockade (knee extension) were about the same for mepivacaine (180 min) and bupivacaine (380 min). With etidocaine, quadriceps muscle force reverted at 580 min and motor blockade outlasted sensory block by 150 min.