Efficacy of Tactile-guided Reversal from Cisatracurium-induced Neuromuscular Block

Background: Because tactile evaluation is the most common form of clinical neuromuscular monitoring, this study examines the relative efficacy of antagonizing residual block at different levels of recovery of the tactile train-of-four (TOF) response.

Methods: Anesthesia was induced in 64 adults with 2-5 microg/kg fentanyl and 1-3 mg/kg propofol and maintained with fentanyl, propofol, and nitrous oxide. The tactile response of the adductor pollicis to TOF stimulation was evaluated at one arm, and the mechanomyographic response was recorded at the other. Patients received 0.15 mg/kg cisatracurium and were randomized to receive 0.07 mg/kg neostigmine on reappearance of the first (group I), second (group II), third (group III), or fourth (group IV) tactile TOF response (16 patients per group). Times from administration of neostigmine until the TOF ratio recovered to 0.7 (R0.7), 0.8 (R0.8), and 0.9 (R0.9) were measured.

Results: Data are presented as median with range in parentheses. R0.7 was 10.3 (5.9-23.4), 7.6 (3.2-14.1), 5.0 (2.0-18.4), and 4.1 (2.4-11.0) min in groups I, II, III, and IV, respectively (P < 0.05, group I > II, III, and IV, group II > IV). R0.8 was 16.6 (8.9-30.7), 9.8 (5.3-25.0), 8.3 (3.8-27.1), and 7.5 (3.0-74.5) min in groups I, II, III, and IV, respectively (P < 0.05, group I > II, III, and IV, group II > IV). R0.9 was 22.2 (13.9-44.0), 20.2 (6.5-70.5), 17.1 (8.3-46.2), and 16.5 (6.5-143.3) min in groups I, II, III, and IV, respectively (no intergroup differences). Ten minutes after neostigmine, a TOF ratio of 0.7 or greater was achieved in 50, 75, 88, and 93% of patients in groups I, II, III, and IV, respectively (P < 0.05 group I > II, III, and IV). At 30 min, a TOF ratio of 0.9 or less was observed in 21, 13, 13, and 7% of patients in groups I, II, III, and IV respectively (no intergroup differences).

Conclusions: To achieve rapid (within 10 min) reversal to a TOF ratio of 0.7 in more than 87% of patients, three or four tactile responses should be present at the time of neostigmine administration. It was not possible within 30 min to achieve a TOF ratio of 0.9 in all patients, regardless of the number of tactile responses present at neostigmine administration.