Study purpose: Train-of-four (TOF) monitoring is often recommended during the continuous use of neuromuscular blockade (NMB) [paralysis] in the ICU. Prior study results are conflicting regarding the benefits of TOF monitoring.
Design: Thirty patients in the medical ICU were randomized to TOF monitoring (n = 16) or to clinical assessment (n = 14) during continuous cisatracurium infusion. TOF monitoring was done at least every 4 h, with the goal being maintenance of one to two twitches. Statistical analysis was performed by two-tailed, unpaired t test (with Bonferroni correction for multiple comparisons), χ2, and Fisher exact test, with p < 0.05 considered significant. Given a power of 80%, and the variance seen in the two groups, we estimate that the sample size used is sufficient to detect a change of ≥ 60 min between groups for recovery time.
Results: The mean recovery time after cessation of paralytics was no different between TOF and clinical assessment (45 ± 7 min vs 38 ± 10 min, respectively [mean ± SEM]). No differences were noted for mean APACHE (acute physiology and chronic health evaluation) II entry scores, glomerular filtration rates, or use of corticosteroids. No significant differences were noted between TOF monitoring and clinical assessment in mean total paralysis time (4,118 ± 1,012 min vs 3,188 ± 705 min, respectively), mean total cisatracurium dose (920 ± 325 mg vs 715 ± 167 mg), or dosage (2.3 ± 0.2 μg/kg/min vs 2.9 ± 0.2 μg/kg/min).
Conclusions: TOF monitoring does not lead to improved recovery time or lower cisatracurium dosing compared with monitoring by clinical assessment. We conclude that TOF monitoring is unnecessary, and careful titration of the neuromuscular blocking agent by clinical assessment alone is sufficient in patients undergoing continuous cisatracurium NMB.