Improved neuromuscular blockade using a novel neuromuscular blockade advisory system: a randomized, controlled, clinical trial

Anesth Analg. 2008 Nov;107(5):1609-17. doi: 10.1213/ane.0b013e318185cfb6.


Background: Conventional incremental bolus administration of neuromuscular blocking (NMB) drugs is associated with limitations in intraoperative control, potential delays in recovery, and residual blockade in the postanesthetic period. To overcome such limitations, we developed a novel adaptive control computer program, the Neuromuscular Blockade Advisory System (NMBAS). The NMBAS advises the anesthesiologist on the timing and dose of NMB drugs based on a sixth-order Laguerre model and the history of the patient's electromyographic responses. Here, we tested the hypothesis that the use of the NMBAS improves NMB compared to standard care.

Methods: We conducted a prospective, randomized, controlled, blinded, parallel-group, clinical trial with n = 73 patients (ASA physical status I-III) undergoing abdominal surgery under general anesthesia > or =1.5 h with NMB using rocuronium. Patients were allocated to standard care or NMBAS-guided rocuronium administration. The primary outcome variable was the incidence of intraoperative events reflecting inadequate NMB. Secondary outcome variables included train-of-four (TOF) ratios at the end of surgery before reversal, the total doses of rocuronium, reversal agents, anesthetics and other drugs, the incidence of postoperative adverse events, and the incidence of anesthesiologist noncompliance with NMBAS recommendations.

Results: Of 73 enrolled patients, n = 30 per group were eligible for analysis. Patient demographics were comparable between the groups. The incidence in total intraoperative events associated with inadequate NMB was significantly lower in the NMBAS group compared to standard care (8/30 vs 19/30; P = 0.004). Mean TOF ratios at the end of surgery before reversal were higher in the NMBAS group (0.59 [95% CI, 0.48-0.69] vs 0.14 [95% CI, 0.04-0.24]; P < 0.0001). Total administered doses of rocuronium, reversal drugs, and other drugs, and the incidence of postoperative adverse events were not different.

Conclusions: Compared to standard practice, NMBAS-guided care was associated with improved NMB quality and higher TOF ratios at the end of surgery, potentially reducing the risk of residual NMB and improving perioperative patient safety.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abdomen / surgery
  • Adult
  • Advisory Committees / organization & administration*
  • Aged
  • Androstanols / administration & dosage
  • Anesthesia, General / standards*
  • Atracurium / administration & dosage
  • Female
  • Health Status
  • Humans
  • Intraoperative Complications / epidemiology
  • Intraoperative Complications / prevention & control
  • Male
  • Middle Aged
  • Neuromuscular Blockade / standards*
  • Neuromuscular Blocking Agents / administration & dosage
  • Neuromuscular Blocking Agents / standards
  • Neuromuscular Blocking Agents / therapeutic use*
  • Pancuronium / administration & dosage
  • Rocuronium
  • gamma-Cyclodextrins / administration & dosage


  • Androstanols
  • Neuromuscular Blocking Agents
  • gamma-Cyclodextrins
  • Atracurium
  • Pancuronium
  • Rocuronium