What is the recommended train of four (TOF) monitoring for patients receiving Nimbex (Cisatracurium)?

Train of Four Monitoring for Cisatracurium (Nimbex)

Quantitative neuromuscular monitoring is essential when administering cisatracurium (Nimbex), with a target train-of-four (TOF) ratio >0.9 before extubation to prevent residual neuromuscular blockade and associated complications. 1

Recommended Monitoring Protocol for Cisatracurium

• Quantitative neuromuscular monitoring should be applied before administration of cisatracurium and used throughout all phases of anesthesia 1
• The ulnar nerve is the most reliable site for monitoring, with the adductor pollicis muscle providing the most accurate assessment 1
• Monitor should be activated after induction of general anesthesia but before administration of cisatracurium 1
• When using cisatracurium in the ICU, train-of-four monitoring should be performed at least every 4 hours 2
• Additional doses of cisatracurium should not be given before there is a definite response to nerve stimulation 3

Interpretation of TOF Monitoring

• With increasing depth of neuromuscular blockade, twitches decrease in force with the fourth twitch (T4) lost first, followed by T3, T2, and finally T1 1
• Absence of tactile or visible TOF fade using a peripheral nerve stimulator only indicates TOF ratio recovery to 0.4 or greater 1
• The "monitoring gap" between 0.4 and 0.9 can only be assessed using quantitative monitoring 1
• Clinical tests of recovery (sustained head-lift, hand grip, tongue depressor tests) are inadequate with sensitivities of only 10-30% 1

Reversal of Cisatracurium

• Adequacy of recovery (TOF ratio >0.9) must be demonstrated and documented before patient awakening and extubation 1
• When using neostigmine for reversal:
  • Administer only when 4 responses to TOF stimulation are visible 1
  • Dose at 0.04 mg/kg with atropine 0.02 mg/kg 1, 4
  • Expect efficacy (TOF ratio ≥0.9) in 10-20 minutes 1
• If using sugammadex (for rocuronium, not cisatracurium):
  • Dose based on depth of blockade 1
  • Continue monitoring after administration to detect potential recurarization 5

Common Pitfalls and Considerations

• Residual neuromuscular blockade (TOF ratio <0.9) occurs in approximately 40% of patients receiving cisatracurium when not properly monitored 6
• Consequences of inadequate recovery include:
  • Generalized muscle weakness and delayed recovery 1
  • Reduced chemoreceptor-mediated responsiveness to hypoxia 1
  • Risk of aspiration and postoperative pulmonary complications 1, 5
  • Accidental awareness during general anesthesia 1
• Many factors can affect the duration of cisatracurium's action:
  • Diuretics, antiarrhythmic agents, aminoglycosides, magnesium, lithium, hypokalemia, hypothermia, and acidosis can increase potency 1, 3
  • Isoflurane or enflurane may prolong the duration of action 3
• Alternative monitoring sites (facial or tibial nerve) may be used if the hand is inaccessible, but facial nerve monitoring increases the risk of residual paralysis five-fold 1

Special Considerations

• Patients with renal dysfunction may have approximately 1 minute slower onset time 3
• Patients with end-stage liver disease may have approximately 1 minute faster onset time 3
• Patients with hemiparesis or paraparesis may demonstrate resistance to cisatracurium in affected limbs; monitoring should be performed on a non-paretic limb 3
• For ICU patients receiving prolonged cisatracurium infusions, continuous monitoring is essential with additional doses administered only after definite response to nerve stimulation 3