What is the recommended protocol for rocuronium (zamifenacin) perfusion during prolonged surgical procedures?

Rocuronium Perfusion Protocol for Prolonged Surgical Procedures

For prolonged surgical procedures, rocuronium perfusion should be initiated at 10-12 mcg/kg/min after early evidence of spontaneous recovery from the intubating dose, with continuous neuromuscular monitoring via Train-of-Four (TOF) to guide individualized dosing adjustments between 4-16 mcg/kg/min. 1

Initial Dosing and Administration

• Begin with an intubating dose of 0.6 mg/kg rocuronium IV bolus, which provides excellent intubating conditions within 2 minutes and maximum blockade within 3 minutes 1
• Wait for early evidence of spontaneous recovery from the intubating dose before starting the continuous infusion 1
• Initiate infusion at 10-12 mcg/kg/min only after early evidence of spontaneous recovery from the intubating dose 1
• If substantial return of neuromuscular function has occurred (more than 10% of control T1), additional bolus doses may be necessary to maintain adequate block for surgery 1

Infusion Maintenance and Monitoring

• Adjust the infusion rate according to the patient's twitch response as monitored with a peripheral nerve stimulator 1, 2
• Clinical trials have shown infusion rates typically range from 4 to 16 mcg/kg/min 1
• Train-of-Four (TOF) monitoring at the adductor pollicis muscle is mandatory to guide dosing and prevent prolonged blockade 2, 3
• For profound neuromuscular blockade (posttetanic count 0-2), a higher infusion rate of approximately 0.758 mg/kg/hr (12.6 mcg/kg/min) may be required 4
• For deep neuromuscular blockade with posttetanic count 1-2, an infusion rate of approximately 0.833 mg/kg/hr (13.9 mcg/kg/min) may be needed 4

Anesthetic Considerations and Adjustments

• When using inhalational anesthetics (particularly enflurane and isoflurane), reduce the infusion rate by 30-50% at 45-60 minutes after the intubating dose due to potentiation effects 1
• Always administer appropriate sedative and analgesic medications concurrently, as rocuronium provides no sedation, analgesia, or amnesia 2
• Prepare infusion solutions by mixing rocuronium with 5% glucose in water or lactated Ringers; these solutions should be used within 24 hours of mixing 1

Recovery and Reversal

• Spontaneous recovery following discontinuation of rocuronium infusion proceeds at rates comparable to those following equivalent total doses administered by repetitive bolus injections 1
• After continuous infusion, train-of-four response typically returns about 60 minutes after stopping the infusion 2, 5
• For reversal of neuromuscular blockade, sugammadex 4 mg/kg provides rapid recovery (median time 1.2-1.3 minutes to TOF ratio of 0.9) 6
• Recovery time after sugammadex administration following deep neuromuscular blockade may be longer (approximately 2.85 minutes) compared to moderate blockade (1.68 minutes) 4

Special Considerations

• For patients with renal or hepatic failure, consider using a benzylisoquinoline muscle relaxant (atracurium/cisatracurium) instead of rocuronium 3
• If rocuronium must be used in these patients, do not modify the initial dose but expect potentially prolonged duration of action 3
• Drug interactions can significantly alter dosing requirements - inhalational anesthetics potentiate the effect of rocuronium 2, 1
• Patients on pyridostigmine show increased sensitivity to rocuronium, requiring a 50-75% reduction in maintenance dosage 2

Common Pitfalls and Caveats

• Failure to monitor neuromuscular function can lead to overdosing or inadequate blockade 2
• Residual neuromuscular blockade can occur if monitoring is inadequate 2
• Continuous rocuronium infusion provides more stable neuromuscular blockade compared to on-demand bolus administration, with fewer additional bolus requests required 7
• The effect-site concentration of rocuronium at the time of recovery to detectable twitch after initial bolus can be a good indicator of optimal effect-site concentration needed during continuous infusion 8