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[Prolonged neuromuscular block induced by mivacurium in a patient treated with cyclophosphamide]
1Service d'Anesthésie Urgences et Réanimation, CHR Rangueil, Toulouse.
Abstract:
A case is reported of prolonged neuromuscular block after mivacurium chloride for laparoscopic cholecystectomy, in a 45 years old patient, treated with cyclophosphamide for a Wegener's granulomatosis. The neuromuscular function monitoring by train-of-four showed a duration of action of 75 min after an intubation dose of 0.20 mg.kg-1. Additional bolus of 1 mg, corresponding to 25% of usual doses, every 10 or 15 min, were sufficient for maintaining muscle relaxation. Spontaneous recovery, without any antagonization, lasted 40 min for a TOF ratio (T4/T1) > or = 70%. Recovery index from 25 to 75% were 13 min. Plasma butyrilcholinesterases activity were reduced to a level of 50%. With reference to literature about succinylcholine, the responsibility of cyclophosphamide is likely, and discussed. This observation shows the value of monitoring the neuromuscular transmission.
Insights
Cyclophosphamide may prolong neuromuscular block from mivacurium chloride, impacting anesthesia recovery. Continuous neuromuscular monitoring is vital for patient safety during surgery.
Area of Science:
- Anesthesiology
- Pharmacology
- Immunology
Background:
- Mivacurium chloride is a common neuromuscular blocking agent.
- Cyclophosphamide is an immunosuppressant used for autoimmune diseases like Wegener's granulomatosis.
- Reduced plasma butyrilcholinesterase activity can prolong the action of certain neuromuscular blockers.
Observation:
- A 45-year-old patient receiving cyclophosphamide experienced prolonged neuromuscular block after mivacurium chloride administration during laparoscopic cholecystectomy.
- Neuromuscular function monitoring (train-of-four) indicated a 75-minute duration of action after the initial intubation dose.
- Additional low-dose boluses were required to maintain muscle relaxation, and spontaneous recovery took 40 minutes.
Findings:
- The patient's plasma butyrilcholinesterase activity was reduced by 50%.
- The prolonged neuromuscular block is likely attributable to the interaction between cyclophosphamide and mivacurium chloride, potentially due to reduced enzyme activity.
- Neuromuscular transmission monitoring demonstrated its value in managing such prolonged effects.
Implications:
- This case highlights a potential drug interaction between cyclophosphamide and mivacurium chloride, necessitating careful anesthetic management.
- Clinicians should consider reduced butyrilcholinesterase activity in patients on cyclophosphamide when administering mivacurium chloride.
- Continuous neuromuscular monitoring is crucial for ensuring adequate recovery and patient safety in cases of suspected prolonged neuromuscular blockade.