The isolated forearm technique is used to monitor intraoperative awareness. However, this technique cannot be applied to patients who must be kept deeply paralysed for >1h, because the tourniquet preventing the neuromuscular blocking agent from paralysing the forearm must be deflated from time to time. To overcome this problem, we tested the feasibility of a ‘reversed’ isolated forearm technique.Methods:
Patients received rocuronium 0.6 mg kg-1 i.v. to achieve muscle paralysis. A tourniquet was then inflated around one upper arm to prevent further blood supply to the forearm. Sugammadex was injected into a vein of this isolated forearm to antagonize muscle paralysis regionally. A dose titration of sugammadex to antagonize muscle paralysis in the isolated forearm was performed in 10 patients, and the effects of the selected dose were observed in 10 additional patients.Results:
The sugammadex dose required to antagonize muscle paralysis in the isolated forearm was 0.03 mg kg-1 in 30 ml of 0.9% saline. Muscle paralysis was antagonized in the isolated forearm within 3.2 min in nine of 10 patients; the rest of the patients' bodies remained paralysed. Releasing the tourniquet 15 min later did not affect the train-of-four count in the isolated forearm but significantly increased the train-of-four count in the other arm by 7%.Conclusions:
Regional antagonization of rocuronium-induced muscle paralysis using a sugammadex dose of 0.03 mg kg-1 injected into an isolated forearm was feasible and did not have relevant systemic effects.Clinical trial registration:
The trial was registered at EudraCT (ref. no. 2013-002164-53) before patient enrolment began.