The primary outcome of sugammadex reversal for rocuronium-induced neuromuscular block (NMB) is a train-of-four ratio (TOFR) of 0.9, not first twitch (T₁) height. We investigated whether the recovery of TOFR or T₁ differs based on the reversal of NMB with neostigmine or sugammadex.

The acceleromyographic responses from 0.6 mg/kg of rocuronium were monitored supramaximally in 80 patients after induction of anesthesia. The TOFR and T₁ height were recorded, and saved in a personal computer using TOF-Watch SX Monitor software in all patients. Patients were randomly assigned to 2 groups to receive either neostigmine 50 µg/kg with glycopyrrolate 10 µg/kg (neostigmine group, n = 40) or sugammadex 2.0 mg/kg (sugammadex group, n = 40). The primary objective was to determine the difference of recovery time between TOFR to 0.9 and T₁ to 0.9 after sugammadex or neostigmine administration during moderate rocuronium-induced NMB.

The recovery pattern of the TOFR 2 min after sugammadex administration was 1.0 or more, but that of T₁ was less than 90% (T₁ / control value) up to 6 min after drug was injected. The recovery pattern of TOFR and T₁ was similar during the 20 min after reversal with neostigmine.

If you have not performed the T₁ monitoring, both TOFR and T₁ should be considered to confirm suitable recovery during the 6 min after reversal with sugammadex during rocuronium-induced moderate NMB.