Background: Re-intubation and re-operation may occasionally be required after neuromuscular block (NMB) reversal. This study evaluated block onset times of a second dose of rocuronium (1.2 mg kg(-1)) after sugammadex reversal of rocuronium 0.6 mg kg(-1).
Methods: In this open-label study of healthy anaesthetized volunteers, subjects received rocuronium 0.6 mg kg(-1), were antagonized at 1-2 post-tetanic counts with sugammadex 4.0 mg kg(-1), and received rocuronium 1.2 mg kg(-1) at 5, 7.5, 10, 15, 20, 22.5, 25, 27.5, 30, 45, or 60 min after sugammadex. Spontaneous recovery occurred after repeat rocuronium dose. Primary endpoints were the onset time of maximal block (time to lowest T(1) value reached) and the clinical duration of block (until T(1)=25%) after repeat rocuronium dose.
Results: Sixteen subjects were included. For subjects receiving rocuronium 1.2 mg kg(-1) 5 min after sugammadex (n=6), mean (sd) onset time (to T(1)=0) was 3.06 (0.97) min; range, 1.92-4.72 min. For repeat dose time points ≥25 min (n=5), mean onset was faster (1.73 min) than for repeat doses <25 min (3.09 min) after sugammadex. The duration of block ranged from 17.7 min (rocuronium 5 min after sugammadex) to 46 min (repeat dose at 45 min). Mean duration was 24.8 min for repeat dosing <25 min vs 38.2 min for repeat doses ≥25 min.
Conclusions: Rapid re-onset of NMB occurred after repeat dose of rocuronium 1.2 mg kg(-1) as early as 5 min after sugammadex in healthy volunteers. Re-onset of block took longer if second rocuronium dose was <25 min after sugammadex. The duration of action of second rocuronium dose increased with later repeat dose time points.