Sugammadex and rescue reversal

Sugammadex has been shown to reverse a deep neuromuscular block and re-establish breathing even when administered after only 3 min following a 1.0–1.2 mg.kg−1 dose of rocuronium [1, 2]. It has been shown, even before sugammadex became available, that spontaneous breathing is resumed at a far earlier point in the recovery than to a train-of-four (TOF) ratio of 0.9 [3–5]. The average time of 2.2 min to a TOF ratio of 0.9 in a manikin, reported recently by Bisschops et al., is therefore much longer than would be required for resumption of spontaneous breathing [6]. Hogg et al. actually reported times of 40 and 48 s for return of diaphragmatic movement and recording of exhaled carbon dioxide in real patients after a 16 mg.kg−1 dose of sugammadex in a simulated cannot intubate, cannot ventilate scenario (CICV) [2]. This was sufficient to allow the oxygen saturation to remain above 88% in all subjects following a three-minute period of 100% oxygen administration immediately before induction of anaesthesia. We were not clear from the article of Bisschops et al. when they decided it was a CICV situation, and why it took an average of 6.7 min to administer sugammadex? Intubation during a rapid sequence induction is usually performed 60 s after the administration of the neuromuscular blocking drug and the next 2 min are more than adequate to determine if it is a difficult intubation and/or ventilation scenario. This would allow sugammadex to be administered within 3 min of administration of rocuronium, as has been done in the simulated studies by Lee et al. and Hogg et al. [1, 2]. Pre-oxygenation allows for a significant period of time before the onset of desaturation [7, 8]. However, it is not clear if the effects of pre-oxygenation were factored into the study by Bisschops et al. [6]. The place where sugammadex is stored should be widely known, it should ideally be available in all operating theatres and, in particular, where out-of-hours emergency work is carried out. Sugammadex can be made available within a minute in such a setting. The choice of using rocuronium to facilitate intubation in the setting described by Bisschops et al. implies that sugammadex would be used to reverse the block rapidly if intubation and/or ventilation were to prove difficult. As such, everyone in that setting should have known where sugammadex was stored. It appears that some of the team members whom the investigators had chosen did not know about sugammadex. We consider it unacceptable that some of the team members would need to read the package insert at the time of such an emergency. The study by Bisschops et al., however, highlights an important practical issue about the use of sugammadex in emergency situations, and that is the calculation of the dose. Although it is easy to calculate the dose for reversing shallow or deep blocks during elective situations, it is clear that it can pose problems when trying to do this in an emergency situation. We would like to suggest a simplified dose regimen for using sugammadex, similar to what is done with neostigmine in standard practice. In the UK, it is probably customary to use the whole contents of a 2.5 mg ampoule of neostigmine for reversal of neuromuscular block. We suggest that the dose of sugammadex should be: vial of 200 mg for superficial/shallow block; vials of 200 mg for deep block; vials of 500 mg for rescue reversal. This would provide an appropriate dose for patients weighing up to 100 kg and would cover a large majority of patients. This dose of sugammadex may be higher than that recommended for patients of low body weight, but there is no issue about the safety of sugammadex in these doses. The dose would have to be increased for heavier patients accordingly. No external funding and no competing interests declared. Previously posted at the Anaesthesia Correspondence website: http://www.anaesthesiacorrespondence.com.