LAUSR

Solt esz et al.'s findings confirm numerous previous findings documenting improved facemask ventilation (FMV) following administration of neuromuscular blocking (NMB) drugs [1]. Despite their unequivocal results, the authors conclude that “checking the ability to mask ventilate before administration of neuromuscular blocking agents remains important, because it provides useful information about the non-paralysed condition of the patient's airway.” If muscle relaxation almost uniformly facilitates FMV, what would be such clinically-relevant “useful information”? The authors cite the correspondence by Pandit [2] in support of their statement. Interestingly, Pandit, in turn, cites a publication by Odeh et al. [3] in support of his statement that NMBDs can make FMV more difficult by relaxationinduced collapse of the upper airways. However, this investigation did not deal with FMV in humans [3]. It examined pressure-flow relationships before and during electrical stimulation of four isolated upper airway muscles in anaesthetised dogs, which hardly reflects clinical reality. In the final paragraph of the publication, the authors write “If difficulty in mask ventilation is observed before paralysis, a shortacting neuromuscular blocking drug should always be preferred over a long-acting one to maximise the chance of return of spontaneous ventilation” [1]. This recommendation is obviously based on the still frequently held view that the administration of suxamethonium preserves the option of restoring adequate spontaneous respiration before severe hypoxaemia develops [2]. However, this view is not fully evidence based. Following the administration of suxamethonium 1 mg.kg , it took as long as 10.5 [4] and 11.2 min [5] for the recovery of the first train-of-four twitch (T1) to 10%, and as long as 8.5 min from the time of tracheal intubation to the return of spontaneous respiration [5]. Surely, in an anaesthetised patient, recovery of T1 to 10% is not equivalent to the restoration of spontaneous respiration sufficient to maintain oxygenation? Thus, although successful ‘awakening’ following neuromuscular blockade has been reported [6], the overall evidence clearly supports the view that after suxamethonium-induced apnoea, “achievement of functional recovery before significant desaturation is not a realistic possibility” [7]. Administration of a NMBD has been compared with ‘crossing the Rubicon’ [8]. This idiom does not only mean passing a point of no return but also implies irrevocable commitment to a risky or revolutionary course of action. It is a potentially dangerous misconception to consider the administration of a NMBD to be the Rubicon. Rather, the anaesthetic ‘Rubicon’ is the administration of a hypnotic at a dose that abolishes spontaneous respiration [8]. In the presence of difficult or impossible FMV in an anaesthetised apnoeic patient whose airway is prone to collapse due to reduced pharyngeal muscle tone, the chances of successfully restoring adequate spontaneous respiration before severe hypoxaemia develops are very small. Thus, once we have crossed that Rubicon (i.e. have abolished