A reply

Authors


We thank Dr Baxter and colleagues for sharing the findings of their departmental survey. Although the experience and confidence in performing advanced airway techniques for the ‘at-risk’ extubation are disappointing, we are not surprised with their findings, which may well represent national trends. Like them, we also hope that the guidelines [1] will act as an impetus for training. Indeed, the Difficult Airway Society (DAS) has already taken a lead by incorporating a masterclass session on extuabtion in its annual scientific meeting. We hope other workshops will also include extubation techniques and that eventually these will be included in the College training curricula.

We fully agree with Law and Duggan’s comment regarding the discrepancy between the relative diameters of the Airway Exchange Catheter and tracheal tube, causing the latter’s leading edge to snag on the glottic structures. Indeed, they reference our own publication highlighting this problem and our solution of using an Aintree Intubation Catheter (AIC) to minimise the gap [2]. We welcome their support for our solution, but felt that the use of the AIC is not always necessary; furthermore, one can only railroad a tube larger than 7 mm over the AIC. Their second comment regarding orientation of the bevel during railroading is absolutely correct and indeed represents an oversight on our part. To clarify: we had meant that the tracheal tube tip should face anteriorly and the bevel posteriorly. We apologise for this oversight.

We agree with Falzon and colleagues that the use of the Guedel airway as a bite block is not safe practice, and it was never our intention to endorse its use for this purpose. In the absence of any evidence to suggest the superiority of the BreatheSafe Bite Block™ over rolled gauze, we were reluctant to recommend the use of a commercially available device. Their technical points relating to the use of rolled gauze are also relevant. We have emphasised the importance of securing a rolled gauze bite block to the tube because we have received personal correspondence from a DAS member describing inhalation of unsecured rolled gauze.

Regarding Copp’s comments, residual residual neuromuscular blockade following extubation is associated with a higher incidence of hypoxaemia and upper airway obstruction [3], and extubation should therefore be performed with a train-of-four (TOF) ratio of 0.9 or ideally, unity. In clinical practice, without the use of an accelerometer, it is not possible to discriminate between TOF ratios of 0.7 and 0.9, and as volunteer studies have shown, significant signs and symptoms of residual block are seen at a TOF ratio of 0.7 [4]. Sugammadex offers the ability for safer and more reliable reversal of neuromuscular blockade, and where an accelerometer is not present reduces the risks associated with an unrecognised low TOF ratio. The combination of rocuronium and suggamadex is a powerful new tool that is superior to conventional cholinesterase inhibitors and should be considered for all ‘at-risk’ extubations. Although we agree with Copp, cost constraints would prohibit making this mandatory, certainly in the UK.

Finally, we thank Gavel and Walker for their comments on the diagnosis and management of laryngospasm. We agree that debris in the pharynx is a significant risk factor for the development of laryngospasm, and suctioning of the pharynx (ideally under direct vision) should be carried out routinely as part of the extubation strategy; this has been explicitly mentioned in the guidelines [1]. We feel that the principles behind the management of laryngospasm are made clear in Table A1. The majority of cases of laryngospasm can be managed with positive pressure and oxygenation and the addition of Larson’s manoeuvre is a simple adjunct that should not delay further treatment if required. We agree that the evidence behind this manoeuvre is anecdotal [5], but it has been successfully used by others [6–8]. Our guidelines are for extubation in the adult population and the doses of propofol and suxamethonium reflect this. We agree, however, that should intravenous access be lost, intramuscular suxamethonium would be preferable as it would not interfere with airway management, as with the intralingual route, nor would it require obtaining further access in the form of an interosseus cannula. On reflection, perhaps a single maximum dose for suxamethonium would have been clearer rather than a dose range.

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