Protecting staff and patients during airway management in the COVID-19 pandemic: are intubation boxes safe?

Editor—We read with interest the correspondence by Cubillos and colleagues¹ and Yong and Chen.² Cubillos and colleagues¹ describe the design and manufacture of a ‘negative-pressure airflow isolation chamber’ to reduce the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission during airway management, and Yong and Chen² report the use of flexible plastic screens and tents for the same purpose. A number of similar reports have been published in recent literature describing the use of various ‘intubation boxes’ and drapes,3, 4, 5 all of which aim to provide a physical barrier to aerosols and droplets. Although these innovations are doubtless well-meaning, we are concerned that any additional protection that such devices may afford is gained at the cost of increased difficulty in managing the airway.

The concept of difficult airway in the critically ill comprises anatomical, physiological, and environmental elements,⁶ exacerbated in the current pandemic by human factors and the communication limitations imposed by highly restrictive personal protective equipment.^{7 , 8} In our own anecdotal experience, coronavirus disease 2019 (COVID-19) appears to be associated with laryngeal oedema independent of that associated with prolonged tracheal intubation,⁹ making airway management potentially more challenging.

We trialled the use of a rigid intubation box similar to that proposed by Canelli and colleagues³ in a simulation setting, and found that the presence of a physical barrier increased the difficulty of tracheal intubation, especially during transition between airway devices and when using intubation adjuncts, such as the gum-elastic bougie (Fig. 1 ). A physical limitation in dexterity when using intubation boxes was predicted by Cubillos and colleagues¹ in their letter, and our experiences support this prediction. However, we are concerned that similar problems may be encountered with all barrier devices. We advise caution in adopting the use of any physical enclosure in practice, as existing airway devices were not designed to be used in conjunction with intubation boxes, and airway management training has hitherto not included their use. There is also the question of how and when to remove barrier enclosures that lack any mechanism for air extraction or exchange without dispersion of high concentrations of aerosolised SARS-CoV-2 virus.

Fig. 1.

Use of a gum-elastic bougie and McGrath videolaryngoscope (Medtronic, Minneapolis, MN, USA) with an intubation box for simulated intubation.

Managing difficult airways in the critically ill is challenging,⁶ and we believe this may be compounded by such home-made aids, however well intentioned. We must protect our staff during high-risk procedures, but not when this confers a threat to patient safety. Whilst both the safety and efficacy of barrier enclosures in airway management remain unproved, our focus should continue to be on the use of appropriate and well-fitted personal protective equipment, worn and disposed of effectively.

Declarations of interest

CS is a former member of the editorial board of BJA Education. The other authors declare no conflicts of interest.