Use of supraglottic airways during the COVID-19 pandemic

November 2021-an update:

Guidance on the use of supraglottic airway (SGA) devices during the COVID-19 pandemic>>

7 May 2020:

This document is produced in response to questions about the use of supraglottic airways (SGAs) during the current pandemic. The advice that it contains is based on the expert opinion of airway specialists and is meant to be valid for both COVID-19 positive and COVID-19 unknown patients. The aim is not to tell colleagues how to deliver anaesthesia, but to offer some reassurance for those who wish to continue to use SGAs when clinically appropriate.

There are three phases to the use of an SGA – insertion, maintenance and removal. SGA insertion may be preceded by mask ventilation of the patient’s lungs, although the need for this can often be avoided by preoxygenation. SGAs decrease the incidence of airway problems including coughing, hypoxia and airway complications at removal when compared with tracheal extubation, and thereby result in a ‘smoother emergence’ [1-4].

It is recognised that the evidence base around aerosol generation and SGAs is lacking and therefore must be extrapolated. Although it seems prudent to define SGA insertion and removal as aerosol generating procedures (AGPs), we are not aware of any research proving – or indeed disproving – this, and there is no published guidance on this issue. Overall, the extent of aerosol generation from SGA insertion and removal is likely to be less than during tracheal intubation and extubation, given that tracheal intubation is the airway procedure most associated with viral transmission [5].

During the maintenance phase of use, a well-seated SGA will provide a leak-free airway in the substantial majority of cases. During spontaneous ventilation, there is unlikely to be any significant airway leak, while during controlled ventilation, airway leak depends on a number of factors: careful patient selection; restriction to appropriate operations; use of an SGA design likely to create a good seal; meticulous insertion technique: use of controlled ventilation with low peak airway pressures. These will minimise the frequency of airway leak and therefore the potential for aerosol generation. In short, it depends on the patient, the procedure, the device and the anaesthetist. Use of a second-generation SGA is likely to improve airway seal [6]. When a significant leak occurs, which is usually apparent after insertion, it is logical to replace the SGA to eliminate the leak or to intubate the trachea. The drain port of a second-generation SGA may provide a potential route for secretion dispersal if the oesophageal seal is particularly poor, but there is currently no evidence either to support or refute this. Overall, it is likely that the quality of the airway seal is more important than the choice of whether to use an SGA or a tracheal tube. Of note, routine use of neuromuscular blocking drugs (NMBDs) is rarely necessary during SGA use. It does not improve SGA performance, complicates the anaesthetic and uses what is currently a limited resource.

Leaks around SGAs can be identified or suggested by several observations, including: abnormal capnograph and spirometry traces, differences between measured inspired and expired tidal volumes or minute volumes, audible leaks, and failure to keep the bags of “bag in bottle’ circle system ventilators at maximum capacity at end expiration when using low fresh gas flows.

Given the lack of evidence to support the increased safety of SGAs over tracheal tubes or vice versa in the current pandemic, the Difficult Airway Society, the Association of Anaesthetists and the Royal College of Anaesthetists see no reason why there should be a change in standard airway management during anaesthesia in COVID-19 positive or unknown patients other than to recommend that if an SGA is used, it should be a second-generation device, and that scrupulous attention should be paid to ensuring a leak-free seal.

References

  1. Brimacombe J. Emergence phase. In Laryngeal Mask airway: 2nd edition. J Brimacombe. Saunders 2005. ISBN 0-7020-2700-6

  2. Luce V, Harkouk H, Brasher C et al. Supraglottic airway devices vs tracheal intubation in children: a quantitative meta-analysis of respiratory complications. Paediatr Anaesth. 2014 Oct;24(10):1088-98.

  3. Nicholson A, Cook TM, Smith AF, Lewis SR, Reed SS. Supraglottic airway devices versus tracheal intubation for airway management during general anaesthesia in obese patients. Cochrane Database of Systematic Reviews 2013, Issue 9. Art. No.: CD010105. DOI: 10.1002/14651858.CD010105.pub2.

  4. Popat M, Mitchell V, Dravid R et al. Difficult Airway Society Guidelines for the management of tracheal extubation. Anaesthesia 2012, 67, 318–340

  5. Tran K, Cimon K, Severn M, Pessoa-Silva CL, Conly J. Aerosol generating procedures and risk of transmission of acute respiratory infections to healthcare workers: a systematic review. PLoS One 2012; 7: e35797.

  6. Lindsay HA, Cook TM, Russo S, Hagberg CA. Supraglottic Airway Techniques: Laryngeal Mask Airways. In Benumof and Hagberg’s airway Management 4th edition. 2018. Elsevier, ISBN 978-0-323-42881-1 .