Limitations of pediatric supraglottic airway devices as conduits for intubation - an in vitro study

Supraglottic airway devices (SGAs) can be used as conduits for intubation, but data and manufacturers' recommendations for pediatric SGA are incomplete and sometimes misleading. This situation can result in the use of incompatible combinations of SGAs and endotracheal tubes (ETTs). To address this mismatch possibility, we performed an in vitro study to establish an overview of possible combinations of SGAs and ETTs.

We tested the passage of ETTs through SGAs in vitro and subsequent SGA removal with eight pediatric SGAs and six ETTs of different sizes in vitro. Results were compared with manufacturers' recommendations. Outcome parameters were the feasibility of passing the ETT through the SGA and then removing the SGA over the ETT.

The Air-Q® and the Air-Q®sp™ SGAs showed the best compatibility with ETTs across all sizes. Whenever intubation was possible, removal was possible for all SGAs with uncuffed ETTs. With many cuffed ETTs, however, SGA removal was impossible because the ETT cuff's pilot balloon was larger than the inner diameter of the SGA. Thus, although intubation was possible, removal of the SGA was not. The manufacturers' booklets do not warn of this limitation.

The use of combinations of SGA and ETTs with a size mismatch can lead to airway complications during intubation or to accidental extubation and tearing of the cuff pilot balloon line when removing the SGA. To avoid these problems, we devised a table that simplifies the choice of an appropriate SGA and ETT combination.