Placement of the feline V-gel Advanced supraglottic airway device and tracheal selectivity during controlled mechanical ventilation: a clinical and tomodensitometric evaluation.

Objectives: The aims of the study was to assess the placement of the V-gel Advanced (V-gel-A) and to evaluate tracheal selectivity during controlled mechanical ventilation, using CT.

Methods: In this prospective clinical study, 20 healthy cats undergoing general anaesthesia for an elective procedure underwent four successive CT scans from the nose to the mid-abdomen: at baseline (no device); after the placement of the V-gel-A, after a controlled mechanical ventilation (CMV) period of 5 mins; and after the placement of an endotracheal tube (ETT). Using both a purpose designed position score and a gas score estimating the quantity of gas in different digestive regions, the position of the V-gel-A and presence of gas in the digestive tract at each step were evaluated. Number of attempts and times required to place the V-gel-A and ETT were recorded and compared.

Results: The V-gel-A was found to be correctly placed, with position scores of 3/5 in six cats, 4/5 in 13 cats and 5/5 in one cat. Imperfect positioning was due to minor axial rotation or incomplete occlusion of the oesophagus by the tip of the device. The gas scores significantly increased after placement of the V-gel-A compared with baseline and after CMV was initiated. Correct positioning of the device was mostly achieved at the first attempt; no significant difference was found in the time required to place V-gel-A vs ETT, nor in the number of attempts (P >0.05).

Conclusions and relevance: The V-gel-A was clinically easy to place and use in both spontaneous and controlled ventilation. The device properly fitted the larynx and was never observed to occlude the airway. However, incomplete occlusion of the oesophagus was frequently observed and may lead to a lack of complete tracheal selectivity.