Streamlined Liner of the Pharynx Airway: Randomised comparison of size selection strategies with regard to patient height versus thyroid cartilage width

Abstract

Streamlined Liner of the Pharynx Airway (SLIPA) is a disposable supraglottic airway. There are two strategies to select the size of SLIPA: by height and width of thyroid cartilage. This study compared the utility of the two strategies in selecting the optimal size. Methods: One hundred forty-two patients were randomly divided into two groups with size selection by height (H) and the maximal width of the thyroid cartilage (T). The SLIPA size was selected by height in group H, and by the width of thyroid cartilage in group T. After inserting SLIPA, the investigator made note of the oropharyngeal leakage pressure (OLP) and the degree of insertion difficulty. We set the OLP as a primary outcome. In cases of an OLP <15 cmH2O, the investigator manipulated the apparatus to try to reposition it. If air still leaked, another attempt was made using a SLIPA one size larger until an OLP >15 cmH2O was achieved in up to three attempts. After insertion, the investigator measured the inspiratory and expiratory tidal volume. Postoperatively, the presence of blood or regurgitated fluid on the device was evaluated. Results: OLP for group T was higher than that of group H (p=0.009). The need for manipulation and the leak fraction was higher in group H than in group T (p=0.008 and 0.034, respectively). The degree of insertion difficulty, number of trials and incidence of blood and regurgitated fluid on the device were similar between the two groups. Conclusions: Both the width and height of thyroid cartilage can be used for selecting the optimal SLIPA size.