Stylet for reinforced laryngeal mask airway

With more widespread use of the reinforced laryngeal mask airway (RLMA), many devices have been created to facilitate its insertion, since it has a longer and more flexible tube (Fig. 4A) than the classic laryngeal mask airway. These are classified into two categories: outer and inner devices. The outer devices (standard Magill forceps [1], Bosworth introducer [2]) have potential disadvantages of causing trauma and occupying the oral space. The inner devices (metal stylet, small tracheal tube [3], combined metal stylet and tracheal tube [4]) also have some problems. It is difficult to remove them after the insertion of the RLMA when the stylet is tightly fitted to the RLMA. If it is too loose, however, it can rotate along its axis. We would like to describe an improved combination metal stylet and tracheal tube (Fig. 5B). Our idea was to use the cuff of the tracheal tube to fix the stylet against the RLMA. It allows tight fixation by inflating the cuff and smooth removal by deflating it after insertion of the RLMA. To produce this stylet for a size 4 RLMA, we used a cuffed tracheal tube (ID 4.5 mm, Lo-ContourTM, Mallinckrodt, Ireland), Nelaton's catheter (No.6, Mizuho, Japan) and a PVC-covered stylet for children (Portex, UK) (Fig. 5A). First, the children's stylet is passed into the Nelaton's catheter. Then, the Nelaton's catheter is passed into the tracheal tube (Fig. 5B). Adequate lubrication of the stylet and tracheal tube allows smooth insertion of the stylet into the RLMA. The length of the tracheal tube just fits the size 4 RLMA, so the distal end does not protrude through the grill of the mask (Fig. 5C). To fix the stylet against the RLMA, the cuff of the tracheal tube is inflated with approximately 0.5 ml of air. This arrangement allows the tube of the RLMA to be rigid enough (Fig. 4B) to insert it easily without trauma. After insertion of the RLMA, the cuff of the tracheal tube is deflated, allowing smooth removal of the stylet without displacing the RLMA. Since we have no adequate stylet for adults to give rigidity to the tracheal tube, the Nelaton's catheter enlarges the stylet. We have found this stylet with a cuffed tracheal tube is convenient for insertion of the RMLA.