BLIND INTUBATION THROUGH THE LARYNGEAL MASK AIRWAY IN PATIENTS WITH DIFFICULT AIRWAYS

Abstract

S240 The use of the Laryngeal Mask Airway (LMA) in the management of the difficult airway, [1] the self-inflating bulb (SIB) in differentiating tracheal from esophageal intubation, and the hollow Cook Airway Exchange Catheter (CAEC) as a tracheal tube changer [2] have all been established. Recently, blind intubation through the LMA using a modified CAEC (with 30[degree sign] tip angulation) and the SIB has been described in patients with normal airways. [3] This report describes successful blind intubation through the LMA using the modified CAEC and the SIB in patients with difficult airways. METHODS: With IRB approval, the technique was used in 17 patients with difficult airways. These patients were: 6 with cervical spine fractures in halobrace apparatus; 2 with severe cervical rheumatoid arthritis and limitations of neck movement; 5 morbidly obese with previously documented difficult intubations; 3 with short thyromental distances and Class IV airways; and 2 who had unexpected Grade 4 laryngoscopic view during laryngoscopy. Except for 2 patients, anesthesia was induced with propofol 1 - 1.5 mg/kg while maintaining spontaneous breathing. A #3 or #4 LMA was blindly inserted and cuff inflated. After the ease of positive pressure ventilation was established, a muscle relaxant was given. A 14F modified CAEC with the tip directed anteriorly was inserted through the LMA until the tip was felt rubbing against the anterior tracheal wall. It was then rotated 180[degree sign], advanced into the trachea, and its tracheal location confirmed by the SIB (Figure 1). Reinflation of the compressed SIB when connected to the CAEC indicated tracheal placement (Insert). The LMA was then removed and a lubricated cuffed tracheal tube (7 or 7.5 mm ID) was railroaded over the CAEC into the trachea. The position of the CAEC was rechecked with the SIB before removal. When 3 attempts to place the CAEC in the trachea failed, the protocol was abandoned in favor of fiberoptic-aided intubation through the LMA. [1]Figure 1RESULTS: All 17 patients were successfully intubated. Nine patients were intubated on the first attempt, 4 patients on the second attempt, and 4 patients during a third attempt. There were no complications and SaO2 remained >90% in all patients. CONCLUSIONS: Although fiberoptic intubation is still considered the "gold standard" for intubation of the difficult airway, we are presenting a possible alternative technique. The 30[degree sign] angulation of the modified CAEC facilitates its placement into the trachea through the LMA, while the SIB assures proper placement of the CAEC before the LMA is removed. Blind intubation through the LMA using this technique in patients with difficult airways is simple and safe, and can be used in patients with bloody airways where fiberoptic visualization may be difficult.