Abstract
We compared two methods of fiberoptic tracheal intubation through the laryngeal mask airway (LMA), the tube method and the guide method, in 50 adult patients.
In the case of the tube method, first, the endotracheal tube (6.5mm ID cuffed tube, ETT) was advanced into the # 3 or # 4 LMA shaft until the tip of the ETT protruded from the LMA grill (ETT/LMA) . After induction of anesthesia and paralysis, the ETT/LMA was inserted and the LMA cuff was inflated. A fiberscope was inserted through the ETT and advanced into the trachea. The ETT passed over the fiberscope into the trachea. The fiberscope was then withdrawn, and the LMA cuff was deflated (n=28).
In the case of the guide method, the LMA was inserted and a fiberscope with the proximal end jacketed with a handmade flexible guide tube was inserted into the trachea. The guide tube was passed over the fiberscope into the trachea, and the fiberscope was withdrawn. A gum-elastic bougie (GEB) was then inserted into the trachea through the guide tube. After this, the guide tube and the LMA were withdrawn leaving the GEB in place. Lastly, an appropriate-sized ETT was passed over the GEB (n=22).
The success rate was 79% with the tube method and 77% with the guide method (NS). The times required for intubation were 236±106sec (mean±SD) and 463±219sec, respectively (P<0.001).
Although the tube method procedure is simpler, the ETT does not always pass over the fiberscope, the 6.5mm ID ETT is sometimes insufficient for ventilation, and the LMA always remains in the larynx. With the guide method, the ETT size is appropriate for the patient and the LMA does not remain in the larynx, but this method is rather time-consuming and complicated.
