Endotracheal Intubation through the Intubating LMA

Park, Young Joo; Kim, Dae Young; Yang, Jong Seok

Abstract

BACKGROUND: The fundamental responsibility of an anesthesiologist is to maintain adequate ventilation and to supply oxygen in the face of unexpected difficulties with tracheal intubation. The laryngeal mask airway (LMA) has been used as a ventilatory device familiarly for routine or difficult intubation but it has been hard to intubate with it the larger than 6 mm internal diameter (ID) endotracheal tube (ET). The intubating LMA is a new prototype of the LMA; it is partey composed of an anatomically curved rigid airway tube of ID 13 mm for larger ET tube insertion (such as ID 9.0 mm) into a 15 mm connector at its outer end which is fixed permanently to a laryngeal mask. This study was performed to evaluate the technique and facility of the intubating LMA as an apparatus for endotracheal intubation when used by an inexperienced anesthesiologist.
METHODS
With informed consent, 43 patients of ASA physical status I or II were selected. Either lubricated polyvinyl chloride or an armored wire tube of ID 7.0 or 7.5 mm was intubated through the No. 4 or 5 intubating LMA. During this procedure, we observed the technical method and success rate, and recorded systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) changes. 24 hours after each operation, we observed subjective symptoms such as sore throat, hoarseness, and difficult in swallowing.
RESULTS
The success rate of intubating LMA insertion was as follows: 33 (77%) patients were successed on first attempt, 6 (14%) patients on second attempt, 4 (9%) patients on third attempt. The insertion of the intubating LMA was carried out facilely without another maneuver such as neck extension or tongue expulsion. The success rate of tracheal intubation was 86.1%. In 32 (74.5%) patients there was easy intubation, but 5 (11.6%) patients required more adjustment and the failure rate with them was 6 (13.9%). SBP, DBP were only increased by endotracheal intubation through the intubating LMA, but HR was significantly increased during both insertion and intubation (p < 0.05). Postoperative sore throat was complained of in 11 patients; hoarseness in 1 patient.
CONCLUSIONS
Insertion of the intubating LMA is facile due to the absence of need for the maneuvers of neck motion or tongue expulsion. The intubating technique through the intubating LMA is a relatively rapid and easy method, but it requires technical experience which in some cases is lacking in inexperienced anesthesiologists.