The Effect of Tracheal Tube Tip Design

A-568

October 14, 2002
2:00:00 PM - 3:30:00 PM
Orange County Convention Center, Room 222 B

The Effect of Tracheal Tube Tip Design on Laryngeal Pass Ability during Oral Tube Exchange Using an Introducer

Hiroshi Makino, M.D.; Takasumi Katoh, M.D.; Syunji Kobayashi, M.D.; Hiromichi Bito, M.D.; Shigehito Satoh, M.D.

Department of Anesthesiology and Intensive Care, Hamamatsu University School of Medicine, Hamamatsu, Japan

INTRODUCTION:
We often experience difficulties in oral tracheal tube exchange using an introducer after one-lung anesthesia. It has been suggested that various aspects of tube design may influence the passage of the tube through the glottis. During fiberoptic intubation, the design of a tracheal tube has been shown to influence the passage of the tube. The purpose of the present study was to compare the ease of passage through the glottis of two different tubes during introducer-guided intubation. One tube was a polyvinyl chloride tube with a standard bevel and the other was a newly designed tube with a hemispherical bevel.

METHODS:
We studied 46 adult patients who were classified as ASA physical status I or II, and who were undergoing elective surgery. The patients were randomly divided into two groups of 23. After the standard induction of anesthesia followed by full muscle relaxation, a 5.0-mm OD introducer(Cook Airway Exchange Catheter,COOKŽ Critical Care.IN) was inserted into the trachea using a direct laryngoscope. Using the introducer as a guide, a size 7.5-mm ID tube (10.3 mm OD; Profile" Soft Seal Cuff Tracheal Tube, SIMS Portex Inc.NH) with a standard bevel was inserted into the trachea in Group N, and a size 7.5-mm ID hemispherical bevel tube (10.0 mm OD; Parker Flex-Tip", Parker Medical,CO) was inserted into the trachea in Group P. The difficulty in passing the tube was assessed by a blinded observer and graded using a four-point scale (grade 1: no difficulty passing the tube; grade 2: obstruction to passing the tube relieved by withdrawal and a 90°anticlockwise rotation; grade 3: obstruction necessitating more than one manipulation or external laryngeal manipulation; grade 4:required direct laryngoscopy). We analyzed the four-point scale using the Wilcoxon signed rank test.

RESULTS:
In 19 patients, no difficulty was shown using the hemispherical bevel tube. In only 4 patients was there any difficulty that necessitated a 90° anticlockwise twist. With the standard bevel tube, no difficulty was experienced with two patients. Grade 2 difficulty was experienced in 9 patients and difficulty necessitating more than one maneuver, head movement, or external laryngeal manipulation was seen in 6 patients. We used direct laryngoscope for 5 patients in Group N, and no patients in Group P. Statistical significance was achieved at P < 0.0001 (Wilcoxon signed rank test).

CONCLUSION:
We conclude that the hemispherical bevel tube may be considered as an adjunct to oral tracheal intubation using an introducer as a guide.
Anesthesiology 2002; 96: A568