A comparison of effects of four different methods to locate tracheal tube

Abstract

Objective To compare the efficacy of four different methods to locate tracheal tube in the tracheal: modified transillumination method, 21/23 cm rule, marked the intubation at a distance, and fiberoptic bronchoscope. Methods A prospective randomized controlled trial was conducted. 120 endotracheally intubated adult patients with American Society of Anesthesiologists (ASA) classification Ⅰ-Ⅱ and admitted to Central Hospital of Fengxian in Shanghai from January to March 2015 were enrolled. The patients were randomly divided into four groups (n = 30) and located by 21/23 cm rule, marked the intubation at a distance, fiberoptic bronchoscope and modified transillumination method (using homemade locator guided by a red laser fiber to position the depth of tube) respectively. An endotracheal tube was inserted and measured the distance of the tube tip to the carina (TTC), vocal cords to tracheal tube cuff (VC-TC) in three different neck positions, i.e. neck in flexion, neutral, and extension position. The number of improper position in four groups was recorded. Results There were no significant differences in gender, age, and body mass index among the four groups. Six of the 30 patients using marked tracheal tuba method failed to find vocal cords with laryngoscope, while the other three methods all completed successfully. ① From neck flexion to extension, TTC was gradually increased, while VC-TC was gradually decreased. In neck flexion and extension positions, TTC distance in the 21/23 cm rule group was significantly shorter than that in the fiberoptic bronchoscope group (cm: 1.44±1.14 vs. 2.11±0.54, 3.01±1.18 vs. 3.80±0.71, both P 0.05). VC-TC distance in the 21/23 cm rule group was significantly longer than that in the modified transillumination, the marked intubation, and the fiberoptic bronchoscope groups in neck neutral and extension positions, respectively (cm: 3.07±1.08 vs. 2.28±0.76, 2.29±0.90, 2.49±0.86; 2.64±0.94 vs. 1.82±0.72, 1.81±0.94, 2.02±0.91, all P < 0.05). TTC and VC-TC distances in three neck positions in the modified transillumination group were shorter than those in the fiberoptic bronchoscope group without statistical significance. ② If TTC was too short, an accidental bronchus intubation could happen, while if VC-TC was too short, an accidental damage of the vocal cord inducing by the cuff press could happen. In the 21/23 cm rule group, there were 7 cases that the tube wrongly inserted to bronchus in neck flexion, and 1 case in neutral and extension positions respectively. In the marked intubation group, there were 4 cases that the tube wrongly inserted into bronchus in neck flexion, and 1 case in neck neutral position, and there were 4 cases that the vocal cords were pressed by the cuffs in extension position. In the modified transillumintion and the fiberoptic bronchoscope groups, there was only 1 case that the tube wrongly inserted to bronchus in neck flexion respectively. Conclusions When neck position changed during trachea intubation, it was easier that the tube wrongly inserted to bronchus for 21/23 cm rule method to locate the position. Bronchus intubations and cuff press vocal cords could happen using the marked tube method, which was less be found using modified transillumination or fiberoptic bronchoscope methods. Finally, the modified transillumination methods can be used to locate with satisfactory effect. Key words: Location of endotracheal; Transillumination; 21/23 cm rule; Marked tube; Fiberoptic bronchoscope