| Objective: To use the correlation index of bedside ultrasonography to confirm the position of endotracheal tube,and compare the predictive value of each index.Methods:Eighty-eight patients have been collected with emergency endotracheal intubation in intensive care unit from Feb,2016 to Feb,2018,including 57 males and 31 females with an average age of 56.5±13.3 years old.Before the endotracheal intubation,the doctor selected the high frequency linear array probe(about 6-13mHz)and placed it horizontally on the neck to quickly identify the related anatomic structures of upper airway.In the process of endotracheal intubation,the doctor putted the ultrasonic probe on different position and monitor timely the following indicators: first,"the bullet sign" may be observed on the thyroid cartilage level when the endotracheal tube went through the glottis.Second,"the double track sign" can be seen on the left neck above sternum incisure level when endotracheal tube was putted into the esophagus.Third,in the middle of the trachea above sternum incisure level,“endotracheal echo ring” may be obtained before and after the cuff has been inflated by water.Single and combined indicators can be used to predict the position of endotracheal tube.The predictive value of ultrasonography in the depth of endotracheal tube can be determined by measuring the distance between the end of the catheter and the tracheal carina.Results: 1.There were 6 patients with esophageal intubation,accounting for 6.8% of all intubation.The typical "double track sign" was seen in all patients.The sensitivity of esophageal intubation predicted by ultrasonography was 100%,the specificity was 97.56%,the youden index was 97.56%,the positive predictive value was 75% and the negative predictive value was 100%,and the AUC was 0.988(95% CI,0.971 to 1.00).2.The value of "endotracheal echo ring" before the cuff has been inflated by water in predicting the endotracheal intubation was the lowest,with the AUC of 0.829(95%CI,0.778-0.88),and the sensitivity of 65.85%.The value of “the bullet sign” in predicting endotracheal tube was slightly lower,with AUC of 0.831(95%CI,0.663-1.0),the sensitivity of 82.93%,the specificity of 83.33%,and AUC of 0.831(95%CI,0.663-1.0).In predicting endotracheal tube,the sensitivity of "the endotracheal echo ring after the cuff has been inflated by water" was 95.12%,the specificity was 100%,the positive predictive value was 100%,and AUC was 0.976(95%CI,0.952-0.999).The AUC of combined “the bullet sign”and "the endotracheal echo ring after the cuff has been inflated by water" was 0.990(95%CI,0.973-1.00).3.There were 54 cases of patients with "the endotracheal echo ring" before the cuff has been inflated by water,which increased to 78 cases after the cuff has been inflated by water(p<0.001),with statistically significant difference between the two groups through the chi-square test.4.A total of 78 cases of patients with "water cuff" were detected on the sternal notch level by ultrasonography.We measured the distance between the end of the catheter and tracheal carina by fiber bronchoscope,which almost locate in the recommended range of 3-7 cm above the tracheal carina[mean(SD)3.63 cm(0.791)cm].Conclusions: 1."The double track sign" can be used to predict esophageal intubation accurately.2.Compared with the single "endotracheal echo ring after the cuff has been inflated by water.",the combined indicators had slightly improved prediction value but need more examination time.There was little clinical difference between them.Therefore,it was suggested to use the single indicator to predict the position of endotracheal tube.3.The display rate of "the endotracheal echo ring" can be significantly increased after the cuff has been inflated by water.The ultrasonic diagnosis rate was improved as well.4."Bullet sign" is not recommend predicting the position of tube in Aged males.5."Water cuff" that is explored by ultrasonography on the level of the suprasternal notch can roughly predict the appropriate depth of endotracheal tube. |
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