Measurements Of Adult Respiratory Tract And Selections Of Double-lumen Tube Size Assisted By Computer Tomography

Objectives : Ultrasound is widely applied in many areas related with airway management,however it can only image the upper part of trachea.This study: 1.To identify the correlations between obtained parameters of trachea and bronchia which were measured by CT.2.To provide a reference for the selection of left double-lumen tube(LDLT)size by measuring transverse tracheal diameter(Tr-TD)with CT,thus predicting the possibility of ultrasound to allow the selection of the individually appropriate DLT size in thoracic anesthesia.Methods:Study 1: The cervical and thoracic CT images of 206 patients were evaluated.Anteroposterior glottic diameter(AP-GD),anteroposterior tracheal diameter(AP-TD),transverse tracheal diameter(Tr-TD),left and right main bronchi diameters(LBD&RBD)and the distance between glottis and carina(G-TL)were measured.All parameters were analyzed statistically.Multiple linear regression analyses were performed to detect the correlations between obtained parameters.Study 2: We enrolled 24 adult thoracic surgery patients aged 20-80 years who required intubation with a LDLT during anesthesia.?Patients with ASA physical status I-III were randomly assigned to two groups(n=12 each): group H(according to gender and height in the selection of LDLTs)and group C(according to Tr-TD measuring with CT in the selection of LDLTs).Measurement of Tr-TD and LBD with CT were performed and recorded before the procedure.The patient's demographic data?the size of used LDLT?intubation time and times?fitness evaluation criterion of LDLT?number of times in adjusting position of LDLT during the procedure and duration of anesthesia were recorded.We also evaluated the quality of lung collapse during one-lung ventilation and postoperative hoarseness and sore throat.All parameters were analyzed statistically.Results:Study 1: The mean anteroposterior diameter of the glottis in adult patients was measured as 19.3 ± 3.3mm.The mean anteroposterior and transverse diameters of the trachea were 19.7 ± 4.3mm and 16.6 ± 2.4mm,respectively.The mean diameters of the left and right main stem bronchi were 12.3 ± 2.0mm and 13.7 ± 2.0mm,respectively.The mean vertical distance between glottis and carina was 125.9 ± 11.4 mm(130.3 ± 10.4 mm for males and 122.0 ± 10.9 mm for females).Significant gender differences were found in all the parameters measured(P<0.05).There was a moderate correlation between LBD and APGD?AP-TD?Tr-TD and height.AP-TD,Tr-TD and height together were the significant predictor of the LBD(r=0.76,P<0.05),in which Tr-TD was the most significant factor.Study 2: The appropriateness of LDLT size of the two groups were: group H: 33% and group C: 75%.Compared with group H,the appropriateness of LDLT size was higher in group C(P<0.05).In addition,the LDLT size selected in group H was significantly small,with a rate of 66%,which was significantly different from that of group C(P <0.05).The quality of lung collapse and the incidence of postoperative hoarseness and sore throat were comparable between the two groups(P> 0.05).Conclusions:1.The matching of DLT with trachea and bronchus is closely related with AP-TD,Tr-TD,AP-GD and height.CT should remain a more reliable method for the selection of individually appropriate DLT size.It may be a basis for helping the selection of DLTs,while considering both Tr-TD and AP-GD.2.Compared with the traditional method,the measurement of Tr-TD by CT is more appropriate for selecting a LDLT size.Ultrasound maybe become an another method for selecting DLT size shortly afterwards.