| Study 1Correlation between tracheal diameters measured by ultrasound with tracheal and left main bronchial diameters measured by CT multiplane reconstructions and prediction of the size of left-sided double-lumen endobronchial tubeObjectiveTo obtain correlation coefficient and regression equation between tracheal diameters measured by ultrasound and left main bronchus mean diameters (mean value of transverse and anteroposterior diameters) measured by multiplane CT reconstructions. To predict the size of left-sided double-lumen endobronchial tube (LDLT) through outer tracheal diameters measured by ultrasound.MethodsIncluding sixty-six adult inpatients received three-dimensional CT scan for medical examination. CT data were measured by Philips iCT (128 slice spiral CT), and the scan range from the neck to the diaphragm. Scan parameters:voltage 120 kV, current 350-200 mA, layer thickness 0.95 mm, layer spacing 0.95 mm. Obtaining coronal and sagittal MPR images using 2D multi-directional recombination technique.CT measurement of tracheal transverse and anteroposterior diameters were made at the suprasternal notch plane. CT measurement of the transverse, anteroposterior and minimum diameters of left main bronchus were made at 1 cm below the carina.NanoMaxx portable ultrasonic device and high frequency linear array probe were used to measure the outer tracheal diameters. The probe was positioned about 3 cm above the upper edge of the patient’s manubrium.The general situation and the results of ultrasonic and CT measurements of male and female patients were compared. The correlation between tracheal diameters measured by ultrasound with tracheal and left main bronchial diameters measured by CT were obtained. The regression equation between the left main bronchus mean diameters measured by CT with tracheal diameters measured by ultrasound or CT were obtained too. The size of LDLT corresponding to the ultrasonic tracheal diameters, CT tracheal transverse diameters or CT tracheal mean diameters were predicted.Results①The ultrasonic tracheal outer diameters of the male was significantly higher than that of the female (p<0.01). From the results of CT measurements, the diameters of trachea and bronchus in male were higher than female (p<0.01), and the individual variation of the shape of the cross section of trachea and left main bronchus of male and female were large, especially the left main bronchus. There was no significant difference between the CT tracheal transverse and anteroposterior diameters of the male and female (P>0.05). The CT left main bronchial transverse diameters of male and female were higher than the anteroposterior diameters (p<0.01).②The correlation coefficients between the CT left main bronchial transverse diameters and the ultrasonic tracheal outer diameters or the CT tracheal transverse diameters were 0.624(p<0.01)and 0.619(p<0.01), respectively. The correlation coefficient between the ultrasonic tracheal outer diameters and the CT tracheal transverse diameters was 0.731 (P< 0.01).The correlation coefficient between the CT left main bronchial minimum diameters and the ultrasonic tracheal outer diameters or the CT tracheal transverse diameters were 0.481(P< 0.01) and 0.496(P< 0.01), respectively. The correlation coefficient between the CT left main bronchial mean diameters and the heights, the ultrasonic tracheal outer diameters, the CT tracheal transverse diameters or the CT tracheal mean diameters were 0.546(P< 0.01),0.591 (P< 0.01),0.565 (P< 0.01) and 0.731 (P< 0.01), respectively.③TThe regression equations, whose unit is millimeter, between the CT left main bronchial mean diameters (i.e.parameter y) and the ultrasonic tracheal outer diameters, the CT tracheal transverse diameters or the CT tracheal mean diameters were y=0.348x+6.349 (p<0.01), y=0.375x+6.728 (p<0.01) and y=0.490x+4.687 (p< 0.01), respectively.④The corresponding ultrasonic tracheal outer diameters to predict different types of Mallinckrodt LDLT (32F,35F,37F,39F and 41F) were≥13.9mm,≥16.5mm, ≥18.3mm,≥19.7mm and≥22.6mm, respectively; the corresponding CT tracheal transverse diameters were ≥11.9mm,≥14.3mm,≥15.9mm,≥17.3mm and≥19.9mm, respectively; and the corresponding CT tracheal mean diameters were≥13.3mm, ≥15.1mm,≥16.4mm,≥17.4mm and≥19.4mm, respectively.ConclusionThe cross-sectional shapes of trachea and left main bronchus has obvious individual differences. The ultrasonic tracheal outer diameters were well correlated with the CT tracheal transverse diameters, the CT left main bronchial transverse diameters or the CT left main bronchial mean diameters. The corresponding ultrasonic tracheal outer diameters to predict 32F,35F,37F,39F and 41F Mallinckrodt LDLT were≥13.9mm,≥16.5mm,≥18.3mm,≥19.7mm and≥22.6mm, respectively. The accuracy and practicality of the data will be verified by the next clinical application research (i.e. our study 2).Study 2Clinical application of tracheal outer diameters measured by ultrasound in predicting the size of left-sided double-lumen endobronchial tubeObjectiveTo analyze the difference of selecting the size of left-sided double-lumen endobronchial tube(LDLT) according to ultrasonic tracheal diameter measurement or the height, and to evaluate the feasibility of selecting the appropriate size of LDLT by ultrasound.Methods140 elective adult thoracic surgery patients, ASA physical status I or II, who required one-lung ventilation were selected, excluding the patients who had the diseases narrowed trachea or main left bronchus, who had asthma, chronic obstructive pulmonary disease or pulmonary infection, or who were not suitable for using LDLT. All patients were randomized to the test group(group A) and the control group(group B)(n=70 each). In group A, the size of LDLT were selected by ultrasonic tracheal diameter measurement based on the results of study 1. In group B, the LDLT were selected according to the patient’s sex and height. The resting capacity of the selected LDLT were measured. All patients were treated with total infusion venus anesthesia(TIVA).The position of LDLT were confirmed by fiberoptic bronchoscopy after intubation. After that, the positive pressure tests were performed. The catheter position were confirmed before OLV. OLV was started immediately before opening the chest, while the surgical-sided catheter lumen was opened to air.The following data were recorded:①The number of the various sizes of LDLT selected in two groups were counted.②The number of the correct, oversized or undersized LDLTs selected in each group were counted.③The peak airway pressure (Ppeak)were recorded immediately before, and 15min after OLV in two groups.④The incidence of hyoxemia was recorded in two groups, and hyoxemia was defined as SpO2<95%.⑤The lung collapse situation of the patients in operation were evaluated by the surgeon.⑥The satisfaction rate of OLV were recorded in two groups. OLV was not satisfied when Ppeak>40cmH2O, or SpO2<95%, or unsatisfied lung collapse were appeared. At this time, the fiber bronchoscopy and corresponding treatment were given.⑦The occurrence rate of hoarseness and sore throat in two groups were recorded at 24 hours after the operation.ResultsIn comparison of the number of the various sizes of LDLT in two groups, the difference of overall composition was statistically significant(P<0.05). The proportion of 32F and 41F LDLT selected in group A were higher than in group B, that was 14.3% vs 0%(P<0.05)and 17.1% vs 4.3%(P<0.05), respectively.Compared with group B, there were the higher proportion of the correct size LDLT (74.3% vs 55.7%, P<0.05) and the less proportion of the undersized LDLT (10.0% vs 24.3%, P<0.01) in group A. There was no significant difference between the two groups in the proportion of the oversized LDLT(15.7% vs 20.0%, P>0.05). In addition, the number of the correct 32F and 41F LDLT in group A is higher than in group B(P<0.05,).There was no significant difference in the airway peak pressure immediately before and 15min after OLV between the two groups(P>0.05).The lung collapse assessment, the incidence of hypoxemia and the satisfaction rate of OLV were not statistically significant between the two groups(P>0.05). The occurrence rate of hoarseness and sore throat in two groups 24 hours after the operation were not statistically significant (P>0.05).ConclusionCompared with the size of LDLT selected by sex and height, the accuracy of selecting the proper size of LDLT by ultrasonic tracheal diameter measurement was higher. Furthermore, there were better identification of the adult patients who required smaller(32F) or greater(41F) size of LDLT. So the potential complications caused by oversized or undersized LDLT would be reduced. The differences on the choice of the size of LDLT had no obvious effect on the lung collapse and the incidence of hypoxemia during OLV.Study 3Clinical application of ultrasound examination in confirming position of left-sided double-lumen endobronchial tubeObjectiveTo evaluate the feasibility of ultrasound lung examination combined with airway pressure monitoring in confirming position of left-sided double-lumen endobronchial tube(LDLT).Methods80 elective adult thoracic surgery patients, ASA physical status I or II, who required one-lung ventilation were selected, excluding the patients who had difficult airway by preoperative evaluation, who had the diseases narrowed trachea or main left bronchus, who had pneumothorax, asthma, chronic obstructive pulmonary disease or pulmonary infection, or who were not suitable for using LDLT. All patients were randomized to the clinical method group (Group A) and the ultrasonic method group (Group B)(n=40 each). All patients were treated with total infusion venus anesthesia(TIVA).The positioning step of LDLT is as follows.At first, the LDLT is confirmed in the trachea. Then the catheter position was assessed and regulated in two groups according to the different methods when the patient was treated with two-lung ventilation and one-lung ventilation, which was applied by sequential clamping of the tracheal and bronchial limbs. During positioning of LDLT, the patient was supine and received mechanical ventilation set to tidal volume 8ml/kg, respiratory frequency 12bpm.The position of LDLT was judged by auscultation of the lungs and airway pressure in Group A. The position of the catheter was assessed as appropriate if breath sounds could be heared only in ventilation side and airway pressure were less than 40cmH2O when one lung ventilation was provided. While in Group B, the position of LDLT was judged by ultrasound examination of pleural and diaphragmatic movement and airway pressure. The position of the catheter was assessed as appropriate if pleura and diaphragm moved only in ventilation side and airway pressure were less than 40cmH2O when one lung ventilation was provided. When examining the pleural movement, the ultrasound high-frequency probe was placed on the 2-4 intercostal and midclavicular line. And the probe was placed on the 7-9 intercostal and anterior axillry line when the diaphragmatic motion was observed.Trying to adjust the LDLT to the right position assessed. If the catheter can not be adjusted to the appropriate position when the positioning time exceeds 5min, then adjustment was stoped. The accurate position of the catheter was judged by the fiber bronchoscopy after the catheter was fixed.The following data were recorded: ①The number of the LDLT whose position was considered as correct by using FOB were counted. ②The positioning times of the LDLT were recorded in two groups.③The accuracy of the two methods in judging the position of the LDLT were analysed. The number of the true positive, true negative, false positive and false negative cases in two group were counted, and the sensitivity, specificity, accuracy, positive predictive value and negative predictive value of the two methods were calculated.ResultsThe number of the correct-position LDLT in Group A and Group B was 24 (60%) and 33 (82.5%), respectively, and the difference was statistically significant (P< 0.05). The positioning time of LDLT in two groups was 148±35 and 152±48 seconds, respectively, and the difference was not statistically significant (P> 0.05).No fase negative cases occurred. There were 24 (60.0%) true positive, one(2.5%)true negative, and 15(37.5%)false positive cases in Group A. In Group B, there were 33(82.5%)true positive,2(5%)true negative, and 5(12.5%)false positive cases. Therefore, the sensitivityand negative predictive values for detection of proper LDLT positioning in both methods were 100%. For the clinical method, the specificity was 6.25%, the accuracy was 62.5%, and positive predictive value was 61.5%; while for the ultrasound method, the specificity was 28.6%, accuracy was 87.5%, and positive predictive value was 86.8%. Among them, the differences of the accuracy and positive predictive value were statistically significant (P< 0.05).ConclusionCompared with the mothod of auscultation and airway pressure monitoring, using ultrasound examination of lung movement and airway pressure monitoring has the higher success rate of LDLT positioning, and higher specificity and accuracy of position evaluation. |
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