Bronchial Diameter Research Articles

Difficulty in inserting left double-lumen endobronchial tubes at the cricoid level in small-statured women: A retrospective study.

Background and Aims:Left double-lumen endobronchial tube (DLT) sizes are selected using tracheal diameters and left mainstem bronchial diameters (LMBDs) determined from chest radiographs or computed tomography (CT) scans. In Western women, 35-Fr or 37-Fr DLTs are often selected. However, difficulties can be encountered when inserting 32-Fr or 35-Fr DLTs in Japanese women. We investigated success rates for 32-Fr or 35-Fr DLT insertion in Japanese women and determined the causes of unsuccessful DLT insertion.Methods:We searched anaesthesia records of Japanese women aged ≥20 years who underwent thoracic surgery with 32-Fr or 35-Fr DLTs between April 2010 and March 2015 in our hospital. In the successful group (SG), patients were intubated using the initially selected DLTs. By contrast, in the unsuccessful group (UG), the DLT size had to be changed. The Mann–Whitney U-test and Fisher's exact test were used to compare groups.Results:The SG included 149 (96.1%) of 155 cases of 32-Fr DLT use and 119 (95.2%) of 125 cases of 35-Fr DLT use. Patient height was significantly lower in the UG than in the SG for the 35-Fr DLT (P = 0.0036). In seven of 12 UG patients (three for 32-Fr and four for 35-Fr), the transverse diameters of cricoid cartilages were smaller than the DLTs' tracheal diameters, thereby preventing passage through the cricoid cartilages.Conclusion:Along with LMBDs, transverse diameters of cricoid cartilages based on CT scans or ultrasonogram findings may help in selecting the appropriate left DLT size.

Quantitative CT Measures of Bronchiectasis in Smokers

Bronchiectasis is frequent in smokers with COPD; however, there are only limited data on objective assessments of this process. The objective was to assess bronchovascular morphology, calculate the ratio of the diameters of bronchial lumen and adjacent artery (BA ratio), and identify those measurements able to discriminate bronchiectasis. We collected quantitative CT (QCT) measures of BA ratios, peak wall attenuation, wall thickness (WT), wall area, and wall area percent (WA%) at matched fourth through sixth airway generations in 21 ever smokers with bronchiectasis (cases) and 21 never-smoking control patients (control airways). In cases, measurements were collected at both bronchiectatic and nonbronchiectatic airways. Logistic analysis and the area under receiver operating characteristic curve (AUC) were used to assess the predictive ability of QCT measurements for bronchiectasis. The whole-lung and fourth through sixth airway generation BA ratio, WT, and WA%were significantly greater in bronchiectasis cases than control patients. The AUCs for the BA ratio to predict bronchiectasis ranged from 0.90 (whole lung) to 0.79 (fourth-generation). AUCs for WT and WA%ranged from 0.72 to 0.75 and from 0.71 to 0.75. The artery diameters but not bronchial diameters were smaller in bronchiectatic than both nonbronchiectatic and control airways (P< .01 for both). Smoking-related increases in the BA ratio appear to be driven by reductions in vascular caliber. QCT measures of BA ratio, WT, and WA%may be useful to objectively identify and quantify bronchiectasis in smokers. ClinicalTrials.gov; No.: NCT00608764; URL: www.clinicaltrials.gov.

High-resolution computed tomography evaluation of the bronchial lumen to vertebral body diameter and pulmonary artery to vertebral body diameter ratios in anesthetized ventilated normal cats.

Objectives Bronchial lumen to pulmonary artery diameter (BA) ratio has been utilized to investigate pulmonary pathology on high-resolution CT images. Diseases affecting both the bronchi and pulmonary arteries render the BA ratio less useful. The purpose of the study was to establish bronchial lumen diameter to vertebral body diameter (BV) and pulmonary artery diameter to vertebral body diameter (AV) ratios in normal cats. Methods Using high-resolution CT images, 16 sets of measurements (sixth thoracic vertebral body [mid-body], each lobar bronchi and companion pulmonary artery diameter) were acquired from young adult female cats and 41 sets from pubertal female cats. Results Young adult and pubertal cat BV ratios were not statistically different from each other in any lung lobe. Significant differences between individual lung lobe BV ratios were noted on combined age group analysis. Caudal lung lobe AV ratios were significantly different between young adult and pubertal cats. All other lung lobe AV ratios were not significantly different. Caudal lung lobe AV ratios were significantly different from all other lung lobes but not from each other in both the young adult and pubertal cats. Conclusions and relevance BV ratio reference intervals determined for individual lung lobes could be applied to both young adult and pubertal cats. Separate AV ratios for individual lung lobes would be required for young adult and pubertal cats. These ratios should allow more accurate evaluation of cats with concurrent bronchial and pulmonary arterial disease.

Pulmonary hydatid cysts: the naturally occurring models for rupture.

Pulmonary hydatid cysts are recognized to have high rate of rupture compared to those in other affected organs. To identify risk factors associated with endobronchial rupture, we prospectively assessed 32 patients with hydatid cysts. There were 21 males and 11 females, with a mean age of 32 ± 15 years (range 9 to 65 years). All patients undergoing thoracotomies for hydatid cysts were included. Demographic data, site, size, and whether cysts were ruptured or intact, were reviewed. Intraoperatively, bronchial fistula diameters were measured. A stepwise multiple logistic regression model was used to analyze the results. Seventeen (53.1%) patients presented with ruptured cysts (group 1) and 15 with intact cysts (group 2). There was a significant difference in mean fistula diameter between groups: 6.16 ± 2 mm in group 1 vs. 0.34 ± 0.19 mm in group 2 (p ≤ 0.0001), which was identified as the only significant risk factor associated with cyst rupture. At the fistula site, the intracystic pressure is unopposed, leading to herniation of the endocyst membrane, disruption of its integrity, and rupture. Therefore, we postulate that this scenario in combination with other coexisting factors could be the possible mechanism for cyst rupture in group 1. This concept may also explain the pathogenesis of the high rate of rupture of pulmonary hydatid cysts. Accordingly, we consider these cysts a naturally occurring model for rupture, which should be treated surgically as soon as the diagnosis is made, to avoid complications.

Effects of successive tracheal resection and anastomosis on tracheal diameter and position of lobar bronchi in dogs.

OBJECTIVE To evaluate the effects of successive large-segment tracheal resection and anastomosis on tracheal diameter and position of lobar bronchi in dogs. ANIMALS 5 adult Beagles. PROCEDURES Right lateral radiographs were obtained for all dogs and used to measure tracheal length. Dogs were then euthanized, and successive segmental tracheal resections (intervals of 10% from 20% to 50% of the tracheal length), each of which was followed by anastomosis, were performed in each cadaver. Tracheobronchoscopy was performed before the first tracheal resection and after each of the anastomoses to evaluate tracheal diameter and changes in position of lobar bronchi. RESULTS Tracheal diameter was minimally affected by resections up to 50% of the tracheal length. Diameter of the trachea and position of bronchi were not affected by resection of 20% of the tracheal length. Changes in the position of various lobar bronchi were detected after resection of 30% of the tracheal length. CONCLUSIONS AND CLINCIAL RELEVANCE In this study, tracheal resections of 20% of the tracheal length were accommodated, possibly as a result of stretching of the annular ligament. Resections of ≥ 30% of the tracheal length altered the position of lobar bronchi. Clinical effects, if any, attributable to these changes in bronchial position remain to be elucidated.

Cricoid and left bronchial diameter in the pediatric population.

Lung isolation in the pediatric population can be problematic. The diameter and length of the right and left mainstem bronchi are not well described in young children. Information regarding these measurements may help determine the appropriate size of endotracheal tubes for endobronchial intubation as well as the development of lung isolation devices for the pediatric population. The present study is based on computed tomography (CT) measurements to evaluate airway dimensions. The goal of this study was to define the relationship between the diameters of the left mainstem bronchus (LMSB) and the cricoid ring, and to study the effect of age, weight, and height on these dimensions. The two-dimensional CT images of 102 children, ranging in age from 1 month to 10 years, undergoing radiological evaluation unrelated to airway symptomatology were examined. The cricoid dimensions (anteroposterior and transverse diameters) were measured using transverse plane images. The LMSB diameter was measured below the carina along the long axis of left main bronchus. Univariate regression analysis was used to determine whether one or more of the variables (age, gender, height, weight) had a predictable relationship with the cricoid and the LMSB diameters. The cricoid as well as the LMSB diameters increase with age, height, and weight. The relationship between the cricoid diameter and the LMSB diameter remains constant across all ages with a ratio of 0.78 ± 0.14. This ratio was slightly larger for girls than boys (0.81 ± 0.16 vs 0.77 ± 0.13). The cricoid to LMSB ratio (relationship) remains constant with respect to age, height, and weight.

Quantitative computed tomography analysis of the airways in patients with cystic fibrosis using automated software: correlation with spirometry in the evaluation of severity.

ObjectiveTo perform a quantitative analysis of the airways using automated software, in computed tomography images of patients with cystic fibrosis, correlating the results with spirometric findings.Materials and MethodsThirty-four patients with cystic fibrosis were studied-20 males and 14 females; mean age 18 ± 9 years-divided into two groups according to the spirometry findings: group I (n = 21), without severe airflow obstruction (forced expiratory volume in first second [FEV1] > 50% predicted), and group II (n = 13), with severe obstruction (FEV1 ≤ 50% predicted). The following tracheobronchial tree parameters were obtained automatically: bronchial diameter, area, thickness, and wall attenuation.ResultsOn average, 52 bronchi per patient were studied. The number of bronchi analyzed was higher in group II. The correlation with spirometry findings, especially between the relative wall thickness of third to eighth bronchial generation and predicted FEV1, was better in group I.ConclusionQuantitative analysis of the airways by computed tomography can be useful for assessing disease severity in cystic fibrosis patients. In patients with severe airflow obstruction, the number of bronchi studied by the method is higher, indicating more bronchiectasis. In patients without severe obstruction, the relative bronchial wall thickness showed a good correlation with the predicted FEV1.

Perioperative outcomes of upper lobectomy according to preservation or division of the inferior pulmonary ligament.

The aim of this study was to investigate the relationship between inferior pulmonary ligament division and postoperative complications. Medical records of 72 non-small cell lung cancer (NSCLC) patients who underwent video-assisted thoracic surgery (VATS) upper lobectomy between March 2012 and November 2013 performed by a single thoracic surgeon at our center were reviewed retrospectively. Patients were categorized into two groups: the division group, who underwent division of the inferior pulmonary ligament, and the preservation group, who did not. The division group included 43 patients (27 right, 16 left), while the preservation group included 29 (11 right, 18 left). Postoperative outcomes such as the presence of pleural effusion, chest tube duration, and changes in the angle and diameter of remnant bronchus were compared; bronchial diameter and angle were measured on three-dimensional (3D) reconstruction chest CT images. Chest tube duration, duration of chest tube drainage >200 mL, and the presence of pleural effusion on chest X-rays taken 1 month after surgery were not significantly different between the two groups (P=0.07, 0.33, and 1.00, respectively). There were also no significant differences between groups in the presence of apical dead space or in change in bronchial angle (P=0.22 and 0.74, respectively). In 3D reconstruction images, changes in the diameter of the right middle, right lower, and left lower lobar (LLL) bronchi were similar between groups (P=0.72, 0.12 and 0.29, respectively). Change in the angle between the right bronchus intermedius (RBI) and the right middle lobar (RML) bronchus and between the RBI and the right lower lobar (RLL) bronchus were significantly different between the division and preservation groups (P=0.02 and 0.05, respectively). Inferior pulmonary ligament division had no clear benefits. Complications related to excessive dislocation of remnant bronchi might be associated with inferior pulmonary ligament division, but further research is needed to elucidate this relationship.

A Bronchial Puncture Mechanism for Transoral Access to the Lung Parenchyma1

A Bronchial Puncture Mechanism for Transoral Access to the Lung Parenchyma1

Computed tomographic assessment of airflow obstruction in smoke inhalation injury: Relationship with the development of pneumonia and injury severity

PurposeThe prediction of pulmonary deterioration in patients with smoke inhalation injury is important because this influences the strategy for patient management. We hypothesized that narrowing of the luminal bronchus due to bronchial wall thickening correlates to respiratory deterioration in smoke inhalation injury patients. MethodsIn a prospective observational study, all patients were enrolled at a single tertiary trauma and critical care center. In 40 patients, chest computed tomographic images were obtained within a few hours after smoke inhalation injury. We assessed bronchial wall thickness and luminal area % on chest computed tomographic images. Airway wall thickness to total bronchial diameter (T/D) ratio, percentage of luminal area, and clinical indices were compared between patients with smoke inhalation injury and control patients. ResultsThe T/D ratio of patients with smoke inhalation was significantly higher than that of control patients (p<0.001), and the luminal area of these patients was significantly smaller than that of control patients (p<0.001). The number of mechanical ventilation days correlated with the initial infusion volume, T/D ratio, and luminal area %. ROC analysis showed a cut-off value of 0.26 for the T/D ratio, with a sensitivity of 79.0% and specificity of 73.7%, and a value of 23.4% for luminal area %, with a sensitivity of 68.4% and specificity of 84.2%. ConclusionsThese data revealed the utility of computed tomography scanning on admission to show that the patients with smoke inhalation injury had airway wall thickening compared to control patients without smoke inhalation injury. Airflow narrowing due to airway wall thickening was related to the development of pneumonia and the number of mechanical ventilation days in patients with smoke inhalation injury. Airflow narrowing is one important factor of respiratory deterioration in smoke inhalation injury.

Bronchiectasis: Mechanisms and Imaging Clues of Associated Common and Uncommon Diseases

Bronchiectasis is permanent irreversible dilatation of the airways and occurs in a variety of pathologic processes. Recurrent infection and inflammation and the resulting chemical and cellular cascade lead to permanent architectural changes in the airways. Bronchiectasis can confer substantial potential morbidity, usually secondary to recurrent infection. In severe cases of bronchiectasis, massive hemoptysis can lead to death. Thin-section computed tomography is the most sensitive imaging modality for the detection of bronchiectasis; findings include bronchial diameter exceeding that of the adjacent pulmonary artery and lack of normal tapering of terminal bronchioles as they course toward the lung periphery. The authors will review various causes of bronchiectasis, including common causes, such as recurrent infection or aspiration, and uncommon causes, such as congenital immunodeficiencies and disorders of cartilage development. The authors will also present an approach emphasizing the distribution (apical versus basal and central versus peripheral) and concomitant findings, such as nodules, cavities, and/or lymphadenopathy, that can assist in narrowing the differential diagnosis. Although an adequate understanding of these underlying causes in conjunction with their specific imaging appearances will allow radiologists to more confidently determine the process causing this common radiologic finding, clinical history and patient demographic characteristics play an integral role in determining a pertinent and concise differential diagnosis.

Bronchial artery hypertrophy is correlated with coronary artery disease

Bronchial arteries support the systemic pulmonary vasculature and physiologically communicate with pulmonary arteries and coronary arteries. While there is evidence supporting the link between pulmonary diseases and bronchial artery hypertrophy (BAH), few data on the correlation between coronary artery disease (CAD) and BAH have been published. To evaluate a possible association between BAH and CAD in patients without known pulmonary diseases undergoing computed tomography coronary angiography (CTCA). This retrospective study was approved by the local ethics committee. One hundred patients with varying degrees of CAD underwent CTCA. Patients were stratified into four groups as follows: group I, 25 patients without CAD or with non-significant CAD; group II, 25 untreated patients with significant CAD; group III, 25 stented patients; group IV, 25 patients with coronary artery bypass grafts. The number and diameter of bronchial arteries were recorded. Correlation between age, CAD, and BAH was estimated. One hundred and ninety-nine bronchial arteries were detected. Approximately 51% were hypertrophic (diameter, >1.5 mm) with a mean diameter of 1.7 ± 0.5 mm. Seventy-six patients showed no pulmonary alterations; 24 were found to have previously undiagnosed pulmonary findings, six of which were severe. Presence and degree of CAD correlated with patients' mean age (60 in group I, 68 in group II, 65 in group III, 69 in group IV; P = 0.023), and mean bronchial artery transverse diameter (1.6 mm, 1.7 mm, 1.8 mm, and 2.0 mm, respectively; P = 0.009). The bronchial artery diameter was not associated with pulmonary findings (P = 0.390). There is an association between CAD and BAH. In patients with no pulmonary alterations, BAH could be caused by undiagnosed underlying CAD.

Evaluation of effects of bronchiectasis on bronchial artery diameter with multidetector computed tomography

Among patients with increased bronchial artery diameter there is a significant association between hemoptysis and bronchiectasis score. The higher score of bronchiectasis, the higher risk of hemoptysis development. To investigate the association of stages of bronchiectasis based on a computed tomography (CT) grading system, with bronchial artery diameter and hemoptysis in patients with bronchiectasis. Patients with lung pathologies other than bronchiectasis, which may cause hemoptysis, were excluded from the study. One hundred and forty-five patients who underwent contrast-enhanced thorax CT by a 64-detector CT for various indications, and who were diagnosed with bronchiectasis, were evaluated retrospectively. CT examinations were carried out by two radiologists with 9 and 4 years of experience with chest radiology, respectively. The diameters of the right and left bronchial arteries were measured 1 cm from the aortic origin and perpendicular to the vessel axis. Cases were assessed based on the Bhalla CT scoring system. The hemoptysis history of every patient was taken. The diameters of the right and left bronchial arteries were significantly greater in patients with scores of 2 and 3 bronchiectasis than in patients with a score of 1. This was significantly greater in patients with a score of 3 than in patients with a score of 2 (P < 0.05). In patients with a score of 1, the right bronchial artery diameter was significantly greater than that of the left bronchial artery (P < 0.05). Right bronchial artery diameters were significantly greater than left bronchial artery diameters in score 3 patients (P < 0.05). A significant association was observed between hemoptysis and bronchiectasis in patients with increased bronchial artery diameter (P < 0.05). In patients with bronchiectasis, as the stage of bronchiectasis increases, the bronchial artery diameters and the risk of hemoptysis increase. We think that in patients who are diagnosed with bronchiectasis via multidetector CT (MDCT), based on scoring with bronchial artery diameters, the risk of hemoptysis can be estimated, and early management plans can be implemented.

The guiding role of the left bronchial inner diameter in the choice of double-lumen endobronchial tube size

目的 探讨左支气管内径值在双腔支气管导管(DLT)型号选择中的指导作用.方法 将300例使用左DLT进行单肺通气的择期胸外科手术患者,随机数字表法分为两组,即:A组(传统方法组:根据患者身高、体质量选择左支气管导管型号)、B组(左支气管内径值组:根据螺旋CT测量患者的左支气管内径值选择合适导管),每组150例.记录每位患者的年龄、性别、身高、体质量、疾病种类、使用的左DLT型号、导管合适度评价指标、肺萎陷质量、术后24 h并发症的发生情况,对记录指标进行统计学分析.结果 两组年龄、性别、身高、体质量及病种构成差异均无统计学意义(均P＞0.05);与A组比较,B组使用的左DLT的型号大(χ2=8.650,P＜0.05),导管的适合度高(P＜0.01),肺萎陷质量高(χ2=6.549,P＜0.05),并且术后24 h并发症的发生率低(χ2=3.991,P＜0.05).结论根据螺旋CT测量左支气管内径值能较准确选择合适的导管型号,在DLT使用中具有指导作用。

Structure–function relationship in COPD revisited: an in vivo microscopy view

BackgroundFibred confocal fluorescence microscopy (FCFM) is a novel technology that allows the in vivo assessment and quantification during bronchoscopy of the bronchial wall elastic fibre pattern, alveolar and vessel diameters...

The comparison of the lengths and diameters of main bronchi measured from two-dimensional and three-dimensional images in the same patients.

BackgroundRecently, multi-planar reconstruction of the three-dimensional (3D) spiral chest CT scan has demonstrated superiority in the evaluation of the tracheobronchial tree. The goal of this study was to measure the lengths of the right and left main bronchi and their anteroposterior (AP) and transverse (TR) diameters using the 3D and two-dimensional (2D) images in the same adult respectively, and to evaluate the degree of correlation between them.MethodsWe measured the lengths of the right and left main bronchi from the carina to the first of their branches and the AP and TR diameters at the mid-portion of the right main bronchus and 2 cm below the carina in the left main bronchus. We determined the size of the left-sided double-lumen tube (DLT) based on the measured AP diameter of the left main bronchus from the 3D and 2D images, respectively.ResultsThere was moderate correlation between the lengths of both main bronchi obtained from the 3D images and the 2D images, and between the AP diameter of the left main bronchus obtained from the 3D images and the 2D images. Same sized DLTs were estimated in 69% of the men and 34% of the women.ConclusionsThe lengths of the right and left main bronchi and their AP and TR diameters obtained from 3D images were not strongly correlated with those from 2D images. Therefore, a further study is needed to verify the superiority of 3D images in selecting the appropriate size of left-sided DLT.

Neuropsychiatric changes precede classic motor symptoms in ALS and do not affect survival

To investigate patient susceptibility to neuropsychiatric symptoms in the context of progression of more classic motor symptoms in amyotrophic lateral sclerosis (ALS) and to examine the impact of neuropsychiatric symptoms on survival. The study cohort consisted of 219 patients with ALS (limb onset = 159; bulbar onset = 60), with neuropsychiatric symptoms measured using the Motor Neuron Disease Behavioural Scale and more classic ALS symptoms assessed by the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised. For detection of symptom susceptibility (neuropsychiatric vs classic motor), a Rasch analysis was applied (n = 219). Cox proportional hazard regression models were used for the survival analysis (n = 115 patients), which incorporated neuropsychiatric and classic motor symptoms. Rasch analysis demonstrated that neuropsychiatric symptoms appeared earlier than classic motor features of ALS. However, differences in neuropsychiatric scores did not affect survival: patients with abnormalities in neuropsychiatric domains did not exhibit a different rate of survival than those without (χ(2), 3.447, p = 0.328, -2 log-likelihood 377.341). Neuropsychiatric symptoms appear before classic motor features in ALS, which corroborates the notion that ALS and frontotemporal dementia lie on a disease continuum. The early detection of neuropsychiatric symptoms will be critical to inform clinical decisions and alleviate carer burden. Importantly, subtle neuropsychiatric symptoms alone do not affect survival in ALS, which in turn confirms their pervasive nature in ALS.

Evaluation of Airway Wall Thickness Via High-Resolution Computed Tomography in Mild Intermittent Asthma

This study aims to evaluate bronchial thickness via thorax high-resolution computed tomography (HRCT) in subjects with mild intermittent asthma in comparison with healthy control subjects. A total of 37 out-patients (mean ± SD age = 36.7 years (9.7 years); 54.8% males) with mild intermittent asthma and 13 healthy control subjects (mean ± SD age = 25.0 years (2.9 years); 61.5% males) were included in this case control study. Data on demographics, pulmonary function test results, and segmental and subsegmental thorax HRCT results were recorded. The ratio of bronchial wall thickness to bronchial lumen diameter (T/D) and bronchial wall area percentage (WA%) were calculated for all cases. Subject and control groups were similar in terms of pulmonary function test results, and total and subsegmental T/D values. Mean ± SD subsegmental WA% values at the level of inferior pulmonary vein (55.6% [16.8%] vs. 41.7% [7.4%], P = .047) and 2 cm above the diaphragm (49.8% [15.8%] vs. 38.6% [10.4%], P = .046) were significantly higher in subjects than control subjects. No significant correlation of overall and subsegmental T/D and WA% values to age in both groups, and to asthma duration in subjects. Our findings revealed an increase in bronchial wall thickness in peripheral airways in subjects with mild intermittent asthma regardless of the duration of asthma. This may indicate a need to also administer anti-inflammatory or bronchodilator therapy, which is effective in peripheral airways during the early period of the disease.

Measurements of the Length and Diameter of Main Bronchi on Three-Dimensional Images in Asian Adult Patients in Comparison With the Height of Patients

To measure the length and diameter of the main bronchus using the three-dimensional reconstruction images from the spiral chest computerized tomography scans in Asian adult patients, and to evaluate the relationship between the height of patients and the length and diameter of main bronchi. Prospective observational study. Academic, tertiary care hospital. Two hundred Asian adults undergoing a chest spiral computerized tomography scan. No intervention. The authors measured the anteroposterior and transverse diameters of the mid-portion of the right main bronchus and 2 cm below the carina of the left main bronchus. In addition, the length of both main bronchi was also measured. The length of the left main bronchus was about 3-4 times greater than its right counterpart. The main bronchus of women was oval-shape, with a large anteroposterior diameter, but the main bronchus of men was round-shape. There was no significant correlation between the measurements of main bronchi and the height of patients. The results showed that there is no direct relationship between the length and diameter of main bronchi and the height of patients. The height is not the criterion for choosing DLT size. Therefore, the authors proposed that 3-D images be used to determine the size of the main bronchi. The diameter of main bronchus using the 3-D images can be used to determine the optimal size of the DLT in a clinical setting, although further studies are needed.

EFFECT OF VENTILATION TECHNIQUE AND AIRWAY DIAMETER ON BRONCHIAL LUMEN TO PULMONARY ARTERY DIAMETER RATIOS IN CLINICALLY NORMAL BEAGLE DOGS

In dogs, a mean broncho-arterial ratio of 1.45 ± 0.21 has been previously defined as normal. These values were obtained in dogs under general inhalational anesthesia using a single breath-hold technique. The purpose of the study was to determine whether ventilation technique and bronchial diameter have an effect on broncho-arterial ratios. Four healthy Beagle dogs were scanned twice, each time with positive-pressure inspiration and end expiration. For each ventilation technique, broncho-arterial ratios were grouped into those obtained from small or large bronchi using the median diameter of the bronchi as the cutoff value. Mean broncho-arterial ratios obtained using positive-pressure inspiration (1.24 ± 0.23) were statistically greater than those obtained at end expiration (1.11 ± 0.20) P = 0.005. There was a strong positive correlation between bronchial diameter and broncho-arterial ratios for both ventilation techniques (positive-pressure inspiration rs = .786, P < 0.0005 and end expiration rs = .709, P < 0.0005). Mean broncho-arterial ratio for the large bronchi obtained applying positive-pressure inspiration was 1.39 cm ± 0.20 and during end expiration was 1.22 cm ± 0.20. Mean broncho-arterial ratio for the small bronchi obtained during positive-pressure inspiration was 1.08 cm ± 0.13 and during end expiration was 1.01 cm ± 0.13. There was a statistically significant difference between these groups (F = 248.60, P = 0.005). Findings indicated that reference values obtained using positive-pressure inspiration or from the larger bronchi may not be applicable to dogs scanned during end expiration or to the smaller bronchi.