Tracheobronchial Obstruction Research Articles

Clinical presentations and diagnostic approaches of pediatric necrotizing tracheobronchitis with influenza A virus and Staphylococcus aureus co-infections

In March 2023, our pediatric intensive care unit (PICU) retrospectively examined six cases of pediatric necrotizing tracheobronchitis (NTB), focusing on co-infections with influenza A virus (IAV) and Staphylococcus aureus (S. aureus). This study aimed to elucidate NTB’s clinical characteristics, diagnostics, and therapeutic approaches. Diagnostics included symptom assessment, microbiological testing that confirmed all patients were positive for IAV H1N1 with a predominant S. aureus co-infection, and bronchoscopy. The patients predominantly exhibited fever, cough, and dyspnea. Laboratory analysis revealed decreased lymphocyte counts and elevated infection markers like C-reactive protein and procalcitonin. Chest computed tomography (CT) scans detected tracheobronchial obstructions in half of the cases, while bronchoscopy showed severe mucosal congestion, edema, necrosis, and purulent-hemorrhagic exudates. Treatments encompassed comprehensive strategies like oxygen therapy, intubation, bronchoscopic interventions, thoracentesis, oseltamivir, and a regimen of antibiotics. Our findings suggested potential correlations between clinical markers, notably lymphocyte count and procalcitonin, and clinical interventions such as the number of rescues and intensive care unit (ICU) duration. This research highlights the importance of early detection and the role of bronchoscopy and specific markers in assessing NTB, advocating for continued research in larger cohorts to better understand its clinical trajectory and refine treatment approaches for this challenging pediatric disease.

Further experience with polydioxanone airway stents in children

AbstractIntroductionThe aims of this study were to update our experience with biodegradable polydioxanone (PDO) airway stents in children, focusing on effectiveness and safety, and to analyze the factors involved in the different outcomes observed.Materials and MethodsRetrospective study of patients managed with PDO stents from 2012 to 2023. Variables collected: demographics, comorbidities, indication, clinical baseline, stent size, location, complications, clinical outcome, and time of follow‐up. Statistical analyses were performed to detect the eventual contribution of variables in the different outcomes observed.ResultsFifty‐four PDO stents were placed in 26 patients (median age, 4 months). All showed severe symptoms of central airway obstruction due to tracheomalacia in nine patients, bronchomalacia five, tracheobronchomalacia 10, and tracheal stenosis two. Stent placement was uneventful in every case: 29 stents in the trachea and 25 in the main bronchi. 53.8% of patients needed successive stenting, and all exhibited comorbidities. Complete clinical resolution was observed in eight cases (30.7%), partial improvement in 13 (50%), unchanged in 4 (15.3%), and worsened in one. Age had a significant positive impact on outcome (6 vs. 3 months; p = 0.024). Additionally, smaller stents were associated with a better outcome (20 vs. 26 mm; p = 0.044). Granulation tissue was the most frequent complication (34.6%). Five patients (19.2%) died due to severe comorbidities, follow‐up was complete in survivors (median, 58 months).ConclusionsPDO stents are safe and effective when dealing with severe tracheobronchial obstruction. Stent‐related granulation tissue continues to be a relevant matter of concern. This issue, together with increased degradation times, deserves further research.

Flexible and Rigid Bronchoscopy for Critically Ill Children on Extracorporeal Membrane Oxygenation.

We aim to describe our experience with bronchoscopy to diagnose and relieve tracheobronchial obstruction in anticipation of decannulation in children on extracorporeal membrane oxygenation (ECMO) support. A retrospective cohort study of children on ECMO between 1/2018 and 12/2022. A total of 107 children required ECMO support during the study period for cardiac (n = 48, 45%), pulmonary (n = 38, 36%), or cardiopulmonary dysfunction (n = 21, 20%). Thirty-seven (35%) patients underwent 99 bronchoscopies while on ECMO. Most (76%, n = 75) experienced no improvement or worsening of chest radiography 24 hours following bronchoscopy. Clinical improvement in tidal volumes 48 hours after the first bronchoscopy was noted in 13/25 patients with available data (p = 0.05). Adverse events were seen in 18 (49%) patients who underwent bronchoscopy, including pneumothorax (n = 8, 22%), pneumonia (n = 7, 19%), pulmonary hemorrhage (n = 6, 16%), and sepsis (n = 5, 14%). ECMO courses were longer (25.4 ± 37.2 vs 6.1 ± 8.8 days, p < 0.0001) and more likely to be complicated by pneumonia (p = 0.0004) and sepsis (p = 0.047) in patients who underwent bronchoscopy compared with those who did not. Adverse events following bronchoscopy were associated with the number of bronchoscopies (p = 0.0003) and the presence of obstructive materials but not with the type of bronchoscopy or indication for ECMO. Mortality rates were similar between patients who underwent bronchoscopy and those who did not. Children requiring bronchoscopy represent a subset of the sickest children on ECMO. Bronchoscopy may provide benefit in children with persistent cardiopulmonary failure who could not otherwise be decannulated. Adverse events are associated with the number of bronchoscopies and the presence of obstructive material. 4 Laryngoscope, 134:4134-4140, 2024.

The "Hitch-Stitch" for Preventing High Tracheal Stent Migration: Expanding Indications and Extended Experience.

Airway stenting is a standard treatment option for tracheo-bronchial obstruction and other conditions like tracheo-esophageal fistula (TEF). To prevent stent migration, a percutaneous fixation strategy called the "hitch-stitch" was described in 2016 as an efficient technique. We describe an extended experience of the "hitch-stitch" for silicone stents in high tracheal stenting situations and expanding indications to metal stents. Seventy-four percutaneous stitches were placed in 54 patients (36 males and 18 females). The mean age of the patients was 42 (±19) years. The indication for stenting was tracheal stenosis in 63/74 (85%) cases and TEF in 11/74 (15%) cases. Silicone stents were used in 56/74 (75.5%) cases while self-expanding metal stents (SEMS) were used in 18/74 (24.5%) cases. The majority of the stents (62/74, 85%) were high tracheal stents. The "hitch-stitch" as an anti-migration strategy had a high success rate, with distal stent migration in only 2 cases (2.7%) as the stitch had given way-these were repositioned and hitched with double stitches. Minor complications included delayed skin healing (2.8%) and suture site infection (1.4%), which was successfully managed with oral antibiotics. Stitch removal was easy with no complications. In this large series of percutaneous "hitch-stitch" as a stent migration prevention strategy, long-term data shows it is safe and effective in an expanded cohort of silicone stents. Its extended utility is the successful application to metal stents, especially in TEF, where the consequences can be deleterious. It is simple to do, with minimal extra requirements and not associated with any significant complications.

Cryoextraction via flexible bronchoscopy in children with tracheobronchial obstruction.

Cryoextraction via flexible bronchoscopy (FB) can be used to alleviate airway obstruction due to blood clots, casts, mucus, and foreign bodies. There is limited literature regarding the utility of cryoextraction to restore airway patency in critically ill children, especially on extracorporeal membrane oxygenation (ECMO). The aims of this study were to describe the clinical course and outcomes of children who underwent cryoextraction via FB. A singlecenter retrospective review of children who underwent cryoextraction via FB between 2017 and 2021 was conducted. The analyzed data included diagnoses, indications for cryoextraction, respiratory support modalities, FB and chest imaging results, and outcomes. Eleven patients aged 3-17 years underwent a total of 33 cryoextraction sessions via FB. Patients required ECMO (n = 9) or conventional mechanical ventilation (CMV) for pneumonia, pulmonary hemorrhage, pulmonary embolism, asthma exacerbation, and cardiorespiratory failure following cardiac surgery. One patient underwent elective FB and cryoextraction for plastic bronchitis. Indications for cryoextraction included airway obstruction due to tracheobronchial thrombi (n = 8), mucus plugs (n = 1), or plastic bronchitis (n = 2). Cryoextraction via FB was performed on patients on ECMO (n = 9) and CMV (n = 2) with 6 patients requiring ≥3 cryoextraction sessions for airway obstruction. There were no complications related to cryoextraction. Patient outcomes included partial (n = 5) or complete (n = 6) restoration of airway patency with ECMO decannulation (n = 5) and death (n = 4) due to critical illness. Cryoextraction via FB is an effective intervention that can be utilized in critically ill children with refractory tracheobronchial obstruction to restore airway patency and to facilitate liberation from ECMO.

Clinical and bronchoscopy features of tracheobronchial tuberculosis in children

To study the clinical and bronchoscopic characteristics of tracheobronchial tuberculosis (TBTB) in children and to identify factors influencing residual airway obstruction or stenosis. The clinical data of children with TBTB were retrospectively collected. The children were divided into two groups based on the last bronchoscopic result within one year of follow-up: a group with residual airway obstruction or stenosis (n=34) and a group without residual airway obstruction or stenosis (n=58). A multivariate logistic regression analysis was used to identify the factors influencing residual airway obstruction or stenosis in children with TBTB. Receiver operating characteristic (ROC) curves were used to analyze the predictive value of the factors influencing residual airway obstruction or stenosis in children with TBTB. A total of 92 children with TBTB were included, and the main symptoms were cough (90%) and fever (68%). In children under 1 year old, the incidence rates of dyspnea and wheezing were significantly higher than in other age groups (P<0.008). Chest CT findings included mediastinal or hilar lymph node enlargement (90%) and tracheobronchial stenosis or obstruction (61%). The lymphatic fistula type was the main type of TBTB observed bronchoscopically (77%). All children received interventional treatment, and the effective rate was 84%. During one year of follow-up, 34 children had residual airway obstruction or stenosis. The TBTB diagnostic time and the initiation of interventional treatment were significantly delayed in the group with residual airway obstruction or stenosis compared with the group without residual airway obstruction or stenosis (P<0.05). The multivariate logistic regression analysis showed that the TBTB diagnostic time was closely related to residual airway obstruction or stenosis in children (P<0.05). ROC curve analysis showed that at the cut-off value of 92 days of TBTB diagnostic time, the area under the curve for predicting residual airway obstruction or stenosis in children with TBTB was 0.707, with a sensitivity of 58.8% and a specificity of 75.9%. The clinical manifestations of TBTB are nonspecific, and symptoms are more severe in children under 1 year old. TBTB should be suspected in children with tuberculosis and chest imaging indicating airway involvement. Delayed diagnosis of TBTB is associated with the development of residual airway obstruction or stenosis.

Imaging of therapeutic airway interventions in thoracic oncology

Tracheobronchial obstruction, haemoptysis, and airway fistulas caused by airway involvement by primary or metastatic malignancies may result in dyspnoea, wheezing, stridor, hypoxaemia, and obstructive atelectasis or pneumonia, and can lead to life-threatening respiratory failure if untreated. Complex minimally invasive endobronchial interventions are being used increasingly to treat cancer patients with tracheobronchial conditions with curative or, most often, palliative intent, to improve symptoms and quality of life. The selection of the appropriate treatment strategy depends on multiple factors, including tumour characteristics, whether the lesion is predominately endobronchial, shows extrinsic compression, or a combination of both, the patient's clinical status, the urgency of the clinical scenario, physician expertise, and availability of tools. Pre-procedure multidetector computed tomography (MDCT) imaging can aid in the most appropriate selection of bronchoscopic treatment. Follow-up imaging is invaluable for the early recognition and management of any potential complication. This article reviews the most commonly used endobronchial procedures in the oncological setting and illustrates the role of MDCT in planning, assisting, and follow-up of endobronchial therapeutic procedures.

Resorbable airway splint, stents, and 3D reconstruction and printing of the airway in tracheobronchomalacia

Tracheobronchomalacia (TBM) is the most common tracheobronchial obstruction. Most cases are mild to moderate; therefore, they do not need surgical treatment. Severe tracheomalacia, however, represents a diagnostic and therapeutic challenge since they are very heterogeneous. In the armamentarium of resources for the treatment of dynamic airway collapse, splints and stents are two underused strategies and yet, they may represent the best alternative in selected cases. Lately, computed tomography 3D reconstruction of the airway has been used for the design of virtual models that can be 3D-printed for the creation of novel devices to address training, simulation, and biotechnological implants for refractory and severe airway malformations. This manuscript examines the role of resorbable stents, splints, and the 3D reconstruction and printing of the pediatric airway in tracheobronchomalacia.

Argon Plasma Coagulation: Elucidation of the Mechanism of Gas Embolism

Background: Argon plasma coagulation (APC) is a tool used in the management of tracheobronchial obstruction or bleeding. Complications include gas embolism which can cause devastating effects including hemodynamic instability, cardiac arrest, and stroke. Multiple theories as to how gas embolism occurs with APC have been postulated; however, none have identified the exact mechanism. Objectives: To identify the mechanism by which APC causes gas embolism in the tracheobronchial tree. Methods: Using an explanted porcine tracheobronchial tree with lung parenchyma, the APC catheter was applied through noncontact and direct contact to the endobronchial airway mucosa via flexible bronchoscopy. This was done at multiple gas flow settings and pulse durations. Visual changes in the mucosa were photographed, videoed, and described. Results: Gross evidence of submucosal gas transfer occurred when the APC catheter was in direct contact with the mucosa at all gas flow settings in all applications, despite using shorter pulse durations. Whenever the catheter was not in contact with the mucosa, there was no transfer of gas at any gas flow setting or pulse duration. Conclusions: Direct mucosal contact with the APC probe leads to submucosal gas deposition and is a likely mechanism for gas entry into the intravascular space. In reported cases of APC-associated gas embolism, presence of a vascularized endobronchial tumor may have increased the risk of gas tracking into the intravascular space. Care should be taken when applying APC during brisk bleeding or limited vision, as inadvertent mucosal contact may occur and could increase the risk of gas embolism.

Painting the Clinical Picture of Congenital Plasminogen Deficiency (C-PLGD) through a Comprehensive Case Study Review

C-PLGD is a rare autosomal recessive multisystem disorder of the fibrinolytic system with a diverse spectrum of clinical manifestations, and is underdiagnosed and difficult to treat. Caused by mutations in thePLGgene, C-PLGD is characterized by extravascular fibrinous deposits on mucous membranes such as the conjunctiva, gingiva, linings of airways and genitourinary tract. The abnormal accumulation or growth of fibrin-rich pseudomembranous lesions have been termed ligneous for their "woody" appearance, and often result in tissue injury and/or organ dysfunction in C-PLGD patients. We present here the results of an exhaustive MEDLINE literature database review undertaken with the PubMed search engine using the key words; 'plasminogen deficiency,' 'hypoplasminogenemia' and 'ligneous conjunctivitis'. Objective:The goal of this review was 1) to achieve a better understanding of the type and prevalence of clinical manifestations of C-PLGD and their outcomes, and 2) to evaluate whether a relationship exists between endogenous plasminogen activity levels and disease manifestations in C-PLGD patients. Methodology: A MEDLINE literature search was conducted by three independent investigators. Publications containing the key words 'plasminogen deficiency,' 'hypoplasminogenemia' and/or 'ligneous conjunctivitis' and reporting human clinical information were selected. Patients' age, sex, endogenous plasminogen levels, and clinical manifestations were tabulated. Results: The search retrieved 414 total citations, and 130 papers with relevant human clinical data were identified for full-length text review. From these, 301 unique C-PLGD patients (237 pediatric and 64 adults) were found to be reported over an 80-year period (from 1957 to 2017) and presented the following outcomes and most common and/or serious clinical manifestations: ligneous conjunctivitis (255 cases), ligneous periodontitis (71 cases), tracheobronchial obstructions (53 cases), hydrocephalus (42 cases), other corneal lesion (15 cases), ligneous vaginitis (24 cases), blindness (6 cases), and death (10 cases). Differences in disease seriousness and prevalence were observed between pediatric and adult patient populations (Table1). Of note, death or hydrocephalus were reported only in pediatric patients. Historical information indicated that 62% of the 301 reported patients were females and 36% males, while 2% of them did not have their gender disclosed. The median age of reported onset of symptoms (and/or diagnosis) was 1 year old for the 176 patients with available data. Of the 130 papers retained and analyzed, 2 studies (Klammt et. al. Thromb Haemost 2011; Tefs et. al. Blood 2006) were selected for additional in-depth analysis. These studies included a subset of 58 C-PLGD patients whose clinical, molecular and plasminogen activity data were available and reliably reported. These patients had a spectrum of plasminogen activity level ranging from 2% to 59% and presented the main following clinical manifestations: ligneous conjunctivitis (52/58), ligneous periodontitis (16/58), tracheobronchial involvement (14/58), ligneous vaginitis (6/58), and hydrocephalus (4/58) (Table 2). Out of this 58-patient cohort, 26 reported a single lesion and had an average plasminogen activity level of 22% while the 32 remaining had 2 or more lesions and an average activity level of 20%, indicating that the level of plasminogen activity may not correlate with the clinical manifestations burden/seriousness. Conclusion:This comprehensive review confirmed that the heterogeneity challenges in clinical evaluation and the overall rarity of C-PLGD can contribute to delayed diagnosis, treatment variability and less than optimal outcomes. With lack of natural history studies or reports of C-PLGD, the data described here can be used to highlight the seriousness of long-term morbidity, promote early and effective management of C-PLGD, and support the ongoing development of novel plasminogen replacement therapy to address the primary underlying drivers of morbidity in C-PLGD. The implementation of natural history studies may play an important role in addressing the knowledge gap in phenotypic expression and long-term impact of C-PLGD on the quality of life of impacted patients. Disclosures Thibaudeau: Liminal BioSciences:Current Employment, Current equity holder in publicly-traded company.Robitaille:Liminal BioSciences:Consultancy, Current equity holder in publicly-traded company, Ended employment in the past 24 months.Ledsham:Liminal BioSciences:Current Employment.Sandset:Liminal BioSciences:Other: Investigator Clinical Trial.

Interventional therapy via flexible bronchoscopy in the management of foreign body-related occlusive endobronchial granulation tissue formation in children.

Occlusive granulation tissue formation, as one of the most common sequelae of chronic foreign body aspiration, can cause tracheobronchial obstruction and delayed fixed airway stenosis necessitating interventions. The aim of this study was to explore the clinical efficacy and safety of interventional therapy via flexible bronchoscopy for treatment of granulation tissue related airway obstruction secondary to foreign body aspiration in children. Patients with long-term foreign body related granulation tissue were treated with flexible bronchoscopy therapeutic modalities, including forceps, cryotherapy, holmium laser, and balloon dilatation. Clinical efficacy was evaluated by clinical symptoms and endoscopic manifestations. A total of eight patients with granulation tissue hyperplasia caused by foreign body in bronchus, with a median age of 29.5 (range, 18-54) months, underwent interventional therapy between January 2016 and December 2019. Four patients received forceps and CO2 cryotherapy and one patient required forceps only. The remaining three patients received holmium laser combined with CO2 cryotherapy, and one of them required additional balloon dilatation. Four cases required a second cryotherapy procedure, and one case received three cryotherapy procedures for extensive granulation tissue. The treatment efficacy was 100% without complications. Interventional procedure via flexible bronchoscopy is a safe, reliable, and effective method in the management of tracheobronchial obstruction and stenosis caused by foreign body-related granulation tissue hyperplasia. It is worthy of clinical application.

Comparison of silicon and metallic bifurcated stents in patients with malignant airway lesions.

Silicon and metallic are two types of stents in use. In this study, we compared complications and long-term survival among patients who received silicon or fully covered, bifurcated self-expandable metallic stents (SEMS) for a malignant tracheobronchial obstruction and/or tracheo/bronchial oesophageal fistulas. Patients in whom Y-shaped stents were used from January 2013 to June 2017 in our interventional pulmonology unit were evaluated retrospectively from patient files. Of the 47 patients, 30 (23 males, 76.7%) were in the silicon stent group and 17 (14 males, 82.4%) were in the covered SEMS group. No differences between the groups were detected in ECOG status, pathological properties of the disease, radiotherapy or chemotherapy history before the procedure, symptoms at presentation, or comorbidities. The most common symptom was dyspnoea (96.7% and 100%), and the most common comorbidity was chronic obstructive pulmonary disease (26.7% and 23.5%). A total of 20 complications (42.6%) were seen, with no significant difference between the groups (silicon, 40%; SEMS, 47.1%; P=. 62). Mean survival was 164.51±38.83days for the silicon stent group and 254.45±103.32days for the SEMS group (P=.588). No differences were observed in 30-, 90- or 180-day mortality between the two groups (P=.966, .846 and .534, respectively). No significant differences in symptom palliation, insertion safety, complication rate or survival were detected between the two types of stent.

Experimental evaluation of self-expandable metallic tracheobronchial stents

Abstract The self-expandable metallic stents have been widely used in tracheobronchial obstruction or fistulation, including the J-shaped and Y-shaped stents, named after the shape of the branch-stem junction of the stent. However, there is scarce data on the mechanical performance of these tracheobronchial stents, which is essential for optimal stent implantation. In this work, eight self-expandable metallic tracheobronchial stents in three types (i.e., straight, J-shaped, and Y-shaped), with or without cover, were characterized. The compression resistance of the stems was investigated through both compression and indentation tests. The bending resistance of the branches in the J-shaped and Y-shaped stents was assessed through the bending test. Our results demonstrated that the covered stents exhibited a significantly higher compression resistance and bending resistance than the uncovered ones. The branches had a minimal impact on the compression resistance of the stem. The branch of the J-shaped stent showed a significantly lower bending resistance than the Y shaped one. This work provides a testing framework for the J-shaped and Y-shaped stents,which could shed some light on the optimal design of stent with branches.

Blood clot removal by cryoextraction in critically ill patients with pulmonary hemorrhage.

Severe pulmonary hemorrhage is a life-threatening complication in critically ill patients. Due to tracheobronchial obstruction, ventilation is often impaired. Traditionally, rigid bronchoscopy is an option for recanalization. However, in comparison to flexible bronchoscopy, the application of rigid bronchoscopy is more complex. Against this background we evaluated the use of flexible cryo-probes for blood clot removal in critically ill patients. Retrospectively, we identified 16 patients (median age: 60 years, 69% male patients), who suffered from severe airway obstruction due to blood clots. All patients required invasive ventilation and 11 patients depended on extracorporeal membrane oxygenation (ECMO). To remove blood clots, flexible bronchoscopic cryoextraction was performed in n=27 cases, whereas rigid bronchoscopy was only needed in two cases. Whereas in 9 cases single flexible cryoextraction was successful immediately, the procedure had to be repeated again in 7 patients. In all cases, tracheobronchial obstruction was treated with success and conditions of invasive ventilation were improved. In no case severe complications were observed. In consideration of the underlying evaluation, we highly recommend flexible cryoextraction as both a safe and less complex technique for blood clot removal in critically ill patients.

DOZ047.106: Internal stents and external splints for complex airway obstruction

Abstract Background Life-threatening airway obstruction due to severe tracheobronchial stenosis or tracheobronchomalacia not amenable to tracheobronchopexy or resection is still a challenge, and warrants aggressive innovative strategies. In this study, our experience with placement of balloon-expandable stents and/or external bioabsorbable splints in children with severe tracheobronchial obstruction was reviewed. Methods All patients with symptomatic severe airway obstruction who underwent interaluminal stent and/or external splint placement (1997–2019) were retrospectively reviewed. The data collected included age, type of obstruction (stenosis or malacia), associated malformations, technical and clinical success, complications, and outcomes. Airway stents were placed under fluoroscopic guidance. Bioabsorbable splints (RapidSorb, Synthes CMF) were custom molded and then secured externally on the collapsing areas under simultaneous bronchoscopic and direct visualization. Results Seventeen patients underwent 14 airway stents (trachea = 5, bronchi = 9) and/or 11 external bioabsorbable splints (trachea = 5, bronchi = 6) at a median age of 5 months (IQR 3–9 months). Fourteen stents were placed in 8 patients, 10 external splints in 8 patients; one patient had two stents and one splint. Indications for stenting were stenotic airways in 11 patients (postoperative = 7, congenital = 4) and severe distal airway malacia in 3. All the external bioabsorbable splints were placed in patients with severe airway malacia secondary to lack of cartilaginous support and/or extrinsic compression. During follow-up 3/9 stented patients and 3/9 splinted patients did not experience any significant adverse events. Six of nine stented patients experienced serious adverse events: significant in-stent stenosis (n = 3), stent migration, and obstructive granulation tissue (n = 1), erosion through airway wall (n = 1), and death (n = 2). Of the nine splinted patients, one bronchial splint fractured, requiring replacement, and five patients required tracheostomies for continued respiratory failure from unilateral pulmonary hypoplasia and residual distal tracheal stenosis (n = 1), severe tracheomalacia (n = 2), subglottic stenosis (n = 1), and laryngeal cleft (n = 1). One patient died a week after surgery. Conclusion Airway internal stenting and external bioabsorbable splinting are effective therapeutic strategies for selected patients with complex airway abnormalities. Bioabsorbable splints are effective in maintaining airway patency, and being absorbable allow for age-proportional growth of the airways. Airway stents can be associated with significant adverse events and therefore should be reserved for patients who have failed other therapeutical strategies.

In vitro degradation and biocompatibility evaluation of typical biodegradable metals (Mg/Zn/Fe) for the application of tracheobronchial stenosis

Tracheobronchial obstruction in children due to benign stenosis or tracheobronchomalacia still remains a challenging matter of concern. Currently, there is 10%–20% complication rate in clinical treatment. The non-biodegradable property of silicone stents and nickel-titanium memory alloy stents take the primary responsibility for drawbacks including stimulating local granulation tissue proliferation, displacement, and stent-related infections. Permanent tracheobronchial stent will be a persistent foreign object for a long time, causing excessive secretion of tracheal mucosa, ulceration and even perforation, which is particularly unsuitable for young children with persistent tracheal growth. In this study, the degradation and biocompatibility performance of three typical biodegradable metals were investigated as potential tracheobronchial stent materials. The results exhibited that these materials showed different degradation behaviors in the simulating respiratory fluid environment compared with SBF. Except for pure iron group, high purity magnesium and zinc showed favorable cell adhesion and proliferation in three culture methodologies (direct culture, indirect culture and extraction culture). The proper corrosion rate and good biocompatibility indicated that high purity magnesium and zinc may be good candidates as tracheobronchial stent materials.

Usefulness of the forced oscillation technique in assessing the therapeutic result of tracheobronchial central airway obstruction.

Pulmonary function tests (PFTs) comprise the traditional method for detecting central airway obstruction (CAO) and evaluating therapeutic effects, but are effort-dependent. By contrast, the forced oscillation technique (FOT) is performed during tidal breathing in an effort-independent mode and is universally used to assess respiratory function in patients with chronic obstructive pulmonary disease (COPD) and asthma. We used the FOT to measure airway resistance and reactance in patients with CAO before and after interventional bronchoscopy and compared the results to data obtained using PFTs. Twelve patients with CAO were recruited from December 2013 to July 2016. The FOT, PFTs, chest computed tomography (CT), COPD Assessment Test (CAT), and the modified Medical Research Council (mMRC) dyspnea scale were employed before and after interventional bronchoscopy. The minimum airway cross-sectional area (MACSA) was calculated using a CT image calculator. Of the 12 patients, 6 had tracheal obstruction and 6 had bronchial obstruction. All FOT measurements, except ΔX5, were significantly improved after interventional bronchoscopy in all cases. The significance of the improvement was greater with the FOT than PFTs. The MACSA, CAT, and mMRC dyspnea scale scores also significantly improved in all cases. Furthermore, only alteration of resistance at 20 Hz (R20) significantly correlated with the alteration of the MACSA after intervention. No significant correlations were found for PFTs. The FOT is suitable and convenient for assessing therapeutic results in patients with tracheobronchial CAO. The alteration of R20 is useful for estimating the airway dilation of CAO after interventional bronchoscopy.

A Case of Massive Hemoptysis as a Catastrophic Complication After Photodynamic Therapy for Recurred Tracheal Malignancy

SESSION TITLE: Cardiothoracic Surgery SESSION TYPE: Global Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Photodynamic therapy is a useful treatment method for tracheal malignancy. However, it sometimes provokes disasterous complications such as dyspnea or hemoptysis. We experienced a case of fatal hemoptysis after photodynamic therapy for tracheal cancer and hereby reported. CASE PRESENTATION: A 37-year old woman was admitted to a hospital for the treatment of her recurred tracheal cancer. She received surgical resection followed by concurrent chemoradiation therapy for her large cell neuroendocrince carcinoma in trachea 3 years before. Photofrin was administrated intravenously at a dose of 2mg/kg. One day after, endoscopic tumor ablation was performed with a light diffusion catheter using a 630mm wavelength light sorce. The patient was given 120J for one session, with duration of 400 seconds. The patient was discharged without complications 5 days after the treatment initially. However, she visited emergency room complaining dyspnea. Bronchoscopic examination showed purulent sputum and ulcerative lesion in treatment lesion. After tolileting sputum and antibiotics administration, the symptom was relieved. At 10th day of hospital stay, she appealed severe dyspnea again and endoscopic toileting was performed. Although no specific signs or symptoms have been appeared for the next 3 days, a massive hemoptysis was suddenly developed. Despite the immediate intensive care, the patient expired on the 13th day of hospitalization. DISCUSSION: Photodynamic therapy has been proved to be feasible and safe for the treatment of airway cancers. However, a patient who had been performed photodynamic therapy and revealed symptoms such as dyspnea should be carefully observed to prevent the tragic results whch might be caused by complications. CONCLUSIONS: PDT is a useful modality for lung cancer in tracheobronchial trees. It could be applied for palliative purpose to reduce symptoms caused by tumor obstruction, or hemoptysis. PDT could be an excellent substitution of surgery for patients with severe comorbidities, or patients who refuse surgery. Risks for fatal complications should be evaluated before the practice. Reference #1: Minnich DJ., Bryant AS., Dooley A., Cerfolio RJ., Photodynamic laser therapy for lesion in the airway., Ann Thorac Surg., 2010 Jun;89(6):1744. Reference #2: Wood DE. Management of malignant tracheobronchial obstruction. Surg Clin North Am. 2002 Jun;82(3):621-42. Reference #3: Guibert N., Mhanna L., Droneau S., Plat G, Didier A., Mazieres J., Hermant C., J Thorac Dis., 2016 Nov;8(11):3343. DISCLOSURE: The following authors have nothing to disclose: Eunjue Yi, Jae Ho Chung, Sungho Lee, Kwang Taik Kim No Product/Research Disclosure Information

An Assessment of the Frequency of Palliative Procedures in Thoracic Surgery

Palliative care is a medical specialty focused on improving the quality of life of patients and their families with life threatening illness by preventing or relieving suffering. An assessment of a thoracic surgery service was performed to identify the scope and frequency of care that was considered palliative and any implications the findings might have on the current thoracic surgery residency curriculum. A retrospective review of a prospectively collected database of general thoracic surgery procedures performed over a 5-year period at a single institution was performed. Procedures considered palliative were reviewed for demographics, diagnoses, palliative prognosis score, treatment, morbidity, operative mortality, and survival. Excluded were referrals from thoracic surgery to other specialties for palliative procedures. During the study period, 3842 procedures were performed of which 884 (23%) were palliative. Indications included pleural or pericardial effusion or both, dysphagia, hemoptysis, tracheobronchial obstruction, bronchopleural fistula, and tracheoesophageal fistula. The majority was related to a malignancy. Only 127 patients (14%) had a palliative care assessment before thoracic surgery consultation. Mean survival following thoracic surgery intervention was 110 days for patients with malignancy. This investigation found that thoracic surgeons commonly care for patients when the intention or indication or both is palliation. Most of these patients have an associated malignancy, a poor performance status and a projected significantly decreased survival compared with the general population. Thoracic surgeons should be familiar with the concepts of palliative care and consideration should be given to expanding exposure to the principles of palliative care in the cardiothoracic residency training curriculum.

Tracheobronchial Obstruction Caused by Primary Mediastinal Lymphoma

Tracheobronchial Obstruction Caused by Primary Mediastinal Lymphoma