Tracheal Resection after Previous Treatment Provides Comparable Outcome to Primary Surgery.

BACKGROUND: Tracheal and laryngotracheal surgery provides both excellent functional results and long-term outcomes in the treatment of tracheal stenosis. Consequently, challenging re-resections are rarely necessary. The purpose of this study was to compare the outcome of (laryngo-)tracheal re-resection and surgery after bronchoscopic interventions with that of primary surgery. METHODS: Patients undergoing resection for benign tracheal stenosis at our center between 1/2016 and 4/2020 were included. Perioperative characteristics and functional outcomes of patients were used for statistical analysis. RESULTS: Sixty-six patients who underwent (laryngo-)tracheal resection were included (previous resection [A = 6], previous stent [B = 6], previous bronchoscopic intervention w/o stenting [C = 19], untreated [D = 35]). Baseline parameters were largely comparable between groups with exception from group B that had significantly worse lung function. Group A necessitated more complex reconstructions (end-to-end: n = 1: 17%| cricotracheal n = 2: 33%| cricotracheal with mucosectomy n = 2: 33%| laryngoplasty: n = 1: 17%) than patients in group D (end-to-end n = 21: 60%| cricotracheal n = 14: 40%). Postoperative outcomes were comparable throughout groups (intensive care unit: 1[1-18] days; hospital stay: 8[5-71] days). Anastomotic complications were higher after previous stenting (A: 0%; B: 33.3%; C: 10.5%; D: 2.9%; B/D p = 0.008| surgical revisions: A: 16.7%; B: 33.3%; C: 0%; D: 5.7%; B/D, p = 0.035). Overall, postoperative lung function was significantly better (forced expiratory volume in 1 second: 63% ± 24 vs. 75% ± 20; p = 0.001 | PeakEF 3.3 ± 1.9 vs. 5.0 ± 2.2L; p = 0.001). No 90-day mortality was observed in any group. Median follow-up was 12(1-47) months. CONCLUSION: In carefully selected patients treated in a specialized center, tracheal or laryngotracheal resection after previous tracheal interventions provides comparable outcome to primary surgery.

Tracheal Stent Buckling and In-stent Stenosis: A Proposed Airway Management Algorithm for Airway Obstruction for Patients With Tracheal Stents.

EMERGENCY AIRWAY management strategies for patients with complications due to tracheobronchial stents are of growing interest to anesthesiologists. Although tracheal stenting increasingly is used to manage tracheobronchial stenosis of both benign and malignant conditions,1-3 official guidelines for the perioperative airway management of patients with tracheobronchial stents in situ are lacking.3 Here, the authors discuss the management of airway obstruction from a tracheal stent strut protrusion and in-stent stenosis in a patient with a self-expanding nitinol tracheal stent in situ. They discuss the airway management strategy employed and outline a pragmatic airway management algorithm for patients with tracheal stents presenting with airway obstruction.

Tracheal Stenosis After Prolonged Intubation Due to COVID-19.

OBJECTIVES: The authors aimed to evaluate the characteristics and management outcomes of patients who developed tracheal stenosis after invasive mechanical ventilation (IMV) due to COVID-19. DESIGN, SETTING, AND PARTICIPANTS: The data of 7 patients with tracheal stenosis and 201 patients without tracheal stenosis after IMV due to COVID-19 between March 2020 and October 2021 were retrospectively analyzed. INTERVENTIONS: Flexible bronchoscopy was performed for the diagnosis of tracheal stenosis and the evaluation of the treatment's effectiveness, and rigid bronchoscopy was applied for the dilatation of tracheal stenosis. MEASUREMENTS AND MAIN RESULTS: In the follow-up period, tracheal stenosis was observed in 7 of 208 patients (2 women, 5 men; 3.3%). The patients were divided into 2 groups as patients with tracheal stenosis (n = 7) and patients without tracheal stenosis (n = 201). There were no statistically significant differences between the 2 groups in terms of age, sex, body mass index, and comorbidities (p > 0.05). The mean duration of IMV of the patients with tracheal stenosis was longer than patients without tracheal stenosis (27.9 ± 13 v 11.2 ± 9 days, p < 0.0001, respectively). Three (43%) of the stenoses were web-like and 4 (57%) of them were complex-type stenosis. The mean length of the stenoses was 1.81 ± 0.82 cm. Three of the patients were treated successfully with bronchoscopic dilatation, and 4 of them were treated with tracheal resection. CONCLUSIONS: Tracheal stenosis developed in 7 of 208 (3.3%) patients with COVID-19 who were treated with IMV. The most important characteristic of patients with tracheal stenosis was prolonged IMV support.

Computational fluid dynamics assessment of congenital tracheal stenosis.

PURPOSE: The severity of congenital tracheal stenosis (CTS) is commonly evaluated based on the degree of stenosis. However, it does not always reflect the clinical respiratory status. We applied computational fluid dynamics (CFD) to the assessment of CTS. The aim of this study was to evaluate its validity. METHODS: CFD models were constructed on 15 patients (12 preoperative models and 15 postoperative models) with CTS before and after surgery, using the computed tomographic data. Energy flux, needed to drive airflow, measured by CFD and the minimum cross-sectional area of the trachea (MCAT) were quantified and evaluated retrospectively. RESULTS: The energy flux correlated positively with the clinical respiratory status before and after surgery (rs = 0.611, p = 0.035 and rs = 0.591, p = 0.020, respectively). Although MCAT correlated negatively with the clinical respiratory status before surgery (rs = -0.578, p = 0.044), there was not significant correlation between the two after surgery (p = 0.572). CONCLUSIONS: The energy flux measured by CFD assessment reflects the respiratory status in CTS before and after surgery. CFD can be an additional objective and quantitative evaluation tool for CTS.

[Total Arch Replacement due to Tracheal Compression by Brachiocephalic Artery with Bovine Aortic Arch:Report of a Case].

A 78-year-old female presented to our institution with a dry cough and dyspnea. Chest computed tomography( CT) revealed tracheal stenosis caused by compression from a brachiocephalic artery with a bovine aortic arch. Subsequently, surgery was performed in which the brachiocephalic artery was resected, and a total arch replacement using a four-branched graft was completed. We paid particular attention to the graft branches, making sure to avoid contact with the trachea. Both the patient's cough and dyspnea dissipated after the surgery, and a CT revealed the tracheal stenosis had been completely relieved. The patient has remained in good condition for the past three years since the surgery showing no respiratory symptoms or thoracic aortic disease. Because the bovine aortic arch is a known risk factor for thoracic aortic disease, rather than simply reconstructing the brachiocephalic artery, we chose a more aggressive surgical treatment to prevent any possible future thoracic aortic disease.

An unusual tracheal foreign body in a middle-aged male with a 15-year history of coal use: a case report.

BACKGROUND: Long-term exposure to coal dust causes respiratory disease. In chest computer tomography (CT), pulmonary nodules, pulmonary interstitial fibrosis and emphysema manifest themselves. However, tracheal foreign bodies caused by coal dust are rarely reported. In this study, we report a special case of a tracheal coal foreign body, in which the patient has neither a history of coal work nor foreign body inhalation. CASE PRESENTATION: A 49-year-old man was diagnosed with chronic obstructive pulmonary disease (COPD) due to chronic cough and exertional dyspnoea. His symptoms gradually worsened despite treatment for COPD. Chest radiograph and CT images showed an irregular high-density nodule inserting fromthe trachea into the right thyroid at approximately the level of the 7th cervical vertebra. Fiberoptic bronchoscopy revealed that the tracheal lumen was mostly blocked. After the surgery, the energy spectrum CT quantitative analysis showed that the foreign body was likely that of a bituminous coal specimen. CONCLUSIONS: For cases in which a foreign body in the airway is highly suspected, early fiberoptic bronchoscopy and radiographic examinations should be performed as soon as possible to avoid misdiagnosis and ensure timely treatment.

Superior Strategy in Benign Tracheal Stenosis Treatment: Surgery or Endoscopy?

INTRODUCTION: Due to the variations in (laryngeal) tracheal stenosis (TS) patient groups, there is still no consensus on which patient should be treated with endoscopy or surgery. The aim of the present study was to generate an algorithm in the light of the related literature and the data obtained from a clinic where both endoscopic and surgical treatments are conducted. METHOD: A retrospective analysis was performed on the data of a total of 56 patients during 2013 to 2019. A total of 38 patients were subject to surgery with 31 as a first treatment option and 7 due to the unsatisfactory results of endoscopic treatments. Endoscopic approaches were tried on a total of 29 patients with 25 as initial treatment and 4 due to postsurgical recurrence. RESULTS: Symptomatic full control ratio was determined as 69% with endoscopic treatments, 89.5% in subglottic stenosis (SGS) surgery (n = 19), and 89.5% in trachea surgery (n = 19). However, success rates with no recurrence were determined, respectively, as 40.0, 36.4, and 36.4% for patients subject to dilatation, stent, or T tube treatment. Dilatation was observed to be successful in patients with stenotic segment lengths of less than 1.5 cm (p = 0.02). Failure rates increased in SGS (p = 0.03) and TS (p = 0.12) in the surgical group with increasing stenotic segment length. The presence of comorbidities was not effective on treatment success. CONCLUSION: Endoscopic methods are preferred in cases of web-like stenosis. Surgical methods should first be considered for other patients and endoscopic methods should be used on patients who are not suited for surgery or in cases of postsurgical recurrence.

Tracheal stenosis due to cervicothoracic hyperlordosis in patients with cerebral palsy treated with posterior spinal fusion: a report of the first two cases.

BACKGROUND: Spinal deformity is frequently identified in patients with cerebral palsy (CP). As it progresses, tracheal stenosis often develops due to compression between the innominate artery and anteriorly deviated vertebrae at the apex of the cervicothoracic hyperlordosis. However, the treatment strategy for tracheal stenosis complicated by spinal deformity in patients with CP remains unknown. CASE PRESENTATION: This study reports two cases: a 19-year-old girl (case 1) and a 17-year-old girl (case 2), both with CP at Gross Motor Function Classification System V. Both patients experienced acute oxygen desaturation twice within the past year of their first visit to our department. X-ray and computed tomography revealed severe scoliosis and cervicothoracic hyperlordosis causing tracheal stenosis at T2 in case 1 and at T3-T4 in case 2, suggesting that their acute oxygen desaturation had been caused by impaired airway clearance due to tracheal stenosis. After preoperative halo traction for three weeks, both patients underwent posterior spinal fusion from C7 to L5 with Ponte osteotomy and sublaminar taping at the proximal thoracic region to correct cervicothoracic hyperlordosis and thoracolumbar scoliosis simultaneously. Postoperative X-ray and computed tomography revealed that the tracheal stenosis improved in parallel with the correction of cervicothoracic hyperlordosis. Case 1 did not develop respiratory failure 1.5 years after surgery. Case 2 required gastrostomy postoperatively due to severe aspiration pneumonia. However, she developed no respiratory failure related to impaired airway clearance at one-year follow-up. CONCLUSIONS: We present the first two cases of CP that developed tracheal stenosis caused by cervicothoracic hyperlordosis concomitant with progressive scoliosis and were successfully treated by posterior spinal fusion from C7 to L5. This enabled us to relieve tracheal stenosis and correct the spinal deformity at the same time. Surgeons must be aware of the possibility of coexisting tracheal stenosis in treating spinal deformity in patients with neurological impairment because the surgical strategy can vary in the presence of tracheal stenosis. This study demonstrated that some patients with CP with acquired tracheal stenosis can be treated with spinal surgery.

Relationship between a Tracheal and Left Pulmonary Artery Stenosis Index and the Prognosis of Pulmonary Artery Sling with Tracheal Stenosis.

Pulmonary artery sling is a rare congenital pulmonary vascular malformation, often associated with tracheal or bronchial stenosis. Surgical treatment of pulmonary artery sling with tracheal stenosis (T) has a high risk of death and a relatively poor prognosis. This study explored the relationship between the T and left pulmonary artery stenosis (P) ratio and the effects of surgery for pulmonary artery sling with tracheal stenosis. Patients undergoing surgery for pulmonary artery sling in our center from January 2010 to December 2018 were retrospectively analyzed. Routine cardiac-enhanced computed tomography (CT) was performed preoperatively, and the P and T diameters were measured on the CT image. The T/P ratio was then calculated and analyzed. Thirty cases of pulmonary artery sling combined with tracheal stenosis were operated under cardiopulmonary bypass. The mean age at operation was 13.8 ± 13.6 months (1.2-57.1 months, Q1-Q3: 5-17 months), and the mean body weight was 8.8 ± 3.5 kg (3.8-17.3 kg, Q1-Q3: 5.8-11.5 kg). Twenty-three patients survived, and seven died, with an overall survival rate of 76.7%. Twenty-four patients underwent left pulmonary artery re-implantation, six patients underwent simultaneous left pulmonary artery re-implantation and slide tracheoplasty, and patients with intracardiac malformations (ventricular septal defect (n = 6) and atrial septal defect (n = 4)) underwent concurrent repair of the intracardiac defect. All cases had different degrees of tracheal stenosis, and the most narrowed trachea occurred with compression by the left pulmonary artery sling. The T/P ratio in the tracheoplasty group was significantly higher than that in the non-tracheoplasty group. The mortality rate in the T/P ≤ 1.15 group was significantly lower than that in the T/P > 1.15 group. Pulmonary artery sling treatment has a high risk of death. Left pulmonary artery re-implantation is an effective and safe surgical method for treating pulmonary artery sling, and slide tracheoplasty is an effective surgical method to correct tracheal stenosis. Children with T > 78.4% should receive active intervention for the tracheal stenosis, and these children have a considerable postoperative survival rate. The T/P ratio can be used to compare the relative superiority of the two compressions. A T/P ratio > 1.15 can be used as a reference index for intervention in tracheal stenosis and is a risk factor for postoperative death.

Pulmonary Artery Sling with Tracheal Stenosis Combined with A Large Ventricular Septal Defect in A Two-Month-Old Boy: A Case Report.

Pulmonary artery sling (PAS) is a rare congenital cardiovascular abnormality. In typical PAS patients, the left pulmonary artery (LPA) arises from the right pulmonary artery and passes between the trachea and esophagus, which possibly causes tracheal stenosis and some respiratory symptoms. PAS typically associates with other cardiovascular anomalies, which may cause difficulties to the treatment of patients. This report described a rare case of a two-month-old boy with PAS, VSD, and tracheal stenosis simultaneously and underwent procedures without tracheoplasty.

LACHT syndrome (Mardini-Nyhan association) with tracheal stenosis in a Thai newborn.

LACHT syndrome, or Mardini-Nyhan association, is an ultra-rare disorder, diagnosed solely by the clinical characteristics of lung agenesis, complex cardiac defects, and thumb anomalies. Only 12 patients have been reported worldwide, and here, we report a new clinical diagnosis of LACHT syndrome. Our patient was a male full-term newborn with left lung agenesis, congenital heart defects including ventricular septal defect, right-sided aortic arch, with aberrant left subclavian artery and Kommerell diverticulum, as well as left preaxial polydactyly and hemivertebra. Our patient appears to be the second LACHT syndrome case to also suffer from tracheal stenosis, which has only been reported once before in conjunction with this syndrome. In light of this, tracheal stenosis may be a phenotype for LACHT syndrome.

Postintubation Tracheal Stenosis Evaluated by Endobronchial Optical Coherence Tomography: A Canine Model Study.

BACKGROUND: The predictors and airway morphological changes during the development of postintubation tracheal stenosis (PITS) have not been well elucidated. OBJECTIVES: To elucidate the validation of endobronchial optical coherence tomography (EB-OCT) in assessing the airway morphological changes in PITS. METHODS: We performed oral endotracheal intubation in 12 beagles to establish the PITS model. EB-OCT was performed respectively before modeling and on the 1st, 7th, and 12th day after extubation in 9 canines, and was conducted consecutively in 3 canines during the development of PITS. Histological findings and the thickness and gray-scale value of the tracheal wall assessed by EB-OCT measurements were analyzed and compared. RESULTS: The tracheal wall edema, granulation tissue proliferation, cartilage destruction in PITS, and airway wall thickening detected by EB-OCT were in concordance with the histopathological measurements. The consecutive EB-OCT observation of the airway structure demonstrated the tracheal wall thickness significantly increased from 344.41 ± 44.19 µm before modeling to 796.67 ± 49.75 µm on the 9th day after modeling (p < 0.05). The airway wall gray-scale values assessed by EB-OCT decreased from 111.19 ± 14.71 before modeling to 74.96 ± 4.08 on the 9th day after modeling (p < 0.05). The gray-scale value was negatively correlated with the airway wall thickness (r = -0.945, p = 0.001). CONCLUSION: The EB-OCT imaging, in concordance with the histopathological finding, was validated for assessing the airway morphological changes during the development of PITS. The EB-OCT evaluation of cartilage damage and gray-scale value measurement might help predict the development and prognosis of PITS.

Vascular Rings With Tracheoesophageal Compression: Management Considerations.

Our series of vascular ring patients treated at Ann & Robert H. Lurie Children's Hospital of Chicago has now exceeded 450 patients (see Central Picture). The recommendations from this review are based on our experience with those patients. Since 1990, we have used preoperative cross-sectional imaging in all vascular ring patients. This has led us to refine our operative strategies and carefully tailor the operation to the individual's unique anatomy. In particular for right aortic arch patients, we now address the Kommerell diverticulum in most cases and carefully consider Kommerell diverticulum resection with left subclavian artery transfer. In double aortic arch patients, we also look for a Kommerell diverticulum and resect the diverticulum if present. This will decrease the number of patients presenting for a reoperation after initial vascular ring surgery. Since 1947, we have operated on 217 patients with a right aortic arch. The median age is 1.5 years. Since 2006, 47 out of 111 patients have had Kommerell diverticulum resection and left subclavian artery transfer to the left carotid artery. Mean length of stay is 4.5 days. In the same time period, 187 patients have been treated for a double aortic arch. The median age is 1 year. Twelve of these patients also had resection of a Kommerell diverticulum. The mean length of stay in this group was 3 days. Advanced preoperative cross-sectional imaging leads to precise operative techniques tailored to the unique anatomy of each vascular ring patient.

Combined Surgical and Endoscopic Approach for Ring-Sling Complex.

BACKGROUND: Left pulmonary artery (LPA) sling (PAS) is a vascular ring, which is frequently associated with long-segment tracheal stenosis (TS). Mortality rate in operated children is still high, especially in cases of severe tracheal hypoplasia and/or associated congenital heart defects (CHDs). We report our experience of treatment and follow-up in a pediatric cohort of patients affected by PAS with severe tracheobronchial involvement. METHODS: From 2005 to 2017, we enrolled 11 children diagnosed with PAS and congenital TS requiring surgical intervention. Echocardiography, computed tomography, and bronchoscopy were performed in all patients. Associated CHD were present in 5 (45%) patients. Tracheal reconstruction techniques included slide tracheoplasty (7/11; 63%), slide tracheoplasty and costal cartilage graft (2/11; 18%), and Hazekamp technique (2/11; 18%).Nine patients underwent LPA direct reimplantation and concomitant tracheoplasty; concomitant surgical repair for CHD was performed in three children. RESULTS: Over a mean follow-up of 30 months (range: 3-75 months), a late mortality of 18% was registered; no early death occurred. Good flow through LPA could be documented in all patients. Ten children required operative bronchoscopies (mean: 16/patients) aimed at stent positioning/removal, treatment of granulomas, and tracheobronchial dilatation. CONCLUSIONS: Severe tracheobronchial stenosis and associated CHD were the main determinants for hospitalization time, intensive assistance, and repeated endoscopic procedures.Patients affected by PAS/TS complex require a careful management at high-specialized centers providing multidisciplinary team.Respiratory endoscopy may play a central role both in preoperatory assessment and in postoperative management of patients showing severe tracheobronchial involvement.

Secondary tracheal distortion in an adult patient after therapy for diphtheria at childhood.

We report a rare case of difficult intubation because of trachea deformation after therapy for diphtheria and subsequent tracheostomy at childhood. The patient was admitted to be subjected to a Bentall procedure, because of ascending aorta dilatation. With a detailed preanesthetic assessment and simulation for intubation by using three-dimensional technology, he was successfully intubated and the operation was accomplished uneventfully. 3D-printed models of the difficult airway enhance imaging of difficult anatomy, assist in simulation and management of potentially problematic intubation, and can be a valuable tool when dealing with airways with potential anatomical malformations.

Subglottic stenosis and endobronchial disease in granulomatosis with polyangiitis.

OBJECTIVES: To describe tracheobronchial disease in patients with granulomatosis with polyangiitis (GPA) and evaluate the utility of dynamic expiratory CT to detect large-airway disease. METHODS: Demographic and clinical features associated with the presence of subglottic stenosis (SGS) or endobronchial involvement were assessed in a multicentre, observational cohort of patients with GPA. A subset of patients with GPA from a single-centre cohort underwent dynamic chest CT to evaluate the airways. RESULTS: Among 962 patients with GPA, SGS and endobronchial disease were identified in 95 (10%) and 59 (6%) patients, respectively. Patients with SGS were more likely to be female (72% vs 53%, P < 0.01), younger at time of diagnosis (36 vs 49 years, P < 0.01), and have saddle-nose deformities (28% vs 10%, P < 0.01), but were less likely to have renal involvement (39% vs 62%, P < 0.01). Patients with endobronchial disease were more likely to be PR3-ANCA positive (85% vs 66%, P < 0.01), with more ENT involvement (97% vs 77%, P < 0.01) and less renal involvement (42% vs 62%, P < 0.01). Disease activity in patients with large-airway disease was commonly isolated to the subglottis/upper airway (57%) or bronchi (32%). Seven of 23 patients screened by dynamic chest CT had large-airway pathology, including four patients with chronic, unexplained cough, discovered to have tracheobronchomalacia. CONCLUSION: SGS and endobronchial disease occur in 10% and 6% of patients with GPA, respectively, and may occur without disease activity in other organs. Dynamic expiratory chest CT is a potential non-invasive screening test for large-airway involvement in GPA.

Assessment of Suspected Vascular Rings and Slings and/or Airway Pathologies Using Magnetic Resonance Imaging Rather Than Computed Tomography.

BACKGROUND: Congenital cardiovascular malformations (CCVM) may cause infrequently airway pathologies (AP) in children and are of prognostic and therapeutic relevance. While computed tomography (CT) is considered first-line imaging modality in many centres, we started using magnetic resonance imaging (MRI) more and more in the last years to detect CCVM and AP to avoid radiation in this patient group. OBJECTIVE: The aim of this retrospective study was to determine and to compare the diagnostic accuracy of CT and MRI when used to detect CCVM and/or AP. METHODS: All patients suspected to have CCVM and/or AP and examined either by CT or MRI between 2000 and 2013 in our hospital were included. Extension and type of CCVM, as well as their relationship to esophagus, trachea or bronchi were assessed and related to findings of tracheobronchoscopy, cardiac catheterization or surgery if available. RESULTS: One hundred six patients (median [range] 4 years [2 days to 66 years]) were examined by CT (n = 27) or MRI (n = 79). In 78 patients (74%), CCVM and/or AP were found with either of the imaging methods. CCVM were found in 63 subjects. Forty-six of 63 subjects had both, CCVM and AP. The presence of CCVM was always detected correctly by CT or MRI, although both techniques had a weakness detecting atretic segments directly. AP (n = 61) were correctly diagnosed in all patients not intubated for artificial ventilation by CT (n = 17) and in all but 2 patients by MRI (39 out of 41). CONCLUSIONS: MRI is sensitive to detect CCVM associated with AP equally to CT without any radiation exposure.

Endobronchial Ultrasound for Benign Tracheal Stenosis.

We reported the role of endobronchial ultrasound as complement to standard diagnostic exams to better define the benign tracheal stenosis (i.e., thickness and tracheal cartilage integrity) and to plan the treatment with flexible instead of rigid bronchoscope. Under sedation and spontaneous ventilation, the flexible bronchoscope was inserted through the laryngeal mask airway that assured the ventilation. The stenosis was first resected with cold scissors and then dilated with balloon catheter. This strategy was successfully applied in five consecutive patients. Inclusion criteria for the procedure were stenosis < 1 cm in length, without tracheomalacia and with integrity of airway cartilage.

Unique Heterogeneous Topological Pattern of the Metabolic Landscape in Rabbit Fetal Lungs following Tracheal Occlusion.

INTRODUCTION: Fetal tracheal occlusion (TO) is currently an experimental approach to drive accelerated lung growth. It is stimulated by mechanotransduction that results in increased cellular proliferation and growth. However, it is currently unknown how TO affects the metabolic landscape of fetal lungs. MATERIALS AND METHODS: TO or sham was performed on fetal rabbits at 26 days followed by lung harvest on day 30. Mass spectrometry was performed to evaluate global metabolic changes. Fluorescence lifetime intensity microscopy (FLIM) was performed to estimate local free/bound NADH relative ratio as an indicator of aerobic glycolysis versus oxidative phosphorylation (glycolysis/OXPHOS). RESULTS: TO results in a metabolic shift from tricarboxylic acid cycle towards glycolysis. FLIM reveals uniform structures in control lungs characterized by similar ratios of free/bound NADH indicating a homogenous topological pattern. Similar uniform structures are observed in shams with some variability in the glycolysis/OXPHOS ratio. In contrast, lungs following TO demonstrate different types of unique distinct topological zones: one with enlarged alveoli and a shift towards glycolysis; the other maintains balance between glycolysis/OXPHOS similar to control lungs. CONCLUSION: We demonstrate for the first time a unique variable topological pattern of metabolism in fetal lungs following TO with a wide variation of metabolism between zones.