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Gunatilaka CC, McKenzie C, Hysinger EB, Xiao Q, Higano NS, Woods JC, Bates AJ. Tracheomalacia Reduces Aerosolized Drug Delivery to the Lung. J Aerosol Med Pulm Drug Deliv 2024; 37:19-29. [PMID: 38064481 PMCID: PMC10877398 DOI: 10.1089/jamp.2023.0023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 10/23/2023] [Indexed: 02/12/2024] Open
Abstract
Rationale: Neonates with respiratory issues are frequently treated with aerosolized medications to manage lung disease or facilitate airway clearance. Dynamic tracheal collapse (tracheomalacia [TM]) is a common comorbidity in these patients, but it is unknown whether the presence of TM alters the delivery of aerosolized drugs. Objectives: To quantify the effect of neonatal TM on the delivery of aerosolized drugs. Methods: Fourteen infant subjects with respiratory abnormalities were recruited; seven with TM and seven without TM. Respiratory-gated 3D ultrashort echo time magnetic resonance imaging (MRI) was acquired covering the central airway and lungs. For each subject, a computational fluid dynamics simulation modeled the airflow and particle transport in the central airway based on patient-specific airway anatomy, motion, and airflow rates derived from MRI. Results: Less aerosolized drug reached the distal airways in subjects with TM than in subjects without TM: of the total drug delivered, less particle mass passed through the main bronchi in subjects with TM compared with subjects without TM (33% vs. 47%, p = 0.013). In subjects with TM, more inhaled particles were deposited on the surface of the airway (48% vs. 25%, p = 0.003). This effect becomes greater with larger particle sizes and is significant for particles with a diameter >2 μm (2-5 μm, p ≤ 0.025 and 5-15 μm, p = 0.004). Conclusions: Neonatal patients with TM receive less aerosolized drug delivered to the lungs than subjects without TM. Currently, infants with lung disease and TM may not be receiving adequate and/or expected medication. Particles >2 μm in diameter are likely to deposit on the surface of the airway due to anatomical constrictions such as reduced tracheal and glottal cross-sectional area in neonates with TM. This problem could be alleviated by delivering smaller aerosolized particles.
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Affiliation(s)
- Chamindu C. Gunatilaka
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | | | - Erik B. Hysinger
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
| | - Qiwei Xiao
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Nara S. Higano
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Jason C. Woods
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Alister J. Bates
- Center for Pulmonary Imaging Research, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati, Ohio, USA
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Bocanegra Evans H, Segnini JM, Doosttalab A, Cordero J, Castillo L. Effect of cartilaginous rings in tracheal flow with stenosis. BMC Biomed Eng 2023; 5:5. [PMID: 37259126 PMCID: PMC10234078 DOI: 10.1186/s42490-023-00068-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 02/24/2023] [Indexed: 06/02/2023] Open
Abstract
BACKGROUND In respiratory fluid dynamics research, it is typically assumed that the wall of the trachea is smooth. However, the trachea is structurally supported by a series of cartilaginous rings that create undulations on the wall surface, which introduce perturbations into the flow. Even though many studies use realistic Computer Tomography (CT) scan data to capture the complex geometry of the respiratory system, its limited spatial resolution does not resolve small features, including those introduced by the cartilaginous rings. RESULTS Here we present an experimental comparison of two simplified trachea models with Grade II stenosis (70% blockage), one with smooth walls and second with cartilaginous rings. The use a unique refractive index-matching method provides unprecedented optical access and allowed us to perform non-intrusive velocity field measurements close to the wall (e.g., Particle Image Velocimetry (PIV)). Measurements were performed in a flow regime comparable to a resting breathing state (Reynolds number ReD = 3350). The cartilaginous rings induce velocity fluctuations in the downstream flow, enhancing the near-wall transport of momentum flux and thus reducing flow separation in the downstream flow. The maximum upstream velocity in the recirculation region is reduced by 38%, resulting in a much weaker recirculation zone- a direct consequence of the cartilaginous rings. CONCLUSIONS These results highlight the importance of the cartilaginous rings in respiratory flow studies and the mechanism to reduce flow separation in trachea stenosis.
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Affiliation(s)
- Humberto Bocanegra Evans
- School of Mechanical Engineering, Purdue University, 1500 Kepner Dr Room 104, West Lafayette, IN, 47905, USA
| | - Jose Montoya Segnini
- School of Mechanical Engineering, Purdue University, 1500 Kepner Dr Room 104, West Lafayette, IN, 47905, USA
| | - Ali Doosttalab
- School of Mechanical Engineering, Purdue University, 1500 Kepner Dr Room 104, West Lafayette, IN, 47905, USA.
| | - Joehassin Cordero
- Department of Otolaryngology, Texas Tech University Health Sciences Center, Lubbock, TX, 79430, USA
| | - Luciano Castillo
- School of Mechanical Engineering, Purdue University, 1500 Kepner Dr Room 104, West Lafayette, IN, 47905, USA
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Ali Akbari Ghavimi S, Gehret PM, Aronson MR, Schipani R, Smith KW, Borek RC, Germiller JA, Jacobs IN, Zur KB, Gottardi R. Drug delivery to the pediatric upper airway. Adv Drug Deliv Rev 2021; 174:168-189. [PMID: 33845038 DOI: 10.1016/j.addr.2021.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 03/22/2021] [Accepted: 04/06/2021] [Indexed: 11/25/2022]
Abstract
Pediatric upper airway disorders are frequently life-threatening and require precise assessment and intervention. Targeting these pathologies remains a challenge for clinicians due to the high complexity of pediatric upper airway anatomy and numerous potential etiologies; the most common treatments include systemic delivery of high dose steroids and antibiotics or complex and invasive surgeries. Furthermore, the majority of innovative airway management technologies are only designed and tested for adults, limiting their widespread implementation in the pediatric population. Here, we provide a comprehensive review of the most recent challenges of managing common pediatric upper airway disorders, describe the limitations of current clinical treatments, and elaborate on how to circumvent those limitations via local controlled drug delivery. Furthermore, we propose future advancements in the field of drug-eluting technologies to improve pediatric upper airway management outcomes.
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Frank-Ito DO, Cohen SM. Orally Inhaled Drug Particle Transport in Computerized Models of Laryngotracheal Stenosis. Otolaryngol Head Neck Surg 2021; 164:829-840. [PMID: 33045904 PMCID: PMC8294408 DOI: 10.1177/0194599820959674] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/25/2020] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Adjuvant management for laryngotracheal stenosis (LTS) may involve inhaled corticosteroids, but metered dose inhalers are designed for pulmonary drug delivery. Comprehensive analyses of drug particle deposition efficiency for orally inhaled corticosteroids in the stenosis of LTS subjects are lacking. STUDY DESIGN Descriptive research. SETTING Academic medical center. METHODS Anatomically realistic 3-dimensional reconstructions of the upper airway were created from computed tomography images of 4 LTS subjects-2 subglottic stenosis and 2 tracheal stenosis subjects. Computational fluid dynamics modeling was used to simulate airflow and drug particle transport in each airway. Three inhalation pressures were simulated, 10 Pa, 25 Pa, and 40 Pa. Drug particle transport was simulated for 100 to 950 nanoparticles and 1 to 50 micron-particles. Particles were released into the airway to mimic varying inhaler conditions with and without a spacer chamber. RESULTS Based on smallest to largest cross-sectional area ratio, the laryngotracheal stenotic segment shrunk by 57% and 47%, respectively, for subglottic stenosis models and by 53% for both tracheal stenosis models. Airflow resistance at the stenotic segment was lower in subglottic stenosis models than in tracheal stenosis models: 0.001 to 0.011 Pa.s/mL vs 0.024 to 0.082 Pa.s/mL. Drug depositions for micron-particles and nanoparticles at stenosis were 0.06% to 2.48% and 0.10% to 2.60% for subglottic stenosis and tracheal stenosis models, respectively. Particle sizes with highest stenotic deposition were 6 to 20 µm for subglottic stenosis models and 1 to 10 µm for tracheal stenosis models. CONCLUSION This study suggests that at most, 2.60% of inhaled drug particles deposit at the stenosis. Particle size ranges with highest stenotic deposition may not represent typical sizes emitted by inhalers.
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Affiliation(s)
- Dennis Onyeka Frank-Ito
- Department of Head and Neck Surgery & Communication Sciences, Duke University Medical Center, Durham, North Carolina, USA
- Computational Biology & Bioinformatics PhD Program, Duke University, Durham, North Carolina, USA
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA
| | - Seth Morris Cohen
- Department of Head and Neck Surgery & Communication Sciences, Duke University Medical Center, Durham, North Carolina, USA
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Computational Fluid Dynamic Analysis of the Pharyngeal Airway after Bimaxillary Orthognathic Surgery in Patients with Mandibular Prognathism. Processes (Basel) 2021. [DOI: 10.3390/pr9010152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
This study aimed to analyze pharyngeal airflow characteristics and their relationship with the skeletal movement of the maxilla and mandible after bimaxillary orthognathic surgery in patients with skeletal class III (mandibular prognathism) malocclusion. Cone-beam computed tomography (CBCT) was conducted before surgery (T0), immediately after surgery (T1), and at least six months after surgery (T2). Digital imaging and communications in medicine files were transferred to InVivo (Anatomage) software to measure the skeletal changes after surgery. The changes in the maxillary and mandibular position, tongue position, and hyoid bone position were analyzed. Patient-specific models were reconstructed using 3D-Doctor software. The models after converting to the stereolithography (STL) file for Ansys integrated computer engineering and manufacturing code for computational fluid dynamics (ICEM CFD), commercial software were used for calculating the geometry, pressure drop and adjusted pressure coefficient value. The total volume of the upper airway including nasal cavity was reduced by 23% immediately after surgery and recovered to 92.2% of the initial volume six months after surgery. The airflow computation analysis showed a decrease in the pressure drop values immediately after surgery and six months after surgery. The adjusted pressure coefficients were slightly different but the change was statistically insignificant. The airflow characteristics computed using the computational fluid dynamics were correlated to the surgical changes. The surgical changes can affect the aerodynamics of the pharyngeal airway. In clinical practice, this knowledge is useful for developing a suitable orthognathic surgery treatment plan.
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Fluid dynamic assessment of tracheal flow in infants with congenital tracheal stenosis before and after surgery. Med Biol Eng Comput 2018; 57:837-847. [PMID: 30421262 DOI: 10.1007/s11517-018-1928-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 10/31/2018] [Indexed: 10/27/2022]
Abstract
Tracheal flow in infants with congenital tracheal stenosis (CTS) was numerically investigated using subject-specific airway models before and after reconstructive surgery. We quantified tracheal flow based on airway resistance during inhalation, and compared it between controls and patients before and after surgery. The airway resistance in each subject was assessed using geometrical parameters of the trachea: the minimum cross-sectional area Amin, the minimum cross-sectional area normalized by the standard deviation of the cross-sectional area Amin/σA, the area ratio of the minimum and maximum cross-sectional area Amin/Amax, and ratio of the normalized standard deviation of cross-sectional area to the mean cross-sectional area σA/Amean. Our numerical results demonstrated that such geometrical parameters could be used to assess the severity of CTS. Since subjects can be more clearly categorized as controls and most preoperative patients in terms of the airway resistance, a simulation using subject-specific airway models can lead us to a precise understanding of tracheal flow, and also provide knowledge about therapeutic decision. Our numerical results also demonstrated that significant surgical expansion of cross-sectional area did not help recover tracheal flow because of expansion loss. These results will be helpful not only when making therapeutic decisions about surgery but also when assessing quality of life in postoperative patients. Graphical abstract.
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