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Chen Y, Yuan Y, Chang Q, Zhang H, Li F, Chen Z. Continuous estimation of respiratory system compliance and airway resistance during pressure-controlled ventilation without end-inspiration occlusion. BMC Pulm Med 2024; 24:249. [PMID: 38769572 PMCID: PMC11107031 DOI: 10.1186/s12890-024-03061-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 05/13/2024] [Indexed: 05/22/2024] Open
Abstract
BACKGROUND Assessing mechanical properties of the respiratory system (Cst) during mechanical ventilation necessitates an end-inspiration flow of zero, which requires an end-inspiratory occlusion maneuver. This lung model study aimed to observe the effect of airflow obstruction on the accuracy of respiratory mechanical properties during pressure-controlled ventilation (PCV) by analyzing dynamic signals. METHODS A Hamilton C3 ventilator was attached to a lung simulator that mimics lung mechanics in healthy, acute respiratory distress syndrome (ARDS) and chronic obstructive pulmonary disease (COPD) models. PCV and volume-controlled ventilation (VCV) were applied with tidal volume (VT) values of 5.0, 7.0, and 10.0 ml/kg. Performance characteristics and respiratory mechanics were assessed and were calibrated by virtual extrapolation using expiratory time constant (RCexp). RESULTS During PCV ventilation, drive pressure (DP) was significantly increased in the ARDS model. Peak inspiratory flow (PIF) and peak expiratory flow (PEF) gradually declined with increasing severity of airflow obstruction, while DP, end-inspiration flow (EIF), and inspiratory cycling ratio (EIF/PIF%) increased. Similar estimated values of Crs and airway resistance (Raw) during PCV and VCV ventilation were obtained in healthy adult and mild obstructive models, and the calculated errors did not exceed 5%. An underestimation of Crs and an overestimation of Raw were observed in the severe obstruction model. CONCLUSION Using the modified dynamic signal analysis approach, respiratory system properties (Crs and Raw) could be accurately estimated in patients with non-severe airflow obstruction in the PCV mode.
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Affiliation(s)
- Yuqing Chen
- Department of Respiratory Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, No.241, West Huaihai Road, Shanghai, 200030, China.
| | - Yueyang Yuan
- School of Mechanical and Electrical Engineering, Hunan City University, Yiyang, 413099, China
| | - Qing Chang
- Department of Respiratory Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, No.241, West Huaihai Road, Shanghai, 200030, China
| | - Hai Zhang
- Department of Respiratory Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, No.241, West Huaihai Road, Shanghai, 200030, China
| | - Feng Li
- Department of Respiratory Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, No.241, West Huaihai Road, Shanghai, 200030, China
| | - Zhaohui Chen
- College of Information Technology, Shanghai Jian Qiao University, Shanghai, 201306, China
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2
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Tuza FADA, de Sá PM, Castro HA, Lopes AJ, de Melo PL. Combined forced oscillation and fractional-order modeling in patients with work-related asthma: a case-control study analyzing respiratory biomechanics and diagnostic accuracy. Biomed Eng Online 2020; 19:93. [PMID: 33298072 PMCID: PMC7724713 DOI: 10.1186/s12938-020-00836-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 11/23/2020] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Fractional-order (FrOr) models have a high potential to improve pulmonary science. These models could be useful for biomechanical studies and diagnostic purposes, offering accurate models with an improved ability to describe nature. This paper evaluates the performance of the Forced Oscillation (FO) associated with integer (InOr) and FrOr models in the analysis of respiratory alterations in work-related asthma (WRA). METHODS Sixty-two individuals were evaluated: 31 healthy and 31 with WRA with mild obstruction. Patients were analyzed pre- and post-bronchodilation. The diagnostic accuracy was evaluated using the area under the receiver operating characteristic curve (AUC). To evaluate how well do the studied models correspond to observed data, we analyzed the mean square root of the sum (MSEt) and the relative distance (Rd) of the estimated model values to the measured resistance and reactance measured values. RESULTS AND DISCUSSION Initially, the use of InOr and FrOr models increased our understanding of the WRA physiopathology, showing increased peripheral resistance, damping, and hysteresivity. The FrOr model (AUC = 0.970) outperformed standard FO (AUC = 0.929), as well as InOr modeling (AUC = 0.838) in the diagnosis of respiratory changes, achieving high accuracy. FrOr improved the curve fitting (MSEt = 0.156 ± 0.340; Rd = 3.026 ± 1.072) in comparison with the InOr model (MSEt = 0.367 ± 0.991; Rd = 3.363 ± 1.098). Finally, we demonstrated that bronchodilator use increased dynamic compliance, as well as reduced damping and peripheral resistance. CONCLUSIONS Taken together, these results show clear evidence of the utility of FO associated with fractional-order modeling in patients with WRA, improving our knowledge of the biomechanical abnormalities and the diagnostic accuracy in this disease.
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Affiliation(s)
- Fábio Augusto D Alegria Tuza
- Biomedical Instrumentation Laboratory, Institute of Biology and Faculty of Engineering, State University of Rio de Janeiro, Haroldo Lisboa da Cunha Pavilion Number 104 and 105, São Francisco Xavier Street 524 Maracanã, Rio de Janeiro, RJ, 20550-013, Brazil
- BioVasc Research Laboratory, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Paula Morisco de Sá
- Biomedical Instrumentation Laboratory, Institute of Biology and Faculty of Engineering, State University of Rio de Janeiro, Haroldo Lisboa da Cunha Pavilion Number 104 and 105, São Francisco Xavier Street 524 Maracanã, Rio de Janeiro, RJ, 20550-013, Brazil
- BioVasc Research Laboratory, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Hermano A Castro
- National School of Public Health, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Agnaldo José Lopes
- School of Medical Sciences, Pulmonary Function Testing Laboratory, State University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
- Rehabilitation Sciences Post-Graduation Program, Augusto Motta University Centre, Rio de Janeiro, Brazil
| | - Pedro Lopes de Melo
- Biomedical Instrumentation Laboratory, Institute of Biology and Faculty of Engineering, State University of Rio de Janeiro, Haroldo Lisboa da Cunha Pavilion Number 104 and 105, São Francisco Xavier Street 524 Maracanã, Rio de Janeiro, RJ, 20550-013, Brazil.
- BioVasc Research Laboratory, Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
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Ribeiro CO, Lopes AJ, de Melo PL. Oscillation Mechanics, Integer and Fractional Respiratory Modeling in COPD: Effect of Obstruction Severity. Int J Chron Obstruct Pulmon Dis 2020; 15:3273-3289. [PMID: 33324050 PMCID: PMC7733470 DOI: 10.2147/copd.s276690] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 11/09/2020] [Indexed: 12/28/2022] Open
Abstract
Purpose This research examines the emerging role of respiratory oscillometry associated with integer (InOr) and fractional order (FrOr) respiratory models in the context of groups of patients with increasing severity. The contributions to our understanding of the respiratory abnormalities along the course of increasing COPD severity and the diagnostic use of this method were also evaluated. Patients and Methods Forty-five individuals with no history of smoking or pulmonary diseases (control group) and 141 individuals with diagnoses of COPD were studied, being classified into 45 mild, 42 moderate, 36 severe and 18 very severe cases. Results This study has shown initially that the course of increasing COPD severity was adequately described by the model parameters. This resulted in significant and consistent correlations among these parameters and spirometric indexes. Additionally, this evaluation enhanced our understanding of the respiratory abnormalities in different COPD stages. The diagnostic accuracy analyses provided evidence that hysteresivity, obtained from FrOr modeling, allowed a highly accurate identification in patients with mild changes [area under the receiver operator characteristic curve (AUC)= 0.902]. Similar analyses in groups of moderate and severe patients showed that peripheral resistance, derived from InOr modeling, provided the most accurate parameter (AUC=0.898 and 0.998, respectively), while in very severe patients, traditional, InOr and FrOr parameters were able to reach high diagnostic accuracy (AUC>0.9). Conclusion InOr and FrOr modeling improved our knowledge of the respiratory abnormalities along the course of increasing COPD severity. In addition, the present study provides evidence that these models may contribute in the diagnosis of COPD. Respiratory oscillometry exams require only tidal breathing and are easy to perform. Taken together, these practical considerations and the results of the present study suggest that respiratory oscillometry associated with InOr and FrOr models may help to improve lung function tests in COPD.
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Affiliation(s)
- Caroline Oliveira Ribeiro
- Biomedical Instrumentation Laboratory, Institute of Biology and Faculty of Engineering, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Agnaldo José Lopes
- Pulmonary Function Laboratory, State University of Rio de Janeiro, Rio de Janeiro, Brazil.,Pulmonary Rehabilitation Laboratory, Augusto Motta University Center, Rio de Janeiro, Brazil
| | - Pedro Lopes de Melo
- Biomedical Instrumentation Laboratory, Institute of Biology and Faculty of Engineering, State University of Rio de Janeiro, Rio de Janeiro, Brazil
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Yasuo M, Kitaguchi Y, Tokoro Y, Kosaka M, Wada Y, Kinjo T, Ushiki A, Yamamoto H, Hanaoka M. Differences Between Central Airway Obstruction and Chronic Obstructive Pulmonary Disease Detected with the Forced Oscillation Technique. Int J Chron Obstruct Pulmon Dis 2020; 15:1425-1434. [PMID: 32606651 PMCID: PMC7310967 DOI: 10.2147/copd.s246126] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 05/24/2020] [Indexed: 12/13/2022] Open
Abstract
Background Obstructive ventilatory disturbances occur in both chronic obstructive pulmonary disease (COPD), a typical disease representative of peripheral airway obstruction, and central airway obstruction (CAO). Pulmonary function tests (PFTs), which depend on patient effort, are traditionally used to evaluate lung function. The forced oscillation technique (FOT) is an effort-independent method for examining lung function during tidal breathing. The FOT is used universally to assess respiratory function in patients with COPD. Several studies have measured FOT to assess ventilatory disturbances in CAO. The results showed that FOT measurements in patients with CAO were similar to those reported in patients with COPD. However, no studies have compared FOT measurements directly between CAO and COPD. The aim of this study was to identify differences in ventilatory disturbances between peripheral and central airway obstructions in COPD and CAO, before patients received pharmacological therapy or bronchoscopic interventions, respectively. Patients and Methods We retrospectively included 16 patients with CAO (10 cases of tracheal obstruction and 6 cases of bronchial obstruction) and 75 treatment-naïve patients with COPD (60 cases in Global Initiative for Chronic Obstructive Lung Disease [GOLD] stage II and 15 cases in GOLD stage III) that were admitted from December 2013 to May 2017. Prior to treatment, patients were examined with the FOT and PFTs. Results All parameters measured with the FOT in the inspiratory phase were significantly worse in patients with CAO than in patients with COPD. The PFTs showed that the CAO group had a significantly lower peak expiratory flow rate. In the airway wall thickening phenotype of COPD, a difference between the inspiratory and expiratory phases of the resonance frequency (ΔFres) was the best indicator for distinguishing between peripheral and central airway obstructions. Conclusion This study compared differences between CAO and COPD (mainly GOLD stage II). We found that the FOT measurement, ΔFres, was the optimal indicator of the difference between the airway wall thickening COPD phenotype and CAO. Thus, the difference might be due to mechanical changes that occur in COPD with airway wall thickening.
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Affiliation(s)
- Masanori Yasuo
- The First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
| | - Yoshiaki Kitaguchi
- The First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
| | - Yayoi Tokoro
- The First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
| | - Makoto Kosaka
- The First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
| | - Yosuke Wada
- The First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
| | - Takumi Kinjo
- The First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
| | - Atsuhito Ushiki
- The First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
| | - Hiroshi Yamamoto
- The First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
| | - Masayuki Hanaoka
- The First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
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A Minimal PKPD Interaction Model for Evaluating Synergy Effects of Combined NSCLC Therapies. J Clin Med 2020; 9:jcm9061832. [PMID: 32545464 PMCID: PMC7356515 DOI: 10.3390/jcm9061832] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/05/2020] [Accepted: 06/09/2020] [Indexed: 02/06/2023] Open
Abstract
This paper introduces a mathematical compartmental formulation of dose-effect synergy modelling for multiple therapies in non small cell lung cancer (NSCLC): antiangiogenic, immuno- and radiotherapy. The model formulates the dose-effect relationship in a unified context, with tumor proliferating rates and necrotic tissue volume progression as a function of therapy management profiles. The model accounts for inter- and intra-response variability by using surface model response terms. Slow acting peripheral compartments such as fat and muscle for drug distribution are not modelled. This minimal pharmacokinetic-pharmacodynamic (PKPD) model is evaluated with reported data in mice from literature. A systematic analysis is performed by varying only radiotherapy profiles, while antiangiogenesis and immunotherapy are fixed to their initial profiles. Three radiotherapy protocols are selected from literature: (1) a single dose 5 Gy once weekly; (2) a dose of 5 Gy × 3 days followed by a 2 Gy × 3 days after two weeks and (3) a dose of 5 Gy + 2 × 0.075 Gy followed after two weeks by a 2 Gy + 2 × 0.075 Gy dose. A reduction of 28% in tumor end-volume after 30 days was observed in Protocol 2 when compared to Protocol 1. No changes in end-volume were observed between Protocol 2 and Protocol 3, this in agreement with other literature studies. Additional analysis on drug interaction suggested that higher synergy among drugs affects up to three-fold the tumor volume (increased synergy leads to significantly lower growth ratio and lower total tumor volume). Similarly, changes in patient response indicated that increased drug resistance leads to lower reduction rates of tumor volumes, with end-volume increased up to 25–30%. In conclusion, the proposed minimal PKPD model has physiological value and can be used to study therapy management protocols and is an aiding tool in the clinical decision making process. Although developed with data from mice studies, the model is scalable to NSCLC patients.
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Saatci E, Saatci E. State-space analysis of fractional-order respiratory system models. Biomed Signal Process Control 2020. [DOI: 10.1016/j.bspc.2019.101820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Ghita M, Copot D, Ghita M, Derom E, Ionescu C. Low Frequency Forced Oscillation Lung Function Test Can Distinguish Dynamic Tissue Non-linearity in COPD Patients. Front Physiol 2019; 10:1390. [PMID: 31803060 PMCID: PMC6877497 DOI: 10.3389/fphys.2019.01390] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 10/25/2019] [Indexed: 01/11/2023] Open
Abstract
This paper introduces the use of low frequencies forced oscillation technique (FOT) in the presence of breathing signal. The hypothesis tested is to evaluate the sensitivity of FOT to various degrees of obstruction in COPD patients. The measurements were performed in the frequency range 0–2 Hz. The use of FOT to evaluate respiratory impedance has been broadly recognized and its complementary use next to standardized method as spirometry and body plethysmography has been well-documented. Typical use of FOT uses frequencies between 4–32 Hz and above. However, interesting information at frequencies below 4 Hz is related to viscoelastic properties of parenchyma. Structural changes in COPD affect viscoelastic properties and we propose to investigate the use of FOT at low frequencies with a fourth generation fan-based FOT device. The generator non-linearity introduced by the device is separated from the linear approximation of the impedance before evaluating the results on patients. Three groups of COPD obstruction, GOLD II, III, and IV are evaluated. We found significant differences in mechanical parameters (tissue damping, tissue elasticity, hysteresivity) and increased degrees of non-linear dynamic contributions in the impedance data with increasing degree of obstruction (p < 0.01). The results obtained suggest that the non-linear index correlates better with degrees of heterogeneity linked to COPD GOLD stages, than the currently used hysteresivity index. The protocol and method may prove useful to improve current diagnosis percentages for various COPD phenotypes.
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Affiliation(s)
- Maria Ghita
- Dynamical Systems and Control Research Group, Ghent University, Ghent, Belgium.,EEDT Core Lab on Decision and Control, Flanders Make Consortium, Ghent, Belgium
| | - Dana Copot
- Dynamical Systems and Control Research Group, Ghent University, Ghent, Belgium.,EEDT Core Lab on Decision and Control, Flanders Make Consortium, Ghent, Belgium
| | - Mihaela Ghita
- Dynamical Systems and Control Research Group, Ghent University, Ghent, Belgium.,EEDT Core Lab on Decision and Control, Flanders Make Consortium, Ghent, Belgium
| | - Eric Derom
- Department of Respiratory Diseases, Ghent University Hospital, Ghent, Belgium
| | - Clara Ionescu
- Dynamical Systems and Control Research Group, Ghent University, Ghent, Belgium.,EEDT Core Lab on Decision and Control, Flanders Make Consortium, Ghent, Belgium.,Department of Automation, Technical University of Cluj-Napoca, Cluj-Napoca, Romania
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8
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Faria ACD, Carvalho ARS, Guimarães ARM, Lopes AJ, Melo PL. Association of respiratory integer and fractional-order models with structural abnormalities in silicosis. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2019; 172:53-63. [PMID: 30902127 DOI: 10.1016/j.cmpb.2019.02.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 01/23/2019] [Accepted: 02/06/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND AND OBJECTIVE Integer and fractional-order models have emerged as powerful methods for obtaining information regarding the anatomical or pathophysiological changes that occur during respiratory diseases. However, the precise interpretation of the model parameters in light of the lung structural changes is not known. This study analyzed the associations of the integer and fractional-order models with structural changes obtained using multidetector computed tomography densitometry (MDCT) and pulmonary function analysis. METHODS Integer and fractional-order models were adjusted to data obtained using the forced oscillation technique (FOT). The results obtained in controls (n = 20) were compared with those obtained in patients with silicosis (n = 32), who were submitted to spirometry, body plethysmograph, FOT, diffusing capacity of the lungs for carbon monoxide (DLCO), and MDCT. The diagnostic accuracy was also investigated using ROC analysis. RESULTS The observed changes in the integer and fractional-order models were consistent with the pathophysiology of silicosis. The integer-order model showed association only between inertance and the non-aerated compartment (R = -0.69). This parameter also presented the highest associations with spirometry (R = 0.81), plethysmography (-0.61) and pulmonary diffusion (R = 0.53). Considering the fractional-order model, the increase in the poorly aerated and non-aerated regions presented direct correlations with the fractional inertance (R = 0.48), respiratory damping (R = 0.37) and hysteresivity (R = 0.54) and inverse associations with its fractional exponent (R = -0.62) and elastance (-0.35). Significant associations were also observed with spirometry (R = 0.63), plethysmography (0.37) and pulmonary diffusion (R = 0.51). Receiver operator characteristic analysis showed a higher accuracy in the FrOr model (0.908) than the eRIC model (0.789). CONCLUSIONS Our study has shown clear associations of the integer and fractional-order parameters with anatomical changes obtained via MDCT and pulmonary function measurements. These findings help to elucidate the physiological interpretation of the integer and fractional-order parameters and provide evidence that these parameters are reflective of the abnormal changes in silicosis. We also observed that the fractional-order model showed smaller curve-fitting errors, which resulted in a higher diagnostic accuracy than that of the eRIC model. Taken together, these results provide strong motivation for further studies exploring the clinical and scientific use of these models in respiratory medicine.
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Affiliation(s)
- Alvaro C D Faria
- Biomedical Instrumentation Laboratory, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil; Laboratory of Clinical and Experimental Research in Vascular Biology (BioVasc), State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Alysson Roncally Silva Carvalho
- Laboratory of Respiration Physiology, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Laboratory of Pulmonary Engineering, Biomedical Engineering Program, Alberto Luis Coimbra Institute of Postgraduation and Research in Engineering, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Alan Ranieri Medeiros Guimarães
- Laboratory of Respiration Physiology, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Laboratory of Pulmonary Engineering, Biomedical Engineering Program, Alberto Luis Coimbra Institute of Postgraduation and Research in Engineering, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Agnaldo J Lopes
- Pulmonary Function Laboratory, Pedro Ernesto University Hospital, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Pedro L Melo
- Biomedical Instrumentation Laboratory, Institute of Biology Roberto Alcantara Gomes, State University of Rio de Janeiro, Rio de Janeiro, Brazil; Laboratory of Clinical and Experimental Research in Vascular Biology (BioVasc), State University of Rio de Janeiro, Rio de Janeiro, Brazil.
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Marinho CDL, Maioli MCP, do Amaral JLM, Lopes AJ, de Melo PL. Respiratory resistance and reactance in adults with sickle cell anemia: Part 2-Fractional-order modeling and a clinical decision support system for the diagnosis of respiratory disorders. PLoS One 2019; 14:e0213257. [PMID: 30845242 PMCID: PMC6405112 DOI: 10.1371/journal.pone.0213257] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 02/19/2019] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND A better understanding of sickle cell anemia (SCA) and improvements in drug therapy and health policy have contributed to the emergence of a large population of adults living with this disease. The mechanisms by which SCA produces adverse effects on the respiratory system of these patients are largely unknown. Fractional-order (FrOr) models have a high potential to improve pulmonary clinical science and could be useful for diagnostic purposes, offering accurate models with an improved ability to mimic nature. Part 2 of this two-part study examines the changes in respiratory mechanics in patients with SCA using the new perspective of the FrOr models. These results are compared with those obtained in traditional forced oscillation (FOT) parameters, investigated in Part 1 of the present study, complementing this first analysis. METHODOLOGY/PRINCIPAL FINDINGS The data consisted of three categories of subjects: controls (n = 23), patients with a normal spirometric exam (n = 21) and those presenting restriction (n = 24). The diagnostic accuracy was evaluated by investigating the area under the receiver operating characteristic curve (AUC). Initially, it was observed that biomechanical changes in SCA included increased values of fractional inertance, as well as damping and hysteresivity (p<0.001). The correlation analysis showed that FrOr parameters are associated with functional exercise capacity (R = -0.57), pulmonary diffusion (R = -0.71), respiratory muscle performance (R = 0.50), pulmonary flows (R = -0.62) and airway obstruction (R = 0.60). Fractional-order modeling showed high diagnostic accuracy in the detection of early respiratory abnormalities (AUC = 0.93), outperforming spirometry (p<0.03) and standard FOT analysis (p<0.01) used in Part 1 of this study. A combination of machine learning methods with fractional-order modeling further improved diagnostic accuracy (AUC = 0.97). CONCLUSIONS FrOr modeling improved our knowledge about the biomechanical abnormalities in adults with SCA. Changes in FrOr parameters are associated with functional exercise capacity decline, abnormal pulmonary mechanics and diffusion. FrOr modeling outperformed spirometric and traditional forced oscillation analyses, showing a high diagnostic accuracy in the diagnosis of early respiratory abnormalities that was further improved by an automatic clinical decision support system. This finding suggested the potential utility of this combination to help identify early respiratory changes in patients with SCA.
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Affiliation(s)
- Cirlene de Lima Marinho
- Biomedical Instrumentation Laboratory—Institute of Biology and Faculty of Engineering, and BioVasc Research Laboratory—Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Jorge Luis Machado do Amaral
- Department of Electronics and Telecommunications Engineering, State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Agnaldo José Lopes
- School of Medical Sciences, Pulmonary Function Testing Laboratory, Rio de Janeiro/RJ, State University of Rio de Janeiro, Rio de Janeiro, Brazil
- Rehabilitation Sciences Post-Graduation Program, Augusto Motta University Centre, Rio de Janeiro, Brazil
| | - Pedro Lopes de Melo
- Biomedical Instrumentation Laboratory—Institute of Biology and Faculty of Engineering, and BioVasc Research Laboratory—Institute of Biology, State University of Rio de Janeiro, Rio de Janeiro, Brazil
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10
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Hasse K, Neylon J, Min Y, O'Connell D, Lee P, Low DA, Santhanam AP. Feasibility of deriving a novel imaging biomarker based on patient-specific lung elasticity for characterizing the degree of COPD in lung SBRT patients. Br J Radiol 2018; 92:20180296. [PMID: 30281329 DOI: 10.1259/bjr.20180296] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE: Lung tissue elasticity is an effective spatial representation for Chronic Obstructive Pulmonary Disease phenotypes and pathophysiology. We investigated a novel imaging biomarker based on the voxel-by-voxel distribution of lung tissue elasticity. Our approach combines imaging and biomechanical modeling to characterize tissue elasticity. METHODS: We acquired 4DCT images for 13 lung cancer patients with known COPD diagnoses based on GOLD 2017 criteria. Deformation vector fields (DVFs) from the deformable registration of end-inhalation and end-exhalation breathing phases were taken to be the ground-truth. A linear elastic biomechanical model was assembled from end-exhalation datasets with a density-guided initial elasticity distribution. The elasticity estimation was formulated as an iterative process, where the elasticity was optimized based on its ability to reconstruct the ground-truth. An imaging biomarker (denoted YM1-3) derived from the optimized elasticity distribution, was compared with the current gold standard, RA950 using confusion matrix and area under the receiver operating characteristic (AUROC) curve analysis. RESULTS: The estimated elasticity had 90 % accuracy when representing the ground-truth DVFs. The YM1-3 biomarker had higher diagnostic accuracy (86% vs 71 %), higher sensitivity (0.875 vs 0.5), and a higher AUROC curve (0.917 vs 0.875) as compared to RA950. Along with acting as an effective spatial indicator of lung pathophysiology, the YM1-3 biomarker also proved to be a better indicator for diagnostic purposes than RA950. CONCLUSIONS: Overall, the results suggest that, as a biomarker, lung tissue elasticity will lead to new end points for clinical trials and new targeted treatment for COPD subgroups. ADVANCES IN KNOWLEDGE: The derivation of elasticity information directly from 4DCT imaging data is a novel method for performing lung elastography. The work demonstrates the need for a mechanics-based biomarker for representing lung pathophysiology.
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Affiliation(s)
- Katelyn Hasse
- 1 Departmentof Radiation Oncology, University of California, Los Angeles Medical Plaza Driveway , Los Angeles, CA , US
| | - John Neylon
- 1 Departmentof Radiation Oncology, University of California, Los Angeles Medical Plaza Driveway , Los Angeles, CA , US
| | - Yugang Min
- 1 Departmentof Radiation Oncology, University of California, Los Angeles Medical Plaza Driveway , Los Angeles, CA , US
| | - Dylan O'Connell
- 1 Departmentof Radiation Oncology, University of California, Los Angeles Medical Plaza Driveway , Los Angeles, CA , US
| | - Percy Lee
- 1 Departmentof Radiation Oncology, University of California, Los Angeles Medical Plaza Driveway , Los Angeles, CA , US
| | - Daniel A Low
- 1 Departmentof Radiation Oncology, University of California, Los Angeles Medical Plaza Driveway , Los Angeles, CA , US
| | - Anand P Santhanam
- 1 Departmentof Radiation Oncology, University of California, Los Angeles Medical Plaza Driveway , Los Angeles, CA , US
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11
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Ribeiro CO, Faria ACD, Lopes AJ, de Melo PL. Forced oscillation technique for early detection of the effects of smoking and COPD: contribution of fractional-order modeling. Int J Chron Obstruct Pulmon Dis 2018; 13:3281-3295. [PMID: 30349233 PMCID: PMC6188181 DOI: 10.2147/copd.s173686] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Purpose The aim of the present study was to evaluate the performance of the forced oscillation technique (FOT) for the early diagnosis of the effects of smoking and COPD. The contributions of the integer-order (InOr) and fractional-order (FrOr) models were also evaluated. Patients and methods In total, 120 subjects were analyzed: 40 controls, 40 smokers (20.3±9.3 pack-years) and 40 patients with mild COPD. Results Initially, it was observed that traditional FOT parameters and the InOr and FrOr models provided a consistent description of the COPD pathophysiology. Mild COPD introduced significant increases in the FrOr inertance, damping factor and hysteresivity (P<0.0001). These parameters were significantly correlated with the spirometric parameters of central and small airway obstruction (P<0.0001). The diagnostic accuracy analyses indicated that FOT parameters and InOr modeling may adequately identify these changes (area under the receiver operating characteristic curve – AUC >0.8). The use of FrOr modeling significantly improved this process (P<0.05), allowing the early diagnosis of smokers and patients with mild COPD with high accuracy (AUC >0.9). Conclusion FrOr modeling improves our knowledge of modifications that occur in the early stages of COPD. Additionally, the findings of the present study provide evidence that these models may play an important role in the early diagnosis of COPD, which is crucial for improving the clinical management of the disease.
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Affiliation(s)
- Caroline Oliveira Ribeiro
- Biomedical Instrumentation Laboratory, Institute of Biology and Faculty of Engineering, State University of Rio de Janeiro, Rio de Janeiro, Brazil,
| | - Alvaro Camilo Dias Faria
- Biomedical Instrumentation Laboratory, Institute of Biology and Faculty of Engineering, State University of Rio de Janeiro, Rio de Janeiro, Brazil,
| | - Agnaldo José Lopes
- Pulmonary Function Laboratory, State University of Rio de Janeiro, Rio de Janeiro, Brazil.,Pulmonary Rehabilitation Laboratory, Augusto Motta University Center, Rio de Janeiro, Brazil
| | - Pedro Lopes de Melo
- Biomedical Instrumentation Laboratory, Institute of Biology and Faculty of Engineering, State University of Rio de Janeiro, Rio de Janeiro, Brazil,
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Shi Y, Zhang B, Cai M, Zhang XD. Numerical simulation of volume-controlled mechanical ventilated respiratory system with 2 different lungs. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2017; 33:e2852. [PMID: 27863120 DOI: 10.1002/cnm.2852] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 11/06/2016] [Indexed: 06/06/2023]
Abstract
Mechanical ventilation is a key therapy for patients who cannot breathe adequately by themselves, and dynamics of mechanical ventilation system is of great significance for life support of patients. Recently, models of mechanical ventilated respiratory system with 1 lung are used to simulate the respiratory system of patients. However, humans have 2 lungs. When the respiratory characteristics of 2 lungs are different, a single-lung model cannot reflect real respiratory system. In this paper, to illustrate dynamic characteristics of mechanical ventilated respiratory system with 2 different lungs, we propose a mathematical model of mechanical ventilated respiratory system with 2 different lungs and conduct experiments to verify the model. Furthermore, we study the dynamics of mechanical ventilated respiratory system with 2 different lungs. This research study can be used for improving the efficiency and safety of volume-controlled mechanical ventilation system.
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Affiliation(s)
- Yan Shi
- School of Automation Science and Electrical Engineering, Beihang University, Beijing, China
- Beijing Engineering Research Center of Diagnosis and Treatment of Respiratory and Critical Care Medicine, Beijing Chaoyang Hospital, Beijing, China
| | - Bolun Zhang
- School of Automation Science and Electrical Engineering, Beihang University, Beijing, China
- Beijing Engineering Research Center of Diagnosis and Treatment of Respiratory and Critical Care Medicine, Beijing Chaoyang Hospital, Beijing, China
| | - Maolin Cai
- School of Automation Science and Electrical Engineering, Beihang University, Beijing, China
- Beijing Engineering Research Center of Diagnosis and Treatment of Respiratory and Critical Care Medicine, Beijing Chaoyang Hospital, Beijing, China
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Ionescu CM, Copot D. Monitoring respiratory impedance by wearable sensor device: Protocol and methodology. Biomed Signal Process Control 2017. [DOI: 10.1016/j.bspc.2017.03.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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14
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Tam A, Bates JHT, Churg A, Wright JL, Man SFP, Sin DD. Sex-Related Differences in Pulmonary Function following 6 Months of Cigarette Exposure: Implications for Sexual Dimorphism in Mild COPD. PLoS One 2016; 11:e0164835. [PMID: 27788167 PMCID: PMC5082824 DOI: 10.1371/journal.pone.0164835] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 10/01/2016] [Indexed: 11/24/2022] Open
Abstract
Female smokers have increased risk of chronic obstructive pulmonary disease (COPD) compared with male smokers who have a similar history of cigarette smoke exposure. We have shown previously that chronic smoke exposure for 6 months leads to increased airway wall remodeling in female C57BL/6 mice compared with male C57BL/6 mice. These differences, however, were not evident in female ovariectomized mice exposed to cigarette smoke. Herein, we report on the pulmonary function test results from the flexiVent system, which was used to determine the potential functional consequences of the histologic changes observed in these mice. We found that tissue damping (G) was increased in female compared to male or ovariectomized female mice after smoke exposure. At low oscillating frequencies, complex input resistance (Zrs) and impedance (Xrs) of the respiratory system was increased and decreased, respectively, in female but not in male or ovariectomized female mice after smoke exposure. Quasistatic pressure-volume curves revealed a reduction in inspiratory capacity in female mice but not in male or ovariectomized female mice after smoke exposure. The remaining lung function measurements including quasistatic compliance were similar amongst all groups. This is the first study characterizing a sexual dimorphism in respiratory functional properties in a mouse model of COPD. These findings demonstrate that increased airway remodeling in female mice following chronic smoke exposure is associated with increased tissue resistance in the peripheral airways. These data may explain the importance of female sex hormones and the increased risk of airway disease in female smokers.
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Affiliation(s)
- Anthony Tam
- Department of Medicine, Centre for Heart Lung Innovation (St. Paul's Hospital), Vancouver, British Columbia, Canada
| | - Jason H. T. Bates
- Department of Medicine, University of Vermont College of Medicine, Burlington, Vermont, United States of America
| | - Andrew Churg
- Department of Pathology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Joanne L. Wright
- Department of Pathology, University of British Columbia, Vancouver, British Columbia, Canada
| | - S. F. Paul Man
- Department of Medicine, Centre for Heart Lung Innovation (St. Paul's Hospital), Vancouver, British Columbia, Canada
| | - Don D. Sin
- Department of Medicine, Centre for Heart Lung Innovation (St. Paul's Hospital), Vancouver, British Columbia, Canada
- * E-mail:
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Early Diagnosis of Respiratory Abnormalities in Asbestos-Exposed Workers by the Forced Oscillation Technique. PLoS One 2016; 11:e0161981. [PMID: 27612198 PMCID: PMC5017649 DOI: 10.1371/journal.pone.0161981] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 08/15/2016] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The current reference test for the detection of respiratory abnormalities in asbestos-exposed workers is spirometry. However, spirometry has several shortcomings that greatly affect the efficacy of current asbestos control programs. The forced oscillation technique (FOT) represents the current state-of-the-art technique in the assessment of lung function. This method provides a detailed analysis of respiratory resistance and reactance at different oscillatory frequencies during tidal breathing. Here, we evaluate the FOT as an alternative method to standard spirometry for the early detection and quantification of respiratory abnormalities in asbestos-exposed workers. METHODOLOGY/PRINCIPAL FINDINGS Seventy-two subjects were analyzed. The control group was composed of 33 subjects with a normal spirometric exam who had no history of smoking or pulmonary disease. Thirty-nine subjects exposed to asbestos were also studied, including 32 volunteers in radiological category 0/0 and 7 volunteers with radiological categories of 0/1 or 1/1. FOT data were interpreted using classical parameters as well as integer (InOr) and fractional-order (FrOr) modeling. The diagnostic accuracy was evaluated by investigating the area under the receiver operating characteristic curve (AUC). Exposed workers presented increased obstruction (resistance p<0.001) and a reduced compliance (p<0.001), with a predominance of obstructive changes. The FOT parameter changes were correlated with the standard pulmonary function analysis methods (R = -0.52, p<0.001). Early respiratory abnormalities were identified with a high diagnostic accuracy (AUC = 0.987) using parameters obtained from the FrOr modeling. This accuracy was significantly better than those obtained with classical (p<0.001) and InOr (p<0.001) model parameters. CONCLUSIONS The FOT improved our knowledge about the biomechanical abnormalities in workers exposed to asbestos. Additionally, a high diagnostic accuracy in the diagnosis of early respiratory abnormalities in asbestos-exposed workers was obtained. This makes the FOT particularly useful as a screening tool in the context of asbestos control and elimination. Moreover, it can facilitate epidemiological research and the longitudinal follow-up of asbestos exposure and asbestos-related diseases.
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Shi Y, Niu J, Cao Z, Cai M, Zhu J, Xu W. Online Estimation Method for Respiratory Parameters Based on a Pneumatic Model. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2016; 13:939-946. [PMID: 26552092 DOI: 10.1109/tcbb.2015.2497225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Mechanical ventilation is an important method to help people breathe. Respiratory parameters of ventilated patients are usually tracked for pulmonary diagnostics and respiratory treatment assessment. In this paper, to improve the estimation accuracy of respiratory parameters, a pneumatic model for mechanical ventilation was proposed. Furthermore, based on the mathematical model, a recursive least-squares algorithm was adopted to estimate the respiratory parameters. Finally, through experimental and numerical study, it was demonstrated that the proposed estimation method was effective and the method can be used in pulmonary diagnostics and treatment.
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Olarte O, De Keyser R, Ionescu CM. Fan-based device for non-invasive measurement of respiratory impedance: Identification, calibration and analysis. Biomed Signal Process Control 2016. [DOI: 10.1016/j.bspc.2016.06.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Faria ACD, Veiga J, Lopes AJ, Melo PL. Forced oscillation, integer and fractional-order modeling in asthma. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2016; 128:12-26. [PMID: 27040828 DOI: 10.1016/j.cmpb.2016.02.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 01/04/2016] [Accepted: 02/16/2016] [Indexed: 06/05/2023]
Abstract
The purpose of this study was to evaluate the use of fractional-order (FrOr) modeling in asthma. To this end, three FrOr models were compared with traditional parameters and an integer-order model (InOr). We investigated which model would best fit the data, the correlation with traditional lung function tests and the contribution to the diagnostic of airway obstruction. The data consisted of forced oscillation (FO) measurements obtained from healthy (n=22) and asthmatic volunteers with mild (n=22), moderate (n=19) and severe (n=19) obstructions. The first part of this study showed that a FrOr was the model that best fit the data (relative distance: FrOr=4.3±2.4; InOr=5.1±2.6%). The correlation analysis resulted in reasonable (R=0.36) to very good (R=0.77) associations between FrOr parameters and spirometry. The closest associations were observed between parameters related to peripheral airway obstruction, showing a clear relationship between the FrOr models and lung mechanics. Receiver-operator analysis showed that FrOr parameters presented a high potential to contribute to the detection of the mild obstruction in a clinical setting. The accuracy [area under the Receiver Operating Characteristic curve (AUC)] observed in these parameters (AUC=0.954) was higher than that observed in traditional FO parameters (AUC=0.732) and that obtained from the InOr model (AUC=0.861). Patients with moderate and severe obstruction were identified with high accuracy (AUC=0.972 and 0.977, respectively). In conclusion, the results obtained are in close agreement with asthma pathology, and provide evidence that FO measurement associated with FrOr models is a non-invasive, simple and radiation-free method for the detection of biomechanical abnormalities in asthma.
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Affiliation(s)
- Alvaro C D Faria
- Biomedical Instrumentation Laboratory, Institute of Biology Roberto Alcantara Gomes and Laboratory of Clinical and Experimental Research in Vascular Biology (BioVasc), State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Juliana Veiga
- Biomedical Instrumentation Laboratory, Institute of Biology Roberto Alcantara Gomes and Laboratory of Clinical and Experimental Research in Vascular Biology (BioVasc), State University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Agnaldo J Lopes
- Pulmonary Function Laboratory, Pedro Ernesto University Hospital, Brazil
| | - Pedro L Melo
- Biomedical Instrumentation Laboratory, Institute of Biology Roberto Alcantara Gomes and Laboratory of Clinical and Experimental Research in Vascular Biology (BioVasc), State University of Rio de Janeiro, Rio de Janeiro, Brazil.
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Pressure dynamic characteristics of pressure controlled ventilation system of a lung simulator. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2014; 2014:761712. [PMID: 25197318 PMCID: PMC4147202 DOI: 10.1155/2014/761712] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 07/22/2014] [Indexed: 11/23/2022]
Abstract
Mechanical ventilation is an important life support treatment of critically ill patients, and air pressure dynamics of human lung affect ventilation treatment effects. In this paper, in order to obtain the influences of seven key parameters of mechanical ventilation system on the pressure dynamics of human lung, firstly, mechanical ventilation system was considered as a pure pneumatic system, and then its mathematical model was set up. Furthermore, to verify the mathematical model, a prototype mechanical ventilation system of a lung simulator was proposed for experimental study. Last, simulation and experimental studies on the air flow dynamic of the mechanical ventilation system were done, and then the pressure dynamic characteristics of the mechanical system were obtained. The study can be referred to in the pulmonary diagnostics, treatment, and design of various medical devices or diagnostic systems.
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Jaworski J, Redlarski G. A compartment model of alveolar–capillary oxygen diffusion with ventilation–perfusion gradient and dynamics of air transport through the respiratory tract. Comput Biol Med 2014; 51:159-70. [DOI: 10.1016/j.compbiomed.2014.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 04/21/2014] [Accepted: 05/01/2014] [Indexed: 10/25/2022]
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21
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Hong ZY, Eun SH, Park K, Choi WH, Lee JI, Lee EJ, Lee JM, Story MD, Cho J. Development of a small animal model to simulate clinical stereotactic body radiotherapy-induced central and peripheral lung injuries. JOURNAL OF RADIATION RESEARCH 2014; 55:648-657. [PMID: 24556815 PMCID: PMC4099992 DOI: 10.1093/jrr/rrt234] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 12/27/2013] [Accepted: 12/31/2013] [Indexed: 06/03/2023]
Abstract
Given the tremendous potential of stereotactic body radiotherapy (SBRT), investigations of the underlying radiobiology associated with SBRT-induced normal tissue injury are of paramount importance. This study was designed to develop an animal model that simulates centrally and peripherally located clinical SBRT-induced lung injuries. A 90-Gy irradiation dose was focally delivered to the central and peripheral areas of the left mouse lung with an image-guided small-animal irradiation system. At 1, 2 and 4 weeks after irradiation, micro-computed tomography (micro-CT) images of the lung were taken. Lung function measurements were performed with the Flexivent® system (SCIREQ©, Montreal, Canada). For the histopathological analysis, the lungs were fixed by perfusing with formalin, and paraffin sections were stained with hematoxylin and eosin and Masson's Trichrome. Gross inspection clearly indicated local lung injury confined to the central and peripheral areas of the left lung. Typical histopathological alterations corresponding to clinical manifestations were observed. The micro-CT analysis results appeared to correlate with the histopathological findings. Mouse lung tissue damping increased dramatically at central settings, compared with that at the control or peripheral settings. An animal model to simulate clinical SBRT-induced central and peripheral lung injuries was developed and validated with histopathological, radiological and functional analyses. This model increases our understanding of SBRT-induced central and peripheral lung injuries and will help to improve radiation therapy in the future.
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Affiliation(s)
- Zhen-Yu Hong
- Department of Radiation Oncology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, South Korea
| | - Sung Ho Eun
- Department of Radiation Oncology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, South Korea
| | - Kwangwoo Park
- Department of Radiation Oncology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, South Korea
| | - Won Hoon Choi
- Department of Radiation Oncology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, South Korea
| | - Jung Il Lee
- Department of Radiation Oncology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, South Korea
| | - Eun-Jung Lee
- Department of Radiation Oncology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, South Korea
| | - Ji Min Lee
- Department of Radiation Oncology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, South Korea
| | - Michael D Story
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jaeho Cho
- Department of Radiation Oncology, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul, 120-752, South Korea
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Ionescu CM, Hernandez A, De Keyser R. A recurrent parameter model to characterize the high-frequency range of respiratory impedance in healthy subjects. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2013; 7:882-892. [PMID: 24473552 DOI: 10.1109/tbcas.2013.2243837] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In this work, a re-visited model of the respiratory system is proposed. Identification of a recurrent electrical ladder network model of the lungs, which incorporates their specific morphology and anatomical structure, is performed on 31 healthy subjects. The data for identification has been gathered using the forced oscillation lung function test, which delivers a non-parametric model of the impedance. On the measured frequency response, the ladder network parameters have been identified and a fractional order has been calculated from the recurrent ratios of the respiratory mechanics (resistance and compliance). The paper includes also a comparison of our recurrent parameter model with another parametric model for high frequency range. The results suggest that the two models can equally well characterize the respiratory impedance over a long range of frequencies. Additionally, we have shown that the fractional order resulting from the recurrent properties of resistance and compliance in the ladder network model is independent of frequency and is not biased by the nose clip wore by the patients during measurements. An illustrative example shows that our re-visited model is sensitive to changes in respiratory mechanics and the fractional order value is a reliable parameter to capture these changes.
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A new approach to modeling of selected human respiratory system diseases, directed to computer simulations. Comput Biol Med 2013; 43:1606-13. [DOI: 10.1016/j.compbiomed.2013.07.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 07/03/2013] [Accepted: 07/05/2013] [Indexed: 11/22/2022]
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Amaral JLM, Lopes AJ, Jansen JM, Faria ACD, Melo PL. Machine learning algorithms and forced oscillation measurements applied to the automatic identification of chronic obstructive pulmonary disease. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2012; 105:183-93. [PMID: 22018532 DOI: 10.1016/j.cmpb.2011.09.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 08/15/2011] [Accepted: 09/22/2011] [Indexed: 05/02/2023]
Abstract
The purpose of this study is to develop a clinical decision support system based on machine learning (ML) algorithms to help the diagnostic of chronic obstructive pulmonary disease (COPD) using forced oscillation (FO) measurements. To this end, the performances of classification algorithms based on Linear Bayes Normal Classifier, K nearest neighbor (KNN), decision trees, artificial neural networks (ANN) and support vector machines (SVM) were compared in order to the search for the best classifier. Four feature selection methods were also used in order to identify a reduced set of the most relevant parameters. The available dataset consists of 7 possible input features (FO parameters) of 150 measurements made in 50 volunteers (COPD, n = 25; healthy, n = 25). The performance of the classifiers and reduced data sets were evaluated by the determination of sensitivity (Se), specificity (Sp) and area under the ROC curve (AUC). Among the studied classifiers, KNN, SVM and ANN classifiers were the most adequate, reaching values that allow a very accurate clinical diagnosis (Se > 87%, Sp > 94%, and AUC > 0.95). The use of the analysis of correlation as a ranking index of the FOT parameters, allowed us to simplify the analysis of the FOT parameters, while still maintaining a high degree of accuracy. In conclusion, the results of this study indicate that the proposed classifiers may contribute to easy the diagnostic of COPD by using forced oscillation measurements.
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Affiliation(s)
- Jorge L M Amaral
- Department of Electronics and Telecommunications Engineering, State University of Rio de Janeiro, Rio de Janeiro, Brazil
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De Keyser R, Ionescu C. Adaptive control of a pressure-controlled artificial ventilator: a simulator-based evaluation using real COPD patient data. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2011; 104:e178-e188. [PMID: 21458877 DOI: 10.1016/j.cmpb.2011.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 10/12/2010] [Accepted: 03/02/2011] [Indexed: 05/30/2023]
Abstract
The paper discusses the application of a direct adaptive controller to a pressure controlled artificial ventilation problem. In pressure controlled ventilators, the manipulated variable is the maximum flow applied to the patient during the active phase (inspiration), and the regulated variable is the peak pressure at end-inspiration. This simulation case study focuses on patients diagnosed with Chronic Obstructive Pulmonary Disease (COPD), which require artificial/mechanical ventilation. An adaptive PID controller ensures peak pressures below critical values, by manipulating the flow delivered by the ventilator. The simulation study is performed on fractional-order models of the respiratory impedance identified from lung function data obtained from 21 COPD patients. Additional simulation studies show the robustness of the controller in presence of varying model parameters from the respiratory impedance of the patient. Possibilities to implement the control strategy as an online adaptive algorithm are also explored. The results show that the design of the control is suitable for this kind of application and provides useful insight on realistic scenarios.
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Affiliation(s)
- Robin De Keyser
- Electrical energy, Systems and Automation Department at Ghent University, Technologiepark, 913, B9052 Gent-Zwijnaarde, Belgium.
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Silva KKD, Lopes AJ, Jansen JM, de Melo PL. Total inspiratory and expiratory impedance in patients with severe chronic obstructive pulmonary disease. Clinics (Sao Paulo) 2011; 66:2085-91. [PMID: 22189734 PMCID: PMC3226604 DOI: 10.1590/s1807-59322011001200014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 07/25/2011] [Accepted: 08/31/2011] [Indexed: 03/31/2023] Open
Abstract
OBJECTIVES Several studies have confirmed the high potential of the forced oscillation technique for the assessment of respiratory modifications related to chronic obstructive pulmonary disease. However, most of these studies did not employ within-breath analyses of the respiratory system. The aim of this study is to analyze respiratory impedance alterations in different phases of the respiratory cycle of chronic obstructive pulmonary disease patients and to evaluate their clinical use. METHODS 39 individuals were evaluated, including 20 controls and 19 individuals with chronic obstructive pulmonary disease who experienced severe airway obstruction. We evaluated the mean respiratory impedance (Zm) as well as values for inspiration (Zi) and expiration cycles (Ze), at the beginning of inspiration (Zbi) and expiration (Zbe). The peak-to-peak impedance (Zpp), and the impedance change (ΔZrs) were also analyzed. The clinical usefulness was evaluated by investigating the sensibility, specificity and the area under the receiver operating characteristic curve. RESULTS The respiratory impedance increased in individuals with chronic obstructive pulmonary disease in all of the studied parameters (Zm, Zi, Ze, Zbi, Zbe, ΔZrs and Zpp). These changes were inversely associated with spirometric parameters. Higher impedances were observed in the expiratory phase of individuals with chronic obstructive pulmonary disease. All of the studied parameters, except for ΔZrs (area under the receiver operating characteristic ,0.8), exhibited high accuracy for clinical use (area under the receiver operating characteristic >0.90; Sensibility ≥ 0.85; Sp ≥ 0.85). CONCLUSIONS The respiratory alterations in severe chronic obstructive pulmonary disease may be identified by the increase in respiratory system impedance, which is more evident in the expiratory phase. These results confirm the potential of within-breath analysis of respiratory impedance for the assessment of respiratory modifications related to chronic obstructive pulmonary disease.
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Affiliation(s)
- Karla Kristine Dames Silva
- State University of Rio de Janeiro, Institute of Biology, Biomedical Instrumentation Laboratory, Rio de Janeiro/RJ, Brazil
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Quint SR, Vaughn BV. Heart period sensitivity to forced oscillations in ventilatory pressure. Eur J Appl Physiol 2010; 110:133-42. [DOI: 10.1007/s00421-010-1478-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/05/2010] [Indexed: 11/30/2022]
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