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Journal of Biomechanical Engineering Jun 2013Both in academic research and in clinical settings, virtual simulation of the cardiovascular system can be used to rapidly assess complex multivariable interactions... (Review)
Review
Both in academic research and in clinical settings, virtual simulation of the cardiovascular system can be used to rapidly assess complex multivariable interactions between blood vessels, blood flow, and the heart. Moreover, metrics that can only be predicted with computational simulations (e.g., mechanical wall stress, oscillatory shear index, etc.) can be used to assess disease progression, for presurgical planning, and for interventional outcomes. Because the pulmonary vasculature is susceptible to a wide range of pathologies that directly impact and are affected by the hemodynamics (e.g., pulmonary hypertension), the ability to develop numerical models of pulmonary blood flow can be invaluable to the clinical scientist. Pulmonary hypertension is a devastating disease that can directly benefit from computational hemodynamics when used for diagnosis and basic research. In the present work, we provide a clinical overview of pulmonary hypertension with a focus on the hemodynamics, current treatments, and their limitations. Even with a rich history in computational modeling of the human circulation, hemodynamics in the pulmonary vasculature remains largely unexplored. Thus, we review the tasks involved in developing a computational model of pulmonary blood flow, namely vasculature reconstruction, meshing, and boundary conditions. We also address how inconsistencies between models can result in drastically different flow solutions and suggest avenues for future research opportunities. In its current state, the interpretation of this modeling technology can be subjective in a research environment and impractical for clinical practice. Therefore, considerations must be taken into account to make modeling reliable and reproducible in a laboratory setting and amenable to the vascular clinic. Finally, we discuss relevant existing models and how they have been used to gain insight into cardiopulmonary physiology and pathology.
Topics: Compliance; Computer Simulation; Hemodynamics; Humans; Hypertension, Pulmonary; Lung; Precision Medicine
PubMed: 23699723
DOI: 10.1115/1.4024141 -
Clinical and Translational Science Mar 2021Forced expiratory volume in one second (FEV ) is a critical parameter for the assessment of lung function for both clinical care and research in patients with asthma.... (Clinical Trial)
Clinical Trial
Forced expiratory volume in one second (FEV ) is a critical parameter for the assessment of lung function for both clinical care and research in patients with asthma. While asthma is defined by variable airflow obstruction, FEV is typically assessed during clinic visits. Mobile spirometry (mSpirometry) allows more frequent measurements of FEV , resulting in a more continuous assessment of lung function over time and its variability. Twelve patients with moderate asthma were recruited in a single-center study and were instructed to perform pulmonary function tests at home twice daily for 28 days and weekly in the clinic. Daily and mean subject compliances were summarized. The agreement between clinic and mobile FEV was assessed using correlation and Bland-Altman analyses. The test-retest reliability for clinic and mSpirometry was assessed by interclass correlation coefficient (ICC). Simulation was conducted to explore if mSpirometry could improve statistical power over clinic counterparts. The mean subject compliance with mSpirometry was 70% for twice-daily and 85% for at least once-daily. The mSpirometry FEV were highly correlated and agreed with clinic ones from the same morning (r = 0.993) and the same afternoon (r = 0.988) with smaller mean difference for the afternoon (0.0019 L) than morning (0.0126 L) measurements. The test-retest reliability of mobile (ICC = 0.932) and clinic (ICC = 0.942) spirometry were comparable. Our simulation analysis indicated greater power using dense mSpirometry than sparse clinic measurements. Overall, we have demonstrated good compliance for repeated at-home mSpirometry, high agreement and comparable test-retest reliability with clinic counterparts, greater statistical power, suggesting a potential for use in asthma clinical research.
Topics: Adolescent; Adult; Asthma; Female; Forced Expiratory Volume; Humans; Male; Middle Aged; Mobile Applications; Monitoring, Ambulatory; Patient Compliance; Pilot Projects; Remote Sensing Technology; Reproducibility of Results; Smartphone; Spirometry; Young Adult
PubMed: 33048470
DOI: 10.1111/cts.12901 -
The Lancet. Respiratory Medicine Dec 2020Patients with COVID-19 can develop acute respiratory distress syndrome (ARDS), which is associated with high mortality. The aim of this study was to examine the... (Comparative Study)
Comparative Study Observational Study
BACKGROUND
Patients with COVID-19 can develop acute respiratory distress syndrome (ARDS), which is associated with high mortality. The aim of this study was to examine the functional and morphological features of COVID-19-associated ARDS and to compare these with the characteristics of ARDS unrelated to COVID-19.
METHODS
This prospective observational study was done at seven hospitals in Italy. We enrolled consecutive, mechanically ventilated patients with laboratory-confirmed COVID-19 and who met Berlin criteria for ARDS, who were admitted to the intensive care unit (ICU) between March 9 and March 22, 2020. All patients were sedated, paralysed, and ventilated in volume-control mode with standard ICU ventilators. Static respiratory system compliance, the ratio of partial pressure of arterial oxygen to fractional concentration of oxygen in inspired air, ventilatory ratio (a surrogate of dead space), and D-dimer concentrations were measured within 24 h of ICU admission. Lung CT scans and CT angiograms were done when clinically indicated. A dataset for ARDS unrelated to COVID-19 was created from previous ARDS studies. Survival to day 28 was assessed.
FINDINGS
Between March 9 and March 22, 2020, 301 patients with COVID-19 met the Berlin criteria for ARDS at participating hospitals. Median static compliance was 41 mL/cm HO (33-52), which was 28% higher than in the cohort of patients with ARDS unrelated to COVID-19 (32 mL/cm HO [25-43]; p<0·0001). 17 (6%) of 297 patients with COVID-19-associated ARDS had compliances greater than the 95th percentile of the classical ARDS cohort. Total lung weight did not differ between the two cohorts. CT pulmonary angiograms (obtained in 23 [8%] patients with COVID-19-related ARDS) showed that 15 (94%) of 16 patients with D-dimer concentrations greater than the median had bilateral areas of hypoperfusion, consistent with thromboembolic disease. Patients with D-dimer concentrations equal to or less than the median had ventilatory ratios lower than those of patients with D-dimer concentrations greater than the median (1·66 [1·32-1·95] vs 1·90 [1·50-2·33]; p=0·0001). Patients with static compliance equal to or less than the median and D-dimer concentrations greater than the median had markedly increased 28-day mortality compared with other patient subgroups (40 [56%] of 71 with high D-dimers and low compliance vs 18 [27%] of 67 with low D-dimers and high compliance, 13 [22%] of 60 with low D-dimers and low compliance, and 22 [35%] of 63 with high D-dimers and high compliance, all p=0·0001).
INTERPRETATION
Patients with COVID-19-associated ARDS have a form of injury that, in many aspects, is similar to that of those with ARDS unrelated to COVID-19. Notably, patients with COVID-19-related ARDS who have a reduction in respiratory system compliance together with increased D-dimer concentrations have high mortality rates.
FUNDING
None.
Topics: Aged; COVID-19; Computed Tomography Angiography; Female; Fibrin Fibrinogen Degradation Products; Humans; Lung; Male; Middle Aged; Pandemics; Prospective Studies; Respiration, Artificial; Respiratory Distress Syndrome; SARS-CoV-2
PubMed: 32861276
DOI: 10.1016/S2213-2600(20)30370-2 -
Respiratory Care Jul 2010This paper reviews the history of aerosol therapy; discusses patient, drug, and device factors that can influence the success of aerosol therapy; and identifies trends... (Review)
Review
This paper reviews the history of aerosol therapy; discusses patient, drug, and device factors that can influence the success of aerosol therapy; and identifies trends that will drive the science of aerosol therapy in the future. Aerosol medication is generally less expensive, works more rapidly, and produces fewer side effects than the same drug given systemically. Aerosol therapy has been used for thousands of years by steaming and burning plant material. In the 50 years since the invention of the pressurized metered-dose inhaler, advances in drugs and devices have made aerosols the most commonly used way to deliver therapy for asthma and COPD. The requirements for aerosol therapy depend on the target site of action and the underlying disease. Medication to treat airways disease should deposit on the conducting airways. Effective deposition of airway particles generally requires particle size between 0.5 and 5 microm mass median aerodynamic diameter; however, a smaller particle size neither equates to greater side effects nor greater effectiveness. However, medications like peptides intended for systemic absorption, need to deposit on the alveolar capillary bed. Thus ultrafine particles, a slow inhalation, and relatively normal airways that do not hinder aerosol penetration will optimize systemic delivery. Aerosolized antimicrobials are often used for the treatment of cystic fibrosis or bronchiectasis, and mucoactive agents to promote mucus clearance have been delivered by aerosol. As technology improves, a greater variety of novel medications are being developed for aerosol delivery, including for therapy of pulmonary hypertension, as vaccines, for decreasing dyspnea, to treat airway inflammation, for migraine headache, for nicotine and drug addiction, and ultimately for gene therapy. Common reasons for therapeutic failure of aerosol medications include the use of inactive or depleted medications, inappropriate use of the aerosol device, and, most importantly, poor adherence to prescribed therapy. The respiratory therapist plays a key role in patient education, device selection, and outcomes assessment.
Topics: Administration, Inhalation; Aerosols; Humans; Lung Diseases; Nebulizers and Vaporizers; Particle Size; Patient Compliance
PubMed: 20587104
DOI: No ID Found -
The European Respiratory Journal Jan 1997Maturational changes in the specific compliance could potentially contribute to the development or clinical presentation of respiratory diseases in infants and children....
Maturational changes in the specific compliance could potentially contribute to the development or clinical presentation of respiratory diseases in infants and children. Changes in the specific compliance during development and its structural basis have been well characterized, but changes in bronchial compliance and the mechanisms involved have received little attention. Semistatic pressure-volume curves were generated for isolated bronchial segments from late-term foetal, immature and adult pigs. A small number of bronchi from human infants were also studied. The amount of cartilage in the bronchial wall of pigs of different ages was measured histologically, and morphometric changes in the wall of inflated bronchi were investigated. The specific compliance of bronchi approximately halved from 1 to 4 weeks of age. No change in specific compliance was observed either between 4 week old and adult pigs, or between late-term foetal and 1 week old pigs. Changes in the total wall and cartilage areas did not correlate with changes in specific compliance. Inflation to 20 cmH2O transmural pressure reduced the total wall area of bronchi from 1 week old pigs. Significant changes in bronchial distensibility occur during the early postnatal period. These changes in specific compliance are not caused by an increase in the amount of cartilage. The increase in luminal volume during inflation of bronchial segments occurs, partially, by compression of the airway wall against the cartilage layer.
Topics: Age Factors; Animals; Animals, Newborn; Bronchi; Cartilage; Compliance; Cryopreservation; Humans; Image Processing, Computer-Assisted; Infant; Inhalation; Lung; Lung Compliance; Lung Volume Measurements; Pressure; Respiration; Respiratory Mechanics; Respiratory Tract Diseases; Swine
PubMed: 9032487
DOI: 10.1183/09031936.97.10010027 -
Primary Care Respiratory Journal :... Jun 2010Chronic obstructive pulmonary disease (COPD) is now the fourth leading cause of death, affects an estimated 24 million Americans, and accounts for over ten million... (Review)
Review
Chronic obstructive pulmonary disease (COPD) is now the fourth leading cause of death, affects an estimated 24 million Americans, and accounts for over ten million physician and emergency department (ED) visits and hospitalisations each year. The diagnosis and management of COPD falls largely to primary care practitioners. Previously, COPD management options were limited, but newer treatments have been shown to slow lung deterioration, reduce symptoms and preserve quality of life. Combination therapy with an inhaled corticosteroid and a long-acting beta2-agonist (ICS/LABA) is an effective therapy for COPD that, compared to other therapies, has been shown to reduce exacerbations, hospitalisations, ED visits and health care costs. This review focuses on the role of combination ICS/LABA therapy in managing COPD, including indications, potential benefits and considerations that affect therapy decisions.
Topics: Adrenal Cortex Hormones; Adrenergic beta-Agonists; Costs and Cost Analysis; Disease Progression; Drug Therapy, Combination; Hospitalization; Humans; Lung; Medication Adherence; Pulmonary Disease, Chronic Obstructive; Respiratory Function Tests
PubMed: 20339822
DOI: 10.4104/pcrj.2010.00020 -
Clinical and Experimental Allergy :... Feb 2009Asthma is a highly prevalent chronic respiratory disease affecting 300 million people world-wide. A significant fraction of the cost and morbidity of asthma derives from... (Review)
Review
Asthma is a highly prevalent chronic respiratory disease affecting 300 million people world-wide. A significant fraction of the cost and morbidity of asthma derives from acute care for asthma exacerbations. In the United States alone, there are approximately 15 million outpatient visits, 2 million emergency room visits, and 500,000 hospitalizations each year for management of acute asthma. Common respiratory viruses, especially rhinoviruses, cause the majority of exacerbations in children and adults. Infection of airway epithelial cells with rhinovirus causes the release of pro-inflammatory cytokines and chemokines, as well as recruitment of inflammatory cells, particularly neutrophils, lymphocytes, and eosinophils. The host response to viral infection is likely to influence susceptibility to asthma exacerbation. Having had at least one exacerbation is an important risk factor for recurrent exacerbations suggesting an 'exacerbation-prone' subset of asthmatics. Factors underlying the 'exacerbation-prone' phenotype are incompletely understood but include extrinsic factors: cigarette smoking, medication non-compliance, psychosocial factors, and co-morbidities such as gastroesophageal reflux disease, rhinosinusitis, obesity, and intolerance to non-steroidal anti-inflammatory medications; as well as intrinsic factors such as deficient epithelial cell production of the anti-viral type I interferons (IFN-alpha and IFN-beta). A better understanding of the biologic mechanisms of host susceptibility to recurrent exacerbations will be important for developing more effective preventions and treatments aimed at reducing the significant cost and morbidity associated with this important global health problem.
Topics: Allergens; Asthma; Comorbidity; Humans; Lung; Models, Biological; Patient Compliance; Psychology; Virus Diseases
PubMed: 19187331
DOI: 10.1111/j.1365-2222.2008.03157.x -
European Respiratory Review : An... Jun 2019Effective treatment of obstructive sleep apnoea (OSA) is primarily determined by adherence to the selected intervention. The most common treatment pathways are... (Review)
Review
Effective treatment of obstructive sleep apnoea (OSA) is primarily determined by adherence to the selected intervention. The most common treatment pathways are mechanical devices such as continuous positive airway pressure (CPAP) or a mandibular advancement device, often combined with weight loss therapy. Weight reduction is usually an adjunct therapy but may be used as a secondary treatment in mild-to-moderate OSA when mechanical treatments cannot be tolerated. To enhance the uptake and adherence to treatment, clinicians may assess patient's personality profiles and psychological readiness. There is a paucity of evidence related to these aspects of patient care and this article outlines the current research in relation to patient presentation, treatment uptake and barriers, and methods to enhance treatment adherence.This article disseminates personality traits observed in patients with OSA and identifies vulnerable groups who may require additional support to increase treatment adherence. It summarises the current evidence for treatment barriers in patients with OSA. Low self-efficacy in relation to CPAP and weight loss adherence will be explored as well as the potential to predict treatment responders and enhance therapeutic uptake and adherence. Extending personality traits into research and clinical practice could potentially result in more successful CPAP therapy and weight loss treatment outcomes.
Topics: Affect; Continuous Positive Airway Pressure; Health Knowledge, Attitudes, Practice; Humans; Lung; Mental Health; Patient Compliance; Personality; Respiration; Self Care; Self Efficacy; Sleep; Sleep Apnea, Obstructive; Treatment Outcome; Weight Loss
PubMed: 31243095
DOI: 10.1183/16000617.0005-2019 -
Sensors (Basel, Switzerland) Apr 2022Continuous positive airway pressure (CPAP) telemonitoring (TMg) has become widely implemented in routine clinical care. Objective measures of CPAP compliance, residual... (Review)
Review
Continuous positive airway pressure (CPAP) telemonitoring (TMg) has become widely implemented in routine clinical care. Objective measures of CPAP compliance, residual respiratory events, and leaks can be easily monitored, but limitations exist. This review aims to assess the role of TMg in CPAP-treated obstructive sleep apnea (OSA) patients. We report recent data related to the accuracy of parameters measured by CPAP and try to determine the role of TMg in CPAP treatment follow-up, from the perspective of both healthcare professionals and patients. Measurement and accuracy of CPAP-recorded data, clinical management of these data, and impacts of TMg on therapy are reviewed in light of the current literature. Moreover, the crucial questions of who and how to monitor are discussed. TMg is a useful tool to support, fine-tune, adapt, and control both CPAP efficacy and compliance in newly-diagnosed OSA patients. However, clinicians should be aware of the limits of the accuracy of CPAP devices to measure residual respiratory events and leaks and issues such as privacy and cost-effectiveness are still a matter of concern. The best methods to focus our efforts on the patients who need TMg support should be properly defined in future long-term studies.
Topics: Continuous Positive Airway Pressure; Follow-Up Studies; Humans; Monitoring, Physiologic; Patient Compliance; Sleep Apnea, Obstructive
PubMed: 35408395
DOI: 10.3390/s22072782 -
Obesity (Silver Spring, Md.) Jan 2015The National Institutes of Health, led by the National Heart, Lung, and Blood Institute, organized a working group of experts to discuss the problem of weight regain... (Review)
Review
OBJECTIVES
The National Institutes of Health, led by the National Heart, Lung, and Blood Institute, organized a working group of experts to discuss the problem of weight regain after weight loss. A number of experts in integrative physiology and behavioral psychology were convened with the goal of merging their perspectives regarding the barriers to scientific progress and the development of novel ways to improve long-term outcomes in obesity therapeutics. The specific objectives of this working group were to: (1) identify the challenges that make maintaining a reduced weight so difficult; (2) review strategies that have been used to improve success in previous studies; and (3) recommend novel solutions that could be examined in future studies of long-term weight control.
RESULTS
Specific barriers to successful weight loss maintenance include poor adherence to behavioral regimens and physiological adaptations that promote weight regain. A better understanding of how these behavioral and physiological barriers are related, how they vary between individuals, and how they can be overcome will lead to the development of novel strategies with improved outcomes.
CONCLUSIONS
Greater collaboration and cross-talk between physiological and behavioral researchers is needed to advance the science and develop better strategies for weight loss maintenance.
Topics: Biomedical Research; Body Weight; Health Behavior; Humans; National Institutes of Health (U.S.); Obesity; Patient Compliance; Research Report; Therapies, Investigational; United States; Weight Loss
PubMed: 25469998
DOI: 10.1002/oby.20967