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Advances in Physiology Education Dec 2017Learning the basic competencies of critical thinking are very important in the education of any young scientist, and teachers must be prepared to help students develop a... (Review)
Review
Learning the basic competencies of critical thinking are very important in the education of any young scientist, and teachers must be prepared to help students develop a valuable set of analytic tools. In my experience, this is best achieved by encouraging students to study areas with little scientific consensus, such as the control mechanisms of the exercise ventilatory response, as it can allow greater objectivity when evaluating evidence, while also giving students the freedom to think independently and problem solve. In this article, I discuss teaching strategies by which physiology, biomedical science, and sport science students can simultaneously develop their understanding of respiratory control mechanisms and learn to critically analyze evidence thoroughly. This can be best achieved by utilizing both teacher-led and student-led learning environments, the latter of which encourages the development of learner autonomy and independent problem solving. In this article, I also aim to demonstrate a systematic approach of critical assessment that students can be taught, adapt, and apply independently. Among other things, this strategy involves: ) defining the precise phenomenon in question; ) understanding what investigations must demonstrate to explain the phenomenon and its underlying mechanisms; ) evaluating the explanations/mechanisms of the phenomenon and the evidence for them; and ) forming strategies to produce strong evidence, if none exists.
Topics: Exercise; Humans; Physiology; Problem Solving; Pulmonary Ventilation; Thinking
PubMed: 29066604
DOI: 10.1152/advan.00086.2017 -
PloS One 2024The Incentive Spirometer (IS) increases lung volume and improves gas exchange by visually stimulating patients to take slow, deep breaths. It prevents respiratory... (Comparative Study)
Comparative Study
Comparative analysis of pulmonary ventilation distribution between low-cost and branded incentive spirometers using electrical impedance tomography in healthy adults: Study protocol.
BACKGROUND
The Incentive Spirometer (IS) increases lung volume and improves gas exchange by visually stimulating patients to take slow, deep breaths. It prevents respiratory complications and treats postoperative atelectasis in patients undergoing abdominal, thoracic, and neurosurgical procedures. Its effectiveness has been validated in studies that support improved lung capacities and volumes in individuals with respiratory complications, postoperative thoracic surgery, upper abdominal surgery, and bariatric surgery. The modified Pachón incentive spirometer (MPIS) is a cost-effective alternative to branded IS. It is crucial to validate whether the MPIS distributes ventilation as effectively as commercial devices do. Ventilation distribution will be measured using electrical impedance tomography.
OBJECTIVE
The aim is to compare the distribution of pulmonary ventilation between the MPIS and another commercial IS in healthy adults using electrical impedance tomography.
METHODS
A crossover clinical trial is proposed to evaluate the measurement of pulmonary ventilation distribution using EIT in a sample of healthy adults. All participants will use a commercial flow IS and the MPIS, with the order of assignment randomized. This research will use electrical impedance tomography to validate the operation of the MPIS.
CONCLUSIONS
This study protocol will compare two incentive spirometers' impact on pulmonary ventilation, potentially endorsing the adoption of a cost-effective device to enhance accessibility for targeted populations.
TRIAL REGISTRATION
The study was registered in ClinicalTrials.gov (NTC05532748).
Topics: Humans; Electric Impedance; Adult; Spirometry; Tomography; Pulmonary Ventilation; Male; Female; Healthy Volunteers; Cross-Over Studies; Lung; Middle Aged; Young Adult
PubMed: 38709742
DOI: 10.1371/journal.pone.0302476 -
Experimental Physiology Feb 2020What is the central question of this study? Acetazolamide and methazolamide both reduce hypoxic pulmonary vasoconstriction equally, but methazolamide does not impair... (Comparative Study)
Comparative Study Randomized Controlled Trial
NEW FINDINGS
What is the central question of this study? Acetazolamide and methazolamide both reduce hypoxic pulmonary vasoconstriction equally, but methazolamide does not impair skeletal muscle function. The effect of methazolamide on respiratory control in humans is not yet known. What is the main finding and its importance? Similar to acetazolamide after chronic oral administration, methazolamide causes a metabolic acidosis and shifts the ventilatory CO response curve leftwards without reducing O sensitivity. The change in ventilation over the change in log provides a more accurate measure of hypoxic sensitivity than the change in ventilation over the change in arterial oxyhaemoglobin saturation.
ABSTRACT
Acetazolamide is used to prevent/treat acute mountain sickness and both central and obstructive sleep apnoea. Methazolamide, like acetazolamide, reduces hypoxic pulmonary vasoconstriction, but has fewer side-effects, including less impairment of skeletal muscle function. Given that the effects of methazolamide on respiratory control in humans are unknown, we compared the effects of oral methazolamide and acetazolamide on ventilatory control and determined the ventilation-log relationship in humans. In a double-blind, placebo-controlled, randomized cross-over design, we studied the effects of acetazolamide (250 mg three times daily), methazolamide (100 mg twice daily) and placebo in 14 young male subjects who were exposed to 7 min of normoxic hypercapnia and to three levels of eucapnia and hypercapnic hypoxia. With placebo, methazolamide and acetazolamide, the CO sensitivities were 2.39 ± 1.29, 3.27 ± 1.82 and 2.62 ± 1.79 l min mmHg (n.s.) and estimated apnoeic thresholds 32 ± 3, 28 ± 3 and 26 ± 3 mmHg, respectively (P < 0.001, placebo versus methazolamide and acetazolamide). The relationship between ventilation ( ) and log (using arterialized venous in hypoxia) was linear, and neither agent influenced the relationship between hypoxic sensitivity ( ) and arterial [H ]. Using rather than Δ /Δ arterial oxyhaemoglobin saturation enables a more accurate estimation of oxygenation and ventilatory control in metabolic acidosis/alkalosis when right- or leftward shifts of the oxyhaemoglobin saturation curve occur. Given that acetazolamide and methazolamide have similar effects on ventilatory control, methazolamide might be preferred for indications requiring the use of a carbonic anhydrase inhibitor, avoiding some of the negative side-effects of acetazolamide.
Topics: Acetazolamide; Adult; Carbonic Anhydrase Inhibitors; Cross-Over Studies; Double-Blind Method; Humans; Male; Methazolamide; Pulmonary Ventilation; Respiration; Young Adult
PubMed: 31595565
DOI: 10.1113/EP088058 -
Magnetic Resonance in Medicine Jan 2017To present an improved and robust method of pulmonary function assessment from time-resolved proton MRI using a matrix pencil (MP) method in combination with a linear...
PURPOSE
To present an improved and robust method of pulmonary function assessment from time-resolved proton MRI using a matrix pencil (MP) method in combination with a linear least squares analysis.
METHODS
Simulations of the signal time course in lung parenchyma were performed to compare the accuracy of Fourier decomposition (FD) and MP methods for the estimation of respiratory and cardiac amplitudes. Series of two-dimensional time-resolved lung images were acquired in healthy volunteers at 1.5 T using ultra-fast steady-state free precession. Qualitative lung ventilation- and perfusion-weighted images as well as a quantitative map of fractional ventilation, perfusion, and blood arrival time were calculated using the proposed MP method and compared with the contemporary FD technique. A region-of-interest analysis was performed on the quantitative data.
RESULTS
The signal analysis performed using MP decomposition resulted in reduced variability of the estimated respiratory and cardiac amplitudes in comparison with FD for both simulated and in vivo data.
CONCLUSION
MP decomposition provides an automatic, robust, and more accurate estimation of amplitudes of respiratory and cardiac signal modulations in the lung parenchyma than the contemporary FD technique. Magn Reson Med 77:336-342, 2017. © 2016 Wiley Periodicals, Inc.
Topics: Algorithms; Computer Simulation; Fourier Analysis; Humans; Image Processing, Computer-Assisted; Least-Squares Analysis; Lung; Magnetic Resonance Imaging; Perfusion Imaging; Pulmonary Ventilation
PubMed: 26757102
DOI: 10.1002/mrm.26096 -
Magnetic Resonance in Medicine Oct 2019To improve the robustness of pulmonary ventilation- and perfusion-weighted imaging with Fourier decomposition (FD) MRI in the presence of respiratory and cardiac...
PURPOSE
To improve the robustness of pulmonary ventilation- and perfusion-weighted imaging with Fourier decomposition (FD) MRI in the presence of respiratory and cardiac frequency variations by replacing the standard fast Fourier transform with the more general nonuniform Fourier transform.
THEORY AND METHODS
Dynamic coronal single-slice MRI of the thorax was performed in 11 patients and 5 healthy volunteers on a 1.5T whole-body scanner using a 2D ultra-fast balanced steady-state free-precession sequence with temporal resolutions of 4-9 images/s. For the proposed nonuniform Fourier-decomposition (NUFD) approach, the original signal with variable physiological frequencies that was acquired with constant sampling rate was retrospectively transformed into a signal with (ventilation or perfusion) frequency-adapted sampling rate. For that purpose, frequency tracking was performed with the synchro-squeezed wavelet transform. Ventilation- and perfusion-weighted NUFD amplitude and signal delay maps were generated and quantitatively compared with regularly sampled FD maps based on their signal-to-noise ratio (SNR).
RESULTS
Volunteers and patients showed statistically significant increases of SNR in frequency-adapted NUFD results compared to regularly sampled FD results. For ventilation data, the mean SNR increased by and in volunteers and patients, respectively; for perfusion data, SNR increased by and . Two patients showed perfusion signal in pulmonary areas with NUFD that could not be imaged with FD.
CONCLUSION
This study demonstrates that using nonuniform Fourier transform in combination with frequency tracking can significantly increase SNR and reduce frequency overlaps by collecting the signal intensity onto single frequency bins.
Topics: Adult; Aged; Aged, 80 and over; Female; Fourier Analysis; Humans; Image Processing, Computer-Assisted; Lung; Magnetic Resonance Imaging; Male; Middle Aged; Perfusion Imaging; Pulmonary Ventilation; Signal-To-Noise Ratio
PubMed: 31111551
DOI: 10.1002/mrm.27803 -
Sensors (Basel, Switzerland) May 2024Regional lung ventilation assessment is a critical tool for the early detection of lung diseases and postoperative evaluation. Biosensor-based impedance measurements,...
Regional lung ventilation assessment is a critical tool for the early detection of lung diseases and postoperative evaluation. Biosensor-based impedance measurements, known for their non-invasive nature, among other benefits, have garnered significant attention compared to traditional detection methods that utilize pressure sensors. However, solely utilizing overall thoracic impedance fails to accurately capture changes in regional lung air volume. This study introduces an assessment method for lung ventilation that utilizes impedance data from the five lobes, develops a nonlinear model correlating regional impedance with lung air volume, and formulates an approach to identify regional ventilation obstructions based on impedance variations in affected areas. The electrode configuration for the five lung lobes was established through numerical simulations, revealing a power-function nonlinear relationship between regional impedance and air volume changes. An analysis of 389 pulmonary function tests refined the equations for calculating pulmonary function parameters, taking into account individual differences. Validation tests on 30 cases indicated maximum relative errors of 0.82% for FVC and 0.98% for FEV1, all within the 95% confidence intervals. The index for assessing regional ventilation impairment was corroborated by CT scans in 50 critical care cases, with 10 validation trials showing agreement with CT lesion localization results.
Topics: Humans; Electric Impedance; Lung; Respiratory Function Tests; Pulmonary Ventilation; Male; Female; Middle Aged; Adult; Aged; Tomography, X-Ray Computed; Biosensing Techniques; Electrodes
PubMed: 38794056
DOI: 10.3390/s24103202 -
Wiley Interdisciplinary Reviews.... Mar 2017The ongoing process of breathing underlies the gas exchange essential for mammalian life. Each respiratory cycle ensues from the activity of rhythmic neural circuits in... (Review)
Review
The ongoing process of breathing underlies the gas exchange essential for mammalian life. Each respiratory cycle ensues from the activity of rhythmic neural circuits in the brainstem, shaped by various modulatory signals, including mechanoreceptor feedback sensitive to lung inflation and chemoreceptor feedback dependent on gas composition in blood and tissues. This paper reviews a variety of computational models designed to reproduce experimental findings related to the neural control of breathing and generate predictions for future experimental testing. The review starts from the description of the core respiratory network in the brainstem, representing the central pattern generator (CPG) responsible for producing rhythmic respiratory activity, and progresses to encompass additional complexities needed to simulate different metabolic challenges, closed-loop feedback control including the lungs, and interactions between the respiratory and autonomic nervous systems. The integrated models considered in this review share a common framework including a distributed CPG core network responsible for generating the baseline three-phase pattern of rhythmic neural activity underlying normal breathing. WIREs Syst Biol Med 2017, 9:e1371. doi: 10.1002/wsbm.1371 For further resources related to this article, please visit the WIREs website.
Topics: Animals; Brain Stem; Central Pattern Generators; Computer Simulation; Models, Neurological; Pulmonary Gas Exchange; Pulmonary Ventilation; Respiration
PubMed: 28009109
DOI: 10.1002/wsbm.1371 -
Proceedings of the American Thoracic... 2005With the emergence of multidetector-row computed tomography (CT) it is now possible to image both structure and function via use of a single imaging modality.... (Review)
Review
With the emergence of multidetector-row computed tomography (CT) it is now possible to image both structure and function via use of a single imaging modality. Breath-hold spiral CT provides detail of the airway and vascular trees along with texture reflective of the state of the lung parenchyma. Use of stable xenon gas wash-in and/or wash-out methods using an axial mode of the CT scanner whereby images are acquired through gating to the respiratory cycle provide detailed images of regional ventilation with isotropic voxel dimensions now on the order of 0.4 mm. Axial scanning during a breath hold and gating to the electrocardiogram during the passage of a sharp bolus injection of iodinated contrast agent provide detailed images of regional pulmonary perfusion. These dynamic CT methods for the study of regional lung function are discussed in the context of other methods that have been used to study heterogeneity of lung function.
Topics: Animals; Humans; Lung Diseases; Mice; Pulmonary Circulation; Pulmonary Ventilation; Tomography, X-Ray Computed; Xenon Radioisotopes
PubMed: 16352755
DOI: 10.1513/pats.200509-099DS -
American Family Physician Mar 2004Spirometry is a powerful tool that can be used to detect, follow, and manage patients with lung disorders. Technology advancements have made spirometry much more... (Review)
Review
Spirometry is a powerful tool that can be used to detect, follow, and manage patients with lung disorders. Technology advancements have made spirometry much more reliable and relatively simple to incorporate into a routine office visit. However, interpreting spirometry results can be challenging because the quality of the test is largely dependent on patient effort and cooperation, and the interpreter's knowledge of appropriate reference values. A simplified and stepwise method is key to interpreting spirometry. The first step is determining the validity of the test. Next, the determination of an obstructive or restrictive ventilatory patten is made. If a ventilatory pattern is identified, its severity is graded. In some patients, additional tests such as static lung volumes, diffusing capacity of the lung for carbon monoxide, and bronchodilator challenge testing are needed. These tests can further define lung processes but require more sophisticated equipment and expertise available only in a pulmonary function laboratory.
Topics: Family Practice; Humans; Office Visits; Pulmonary Ventilation; Respiratory Tract Diseases; Spirometry; Terminology as Topic
PubMed: 15023009
DOI: No ID Found -
Magnetic Resonance in Medicine Jan 2005Increasing use of transgenic animal models for pulmonary disease has raised the need for methods to assess pulmonary structure and function in a physiologically stable...
Increasing use of transgenic animal models for pulmonary disease has raised the need for methods to assess pulmonary structure and function in a physiologically stable mouse. We report here an integrated protocol using magnetic resonance microscopy with gadolinium (Gd)-labeled starburst dendrimer (G6-1B4M-Gd, MW = 192 +/- 1 kDa, R(h) = 5.50 +/- 0.04 nm) and hyperpolarized (3)helium ((3)He) gas to acquire images that demonstrate pulmonary vasculature and ventilated airways in live mice (n = 9). Registered three-dimensional images of (1)H and (3)He were acquired during breath-hold at 2.0 T using radial acquisition (total acquisition time of 38 and 25 min, respectively). The macromolecular Gd-labeled dendrimer (a half-life of approximately 80 min) increased the signal-to-noise by 81 +/- 30% in the left ventricle, 43 +/- 22% in the lung periphery, and -4 +/- 5% in the chest wall, thus increasing the contrast of these structures relative to the less vascular surrounding tissues. A constant-flow ventilator was developed for the mouse to deliver varied gas mixtures of O(2) and N(2) (or (3)He) during imaging. To avoid hypoxemia, instrumental dead space was minimized and corrections were made to tidal volume lost due to gas compression. The stability of the physiologic support was assessed by the lack of spontaneous breathing and maintenance of a constant heart rate. We were able to stabilize the mouse for >8 hr using ventilation of 105 breath/min and approximately 0.2 mL/breath. The feasibility of acquiring both pulmonary vasculature and ventilated airways was demonstrated in the mouse lung with in-plane spatial resolution of 70 x 70 microm(2) and slice thickness of 800 microm.
Topics: Anesthesia; Animals; Contrast Media; Imaging, Three-Dimensional; Lung; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Male; Mice; Mice, Inbred C57BL; Pulmonary Ventilation; Respiration, Artificial; Ventilation-Perfusion Ratio
PubMed: 15690504
DOI: 10.1002/mrm.20307