Quiet Breathing Research Articles

Pelvic floor muscle length changes with breathing in males: A preliminary report

The study aimed to identify whether pelvic floor muscles modulate length with breathing, and if any length changes induced by breathing relate to abdominal cavity displacement and intra-abdominal pressure. To investigate these relationships, displacement of pelvic landmarks that related to pelvic floor muscle length using transperineal ultrasound imaging, breath volume, intra-abdominal pressure, abdominal and ribcage displacement, and abdominal and anal sphincter muscle electromyography were measured during quiet breathing and breathing with increased dead-space in ten healthy men. Pelvic floor muscle landmark displacement modulated with ribcage motion during breathing. This relationship was stronger for: i) motion of the urethrovesical junction (puborectalis muscle length change) than the mid-urethra landmark (striated urethral sphincter muscle length change), and ii) dead-space breathing in standing than dead-space breathing in supine or quiet breathing in standing. In most (but not all) participants, the urethrovesical junction descended during inspiration and elevated during expiration. Striated urethral sphincter length changes during the respiratory cycle was independent of intra-abdominal pressure. In summary, breathing involves pelvic floor muscle length changes and is consistent with the role of these muscles during respiration to aid maintenance of continence, lung ventilation and/or provision of support to the abdominal cavity. Clinicians who train pelvic floor muscles need to be aware that length change of pelvic floor muscles is expected with breathing.

The Influence of Breathing Exercises on Regional Ventilation in Healthy and Patients with Chronic Obstructive Pulmonary Disease

We hypothesized that the respiratory exercises have uniform effects on ventilation in healthy subjects but the effects varied in patients with chronic obstructive pulmonary disease (COPD). In this study, a total of 30 healthy volunteers and 9 patients with COPD were included. Data were recorded continuously during (1) diaphragmatic breathing; (2) pursed lip breathing with full inhalation; (3) pursed lip combining diaphragmatic breathing. The sequence of the three breathing exercises was randomized using machine generated random permutation. Spatial and temporal ventilation distributions were evaluated with electrical impedance tomography. Results showed that, tidal volume was significantly larger during various breathing exercises compared to quiet tidal breathing, in both healthy and COPD (p < 0.01). However, for other EIT-based parameters, statistical significances were only observed in healthy volunteers, not in patients. Diaphragmatic breathing alone might not be able to decrease functional residual capacity in COPD and the effect varied largely from patient to patient (6:3, decrease vs. increase). Ventilation distribution moved toward ventral regions in healthy during breathing exercises (p < 0.0001). Although this trend was observed in the COPD, the differences were not significant. Ventilation became more homogeneous when diaphragmatic breathing technique was implemented (p < 0.0001). Again, the improvements were not significant in COPD. Regional ventilation delay was relatively high in COPD and comparable in various breathing periods. In conclusions, the impact of pursed lip and diaphragmatic breathing varied in different patients with COPD. Breathing exercise may need to be individualized to maximize the training efficacy with help of EIT.

Impaired diaphragmatic motility in treatment-naive adult patients with spinal muscular atrophy improved during nusinersen treatment.

The leading clinical feature of 5q-associated spinal muscular atrophy (SMA) is symmetric, proximal muscle weakness. Muscles involved in ventilation exhibit a specific pattern of denervation: intercostal muscles are severely atrophic, whereas the diaphragm muscle is less affected. The aim of this study was to investigate the involvement of diaphragmatic function by ultrasound imaging in adult patients with SMA and to quantify dynamics of diaphragmatic function during nusinersen treatment. Diaphragmatic thickness, thickening, and excursion during quiet breathing were assessed in 24 adult patients with SMA type 2 and 3 by diaphragm ultrasound imaging before and during nusinersen treatment and were correlated with spirometric parameters. Diaphragm thickness was not reduced, but increased in a remarkable proportion of patients, whereas diaphragm thickening and excursion were reduced in about 20% to 30% of nusinersen-naive, adult patients with SMA types 2 and 3. During 26 months of nusinersen treatment, diaphragm thickening fraction and excursion improved. Diaphragm ultrasound imaging can provide disease- and treatment-relevant information that is not identified during routine clinical assessments and may therefore be a valuable complementary outcome measure.

Interaction of breathing pattern and posture on abdominal muscle activation and intra-abdominal pressure in healthy individuals: a comparative cross-sectional study

We aimed to assess the effects of interaction between several breathing patterns and postures on abdominal muscle activation and intra-abdominal pressure (IAP). This comparative cross-sectional study enrolled fourteen healthy university students majoring in sports science and/or physical education. They performed four active breathing tasks: quiet nasal breathing (Q-Bre), nasal deep breathing (Deep-Bre), completely forced expiration (Forced-Expi), and exertional nasal inhalation with abdominal muscles with isometric contraction (Exertion-Inspi) in the elbow-toe plank and supine postures. Breathing volume; IAP; and transverse abdominis-internal oblique muscle (TrA-IO) and external oblique muscle (EO) activities were recorded. Abdominal muscle activity and IAP significantly interacted with breathing pattern and postures during the expiratory phase (p < 0.05). In the inspiratory phase, TrA-IO activity was significantly affected by breathing pattern and EO activity with posture (p < 0.05). TrA-IO activity significantly increased during Forced-Expi in the supine posture (47.6% of the maximum voluntary contraction) and Exertion-Inspi in the elbow-toe posture (35.7%), whereas no differences were found during Deep-Bre or Q-Bre (< 20%). EO activity increased in the elbow-toe posture (22.5–30.6%) compared with that in the supine posture (< 5%) during all breathing tasks. IAP values were low during all tasks (< 15%) except for Forced-Expi (24.9%). Abdominal muscle activation and IAP interacted with the breathing pattern and posture.

Effect of bronchial thermoplasty on static and dynamic lung compliance and resistance in patients with severe persistent asthma

RationaleBronchial thermoplasty (BT) reduces severity and frequency of bronchoconstriction and symptoms in severe, persistent asthmatics although it is usually not associated with change in spirometric variables. Other than spirometry. there are almost no data on changes in lung mechanics following BT. ObjectiveTo assess lung static and dynamic lung compliance (Cst,L and Cdyn,L, respectively) and static and dynamic lung resistance (Rst,L and Rdyn,L, respectively) before and after BT in severe asthmatics using the esophageal balloon technique. MethodsRdyn,L and Cdyn,L were measured at respiratory frequencies up to 145 breaths/min, using the esophageal balloon technique in 7 patients immediately before and 12–50 weeks after completing a series of 3 BT sessions. ResultsAll patients experienced improved symptoms within a few weeks following completion of BT. Pre-BT, all patients exhibited frequency dependency of lung compliance, with mean Cdyn,L decreasing to 63% of Cst,L at maximum respiratory rates. Post-BT, Cst,L did not change significantly from pre-thermoplasty values, while Cdyn,L diminished to 62%% of Cst,L. In 4 of 7 patients, post-BT values of Cdyn,L were consistently higher than pre-BT over the range of respiratory rates. RL in 4 of 7 patients during quiet breathing and at higher respiratory frequencies decreased following BT. ConclusionsPatients with severe persistent asthma exhibit increased resting lung resistance and frequency dependence of compliance, the magnitudes of which are ameliorated in some patients following bronchial thermoplasty and associated with variable change in frequency dependence of lung resistance. These findings are related to asthma severity and may be related to the heterogeneous and variable nature of airway smooth muscle modeling and its response to BT.

FBG-Based Mattress for Heart Rate Monitoring in Different Breathing Conditions

In recent years, extensive investigations have been geared toward finding unobtrusive solutions for monitoring cardiorespiratory activity as an alternative to traditional clinical methods. Among others, the ones based on fiber Bragg grating sensors (FBGs) reveal remarkable promise for monitoring respiratory (RR) and heart rate (HR). The present study investigates the performance of a mattress based on a thirteen FBG-array for HR continuous estimation. Firstly, a metrological characterization was performed to assess system characteristics under frequencies simulating typical HR values (i.e., 60 beats per minute -bpm-, 90 bpm, and 120 bpm). Then, the proposed device was tested on eight healthy volunteers (both males and females) in the presence of different breathing stages (i.e., quiet breathing and tachypnea) and while mimicking common sleeping postures (i.e., supine, left side, and prone). The assessment of HR measurements under different breathing regimes and postures has rarely been addressed in FBG-based technologies. The achieved results suggest the proposed mattress has promising capability in reliably estimating HR values. These results together with the ones obtained in terms of RR monitoring in a recent study reveal the high potential for monitoring cardiorespiratory activity.

Quantification of False Vocal Fold Hyperfunction During Quiet Breathing in Muscle Tension Dysphonia.

False vocal fold (FVF) hyperfunction during phonation is thought to be a diagnostic sign of primary muscle tension dysphonia (pMTD). However, hyperfunctional patterns with phonation are also observed in typical speakers. This study tested the hypothesis that FVF posturing during quiet breathing, as measured by the curvature of FVF, could differentiate patients with pMTD from typical speakers. Laryngoscopic images were collected prospectively in 30 subjects with pMTD and 33 typical speakers. Images were acquired at the end of expiration and maximal inspiration during quiet breathing, during sustained /i/, and during loud phonation before and after a 30-min vocal loading task. The FVF curvature (degree of concavity/convexity) was quantified using a novel curvature index (CI, >0 for hyperfunctional/convex, <0 for "relaxed"/concave) and compared between the two groups. At end-expiration, the pMTD group adopted a convex FVF contour, whereas the control group adopted a concave FVF contour (mean CI 0.123 [SEM 0.046] vs. -0.093 [SEM 0.030], p = 0.0002) before vocal loading. At maximal inspiration, the pMTD group had a neutral/straight FVF contour, whereas the control group had a concave FVF contour (mean CI 0.012 [SEM 0.038] vs. -0.155 [SEM 0.018], p = 0.0002). There were no statistically significant differences in FVF curvature between groups in either the sustained voiced or loud conditions. Vocal loading did not change any of these relationships. A hyperfunctional posture of the FVFs during quiet breathing especially at end-expiration may be more indicative of a hyperfunctional voice disorder than supraglottic constriction during voicing. 3 Laryngoscope, 133:3449-3454, 2023.

Aerosol Particle Size Influences the Infectious Dose and Disease Severity in a Golden Syrian Hamster Model of Inhalational COVID-19.

Background: Significant evidence suggests that SARS-CoV-2 can be transmitted via respiratory aerosols, which are known to vary as a function of respiratory activity. Most animal models examine disease presentation following inhalation of small-particle aerosols similar to those generated during quiet breathing or speaking. However, despite evidence that particle size can influence dose-infectivity relationships and disease presentation for other microorganisms, no studies have examined the infectivity of SARS-CoV-2 contained in larger particle aerosols similar to those produced during coughing, singing, or talking. Therefore, the aim of the present study was to assess the influence of aerodynamic diameter on the infectivity and virulence of aerosols containing SARS-CoV-2 in a hamster model of inhalational COVID-19. Methods: Dose-response relationships were assessed for two different aerosol particle size distributions, with mass median aerodynamic diameters (MMADs) of 1.3 and 5.2 μm in groups of Syrian hamsters exposed to aerosols containing SARS-CoV-2. Results: Disease was characterized by viral shedding in oropharyngeal swabs, increased respiratory rate, decreased activity, and decreased weight gain. Aerosol particle size significantly influenced the median doses to induce seroconversion and viral shedding, with both increasing ∼30-fold when the MMAD was increased. In addition, disease presentation was dose-dependent, with seroconversion and viral shedding occurring at lower doses than symptomatic disease characterized by increased respiratory rate and decreased activity. Conclusions: These results suggest that aerosol particle size may be an important factor influencing the risk of COVID-19 transmission and needs to be considered when developing animal models of disease. This result agrees with numerous previous studies with other microorganisms and animal species, suggesting that it would be generally translatable across different species. However, it should be noted that the absolute magnitude of the observed shifts in the median doses obtained with the specific particle sizes utilized herein may not be directly applicable to other species.

Respiratory Movements at Different Ages.

Background and Objectives: The current study aimed to better understand the changes in respiration that occur with aging in men and women to provide accurate recommendations for breathing exercises to improve health. Materials and Methods: A total of 610 healthy subjects, aged 20 to 59, participated in the study. They performed quiet breathing while wearing two respiration belts (Vernier, Beaverton, OR, USA) at the height of the navel and at the xiphoid process to record abdominal motion (AM) and thoracic motion (TM), respectively. Vital capacity, representing maximal inhalation movement, was measured using a spirometer (Xindonghuateng, Beijing, China). After exclusion, 565 subjects (164 men, aged 41 ± 11; 401 women, aged 42 ± 9) were included for statistical analysis using the Kruskal-Wallis U test and stepwise multiple linear regression. Results: Abdominal motion and its contribution to spontaneous breathing were significantly larger for older men, while the contribution of thoracic motion was smaller for older men. There was no significant difference in thoracic motion between the younger and older men. The differences in women's respiratory movements among various ages were mild and negligible. The contribution of thoracic motion to spontaneous breathing in women was larger than in men for those of older ages (40-59 years), but not for those of younger ages (20-39 years). Additionally, men's and women's vital capacities were less in those of older ages, and the men's were larger than the women's. Conclusions: The findings indicate that men's abdominal contribution to spontaneous breathing increased from 20 to 59 years of age due to increased abdominal motion. Women's respiratory movements did not change much with aging. The maximal inhalation movement became smaller with aging for men and women. Healthcare professionals should focus on improving thoracic mobility when addressing health concerns about aging.

Normative data for certain vocal fold biomarkers among young normophonic adults using ultrasonography

PurposeThe current study aimed to profile vocal fold morphology, vocal fold symmetry, gender and task-specific data for vocal fold length (VFL) and vocal fold displacement velocity (VFDV) in young normophonic adults in the age range of 18–30 years using ultrasonography (USG).MethodsParticipants underwent USG across quiet breathing, /a/ phonation and /i/ phonation tasks, and acoustic analysis was conducted to explore the relationship between USG and acoustic measures.ResultsThe study found that males have longer vocal folds than females, and overall greater velocities were observed in /a/ phonation, followed by /i/ phonation, with the lowest velocity observed in the quiet breathing task.ConclusionsThe obtained norms can be used as a quantitative benchmark for analyzing the vocal fold behavior in young adults.

Ultrasound assessment of the respiratory system using diaphragm motion-volume indices.

Although previous studies have determined limit values of normality for diaphragm excursion and thickening, it would be beneficial to determine the normal diaphragm motion-to-inspired volume ratio that integrates the activity of the diaphragm and the quality of the respiratory system. To determine the normal values of selected ultrasound diaphragm motion-volume indices, subjects with normal pulmonary function testing were recruited. Ultrasound examination recorded diaphragm excursion on both sides during quiet breathing and deep inspiration. Diaphragm thickness was also measured. The inspired volumes of the corresponding cycles were systematically recorded using a spirometer. The indices were calculated using the ratio excursion, or percentage of thickening, divided by the corresponding breathing volume. From this corhort, normal values and limit values for normality were determined. These measurements were compared to those performed on the healthy side in patients with hemidiaphragm paralysis because an increase in hemidiaphragm activity has been previously demonstated in such circumstances. A total of 122 subjects (51 women, 71 men) with normal pulmonary function were included in the study. Statistical analysis revealed that the ratio of excursion, or percentage of thickening, to inspired volume ratio significantly differed between males and females. When the above-mentioned indices using excursion were normalized by body weight, no gender differences were found. The indices differed between normal respiratory function subjects and patients with hemidiaphragm paralysis (27 women, 41 men). On the paralyzed side, the average ratio of the excursion divided by the inspired volume was zero. On the healthy side, the indices using the excursion and the percentage of thickening during quiet breathing or deep inspiration were significantly increased comparedto patients with normal lung function. According to the logistic regression analysis, the most relevant indice appeared to be the ratio of the excursion measured during quiet breathing to the inspired volume. The normal values of the diaphragm motion-volume indices could be useful to estimate the performance of the respiratory system. Proposed indices appear suitable in a context of hyperactivity.

The effectiveness of the respiratory muscles in children with oncohematological diseases after hematopoietic stem cell transplantation

The article analyzes the effectiveness of the respiratory muscles by measuring inspiratory mouth occlusion pressure at 0.1 seconds during quiet breathing (P0.1) and maximum voluntary ventilation maneuver (P0.1 max ) in children with acute leukemia and acquired idiopathic aplastic anemia after allogeneic hematopoietic stem cell transplantation (HSCT). We carried out a comparative analysis of the Р0.1 and Р0.1 max values measured before HSCТ and on days +30, +90, +180 and +360. In a group of patients with acquired idiopathic aplastic anemia, we revealed a significant decrease in these values starting from day +30, followed by a recovery to baseline values by one year of follow-up. In children with acute leukemia, effectiveness of the respiratory muscles was increased after 360 days of transplantation as a result of the aggravation of impaired ventilation. This method for measuring airway occlusion pressure can be used in a comprehensive assessment of the functional state of the respiratory system for the timely diagnosis of pulmonary complications after HSCT. The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of Ministry of Healthcare of the Russian Federation.

The influence of gravity on electrical impedance tomography measurements during upper body position change

ObjectiveThe aim of the study was to examine the influence of gravity on regional ventilation measured by electrical impedance tomography (EIT) with the standard electrode belt position at the 5th intercostal space during tilting from supine to sitting positions. MethodsA total of 30 healthy volunteers were examined prospectively in supine position during quiet tidal breathing. Subsequently, the bed was tilted so that the upper body of the subjects achieved 30, 60 and 90° every 3 min. Regional ventilation distribution and end-expiratory lung impedance (EELI) were monitored with EIT throughout the whole experiment. Absolute tidal volumes were measured with spirometry and the volume-impedance ratio was calculated for each position. ResultsThe volume-impedance ratio did not differ statistically between the studied body positions but 11 subjects exhibited a large change in ratio at one of the positions (outside 99.3% coverage). In general, ventilation distribution became more heterogeneous and moved towards dorsal regions as the upper body was tilted to 90-degree position. EELI increased and tidal volume decreased. The lung regions identified at various positions differed significantly. ConclusionGravity has non-negligible influence on EIT data, as the upper body tilted from supine to sitting positions. The standard electrode belt position might be reconsidered if ventilation distribution is to be compared between supine and sitting positions.

Application of Nanotechnology in a Novel Air Purifier for Remediation of Airborne Pathogen and to Prevent the Spread of COVID-19

The spread of COVID-19 occurs via airborne transmission. With a constant and variable spread of COVID-19, indoor air-quality has become a major concern all over the world. People who are infected with COVID can release particles and droplets of respiratory fluids that contain the SARS CoV-2 virus into the air when they exhale (e.g., quiet breathing, speaking, singing, exercise, coughing, sneezing). Once infectious droplets are exhaled, they move outward from the person (the source) into the surrounding environment; these droplets carry the virus and transmit infection. Indoors, the very fine droplets and particles will continue to spread through the air in the room or space and can accumulate. Harmful pathogenic organisms like fungi, bacteria and viruses, as the one responsible for causing contagious diseases like the ongoing pandemic of COVID-19 can also be successfully destroyed and neutralized. We have developed and studied the efficiency of the AFL Mini Sanifier II® in a simulated environment of a fiberglass chamber using various types of meters to assess the suspended particulate matter (PM) in the ambient air. We also report the development of a novel face mask that was assessed for safety measures and further improvement by the researchers in the West Texas A&amp;M University. The mask is user friendly and portable, equipped with a small internal fan that supplies a continuous air to the user preventing the suffocating effect caused by the other masks. The novel mini air purifier is equipped with the advanced nanotechnology that cleans and sanitizes both the air and surfaces and subsequently has been shown to reduce common allergy, asthma and hay fever related symptoms. This mask and the mini air purifier function in an advanced way to combat all forms of airborne pathogens including the bacteria, viruses, mold spores and harmful Volatile Organic Compounds (VOC) present in the air.

Wearable pulmonary monitoring system with integrated functional lung imaging and chest sound recording: a clinical investigation in healthy subjects

Objective. Current wearable respiratory monitoring devices provide a basic assessment of the breathing pattern of the examined subjects. More complex monitoring is needed for healthcare applications in patients with lung diseases. A multi-sensor vest allowing continuous lung imaging by electrical impedance tomography (EIT) and auscultation at six chest locations was developed for such advanced application. The aims of our study were to determine the vest’s capacity to record the intended bio-signals, its safety and the comfort of wearing in a first clinical investigation in healthy adult subjects. Approach. Twenty subjects (age range: 23–65 years) were studied while wearing the vests during a 14-step study protocol comprising phases of quiet and deep breathing, slow and forced full expiration manoeuvres, coughing, breath-holding in seated and three horizontal postures. EIT, chest sound and accelerometer signals were streamed to a tablet using a dedicated application and uploaded to a back-end server. The subjects filled in a questionnaire on the vest properties using a Likert scale. Main results. All subjects completed the full protocol. Good to excellent EIT waveforms and functional EIT images were obtained in 89% of the subjects. Breathing pattern and posture dependent changes in ventilation distribution were properly detected by EIT. Chest sounds were recorded in all subjects. Detection of audible heart sounds was feasible in 44%–67% of the subjects, depending on the sensor location. Accelerometry correctly identified the posture in all subjects. The vests were safe and their properties positively rated, thermal and tactile properties achieved the highest scores. Significance. The functionality and safety of the studied wearable multi-sensor vest and the high level of its acceptance by the study participants were confirmed. Availability of personalized vests might further advance its performance by improving the sensor-skin contact.

Diaphragmatic ultrasonography in patients with IPF: Is diaphragmatic structure and mobility related to fibrosis severity and pulmonary functional changes?

There is evidence to suggest that dyspnea and impaired exercise capacity are associated with respiratory muscle dysfunction in idiopathic pulmonary fibrosis (IPF) patients. We aimed to evaluate the functions of the diaphragm with ultrasonography (US) and to determine the correlation of the data obtained with the pulmonary function parameters of the patients, exercise capacity, and the extent of fibrosis radiologically. Diaphragmatic mobility, thickness, and thickening fraction (TF) were measured by ultrasonography in IPF patients and the control group. The correlation between these measurements, pulmonary function tests (PFT), six-minute walking test (6MWT), mMRC score, and total fibrosis score (TFS) was evaluated. Forty-one IPF patients and twenty-one healthy volunteers were included in the study. No difference was found between the patient and control groups in diaphragmatic mobility during quiet breathing (QB) on ultrasound (2.35 cm and 2.56 cm; p= 0.29). Diaphragmatic mobility during deep breathing (DB) was found to be lower in the patient group when compared to the control group (5.02 cm and 7.66 cm; p<0.0001). Diaphragmatic thickness was found to be higher during QB and DB in IPF patients (0.33 cm and 0.31 cm, p= 0.043; 0.24 cm and 0.22 cm, p= 0.045). No difference was found between the two groups in terms of thickening fraction (39.37%, 44.16%; p= 0.49). No significant correlation was found between US measurements and PFT, 6MWT, mMRC score, and TFS in IPF patients (p> 0.05). The functions of the diaphragm do not appear to be affected in patients with mild-to-moderate restrictive IPF. This study showed that there was no relationship between diaphragmatic functions and respiratory function parameters and the extent of fibrosis. Further studies, including advanced stages of the disease, are needed to understand the changes in diaphragmatic functions in IPF and to determine whether this change is associated with respiratory function parameters and the extent of fibrosis.

Diaphragm excursion correlates with performance and ventilation on the 6-min walk test in children with sickle cell disease.

Diaphragm function may be impaired in children with sickle cell disease (SCD). We hypothesized that diaphragm function is related to performance and ventilation on the 6-min walk test (6MWT). Respiratory muscle testing, diaphragm ultrasonography, and the 6MWT with portable gas analysis were performed on children with SCD and age- and sex-matched controls. Fourteen children with SCD were enrolled. Comparisons were made between nine children with SCD (9.89 2.93 years) and nine controls (10.33 2.35 years). Diaphragm thickness at total lung capacity, thickening fraction, and excursion time during quiet breaths and deep breaths (DB), all normalized by forced vital capacity, were greater in children with SCD ( 0.05 for all). 6MWT distance was shorter in children with SCD (450.87 74.2 m vs. 579.22 72.46 m, 0.01). Tidal volume ( ), minute ventilation ( ), and oxygen consumption ( ) were also lower ( 0.05 for all). DB excursion correlated positively with 6MWT distance ( 0.648, 0.023) and negatively with rate of perceived exertion (RPE) ( -0.759, 0.003). RPE correlated negatively with distance ( -0.680, 0.015). DB excursion time correlated positively with distance ( 0.611, 0.035), ( 0.770, 0.009), ( 0.736, 0.015), and ( 0.751, 0.012). Increased diaphragm excursion may be a strategy used to relieve air hunger while longer excursion time may reflect compensations to increase lung recruitment. Further studies are needed to better understand how these mechanisms affect exercise tolerance in children with SCD.

Breathing patterns of conversation partners

Previous research has shown that breathing patterns of conversation partners can become synchronized. For example, when one conversation partner is speaking, the listening partner's breathing patterns more closely resemble speech breathing than tidal breathing (McFarland, 2001). The present study aims to replicate and extend these findings using an unconventional instrumental setup consisting of a single inductive plethysmograph machine shared by both conversation partners. In addition to scripted and unscripted conversational speech, single-subject quiet breathing and speech breathing tasks of increasing length and complexity were also recorded using conventional inductive plethysmography, and used as baseline data for interpretating the conversational speech breathing data.

A Recent Update on SARS-CoV-2 Transmission and its Variants: Transmission, Pathogenic Mechanism, and Treatment

Abstract: Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 virus was first reported in China. As of April 17, 2022, over 500 million confirmed cases and over 6 million deaths have been reported worldwide. COVID-19 is transmitted through respiratory droplets and other contact routes in the human community. Fine respiratory droplets and aerosol particles enter into the respiratory tract and come in the contact with mucous membranes. The SARS-CoV-2-containing droplets spread into the environment by quiet breathing, speaking, exercise, coughing, and sneezing of COVID-19-infected individuals. World Health Organization (WHO) have been released several guidelines for controlling COVID-19 which include maintaining personal hygiene, social distance, and COVID-19 vaccination. A higher transmission rate of SARS-CoV-2 has been reported and the transmission rate also depends on several variants of SARS-CoV-2. SARS-CoV-2 genome is a single-stranded positive (+) sense RNA of about 26- 32 kb nucleotides and has 80% similarity to the bat SARS-CoV. SARS-CoV-2 enters the host cell through the interaction between spike proteins of the virus and the host cell surface receptor. Acute Respiratory Distress Syndrome and lung injury lead to the death of SARS-CoV-2-infected people. Several vaccines for COVID-19 have been developed, giving protection from COVID-19 and reducing the transmission rate. Developed vaccines are not 100% effective against SARS-CoV-2 due to variations in the genetic makeup of SARS-CoV-2. Thereby, further research is the need of the hour. This review summarizes SARS-CoV-2 and its several variants and their transmission, genomic characterization, pathogenhost interaction mechanisms, diagnostic methods, and potential treatment approach for SARS-CoV-2.

Ultrasound assessment of the relation between the quantity of pleural effusion and diaphragmatic functions

Background Diaphragm is a necessary respiratory muscle. In cases with pleural effusion, abnormal diaphragmatic functions may be observed. Thoracic ultrasound is a simple, accurate, and noninvasive method to investigate the relation between the quantity of pleural effusion and diaphragmatic functions. Aim The work was done to clarify the relation between the quantity of pleural effusion and diaphragmatic functions using ultrasound. Patients and methods A prospective case–control study, where patients were divided into two groups: GI (cases), 20 patients with pleural effusion for ultrasound evaluation of the relation between the quantity of pleural effusion and diaphragmatic functions, and GII, (controls) 20 healthy volunteers without pleural effusion for ultrasound assessment of diaphragmatic functions. Between 2019 and 2020, clinical assessment, routine investigations, and demographic and radiological data were reviewed for the two groups. Results Thoracic ultrasound for GI at different quantities of pleural effusions revealed significant differences in diaphragmatic functions such as thickness at the end of inspiration, diaphragm thickening fraction, excursion at deep breathing, and excursion at quiet breathing. The statistical comparison of sonographic findings between GI and GII showed significant differences in the thickness at the end of expiration, thickness at the end of inspiration, diaphragmatic thickening fraction, excursion at quiet breathing, and excursion at deep breathing. These changes are proportionate to the quantity of pleural effusion. Conclusion There is an adverse effect of pleural effusion at different quantities on diaphragmatic functions as observed by thoracic ultrasound.