Expiratory Resistance Research Articles

Differences in pulmonary function measured by oscillometry between horses with mild-moderate equine asthma and healthy controls.

The diagnosis of mild-moderate equine asthma (MEA) can be confirmed by airway endoscopy, bronchoalveolar lavage fluid (BALf) cytology, and lung function evaluation by indirect pleural pressure measurement. Oscillometry is a promising pulmonary function test method, but its ability to detect subclinical airway obstruction has been questioned. To evaluate the differences in lung function measured by oscillometry between healthy and MEA-affected horses. Prospective case-control clinical study. Thirty-seven horses were divided into healthy and MEA groups, based on history and clinical score; the diagnosis of MEA was confirmed by airway endoscopy and BALf cytology. Horses underwent oscillometry at frequencies ranging from 2 to 6 Hz. Obtained parameters included whole-breath, inspiratory, expiratory, and the difference between inspiratory and expiratory resistance (Rrs) and reactance (Xrs). Differences between oscillometry parameters at different frequencies were evaluated within and between groups by repeated-measures two-way ANOVA and post hoc tests with Bonferroni correction. Frequency dependence was compared between groups by t test. For significant parameters, a receiver operating characteristics curve was designed, cut-off values were identified and their sensitivity and specificity were calculated. Statistical significance was set at p < 0.05. No significant differences in Xrs and Rrs were observed between groups. The frequency dependence of whole-breath and inspiratory Xrs significantly differed between healthy (respectively, -0.03 ± 0.02 and -0.05 ± 0.02 cmH2O/L/s) and MEA (-0.1 ± 0.03 and -0.2 ± 0.02 cmH2O/L/s) groups (p < 0.05 and p < 0.01). For inspiratory Xrs frequency dependence, a cut-off value of -0.06 cmH2O/L/s was identified, with 86.4% (95% CI: 66.7%-95.3%) sensitivity and 66.7% (95% CI: 41.7%-84.8%) specificity. Sample size, no BALf cytology in some healthy horses. Oscillometry can represent a useful non-invasive tool for the diagnosis of MEA. Specifically, the evaluation of the frequency dependence of Xrs may be of special interest.

Oscillometry Reference Values for Children and Adolescents

BackgroundOscillometry devices allow quantification of respiratory function at tidal breathing but device-specific reference equations are scarce: the present study aims to create sex-specific oscillometric reference values for children and adolescents using the Resmon PRO FULL device.MethodsHealthy participants (N=981) aged 6 to 17 years of the Austrian LEAD general population cohort were included. Subjects had normal weight (BMI≤99th percentile) and normal lung volumes (total lung capacity (TLC)≥lower limit of normal). Oscillometry data were collected using a single frequency mode of 8 Hz. Sex-specific prediction equations were developed for total (tot), inspiratory (insp) and expiratory (exp) resistance (R) and reactance (X) as well as for the modulus of impedance (Z) value using the LMS (lambda, mu, sigma) method. Height was used as a single covariate.ResultsReference equations for all oscillometry parameters were created for Caucasian children aged 6 to 17 years with a height span from 101 to 183 cm and a lung volume span from 1.7 L to 8.8 L TLC. R and Z values progressively decrease and X values increase with increasing height. Oscillometry parametersversuslung volume curves differ from thoseversusheight curves. Stratified for lung size, no sex differences are found for oscillometry parameters.ConclusionOur study provides reference values for oscillometry parameters in children and adolescents using strictly defined criteria for weight and lung volumes. No sex related differences in oscillometry parameters corrected for height or lung size are found.

Airway mechanics alters generation of cough motor pattern.

Effects of sequential increase in airway resistance: no, low (5 kPa.s/l), high (24 kPa.s/l), and complete block in the inspiratory or expiratory phase of mechanically induced cough on the cough motor pattern were studied in 16 anesthetized (pentobarbital) spontaneously breathing cats (3.70±0.15 kg, 11♂, 5♀). Esophageal pressure and electromyographic activities of the diaphragm during inspiration and abdominal muscles during expiration were analyzed. No significant changes in the number of coughs occurred. Inspiratory occlusion caused a prolongation of cough inspiratory phase, cough inspiratory diaphragm activity, and all cough-related activity. Inspiratory occlusion along with high resistance increased inspiratory esophageal pressure amplitude, total cough cycle duration and the time between maximum activity of the diaphragm and abdominal muscles. High expiratory resistance and occlusion resulted in increased cough expiratory esophageal pressure amplitude, a longer active portion of cough expiration, and cough abdominal activity. Expiratory occlusion also prolonged cough expiratory phase, all cough activity, and total cough cycle. Significantly increased airway resistance and occlusion induce secondary, in addition to mechanical, changes in cough by significantly modulating the generated cough motor pattern. A certain level of resistance appears to be successfully compensated, resulting in minimal changes in coughing characteristics, including expiratory airflow and the rising time of the airflow. Afferent feedback from the respiratory tract, particularly volume feedback, represents a significant factor in modulating cough, mainly under various pathological conditions in the respiratory system.

Slowing lung deflation by increasing the expiratory resistance enhances FRC in preterm rabbits.

As very preterm infants have surfactant-deficient and highly incompliant lungs, slowing lung deflation during expiration might help preserve functional residual capacity(FRC) during lung aeration. In this study, we investigated the effect of expiratory resistance(Re) on lung aeration during positive pressure ventilation in preterm rabbits immediately after birth. Preterm rabbit pups were delivered at 29 days gestation, mechanically ventilated from birth and simultaneously imaged to measure lung aeration using phase-contrast X-ray. Re was varied by altering the length (0, 60 or 1000 mm) of the expiratory circuit. Increasing Re led to a decrease in lung deflation rates and both peak expiratory flows and flow rates at mid-deflation. As a result, the rate of de-acceleration(slowing) in lung deflation when approaching FRC was markedly reduced with increasing resistance. During lung aeration, FRC was significantly different between resistance groups and was significantly higher over time in the high compared to the low resistance group. While FRC values tended to be higher with higher Re, they were not significantly different at end-ventilation (t = 7 min). Increasing Re of the ventilation circuit during lung aeration in preterm rabbits immediately after birth decreased lung deflation rates and increased the accumulation of FRC over time. The expiratory phase of the ventilatory cycle has been largely overlooked as an opportunity to improve ventilation in preterm infants after birth. Increasing the expiratory resistance of the ventilator circuit during lung aeration in preterm rabbits immediately after birth markedly decreased lung deflation rates and increased FRC accumulation, compared to a low expiratory resistance. This indicates that ventilation devices that reduce the "work of breathing" by reducing the expiratory resistance, may have the unintended effect of reducing FRC, particularly in extremely preterm infants that have surfactant deficient highly incompliant lungs.

Expiratory flow limitation during mechanical ventilation: real-time detection and physiological subtypes

BackgroundTidal expiratory flow limitation (EFLT) complicates the delivery of mechanical ventilation but is only diagnosed by performing specific manoeuvres. Instantaneous analysis of expiratory resistance (Rex) can be an alternative way to detect EFLT without changing ventilatory settings. This study aimed to determine the agreement of EFLT detection by Rex analysis and the PEEP reduction manoeuvre using contingency table and agreement coefficient. The patterns of Rex were explored.MethodsMedical patients ≥ 15-year-old receiving mechanical ventilation underwent a PEEP reduction manoeuvre from 5 cmH2O to zero for EFLT detection. Waveforms were recorded and analyzed off-line. The instantaneous Rex was calculated and was plotted against the volume axis, overlapped by the flow-volume loop for inspection. Lung mechanics, characteristics of the patients, and clinical outcomes were collected. The result of the Rex method was validated using a separate independent dataset.Results339 patients initially enrolled and underwent a PEEP reduction. The prevalence of EFLT was 16.5%. EFLT patients had higher adjusted hospital mortality than non-EFLT cases. The Rex method showed 20% prevalence of EFLT and the result was 90.3% in agreement with PEEP reduction manoeuvre. In the validation dataset, the Rex method had resulted in 91.4% agreement. Three patterns of Rex were identified: no EFLT, early EFLT, associated with airway disease, and late EFLT, associated with non-airway diseases, including obesity. In early EFLT, external PEEP was less likely to eliminate EFLT.ConclusionsThe Rex method shows an excellent agreement with the PEEP reduction manoeuvre and allows real-time detection of EFLT. Two subtypes of EFLT are identified by Rex analysis.Trial registration: Clinical trial registered with www.thaiclinicaltrials.org (TCTR20190318003). The registration date was on 18 March 2019, and the first subject enrollment was performed on 26 March 2019.

Cardiorespiratory Effects of Yogic Versus Slow Breathing in Individuals with a Spinal Cord Injury: An Exploratory Cohort Study.

Background: An intricate physiological and pathophysiological connection exists between the heart and lungs, which is especially important in individuals with spinal cord injury (SCI). While an exercise intervention may seem the best approach to leverage this relationship, the prior work has shown that, despite numerous health benefits, regular exercise training does not improve cardiorespiratory control in individuals with SCI. Breath training presents an alternative intervention that is uniquely accessible, with yogic breathing directly engaging linked fluctuations in respiration and cardiovascular control. In addition, there is evidence across a range of populations that regular yogic breathing reduces cardiovascular disease risk. It is possible that the chronic decrease in breathing frequency associated with regular yogic breathing, rather than the specific yogic breathing techniques themselves, is the primary contributor to the observed risk reduction. Methods: Therefore, in 12 individuals with traumatic SCI from C4 to T8, the authors compared Unpaced and conventional 0.083 Hz (Slow) paced breathing with various yogic breathing techniques including: (1) inspiratory-expiratory breath holds (i.e., Kumbhaka or "Box Breathing"), (2) extended exhalation (1:2 duty cycle), and (3) expiratory resistance via throat constriction (i.e., Ujjayi). Beat-to-beat heart rate and blood pressure were measured as well as end-tidal CO2 and O2 saturation were measured. Statistical analysis was performed using a one-way repeated-measures analysis of variance with post hoc pairwise t tests corrected for multiple comparisons. Results: As expected, all slow breathing patterns markedly increased respiratory sinus arrhythmia (RSA) compared with Unpaced in all (n = 12) individuals. More importantly, Ujjayi breathing appeared to improve ventilatory efficiency over Unpaced breathing in individuals with SCI by increasing O2 saturation (97.6% vs. 96.1%; p = 0.042) and tended to decrease end-tidal CO2 (32 mmHg vs. 35 mmHg; p = 0.08). While other slow breathing patterns demonstrated similar effects, only Ujjayi improved RSA while increasing heart rate and improving ventilatory efficiency. Conclusions: Hence, slow breathing per se can result in important cardiorespiratory changes, but the yogic breathing practice of Ujjayi, with glottic throat resistance, may hold the greatest promise for improving cardiorespiratory control in individuals with SCI (CTR ID No. NCT05480618).

Instrumental Assessment of Aero-Resistive Expiratory Muscle Strength Rehabilitation Devices.

Expiratory muscle strength training (EMST) is increasingly being used to treat voice, cough, and swallowing deficits in a wide range of conditions. However, a multitude of aero-resistive EMST models are commercially available, and the absence of side-by-side comparative data interferes with clinicians' ability to assess which model is best suited to a particular client's needs. The primary aim of this research was to test and compare the pressure and flow parameters of six currently available EMST models to help inform clinical decision making. We identified and tested five devices of each of six different EMST models to generate benchmark data for minimum trigger pressures across settings. The reliability was tested within each device and between five devices of the same model across settings using coefficient of variation. All six models required higher pressures to initiate flow at the highest setting compared to the lowest setting, as expected. Detailed descriptive statistics for each model/setting combination include average flow-triggering pressure for each model/setting and the variability across trials within a device and across devices of the same model. From these, ranked order of the least to most stable EMST model was derived. Systematic testing of several commercially available expiratory resistance training devices yielded clinical benchmarks and reliability data to aid clinicians in selecting an appropriate therapy device and regimen for a client based on their available airflow and air pressure as well as reliability of the device. These findings allow clinicians to directly compare key parameters across EMST devices.

MODIFIED ULTRAFILTRATION IMPROVES LUNG MECHANICS IN CONGENITAL CARDIAC SURGERY - A FACT OR FUTILE: A PROSPECTIVE, OBSERVATIONAL, SINGLE-CENTER STUDY

Objective: Cardiac surgeries involving cardiopulmonary bypass (CPB) can have adverse effects on patients, potentially increasing morbidity. In infants who possess lower blood volume and are exposed to the more artificial surface and larger prime volumes of the CPB, the harmful effects can be significant. Several studies have indicated that modified ultrafiltration (MUF) may yield beneficial effects in cardiac surgery by reducing inflammatory markers, improving hemodynamics, and decreasing excess body water. Our study seeks to evaluate the impact of MUF on pulmonary mechanics in infants undergoing cardiac surgeries on CPB. Methods: This prospective, observational, single-center study was conducted on 56 infants with congenital heart disease, who underwent cardiac surgery, followed by CPB, were included in this study. The primary outcomes were oxygen saturation (SPO2), hemoglobin (Hb), peak inspiratory pressure (Ppeak), and plateau pressure (Pplat). The secondary outcomes were systolic and diastolic invasive blood pressures (IBPs), mean arterial pressure (MAP), mean airway pressure (Pmean), static lung compliance (C-stat), dynamic lung compliance (C-dyn), expiratory resistance (Re), and work of breathing (WOB). Results: A statistically significant increase in SPO2 (98.7 vs. 99.1), Hb (8.3 vs. 13.3), IBPsystolic (85 vs. 90), IBPdiastolic (56 vs. 61.4), and MAP (66.4 vs. 73.2) was observed in congenital cardiac surgery and CPB patients after MUF (all p&lt;0.05). A statistically significant post-procedural decline in Ppeak (18.8 vs. 18.3), Pplat (18.4 vs. 18.1), Re (79.8 vs. 78), and WOB (1.4 vs. 1.3) was also observed (all p&lt;0.05). However, no significant pre-procedural versus post-procedural differences were observed in Pmean, C-stat, and C-dyn (all p&gt;0.05). Conclusion: MUF effectively improved lung mechanics, oxygen saturation, myocardial contractility, hematocrit, and hemodynamics, and minimized the blood transfusion requirement after CPB in infants with congenital heart disease. Future studies should reinvestigate these outcomes with a larger sample size for an extended follow-up duration.

Six methods to determine expiratory time constants in mechanically ventilated patients: a prospective observational physiology study

BackgroundExpiratory time constant (τ) objectively assesses the speed of exhalation and can guide adjustments of the respiratory rate and the I:E ratio with the goal of achieving complete exhalation. Multiple methods of obtaining τ are available, but they have not been compared. The purpose of this study was to compare six different methods to obtain τ and to test if the exponentially decaying flow corresponds to the measured time constants.MethodsIn this prospective study, pressure, flow, and volume waveforms of 30 postoperative patients undergoing volume (VCV) and pressure-controlled ventilation (PCV) were obtained using a data acquisition device and analyzed. τ was measured as the first 63% of the exhaled tidal volume (VT) and compared to the calculated τ as the product of expiratory resistance (RE) and respiratory system compliance (CRS), or τ derived from passive flow/volume waveforms using previously published equations as proposed by Aerts, Brunner, Guttmann, and Lourens. We tested if the duration of exponentially decaying flow during exhalation corresponded to the duration of the predicted second and third τ, based on multiples of the first measured τ.ResultsMean (95% CI) measured τ was 0.59 (0.57–0.62) s and 0.60 (0.58–0.63) s for PCV and VCV (p = 0.45), respectively. Aerts method showed the shortest values of all methods for both modes: 0.57 (0.54–0.59) s for PCV and 0.58 (0.55–0.61) s for VCV. Calculated (CRS * RE) and Brunner’s τ were identical with mean τ of 0.64 (0.61–0.67) s for PCV and 0.66 (0.63–069) s for VCV. Mean Guttmann’s τ was 0.64 (0.61–0.68) in PCV and 0.65 (0.62–0.69) in VCV. Comparison of each τ method between PCV and VCV was not significant. Predicted time to exhale 95% of the VT (i.e., 3*τ) was 1.77 (1.70–1.84) s for PCV and 1.80 (1.73–1.88) s for VCV, which was significantly longer than measured values: 1.27 (1.22–1.32) for PCV and 1.30 (1.25–1.35) s for VCV (p < 0.0001). The first, the second and the third measured τ were progressively shorter: 0.6, 0.4 and 0.3 s, in both ventilation modes (p < 0.0001).ConclusionAll six methods to determine τ show similar values and are feasible in postoperative mechanically ventilated patients in both PCV and VCV modes.

Collagen Tubular Airway-on-Chip for Extended Epithelial Culture and Investigation of Ventilation Dynamics.

The lower respiratory tract is a hierarchical network of compliant tubular structures that are made from extracellular matrix proteins with a wall lined by an epithelium. While microfluidic airway-on-a-chip models incorporate the effects of shear and stretch on the epithelium, week-long air-liquid-interface culture at physiological shear stresses, the circular cross-section, and compliance of native airway walls have yet to be recapitulated. To overcome these limitations, a collagen tube-based airway model is presented. The lumen is lined with a confluent epithelium during two-week continuous perfusion with warm, humid air while presenting culture medium from the outside and compensating for evaporation. The model recapitulates human small airways in extracellular matrix composition and mechanical microenvironment, allowing for the first time dynamic studies of elastocapillary phenomena associated with regular breathing and mechanical ventilation, as well as their impactson the epithelium. A case study reveales increasing damage to the epithelium during repetitive collapse and reopening cycles as opposed to overdistension, suggesting expiratory flow resistance to reduce atelectasis. The model is expected to promote systematic comparisons between different clinically used ventilation strategies and, more broadly, to enhance human organ-on-a-chip platforms for a variety of tubular tissues.

Cytokine mRNA expression in the bronchoalveolar lavage cells from horses affected by different equine asthma subtypes

Equine asthma (EA) is a respiratory syndrome associated with the increase of different leukocyte populations in the bronchoalveolar lavage fluid (BALF). Its pathogenetic mechanisms remain unclear. This study aimed to evaluate the associations between the mRNA expression of different cytokines in the BALF, different EA subtypes and lung function. Fifteen horses underwent physical examination, airway endoscopy, BALF cytology and lung function testing (8/15). One horse did not have evidence of EA and was used as healthy reference, while the others were classified as affected by neutrophilic or mixed granulocytic EA. Cells isolated from the residual BALF were used for IL-1β, IL-2, IFN-γ, IL-4, IL-17A genes expression by quantitative RT-PCR., Cytokine expression was compared between groups, and their correlations with BALF leukocyte and lung function were evaluated. IL-1β expression was positively correlated with BALF neutrophils count (p=0.038, r=0.56) and with increased expiratory resistance (p=0.047, r=0.76). IFN-γ was correlated with BALF mast cells (p=0.029, r=0.58). IL-4 was higher in horses with mixed granulocytic EA than neutrophilic (p=0.008), positively correlated with BALF mast cells (p=0.028, r=0.59) and inversely with whole-breath (p=0.046, r=-0.76) and expiratory reactance (p=0.003, r=-0.93). Finally, IL-17A was inversely correlated with expiratory reactance (p=0.009, r=-0.92). These results support that multiple immune responses are involved in EA pathogenesis; innate, Th2, and Th17 responses. Innate immunity appeared associated with neutrophilic inflammation, and Th2 response with increased mast cells. The role of Th1 response in EA remains questionable.

Influence of the breathing pattern on the pulmonary function of endurance-trained athletes

Proper functioning of the respiratory system is one of the most important determinants of human health. According to current knowledge, the diaphragmatic breathing pattern seems to be the most favourable. However, recent reports indicate that athletes often have dysfunctional breathing patterns, which may be associated with an increased risk of musculoskeletal injuries. The influence of the type of breathing pattern on the mechanical airways in athletes has not been investigated. The aim of the present study was to determine the characteristics and relationships between breathing patterns and respiratory function in athletes. This study included 69 Polish elite endurance athletes (♂40, ♀29) in different sports disciplines and 44 (♂17, ♀27) healthy nonathletes as a control group. All participants underwent pulmonary function tests (spirometry, plethysmography, diffusion capacity for carbon monoxide) with assessment of breathing patterns by the Hi–Lo test. Inspiratory and expiratory resistance (R) and reactance (X) of the respiratory system at a given frequency (5 Hz, 11 Hz, and 19 Hz) were measured by a noninvasive forced oscillation technique. In this study, almost half of the athletes (44.92%) had dysfunctional breathing patterns, although at a lower rate than that in the control group. Diaphragmatic breathing patterns were characterized by higher spirometric, plethysmographic and DLCO values compared to thoracic or abdominal breathing patterns. Similarly, lower inspiratory reactance at 5 Hz (X5%pred.) was observed in the diaphragmatic pattern compared to the thoracic pattern. A diaphragmatic breathing pattern is associated with better pulmonary function test results. However, this study revealed a dysfunctional breathing pattern in almost half of the athletes. These results suggest that the assessment of breathing patterns and the implementation of breathing exercises in athletes are essential to promote proper breathing patterns.

Within-breath oscillometry for identifying exercise-induced bronchoconstriction in pediatric patients reporting symptoms with exercise.

Evaluating oscillometry parameters separately for the inspiratory and expiratory breath phases and their within-breath differences can help to identify exercise-induced bronchoconstriction (EIB) in pediatric outpatients disclosing exercise-induced symptoms (EIS). To assess the response in impedance parameters following an exercise challenge in patients reporting EIS. Sixty-eight patients reporting EIS (34 asthmatics and 34 suspected of asthma, age mean = 10.8 years, range = 6.0-16.0) underwent an incremental treadmill exercise test. Spirometry was performed at baseline and 1, 5-, 10-, 15-, and 20-min post exercise. Oscillometry was performed at baseline and at 3- and 18-min post exercise. Bronchodilator response to 200 µg albuterol was then assessed. EIB was defined as a forced expiratory volume in 1 s (FEV1) fall ≥10% from baseline. Expiratory and inspiratory resistance (Rrs) and reactance (Xrs), their z-score (Ducharme et al. 2022), and their mean within-breath differences (ΔRrs = Rrsexp-Rrsinsp, ΔXrs = Xrsexp-Xrsinsp) were calculated. Receiver operating characteristic (ROC) curves and their areas (AUCs) were used to evaluate impedance parameters' performances in classifying EIB. Asthmatic patients developed EIB more frequently than those suspected of asthma [18/34 (52.9%) vs. 2/34 (5.9%), p < 0.001]. In the 20 subjects with EIB, Rrsinsp, Rrsexp, Xrsinsp, and Xrsexp peaked early (3'), and remained steady except for Xrsinsp, which recovered faster afterward. ΔXrs widened 18 min following the exercise and reversed sharply after bronchodilation (BD) (-1.81 ± 1.60 vs. -0.52 ± 0.80 cmH2O × s/L, p < 0.001). Cutoffs for EIB leading to the highest AUCs were a rise of 0.41 in z-score Rrsinsp (Se: 90.0%, Sp: 66.7%), and a fall of -0.64 in z-score Xrsinsp (Se: 90.0%, Sp: 75.0%). Accepting as having "positive" postexercise oscillometry changes those subjects who had both z-scores beyond respective cutoffs, sensitivity for EIB was 90.0% (18/20) and specificity, 83.3% (40/48). Oscillometry parameters and their within-breath differences changed markedly in pediatric patients presenting EIB and were restored after the bronchodilator. Strong agreement between z-scores of inspiratory oscillometry parameters and spirometry supports their clinical utility, though larger studies are required to validate these findings in a broader population.

Восстановительная терапия больных бронхиальной астмой: в фокусе дыхательная гимнастика с экспираторным сопротивлением

Aim: to evaluate the effectiveness of high-resistance breathing exercises using flutter as a method of rehabilitation therapy for asthma. Patients and Methods: the patients with asthma were divided into two groups. Group 1 (n=40) received breathing exercises as part of their treatment, which consisted of quiet inhalation through the nose and exhalation into the flutter for 3–5 minutes daily, for a total of 14 procedures per course, in addition to their baseline therapy. In group 2 (n=40), patients received similar drug therapy without performing breathing exercises. The control group (n=40) consisted of healthy volunteers who performed breathing exercises as in group 1. We analyzed changes in clinical and functional parameters over time after a single application of the rehabilitation technique, as well as at baseline and after completing treatment (after 14 days). Results: showed a significant increase (p&lt;0.05) in external respiration indices, specifically forced expiratory volume in the 1st second, forced vital capacity (FVC), and expiratory reserve volume in groups 1 and 2. Furthermore, group 1 reported a significant increase (p&lt;0.05) in the time to hold breath, as well as an increase in peak expiratory flow, peak expiratory flow rate (PEFR), and a decrease in the daily variation of PEFR and minute ventilation. After two weeks of treatment, group 1 showed significant improvement. The study showed a decrease in choking incidents, reduced need for bronchodilators, and improvement in symptoms such as cough, dyspnea, expectoration of sputum, its character, and wheezing. Additionally, there was an improvement in disease control and exercise tolerance as demonstrated by the results of the 6-minute walk test. Group 2 showed a stable disease course during the follow-up, but no significant changes in clinical manifestations or pharmacological therapy were reported. In this study, it was found that flutter therapy had a significant and moderate favorable effect on 80% and 20% of patients with asthma, respectively. However, this effect was only maintained in patients who regularly practiced high-resistance breathing exercises. No adverse events were reported. Conclusion: high-resistance breathing exercises can reduce hyperventilation and improve bronchial patency in patients with asthma. Additionally, flutter therapy can decrease the doses of bronchodilators, improve FVC, and positively impact the disease course. KEYWORDS: asthma, breathing exercises, expiratory resistance, flutter therapy. FOR CITATION: Alekseenko S.N., Churyukina E.V., Ukhanova O.P., Kas'yanova T.R., Kotieva I.M., Kokova L.N., Dodokhova M.A., AndreevaV.O., Puzikova O.Z., Popova V.A., Sozaeva D.I. Rehabilitation therapy in asthma: focus on high-resistance breathing exercises. Russian Medical Inquiry. 2024;8(3):143–149 (in Russ.). DOI: 10.32364/2587-6821-2024-8-3-4.

The IL-31/TRPV1 pathway mediates allergic asthma exacerbated by DINP dermal exposure in OVA-sensitized Balb/c mice

BackgroundThe potential role of dermal exposure diisononyl phthalate (DINP) as an adjuvant in allergic inflammation and asthma has been suggested. However, the current findings do not provide enough evidence to support this claim. ObjectivesThe purpose of this investigation was to examine the impact and mechanisms of allergic asthma exacerbation through the dermal exposure to DINP. MethodsThe study was undertaken using OVA-sensitized mice. Lung histopathology and airway hyperreactivity (AHR) were assessed. Expression levels of immunoglobulins (t-IgE, OVA-IgE and OVA-IgG1), cytokines (IL-31, IL-4, IL-5, IL-6, IL-13 and INF-γ), and TRPV1 were measured. To investigate the mechanism by which allergic asthma worsens due to dermal exposure to DINP, the blockade analysis using the IL-31 antagonist SB-431542 and the TRPV1 antagonist capsazepine (CZP) were performed. ResultsThe findings of the study revealed that the simultaneous exposure to DINP and OVA resulted in an increase in inspiratory resistance (Ri) and expiratory resistance (Re), a decrease in the minimum value of lung dynamic compliance (Cldyn), and worsened airway remodeling. Additionally, it was found that this exposure led to an increase in the levels of IL-31 and TRPV1, which are biomarkers of Th2 cytokines (IL-4, IL-5, IL-6, and IL-13), as well as immunoglobulins (Total IgE, OVA-lgE, and OVA-IgG1), while decreasing the biomarker of Th1 cytokines (IFN-γ). However, these impairments showed improvement after the administration of SB-431542 or CZP. ConclusionThe findings of this research indicate that the IL-31/TRPV1 pathway plays a moderating function in OVA-induced allergic asthma worsened by dermal exposure to DINP.

How important is the Expiratory Resistance Level in the Expiratory Positive Airway Pressure (EPAP) Mask?

EPAP masks have been found to be effective in patients with snoring and obstructive sleep apnea and are FDA cleared for such purpose. EPAP masks are not always effective, but the reason for lack of effectiveness in some patients is not well understood. EPAP masks offer different levels of expiratory resistance, but it is not clear if such difference in expiratory resistance makes one mask more effective than another mask. Intuitively it is reasonable to think that more expiratory resistance would provide more pressure and therefore maybe more effective. That may not be so. We offer evidence that shows why expiratory resistance may not be an important factor that determines the effectiveness of the mask. Regardless of how much expiratory resistance, all EPAP masks work comparable to a low level of CPAP therapy and are more suitable for use in patients with snoring and mild to moderate obstructive sleep apnea. Having more expiratory resistance does not necessarily mean a more effective mask. A user should not worry too much about how much resistance a mask has and focus more on how comfortable is the mask and if they get better and quieter sleep

Effectiveness of Calcium Alginate Dressing in Combination with Nasal Endoscopic Bipolar Electrocoagulation and Low-Temperature Plasma Knife Treatment on Bleeding Volume, Nasal Ventilation, Stress Response, and Recurrence Rate in Patients with Refractory Epistaxis

The aim of this study was to compare the effects of nasal endoscopic bipolar electrocoagulation (BE) and low-temperature plasma knife (LPK) treatment on intractable epistaxis (IE) in order to provide a reference and guidance for future treatment options for IE. A total of 109 patients with IE admitted to Dongying People’s Hospital from June 2021 to May 2022 were selected for the study. Of these, 58 were treated with BE (BE group) and 51 were treated with LPK (LPK group). The nasal cavities of patients in the BE and LPK groups were filled with a gelatin sponge and calcium alginate dressing, respectively, after surgery. The clinical efficacy, operation time, hemostasis time, and intraoperative bleeding volume of the two groups were compared. Patients’ unilateral inspiratory resistance (IR), expiratory resistance (ER), bilateral total inspiratory resistance (TIR), and total expiratory resistance (TER) were measured using a nasal resistance tester, and pain was assessed using a visual analog scale (VAS). Serum epinephrine (E), norepinephrine (NE), and cortisol (Cor) levels were also measured in patients before and after surgery, and complications were recorded. The recurrence of IE was measured at a 6-month follow-up after discharge from the hospital. There were no differences in clinical efficacy, hemostasis time, or intraoperative bleeding between groups (P &gt;0.05), and the operative time was longer in both BE groups (P &lt;0.05). In addition, postoperative IR, ER, TIR, and TER were higher in the BE group than in the LPK group, and the VAS score results were also higher at 1 d postoperatively (P &lt;0.05). After surgery, E, NE, and Cor were elevated in both groups; more so in the BE group than in the LPK group (P &lt;0.05). Differences in the incidence of complications and prognostic recurrence rates between groups were not statistically significant (P &gt;0.05).

Impact of different fracture types in the pyriform buttress area on nasal airway function

IntroductionFractures in the pyriform buttress area adversely affect facial appearance and nasal airway patency. Nasal airway function has received less attention than aesthetic problems in the literature. This retrospective study classified the different fracture types in this area and determined their impact on nasal airway function.MathodsThree-dimensional computed tomography images of patients with fractures in the pyriform buttress area were analyzed to identify the exact fracture pattern. The nasal airway functions were evaluated and compared between patients with different fracture patterns using acoustic rhinometry, rhinomanometry, and the nasal obstruction symptom evaluation scale.Results Overall, 47 patients, including 16 with type I fractures (high fracture line; group I), 16 with type II fractures (intermediate fracture line; group II), and 15 with type III fractures (low fracture line; group III), were included in the study. The mean minimal cross-sectional area (MCA), total nasal inspiratory resistance (Tri) and total nasal expiratory resistance (Tre) of group I were 0.51 ± 0.06 cm2, 1.67 ± 0.11 kPa L−1 s−1, and 1.66 ± 0.12 kPa L−1 s−1, respectively; those of group II were 0.48 ± 0.07 cm2, 1.89 ± 0.15 kPa L−1 s−1, and 1.88 ± 0.14 kPa L−1 s−1, respectively; and those of group III were 0.36 ± 0.04 cm2, 1.94 ± 0.21 kPa L−1 s−1, and 2.01 ± 0.34 kPa L−1 s−1, respectively. The nasal obstruction symptom evaluation (NOSE) scale scores for groups I, II, and III were 7.188, 9.813, and 13.27, respectively.Conclusion Therefore, the severity of the nasal airway obstruction depends on the displacement of the fractured bones in patients with fractures in the pyriform buttress area. The most profound nasal obstruction occurs in patients with the lowest fracture line.

Modified forced expiration technique using expiratory resistance in adults with cystic fibrosis.

Participation in airway clearance techniques (ACT) is important to minimise development of irreversible airway obstruction in patients with cystic fibrosis (CF). Positive expiratory pressure (PEP) and expiratory resistance devices (ERD) are often used as they can improve collateral ventilation and aid in the shearing of mucus from airways. This project looked to identify whether utilising an ERD during a forced expiration technique (FET) improves ease of expectoration, sputum amount and coughing frequency in patients with CF. Patients with CF admitted for a respiratory exacerbation completed two sessions of 10 cycles of their usual ACT with half of the FET components performed with an ERD, half with FET alone. EOE, sputum wet weight, cough frequency and patient preference were similar between groups. Improved EOE without the ERD was found in participants who usually use PEP for their ACT regime. Combining the FET with a PEP mask did not improve EOE and other outcomes in this small study. Investigating the efficacy of this technique within a larger population is warranted.

A case of herpes zoster-related phrenic nerve palsy: Effect of home-based pulmonary rehabilitation

Here, we report the case of a 62-year-old man with herpes zoster-related phrenic nerve palsy, which was evident in clinical, radiological, and electrodiagnostic studies. To aid clinical recovery and preserve pulmonary function, we designed a home-based pulmonary rehabilitation program consisting of air-stacking exercises using ambu-bagging, respiratory muscle training to improve the strength and endurance of inspiratory and expiratory muscles, and aerobic and resistance exercises of the upper and lower limbs to improve and prevent the decline of cardiorespiratory fitness. The patient was monitored, and the exercises were adjusted through regular outpatient follow-up. During the overall follow-up period of 26 months, pulmonary rehabilitation led to an increase in forced vital capacity from 2,020 to 3,160 mL, and improved the diaphragmatic height index from -4.46 to 0.28. Clinical symptoms also showed notable improvement, as the Borg Rating of Perceived Exertion scale score decreased from 17 to 7. We found that a home-based, self-performed pulmonary rehabilitation program could promote recovery from herpes zoster-related phrenic nerve palsy. Not only is this important for the rapid restoration of respiratory function and symptomatic relief, it can also protect patients from respiratory complications.