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PubMed2006

Static pressure-volume curves and body posture in severe chronic bronchitis.

Based on prior data, the current authors hypothesised that beneficial pronation effects on gas exchange and respiratory mechanics might be maximised in severely hyperinflated chronic bronchitis patients. The current authors also sought to elucidate underlying mechanisms and to determine whether pronation effects are reflected by postural changes in inspiratory pressure-volume (P-V) curve characteristics. A total of 16 mechanically ventilated patients (for 16-36 h) with chronic bronchitis exacerbation were studied in pre-prone semirecumbent (SREC), prone and post-prone SREC postures. Static respiratory system intrinsic positive end-expiratory pressure (PEEPi,rs) was >12 cmH2O. Haemodynamics, partitioned respiratory mechanics, gas exchange, and lung volumes were determined at zero external positive end-expiratory pressure. P-V curves were constructed from functional residual capacity. End-expiratory lung volume exceeded opening volume. Prone position versus pre-prone SREC resulted in 20% reduced pressure at the lower inflection point (LIP) and 17% increased volume at the upper inflection point of the lung P-V curve, improved lung mechanics and volumes, oxygenation, and carbon dioxide arterial tension (Pa,CO2). In multiple linear regression, postural decreases in PEEPi,rs and additional lung resistance independently predicted postural decreases in lung LIP pressure and Pa,CO2), respectively. In conclusion, in severely hyperinflated patients, pronation reduces lung lower inflection point pressure and increases lung upper inflection point volume. Pronation effects on ventilation homogeneity and carbon dioxide arterial tension are maximised, implying that pronation can be useful during early controlled ventilation.

Aged↗

PubMed2006

Dynamic airflow limitation after topical anaesthesia of the upper airway.

This prospective before-and-after observational study investigated the effect of upper airway anaesthesia on dynamic airflow. Six consenting ASA 1 adults, all authors of this study, underwent a series of spirometric measurements before and after topical anaesthesia of the upper airway using lignocaine. Peak inspiratory flow rate, forced inspiratory flow between 25% and 75% of the maximum inhaled volume, forced expiratory volume at 1 second, and forced vital capacity in the supine and sitting positions were measured. The measured inspiratory parameters were significantly reduced after lignocaine topical anaesthesia of the upper airway. Expiratory flow parameters were not affected. We conclude that topical anaesthesia of the upper airway leads to dynamic inspiratory airflow limitation.

Administration, Topical↗

PubMed1986

Lung function and respiratory muscle strength after propranolol in thyrotoxicosis.

Thirty-five thyrotoxic patients were assessed before treatment, after treatment with propranolol, and after antithyroid drugs. The first group of patients (n = 17) performed the following tests at all three assessment points: forced expiratory volume in the first second (FEV1), vital capacity (VC), functional residual capacity (FRC), residual volume (RV), total lung capacity (TLC), maximal mid-expiratory flow rate (MMFR), diffusing capacity for carbon monoxide (DLCO), and maximum static inspiratory and expiratory mouth pressures (PImax and PEmax). Arterial blood gas analysis was also performed for the first group of patients. No significant changes were seen either after propranolol or after antithyroid drugs in the FRC, RV, TLC, MMFR, DLCO, or blood gases. The remaining 18 patients, group 2, performed only the FEV1, VC, PImax, and PEmax tests at each assessment. The only index of respiratory function that improved significantly after propranolol was PImax (from 46.5 +/- 16.5 to 53.2 +/- 22 cmH2O, p less than 0.01). This suggests that adrenergic excess may play a role in thyrotoxic inspiratory muscle weakness. After antithyroid drugs, PImax, PEmax, FEV1, and VC all increased significantly as expected.

Adolescent↗

PubMed2005

Inflammatory markers are associated with ventilatory limitation and muscle dysfunction in obstructive lung disease in well functioning elderly subjects.

BACKGROUND: Inflammatory markers are increased in chronic obstructive pulmonary disease (COPD) and are hypothesised to play an important part in muscle dysfunction and exercise intolerance. METHODS: The Health Aging and Body Composition (Health ABC) study is a prospective observational cohort of well functioning individuals aged 70-79 years. A cross sectional analysis of the baseline data was conducted to examine the association between inflammatory markers and ventilatory limitation, muscle strength, and exercise capacity. These associations were compared in participants with and without obstructive lung disease (OLD). RESULTS: Of the 3075 participants enrolled in the Health ABC cohort, OLD was identified by spirometric testing in 268 participants and 2005 participants had normal spirometric results. Of the participants with OLD, 35%, 38%, and 27% participants had mild, moderate, and severe OLD, respectively. Participants with OLD had lower quadriceps strength (102.5 Nm v 108.9 Nm, p = 0.02), lower maximum inspiratory pressure (64.7 cm H(2)O v 74.2 cm H(2)O, p<0.0001), higher systemic interleukin (IL)-6 levels (2.6 pg/ml v 2.2 pg/ml, p<0.0001), and higher C-reactive protein (CRP) levels (3.5 mg/l v 2.5 mg/l, p<0.0001) than those with normal spirometry. In participants with OLD and those with normal spirometry, forced expiratory volume in 1 second (FEV(1)) was associated with IL-6 (adjusted regression coefficients (beta) = -5.3 (95% CI -9.1 to-1.5) and -3.1 (95% CI -4.3 to -1.9), respectively). IL-6 and TNF were also associated with quadriceps strength among participants with OLD and those with normal spirometry (beta = -6.4 (95% CI -12.8 to -0.03) and -3.4 (95% CI -5.4 to -1.3), respectively, for IL-6 and beta = -10.1 (95% CI -18.7 to -1.5) and -3.8 (95% CI -7 to -0.6), respectively, for TNF). IL-6, quadriceps strength, and maximum inspiratory pressures were independent predictors of reduced exercise capacity in both groups. CONCLUSIONS: In well functioning elderly subjects with or without OLD, IL-6 is associated with reduced FEV(1), quadriceps strength, and exercise capacity.

Aged↗

PubMed1993

Lung volume and effectiveness of inspiratory muscles.

We related inspiratory muscle activity to inspiratory pressure generation (Pmus) at different lung volumes in five seated normal subjects. Integrated electromyograms were recorded from diaphragmatic crura (Edi), parasternals (PS), and lateral external intercostals (EI). At 20% increments in the vital capacity (VC) subjects relaxed and then made graded and maximal inspiratory efforts against an occluded airway. At any given level of pressure generation, Edi, PS, and EI increased with increasing lung volume. The Pmus generated at total lung capacity as a fraction of that at a low lung volume (between residual volume and 40% VC) was 0.39 +/- 0.15 (SD) for the diaphragm, 0.20 +/- 0.06 for PS, and 0.22 +/- 0.04 for the lateral EI muscles. Our results indicate a lesser volume dependence of the Pmus-EMG relationship for the diaphragm than for PS and EI muscles. This difference in muscle effectiveness with lung volume may reflect differences in length-tension and/or geometric mechanical advantage between the rib cage muscles and the diaphragm.

Diaphragm↗

PubMed2002

Respiratory muscle stretch gymnastics in patients with post coronary artery bypass grafting pain: impact on respiratory muscle function, activity, mood and exercise capacity.

A new rehabilitation (New-RH) program including respiratory muscle stretch gymnastics (RMSG) was developed to alleviate post-coronary artery bypass grafting pain (PCP). Effects on respiratory muscle function, pain, activities of daily living (ADL), mood and exercise capacity were investigated. Subjects were 16 consecutive patients undergoing median full sternotomy coronary artery bypass grafting (CABG), and were randomly divided into equal New-RH (S-group) and conventional therapy (C-group) groups. Rib cage dominant breathing was observed postoperatively in both groups. With preoperative tan deltaVrc/deltaVab, increases at 1-week postoperatively and decreases at discharge for S-group tended to exceed those of C-group (p > .05). Decreased maximum inspiratory and expiratory pressure status for functional residual capacity and percent forced expiratory volume in one second at discharge again only tended to be smaller for S-group (p > .05). S-group displayed significantly reduced pain around both scapulas at discharge (p = .049), and increased mean overall ADL and profile of mood states (POMS)/Vigor scores (p = .031 and p = .018, respectively). POMS/Tension-Anxiety scores at discharge for S-group were significantly smaller than those preoperatively (p = .025), and S-group displayed significantly increased distance walked over 6-minutes at discharge than C-group (p = .029). New-RH improves patient participation in exercise therapy and increases exercise capacity by reducing PCP, relieving anxiety and tension, and improving ADL.

Activities of Daily Living↗

PubMed1993

Dependence of maximal flow-volume curves on time course of preceding inspiration.

Thirteen normal subjects, sitting in a body plethysmograph and breathing through a pneumotachograph, performed forced vital capacity maneuvers after a rapid inspiration without or with an end-inspiratory pause (maneuvers 1 and 2) and after a slow inspiration without or with an end-inspiratory pause (maneuvers 3 and 4), the pause lasting 4-6 s. Inspirations were initiated close to functional residual capacity. At all lung volumes, expiratory flow was larger with maneuver 1 than with any other maneuver and, over the upper volume range, larger with maneuver 3 than with maneuver 4, whereas it was similar for maneuvers 2 and 4. Relative to corresponding values with maneuver 4, peak expiratory flow was approximately 16 and approximately 4% larger with maneuvers 1 and 3, respectively, whereas forced expiratory volume in 1 s increased by approximately 5% only with maneuver 1. The time dependence of maximal flow-volume curves is consistent with the presence of viscoelastic elements within the respiratory system (D'Angelo et al. J. Appl. Physiol. 70: 2602-2610, 1991).

Adult↗

PubMed1997

Effect of surgical lung volume reduction on breathing patterns in severe pulmonary emphysema.

Surgical lung volume reduction may improve pulmonary function and dyspnea in advanced pulmonary emphysema. To investigate mechanisms of these beneficial effects we studied breathing patterns before and after surgery. Nineteen patients with diffuse pulmonary emphysema (FEV1 < 35% of predicted, total lung capacity > 130% predicted) were studied within 1 mo before, and 1.5 to 7 mo after thoracoscopic volume reduction. Changes of rib cage and abdominal volumes were monitored with calibrated respiratory inductive plethysmography for 20 to 60 min during natural breathing at rest. Pulmonary function and dyspnea were also assessed. Postoperative tidal volumes, respiratory cycle times, and minute ventilation were not significantly different from preoperative values. The contribution of abdominal volume changes to tidal volumes increased from a mean +/- SD of 43 +/- 17% preoperatively to 58 +/- 14% postoperatively (p = 0.03). The fraction of inspiratory time with abdominal paradoxical motion decreased from 12.3 +/- 8.3% preoperatively to 5.1 +/- 5.1% postoperatively (p = 0.02). The phase shift between rib cage and abdominal motion was reduced postoperatively. Hyperinflation, airway obstruction, and subjective ratings of dyspnea were significantly improved. The better synchronization of rib cage-abdominal motion and the greater contribution of abdominal volume changes to tidal volumes are consistent with a reduction of inspiratory loading and a greater force-generating capacity of the diaphragm after surgery.

Adult↗

PubMed1994

Do canine scalene and sternomastoid muscles play a role in breathing?

To assess the respiratory function of the scalene and sternomastoid muscles in the dog, we studied the effect of graded increases in inspiratory airflow resistance and single-breath airway occlusion on the electrical activity of these muscles in 18 supine anesthetized spontaneously breathing animals. The sternomastoids never showed any activity, and the scalenes showed some inspiratory activity during occlusion in only two animals. The adoption of the prone position and bilateral cervical vagotomy did not affect this pattern. Hypercapnia also did not elicit any sternomastoid activity and induced scalene inspiratory activity during occlusion in only four of nine animals. On microscopic examination, however, both muscles were found to contain large numbers of spindles, suggesting that they have the capacity to respond to stretch. In addition, with increases in inspiratory resistance, both the sternum and ribs were displaced in the caudal direction. As a result, the scalenes demonstrated a gradual inspiratory lengthening and the normal inspiratory lengthening of the sternomastoids was accentuated. Additional studies in three unanesthetized animals showed consistent activity in the scalene and sternomastoid muscles during movements of the trunk and neck but no activity during breathing, including occluded breathing. These observations thus indicate that the alpha-motoneurons of the scalene and sternomastoid muscles in the dog have very small central respiratory drive potentials with respect to their critical firing threshold. In this animal, these muscles do not have a significant respiratory function.

Action Potentials↗

PubMed1991

What factors explain racial differences in lung volumes?

In order to examine the physical characteristics that may determine racial differences in lung volumes, we studied healthy, nonsmoking Caucasian, Chinese and Indian males of similar ages (range 18-51 yrs). We measured spirometric function, flow volume curves, lung volumes, inspiratory and expiratory muscle pressures, alveolar distensibility and diffusing capacity, together with height, weight and fat free mass. Chest shape was measured using radiographs. The mean total lung capacity and vital capacity in the Caucasian group, expressed as percentage predicted, were 5 and 10% higher than in the Chinese group and 17 and 20% higher than in the Indian group. Chinese values for these measurements were 12 and 10% greater than Indian. We found that Caucasians had higher fat free masses, higher inspiratory and expiratory muscle pressures and wider chests than the other races. The Caucasians and Chinese had longer chests than the Indians. There was no difference in alveolar distensibility or in the diffusion coefficient between the groups. These findings suggest that Caucasians have larger lung volumes than Chinese and Indians because they have increased numbers of alveoli and physically larger chest cavities, and not because of greater alveolar distensibility. Chest dimensions, together with height and race explained 90% of the variation in forced vital capacity and 86% of the variation in total lung capacity. Height multiplied by fat free mass, a "physique factor", previously suggested as the best predictive factor for forced vital capacity in Caucasians, did not account for much of the variation in forced vital capacity between Caucasians and Indians, presumably because it takes no account of differences in chest dimensions.

Adolescent↗

PubMed1981

Standardization of inhalation provocation tests: influence of nebulizer output, particle size, and method of inhalation.

Standardization of inhalation tests requires a knowledge of factors that will affect the response. We measured the output and particle size of six types of nebulizers used for inhalation tests. Output varied considerably between nebulizers of different types (0.12 to 1.59 ml/min) and to a lesser extent between nebulizers of the same type. Particle size varied between 0.8 and 5.2 micrometer aerodynamic mass median diameter (AMMD). The influence of these two properties on bronchial response to inhaled methacholine was examined. Nebulizer output but not particle size (between 1.3 and 3.6 micrometer AMMD) altered the response. We also examined the effect of change in inspiratory time during inhalation from residual volume to total lung capacity on lung deposition of radiolabeled aerosol and on the provocative concentration of histamine required to reduce the 1-sec forced expiratory volume (FEV1) by 20% (PC20). A reduction in inspiratory time from 8 to 2 sec resulted in a lower total lung dose, relatively more aerosol deposited in central airways, and a higher PC20. The results emphasize the importance of keeping nebulizer output and pattern of breathing constant when performing inhalation provocation tests if consistent results are to be obtained.

Aerosols↗

PubMed2003

Comparison of a new desktop spirometer (Spirospec) with a laboratory spirometer in a respiratory out-patient clinic.

BACKGROUND: The performance of spirometers is often evaluated under ideal conditions with computer-generated waveforms or in vivo testing with healthy subjects. Real-life conditions are less ideal because of comorbidities, age of the subjects, and a variety of air flow limitations. Evaluation of new spirometry equipment can also be performed under these less favorable conditions. The Spirospec is a new desktop spirometer that is commercially available, but its accuracy has not been evaluated in a clinical setting. OBJECTIVE: Test the Spirospec with subjects with normal and pathologic pulmonary function. METHODS: A group of 45 patients (mean age 38.4 years, 27 male) booked for evaluation in the pulmonary function laboratory of a tertiary care university hospital were tested with both a Spirospec and a standard Jaeger Masterlab 4.0 spirometer, according to the guidelines of the American Thoracic Society. Three subgroups (normal spirometry, obstructive air flow limitation, and restrictive air flow limitation) of 15 consecutive subjects each underwent spirometry. RESULTS: Pulmonary function measurements from the Spirospec correlated closely (r = 0.95-0.99) with those from the Masterlab 4.0, showing good limits of agreement and differences between the 2 devices: forced vital capacity 0.03 L, forced expiratory volume in the first second (FEV(1)) -0.01 L, peak expiratory flow -0.41 L/s, peak inspiratory flow 0.43 L/s, forced expiratory flow at 50% of total lung capacity 0.13 L/s, and forced expiratory flow at 75% of total lung capacity 0.12 L/s. With the exception of forced vital capacity and FEV(1), these differences were statistically significant (p < 0.05). CONCLUSION: The Spirospec is comparable to the Masterlab 4.0, with high accuracy for FEV(1) and forced vital capacity and clinically acceptable differences in the measured flow variables.

Adult↗

PubMed1977

Human nasal mucosal function at controlled temperatures.

We exposed 16 healthy human volunteers to air temperatures ranging from 7 to 39 degrees C and measured nasal mucus flow, nasal airflow resistance, forced vital capacity, rectal and body surface temperature, and air temperature within the nasal passage. A moderate fall in nasal mucus flow rate in the anterior and middle parts of the nose was observed with temperature above or below 23 degrees C. The nasal airflow resistance decreased in warm air and tended to increase in cold air. No significant changes in forced vital capacities or rectal temperature were observed. Nasopharyngeal end inspiratory air temperatures at 23 degrees C averaged 32.6 degrees C. At environmental temperatures of 15 and 31 degrees C they average 28.1 and 32.8 degrees C, respectively. Although we found alterations in upper airway function associated with altered inspired air temperature, over the range of 32 degrees C studied these changes were of minor physiological significance.

Acclimatization↗

PubMed2001

Pulmonary function tests, aerobic capacity, respiratory muscle strength and endurance of patients with rheumatoid arthritis.

Patients with rheumatoid arthritis (RA) show lower cardiorespiratory fitness than normal subjects. This study was planned to investigate the pulmonary function tests (PFT), respiratory muscle strength and endurance, and aerobic capacity of patients with RA, as well as the relationship of these parameters to clinical and functional status. Twenty-five RA patients aged 25-71 (48.52 +/- 14.09) and 21 control subjects aged 25-66 (45.67 +/- 13.27) participated in the study. PFT, maximum volunteer ventilation, maximum inspiratory and maximum expiratory pressures and cardiorespiratory exercise tests were carried out in all subjects to evaluate the respiratory involvement, inspiratory and expiratory muscle strength and endurance, and aerobic capacity. Patients' duration of disease, smoking and alcohol habits, duration of morning stiffness, visual analogue scale scores, ARA functional classifications and Ritchie articular indexes were recorded. All the patients and control subjects were non-exercising individuals. As a result, we found that RA patients have normal PFT but reduced respiratory muscle strength and endurance, and also reduced aerobic capacity compared to controls. According to this result, respiratory and aerobic exercises may be recommended to improve respiratory muscle strength and endurance and aerobic capacity in these patients.

Adult↗

PubMed1996

Pulmonary emphysema: quantitative CT during expiration.

PURPOSE: To determine whether measurement of the relative area of lung with attenuation coefficients lower than a certain threshold on thin-section computed tomographic (CT) scans obtained during expiration is a valuable method of quantifying the extent of pulmonary emphysema. MATERIALS AND METHODS: Eighty-nine patients underwent CT (with 1-mm collimation) preoperatively during inspiration and expiration. Relative areas of lung with attenuation coefficients lower than various thresholds were calculated. These relative areas were compared with areas found macroscopically to have emphysema (59 patients [51 men, eight women; aged 40-77 years]) and with two microscopic indices (35 patients [29 men, six women; aged 42-77 years]) assessed on the resected specimens. RESULTS: The valid expiratory CT thresholds were found to be -820 and 910 HU for microscopic and macroscopic emphysema, respectively. However, results of stepwise multiple regression analyses showed that the inspiratory threshold of -950 HU was superior for both macroscopically and microscopically quantified emphysema. The correlation coefficients in expiratory CT were higher for the pulmonary volumes but similar for the diffusing capacity. CONCLUSION: Expiratory quantitative CT is not as accurate as inspiratory CT for quantifying pulmonary emphysema and probably reflects air trapping more than reduction in the alveolar wall surface.

Adult↗

PubMed1981

Importance of inspiratory muscle tone in maintenance of FRC in the newborn.

The importance of inspiratory muscle tone in the maintenance of functional residual capacity (FRC) in newborns was studied in eight premature infants with birth weights of 1,166 +/- 217 g and gestational age 29 +/- 1.9 wk (mean +/- SD). Rib cage and abdominal anteroposterior diameters were monitored with magnetometers, and electromyograms of the diaphragm and intercostal muscles were recorded with surface electrodes. Sleep state was monitored using electrooculogram and behavioral criteria. We assessed the decrease in tonic activity of the inspiratory muscles and the fall in end-expiratory lung volume during apnea compared with the period just preceding apnea. A total of 98 apneas were analyzed. In all instances a decrease in diaphragmatic and intercostal tone was associated with a decrease in the anteroposterior diameter of both rib cage and abdomen, indicating a fall in FRC. These changes were more marked during quiet sleep than during rapid-eye-movement sleep (P less than 0.01). Our results suggest that inspiratory muscle tone is a major determinant of FRC in the newborn.

Apnea↗

PubMed2000

Assessment and monitoring of flow limitation and other parameters from flow/volume loops.

Flow/volume (F/V) spirometry is routinely used for assessing the type and severity of lung disease. Forced vital capacity (FVC) and timed vital capacity (FEV1) provide the best estimates of airflow obstruction in patients with asthma, chronic obstructive pulmonary disease (COPD) and emphysema. Computerized spirometers are now available for early home recognition of asthma exacerbation in high risk patients with severe persistent disease, and for recognition of either infection or rejection in lung transplant patients. Patients with severe COPD may exhibit expiratory flow limitation (EFL) on tidal volume (VT) expiratory F/V (VTF/V) curves, either with or without applying negative expiratory pressure (NEP). EFL results in dynamic hyperinflation and persistently raised alveolar pressure or intrinsic PEEP (PEEPi). Hyperinflation and raised PEEPi greatly enhance dyspnea with exertion through the added work of the threshold load needed to overcome raised pleural pressure. Esophageal (pleural) pressure monitoring may be added to VTF/V loops for assessing the severity of PEEPi: 1) to optimize assisted ventilation by mask or via endotracheal tube with high inspiratory flow rates to lower I:E ratio, and 2) to assess the efficacy of either pressure support ventilation (PSV) or low level extrinsic PEEP in reducing the threshold load of PEEPi. Intraoperative tidal volume F/V loops can also be used to document the efficacy of emphysema lung volume reduction surgery (LVRS) via disappearance of EFL. Finally, the mechanism of ventilatory constraint can be identified with the use of exercise tidal volume F/V loops referenced to maximum F/V loops and static lung volumes. Patients with severe COPD show inspiratory F/V loops approaching 95% of total lung capacity, and flow limitation over the entire expiratory F/V curve during light levels of exercise. Surprisingly, patients with a history of congestive heart failure may lower lung volume towards residual volume during exercise, thereby reducing airway diameter and inducing expiratory flow limitation.

Asthma↗

PubMed2005

Reduced inspiratory muscle endurance following successful weaning from prolonged mechanical ventilation.

STUDY OBJECTIVES: Respiratory muscle weakness and decreased endurance have been demonstrated following mechanical ventilation. However, its relationship to the duration of mechanical ventilation is not known. The aim of this study was to assess respiratory muscle endurance and its relationship to the duration of mechanical ventilation. DESIGN: Prospective study. SETTING: Tertiary teaching hospital ICU. PATIENTS: Twenty subjects were recruited for the study who had received mechanical ventilation for > or = 48 h and had been discharged from the ICU. MEASUREMENTS: FEV1, FVC, and maximal inspiratory pressure (P(I(max)) at functional residual capacity were recorded. The P(I(max)) attained following resisted inspiration at 30% of the initial P(I(max)) for 2 min was recorded, and the fatigue resistance index (FRI) [P(I(max)) final/P(I(max))initial] was calculated. The duration of ICU length of stay (ICULOS), duration of mechanical ventilation (MVD), duration of weaning (WD), and Charlson comorbidities score (CCS) were also recorded. Relationships between fatigue and other parameters were analyzed using the Spearman correlations (rho). RESULTS: Subjects were admitted to the ICU for a mean duration of 7.7 days (SD, 3.7 days) and required mechanical ventilation for a mean duration of 4.6 days (SD, 2.5 days). The mean FRI was 0.88 (SD, 0.13), indicating a 12% fall in P(I(max)), and was negatively correlated with MVD (r = -0.65; p = 0.007). No correlations were found between the FRI and FEV1, FVC, ICULOS, WD, or CCS. CONCLUSIONS: Patients who had received mechanical ventilation for > 48 h have reduced inspiratory muscle endurance that worsens with the duration of mechanical ventilation and is present following successful weaning. These data suggest that patients needing prolonged mechanical ventilation are at risk of respiratory muscle fatigue and may benefit from respiratory muscle training.

Adult↗