Tonic inspiratory muscle activity as a cause of hyperinflation in asthma

1981 ◽  
Vol 50 (2) ◽  
pp. 279-282 ◽  
Author(s):  
N. Muller ◽  
A. C. Bryan ◽  
N. Zamel
Keyword(s):  
Muscle Activity ◽  
Inspiratory Muscle ◽  
Tonic Activity ◽  
Surface Electrodes ◽  
Inspiratory Muscles ◽  
Thoracic Gas Volume ◽  
Before And After ◽  
Male Patients ◽  
Gas Volume ◽  
Proportional Reduction

We studied tonic activity of the inspiratory muscles during exacerbation of asthma in five female and two male patients. Exacerbation was provoked by withholding bronchodilatory medication for 12 h prior to the study. Thoracic gas volume (TGV) at the end of resting expiration was determined before and after albuterol (salbutamol) inhalation with a body plethysmograph. Intercostal muscle electromyogram (EMG) was recorded with surface electrodes and diaphragmatic EMG with esophageal electrodes. Tonic activity was defined as electrical activity in the EMG present throughout expiration. After salbutamol the TGV decreased 13.4 +/- 2.9% (mean +/- SE) (P less than 0.01). This decrease in TGV was accompanied by a proportional reduction in tonic intercostal (r = 0.78, P less than 0.05) and diaphragmatic activity (r = 0.84, P less than 0.05). These findings suggest that the hyperinflation present during exacerbation of asthma is at least in part due to active inspiratory muscle activity present throughout expiration.

Tonic inspiratory muscle activity as a cause of hyperinflation in histamine-induced asthma

1980 ◽  
Vol 49 (5) ◽  
pp. 869-874 ◽  
Author(s):  
N. Muller ◽  
A. C. Bryan ◽  
N. Zamel
Keyword(s):  
Lung Volume ◽  
Muscle Activity ◽  
Normal Subjects ◽  
Inspiratory Muscle ◽  
Intercostal Muscle ◽  
Tonic Activity ◽  
Surface Electrodes ◽  
Inspiratory Muscles ◽  
Thoracic Gas Volume ◽  
Gas Volume

We studied the change in tonic activity of the inspiratory muscles during acute hyperinflation. Hyperinflation was provoked in two asthmatic and three normal subjects by progressively doubling doses of histamine. Changes in lung volume were determined with magnetometers and with a body plethysmograph. Intercostal muscle activity was recorded with surface electrodes and diaphragmatic activity with esophageal electrodes. Tonic activity was defined as electrical activity in the electromyogram present at end expiration. After histamine the maximal observed increase in plethysmographic thoracic gas volume in the five subjects was 29.8 +/- 6.4% of control (mean +/- SE). Hyperinflation was accompanied by a significant increase in tonic activity of the intercostal muscles (P < 0.01) and the diaphragm (P < 0.01). There was a significant correlation between the increase in thoracic gas volume and the increase in tonic intercostal (r = 0.82, P = 0.003) and diaphragmatic (r = 0.89, P = 0.003) activity. We conclude that histamine-induced hyperinflation is accompanied by persistent inspiratory muscle activity throughout expiration.

Pulmonary response to threshold levels of sulfur dioxide (1.0 ppm) and ozone (0.3 ppm)

1985 ◽  
Vol 58 (6) ◽  
pp. 1783-1787 ◽  
Author(s):  
L. J. Folinsbee ◽  
J. F. Bedi ◽  
S. M. Horvath
Keyword(s):  
Sulfur Dioxide ◽  
Pulmonary Response ◽  
Rest Periods ◽  
Pollutant Concentrations ◽  
Thoracic Gas Volume ◽  
Exercise Ventilation ◽  
Before And After ◽  
Residual Capacity ◽  
Gas Volume ◽  
Male Subjects

We exposed 22 healthy adult nonsmoking male subjects for 2 h to filtered air, 1.0 ppm sulfur dioxide (SO2), 0.3 ppm ozone (O3), or the combination of 1.0 ppm SO2 + 0.3 ppm O3. We hypothesized that exposure to near-threshold concentrations of these pollutants would allow us to observe any interaction between the two pollutants that might have been masked by the more obvious response to the higher concentrations of O3 used in previous studies. Each subject alternated 30-min treadmill exercise with 10-min rest periods for the 2 h. The average exercise ventilation measured during the last 5 min of exercise was 38 1/min (BTPS). Forced expiratory maneuvers were performed before exposure and 5 min after each of the three exercise periods. Maximum voluntary ventilation, He dilution functional residual capacity, thoracic gas volume, and airway resistance were measured before and after the exposure. After O3 exposure alone, forced expiratory measurements (FVC, FEV1.0, and FEF25–75%) were significantly decreased. The combined exposure to SO2 + O3 produced similar but smaller decreases in these measures. There were small but significant differences between the O3 and the O3 + SO2 exposure for FVC, FEV1.0, FEV2.0, FEV3.0, and FEF25–75% at the end of the 2-h exposure. We conclude that, with these pollutant concentrations, there is no additive or synergistic effect of the two pollutants on pulmonary function.

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

1981 ◽  
Vol 51 (4) ◽  
pp. 830-834 ◽  
Author(s):  
J. Lopes ◽  
N. L. Muller ◽  
M. H. Bryan ◽  
A. C. Bryan
Keyword(s):  
Muscle Tone ◽  
Inspiratory Muscle ◽  
Rapid Eye Movement Sleep ◽  
Sleep State ◽  
Quiet Sleep ◽  
Rib Cage ◽  
Surface Electrodes ◽  
Inspiratory Muscles ◽  
Residual Capacity ◽  
Behavioral Criteria

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.

Airway anesthesia effects on hypercapnic breathing pattern in humans

1983 ◽  
Vol 55 (2) ◽  
pp. 368-376 ◽  
Author(s):  
T. Y. Sullivan ◽  
P. L. Yu
Keyword(s):  
Airway Resistance ◽  
Vital Capacity ◽  
Breathing Pattern ◽  
Minute Ventilation ◽  
Normal Subjects ◽  
Inspiratory Time ◽  
Abrupt Increase ◽  
Thoracic Gas Volume ◽  
Before And After ◽  
Gas Volume

Minute ventilation (VE) and breathing pattern during an abrupt increase in fractional CO2 were compared in 10 normal subjects before and after airway anesthesia. Subjects breathed 7% CO2-93% O2 for 5 min before and after inhaling aerosolized lidocaine. As a result of airway anesthesia, VE and tidal volume (VT) were greater during hypercapnia, but there was no effect on inspiratory time (TI). Therefore, airway anesthesia produced an increase in mean inspiratory flow (VT/TI) during hypercapnia. The increase in VT/TI was compatible with an increase in neuromuscular output. There was no effect of airway anesthesia on the inspiratory timing ratio or the shape and position of the curve relating VT and TI. We also compared airway resistance (Raw), thoracic gas volume, forced vital capacity, forced expired volume at 1s, and maximum midexpiratory flow rate before and after airway anesthesia. A small (0.18 cmH2O X l-1 X s) decrease in Raw occurred after airway anesthesia that did not correlate with the effect of airway anesthesia on VT/TI. We conclude that airway receptors accessible to airway anesthesia play a role in hypercapnic VE.

scholarly journals Performance Evaluation of Fixed Sample Entropy in Myographic Signals for Inspiratory Muscle Activity Estimation

Entropy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 183 ◽  
Author(s):  
Manuel Lozano-García ◽  
Luis Estrada ◽  
Raimon Jané
Keyword(s):  
Muscle Activity ◽  
Muscle Activation ◽  
Cardiac Activity ◽  
Sample Entropy ◽  
Inspiratory Muscle ◽  
Chronic Obstructive ◽  
Inspiratory Muscles ◽  
Fixed Sample ◽  
Cross Covariance ◽  
Activity Estimation

Fixed sample entropy (fSampEn) has been successfully applied to myographic signals for inspiratory muscle activity estimation, attenuating interference from cardiac activity. However, several values have been suggested for fSampEn parameters depending on the application, and there is no consensus standard for optimum values. This study aimed to perform a thorough evaluation of the performance of the most relevant fSampEn parameters in myographic respiratory signals, and to propose, for the first time, a set of optimal general fSampEn parameters for a proper estimation of inspiratory muscle activity. Different combinations of fSampEn parameters were used to calculate fSampEn in both non-invasive and the gold standard invasive myographic respiratory signals. All signals were recorded in a heterogeneous population of healthy subjects and chronic obstructive pulmonary disease patients during loaded breathing, thus allowing the performance of fSampEn to be evaluated for a variety of inspiratory muscle activation levels. The performance of fSampEn was assessed by means of the cross-covariance of fSampEn time-series and both mouth and transdiaphragmatic pressures generated by inspiratory muscles. A set of optimal general fSampEn parameters was proposed, allowing fSampEn of different subjects to be compared and contributing to improving the assessment of inspiratory muscle activity in health and disease.

Inspiratory muscle activity during unloaded and obstructed rebreathing in dogs

1988 ◽  
Vol 64 (1) ◽  
pp. 90-101 ◽  
Author(s):  
E. D'Angelo ◽  
N. Garzaniti ◽  
F. Bellemare
Keyword(s):  
Muscle Activity ◽  
Moving Average ◽  
Inspiratory Muscle ◽  
Central Control ◽  
Control Mechanisms ◽  
Peak Activity ◽  
Airway Occlusion ◽  
Inspiratory Muscles ◽  
Thoracic Muscles ◽  
Proprioceptive Inputs

Moving-average electromyogram (EMG) of the diaphragm (DI), scalenes, and cranial and caudal parasternals was assessed in anesthetized, supine, and head-up dogs during rebreathing. The shape of EMG trajectory was similar for all muscles and conditions; activation of different muscles could be thus compared on the basis of changes in peak activity. In intact dogs changes in peak activity were greater for the scalenes and cranial parasternals than for the caudal parasternals and greater for the inspiratory thoracic muscles (ITM) than for the DI. Posture, vagotomy, and cordotomy at C7-T1 did not affect the rate of rise of DI activity. The relations between peak activity of ITM did not change because of posture, vagotomy, and phrenicotomy. Vagotomy selectively depressed the rate of rise of ITM activity, but relative changes in peak ITM activity for a given change in peak DI activity were independent of intact vagi. Differences in the pattern of activation between inspiratory muscles with rebreathing are largely independent of proprioceptive inputs and likely reflect properties of central control mechanisms. However, airway occlusion at end expiration caused a reflex fall of DI activity and reflex increase of ITM activity in intact and vagotomized dogs. Cordotomy at C7-T1 did not change DI response, whereas reduction of ITM activity occurred after phrenicotomy, indicating that both facilitatory and inhibitory segmental inputs are involved in ITM response to loading.

Effect of a previous deep inspiration on airway resistance in man

1961 ◽  
Vol 16 (4) ◽  
pp. 717-719 ◽  
Author(s):  
Jay A. Nadel ◽  
Donald F. Tierney
Keyword(s):  
Airway Resistance ◽  
Healthy Adult ◽  
Transpulmonary Pressure ◽  
The Body ◽  
Deep Inspiration ◽  
Thoracic Gas Volume ◽  
Before And After ◽  
Residual Capacity ◽  
Gas Volume ◽  
Control State

We measured airway resistance and thoracic gas volume by the body plethysmograph technique, and transpulmonary pressure in seven healthy, adult subjects, before and after induction of bronchoconstriction. A deep inspiration never altered airway resistance, measured at functional residual capacity in the control state, but always reduced it for 1—2 min when bronchoconstriction was present. Discrepancies in data published on airway resistance may be due to use of methods which require a deep inspiration, or to occurrence of a spontaneous deep inspiration shortly before the test. Submitted on January 13, 1961

scholarly journals Effects of Inspiratory Muscles Training Plus Rib Cage Mobilization on Chest Expansion, Inspiratory Accessory Muscles Activity and Pulmonary Function in Stroke Patients

2020 ◽  
Vol 10 (15) ◽  
pp. 5178
Author(s):  
Shin Jun Park
Keyword(s):  
Pulmonary Function ◽  
Muscle Activity ◽  
Inspiratory Muscle ◽  
Inspiratory Muscle Training ◽  
Control Group ◽  
Muscle Training ◽  
Rib Cage ◽  
Joint Mobilization ◽  
Chest Expansion ◽  
Inspiratory Muscles

After stroke, limited ribcage movement may lead to impaired respiratory function. Combining threshold inspiratory muscle training with rib cage joint mobilization has been shown to enhance the recovery of respiratory function in patients with stroke. The present study investigated whether the combination of rib cage joint mobilization and inspiratory muscle training would improve chest expansion, inspiratory muscle activity, and pulmonary function after stroke. Thirty stroke patients were recruited and randomly assigned to one of the two groups, namely 6-week rib cage joint mobilization with inspiratory muscle training (experimental group) or inspiratory muscle training alone (control group). Outcome measures included upper and lower chest expansion, activity of accessory inspiratory muscles (latissimus dorsi (LD) and upper trapezius (UT)), and pulmonary function (forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and peak expiratory flow (PEF)). All evaluations were conducted at baseline and after 6 weeks of inspiratory muscle training. Significant increases were observed in upper and lower chest expansion, LD and UT muscle activity, FVC, FEV1, and PEF in both the groups. Upper and lower chest expansion and muscle activity of UT and LD were significantly higher in the experimental group than in the control group. No significant differences were observed in FVC, FEV1, and PEF between the groups. Inspiratory muscle training is effective in improving chest expansion, inspiratory muscle activity, and pulmonary function after stroke. The addition of rib cage joint mobilization further increases chest expansion and inspiratory muscle activity.

Breathing in Singing

2014 ◽  
pp. 86-108
Author(s):  
Alan Watson
Keyword(s):  
Abdominal Wall ◽  
Muscle Activity ◽  
Abdominal Muscle ◽  
Inspiratory Muscle ◽  
Lung Volumes ◽  
Inspiratory Muscles

Accounts of breathing in methodological books on singing are often confusing or inaccurate rather than helpful. This chapter provides an overview of the principles ofrespiration and how this is modified for singing. Inspiration results from an increase inthoracic dimensions caused by activity in the diaphragm and external intercostal muscles.At high lung volumes the sternocleidomastoids and scalenes also aid chest expansion.Subglottic pressure is created during expiration by the contraction of the abdominal wall,predominantly as a result of lateral abdominal muscle activity, which drives the relaxeddiaphragm upwards while simultaneously the internal intercostals pull the ribsdownwards. When the lungs are full and the inspiratory muscles release, elastic recoilforces alone can drive out the air and in order to regulate subglottic pressure theseforces must be resisted by gradually reducing inspiratory muscle activity. How different patterns of activity in these and other muscles contribute to singing is described and theway in which similar ends can be achieved by different means in different singers isexplained.

Influence of panting frequency on plethysmographic measurements of thoracic gas volume

1982 ◽  
Vol 52 (3) ◽  
pp. 739-747 ◽  
Author(s):  
A. B. Bohadana ◽  
R. Peslin ◽  
B. Hannhart ◽  
D. Teculescu
Keyword(s):  
High Frequency ◽  
Healthy Subjects ◽  
Airflow Obstruction ◽  
Gastric Balloon ◽  
Gas Compression ◽  
Thoracic Gas Volume ◽  
Mouth Pressure ◽  
Before And After ◽  
Flow Pressure ◽  
Gas Volume

Using an integrated flow pressure-corrected body plethysmograph we obtained total lung capacities (TLC) derived from thoracic gas volumes measured at low, medium, and high panting frequencies in 10 healthy men and in 13 patients with chronic airflow obstruction before and after an aerosol of albuterol. Using a gastric balloon we also assessed gastric-to-mouth pressure ratios (delta Pga/delta Pm). In patients before albuterol, estimated TLC remained unchanged from low to medium and increased (not significantly) from medium to high frequency. Healthy subjects and patients after albuterol showed a significant decrease in TLC from low to medium panting frequencies, which persisted after correcting the data for abdominal gas compression using observed delta Pga/delta Pm. In patients after albuterol the results may be explained, at least in part, by intrathoracic airway compliance and mechanical inhomogeneity of the lung. In healthy subjects a remote possibility is the association of mechanical inhomogeneity and nonuniform pleural pressure.

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