The Relationship between Lung Volume and Standard Scalar ECG Parameters in Normal Subjects

CHEST Journal ◽  
1989 ◽  
Vol 95 (3) ◽  
pp. 530-534
Author(s):  
John D. Parker ◽  
John E. Fay ◽  
F. James Brennan ◽  
Lutz Forkert
Keyword(s):  
Lung Volume ◽  
Normal Subjects ◽  
The Relationship

Respiratory movements of the vocal cords

1983 ◽  
Vol 54 (5) ◽  
pp. 1269-1276 ◽  
Author(s):  
T. Brancatisano ◽  
P. W. Collett ◽  
L. A. Engel
Keyword(s):  
Lung Volume ◽  
Respiratory Control ◽  
Respiratory Muscles ◽  
Normal Subjects ◽  
Tight Coupling ◽  
Tidal Breathing ◽  
Vocal Cords ◽  
Residual Capacity ◽  
The Relationship ◽  
Respiratory Movements

We examined the movements of the vocal cords during tidal breathing, panting, and large changes in lung volume in 12 normal subjects. The glottis was observed with a fiber-optic bronchoscope, and the glottic image was recorded together with flow, volume, and a time marker onto videotape. Phasic respiratory swings in glottic width (dg) and glottic area (Ag) were reproducible in all subjects but differed substantially between subjects. In the group as a whole dg and Ag increased during inspiration to 10.1 +/- 5.6 mm and 126 +/- 8 mm2 (mean +/- SE), respectively, whereas during expiration the lowest values were 5.7 +/- 0.5 mm and 70 +/- 7 mm2, respectively. These extreme dimensions corresponded closely to the midtidal volume points in the respiratory cycle. Glottic width during vital capacity (VC) expirations was nearly 30% greater at a flow of 1.2 l/s than at 0.5 l/s, but the relationship between dg and lung volume differed between subjects. When swings in dg were minimized by panting, there was no difference in dg between functional residual capacity (FRC) and a volume corresponding to midinspiratory capacity. However, tidal breathing at this lung volume was associated with a 20% decrease in dg compared with breathing at FRC. Our observations indicate a tight coupling between the pattern of glottic movement and the respiratory volume cycle. The results suggest that during voluntary respiratory maneuvers both intrinsic laryngeal and respiratory muscles are recruited, participating as effector organs in ventilatory and respiratory control.

Psychophysics of inspiratory muscle force

1983 ◽  
Vol 54 (5) ◽  
pp. 1216-1221 ◽  
Author(s):  
D. G. Stubbing ◽  
E. H. Ramsdale ◽  
K. J. Killian ◽  
E. J. Campbell
Keyword(s):  
Lung Volume ◽  
Muscle Force ◽  
Psychophysical Function ◽  
Normal Subjects ◽  
Inspiratory Muscle ◽  
Inspiratory Pressure ◽  
Sensory Magnitude ◽  
Rib Cage ◽  
Muscle Groups ◽  
The Relationship

The perceived magnitude of static inspiratory muscle pressure was studied in normal subjects using psychophysical techniques. The sensory magnitude of a range of inspiratory pressures increased as the magnitude of the pressure increased. When the duration of the inspiratory pressure was controlled, the sensory magnitude also increased as duration increased. The relationship can be described by a single psychophysical function, psi = k x P1.234 x t0.62, where psi is perceived magnitude, P is inspiratory pressure, t is duration, and k is a constant. Use of different muscle groups and changes in lung volume altered the perceived magnitude of static inspiratory pressures. When static inspiratory pressures were generated by the abdomen-diaphragm, the perceived magnitude was significantly greater (P less than 0.01) than when they were generated by the rib cage. When lung volume was increased, the perceived magnitude of pressure was reduced. The results show that the perceived magnitude of static inspiratory pressures is affected by the pressure itself, pressure duration, the muscles used, and the lung volume at which the pressure is generated.

Airway distensibility in healthy and asthmatic subjects: effect of lung volume history

2000 ◽  
Vol 88 (4) ◽  
pp. 1413-1420 ◽  
Author(s):  
David Peter Johns ◽  
John Wilson ◽  
Richard Harding ◽  
E. Haydn Walters
Keyword(s):  
Lung Volume ◽  
Total Lung Capacity ◽  
Normal Subjects ◽  
Residual Volume ◽  
Tidal Breathing ◽  
Lung Capacity ◽  
Mild Asthmatic ◽  
The Relationship ◽  
Asthmatic Group ◽  
Volume History

Anatomic dead space (Vd) is known to increase with end-inspiratory lung volume (EILV), and the gradient of the relationship has been proposed as an index of airway distensibility (ΔVd). The aims of this study were to apply a rapid method for measuring ΔVd and to determine whether it was affected by lung volume history. Vd of 16 healthy and 16 mildly asthmatic subjects was measured at a number of known EILVs by using a tidal breathing, CO2-washout method. The effect of lung volume history was assessed by using three tidal breathing regimens: 1) three discrete EILVs (low/medium/high; LMH); 2) progressively decreasing EILVs from total lung capacity (TLC; TLC-RV); and 3) progressively increasing EILVs from residual volume (RV; RV-TLC). ΔVd was lower in the asthmatic group for the LMH (25.3 ± 2.24 vs. 21.2 ± 1.66 ml/l, means ± SE) and TLC-RV (24.3 ± 1.69 vs. 18.7 ± 1.16 ml/l) regimens. There was a trend for a lower ΔVd in the asthmatic group for the RV-TLC regimen (23.3 ± 2.19 vs. 18.8 ± 1.68 ml/l). There was no difference in ΔVd between groups. In conclusion, mild asthmatic subjects have stiffer airways than normal subjects, and this is not obviously affected by lung volume history.

Effects of thoracic volume and shape on electromechanical coupling in abdominal muscles

1984 ◽  
Vol 56 (5) ◽  
pp. 1294-1301 ◽  
Author(s):  
A. R. Hill ◽  
D. L. Kaiser ◽  
D. F. Rochester
Keyword(s):  
Lung Volume ◽  
Electromechanical Coupling ◽  
Muscle Length ◽  
Normal Subjects ◽  
Abdominal Muscle ◽  
Abdominal Muscles ◽  
Lung Volumes ◽  
Residual Capacity ◽  
Abdominal Surface ◽  
The Relationship

To assess the effects of lung volume and chest wall configuration on electromechanical coupling of the abdominal muscles, we examined the relationship between abdominal muscle pressure ( Pmus ) and electrical activity ( EMGab ) in eight normal subjects during expiratory efforts at lung volumes ranging from functional residual capacity (FRC) to FRC + 2.0 liters. At and above FRC, increases of lung volume did not significantly alter either the Pmus - EMGab relationship or abdominal surface linear dimensions, although expiratory efforts displaced the abdomen inward from its relaxed position. We attribute the constancy of delta Pmus /delta EMG above FRC to the negligible effects of increasing lung volume on abdominal configuration and muscle length. Expiratory efforts performed at lung volumes below FRC resulted in a wider range of abdominal indrawing . Under these conditions the EMGab required to augment Pmus by 30–40 cmH2O increased as the abdomen was displaced inward. This decrease of delta Pmus /delta EMGab appears to reflect muscle shortening, flattening of the abdominal wall, and possibly deformation of the rib cage.

Effect of volume history on changes in DLcoSB-3EQ with lung volume in normal subjects

1992 ◽  
Vol 73 (2) ◽  
pp. 434-439 ◽  
Author(s):  
D. J. Cotton ◽  
F. Taher ◽  
J. T. Mink ◽  
B. L. Graham
Keyword(s):  
Lung Volume ◽  
Normal Subjects ◽  
Breath Holding ◽  
Diffusing Capacity ◽  
Tidal Breathing ◽  
Inspiratory Capacity ◽  
Deep Breath ◽  
Residual Capacity ◽  
The Relationship ◽  
Volume History

The purpose of this study was to determine the relationship between the three-equation diffusing capacity for carbon monoxide (DLcoSB-3EQ) and lung volume and to determine how this relationship was altered when maneuvers were immediately preceded by a deep breath. DLcoSB-3EQ maneuvers were performed in nine healthy subjects either immediately after a deep breath or after tidal breathing for 10 min. The maneuvers consisted of slow inhalation of test gas from functional residual capacity to 25, 50, 75, or 100% of the inspiratory capacity and, without breath holding, slow exhalation to residual volume. After either a deep breath or tidal breathing, we found that DLcoSB-3EQ decreased nonlinearly with decreasing lung volume. At all lung volumes, DLcoSB-3EQ was significantly greater when measured after a deep breath than after tidal breathing. This effect increased as lung volume decreased, so that the greatest difference between DLcoSB-3EQ after a deep breath and that after tidal breathing occurred at the lowest lung volume. We conclude that a deep breath or spontaneous sigh has a role in reestablishing the pathway for gas exchange during tidal breathing.

Pulmonary resistance and state of inflation of lungs in normal subjects and in patients with airway obstruction

1959 ◽  
Vol 14 (5) ◽  
pp. 727-732 ◽  
Author(s):  
Tsung O. Cheng ◽  
Malcolm P. Godfrey ◽  
Richard H. Shepard
Keyword(s):  
High Resistance ◽  
Lung Volume ◽  
Vital Capacity ◽  
Total Lung Capacity ◽  
Normal Subjects ◽  
Viscous Resistance ◽  
Pulmonary Resistance ◽  
Lung Capacity ◽  
Normal Resistance ◽  
The Relationship

The relationship between pulmonary resistance and the state of inflation of the lung was estimated throughout the expired vital capacity, using the multiple interrupter of Clements and Elam and a servo-spirometer. In normal subjects the pulmonary resistance was lowest near full inflation and remained relatively constant until about 80% of the vital capacity had been expired. It then rose abruptly and approached infinity at full expiration. In patients with obstructed airways, this relationship was altered in one of several ways: 1) normal resistance near full inflation increasing to high levels early in the expired vital capacity, 2) high resistance near full inflation with little further rise until late in expiration and 3) various combinations of the above. The first pattern probably reflects changes in the small, relatively flaccid airways while the second pattern probably reflects changes in the large, relatively rigid airways or in pulmonary viscous resistance. The type of relationship between resistance and lung volume also appears to influence the partition of the total lung capacity. Submitted on February 17, 1959

Nonlinear Analysis of Visual Evoked Potentials Elicited by Color Stimulation

1997 ◽  
Vol 36 (04/05) ◽  
pp. 315-318 ◽  
Author(s):  
K. Momose ◽  
K. Komiya ◽  
A. Uchiyama
Keyword(s):  
Visual System ◽  
Evoked Potentials ◽  
Visual Evoked Potentials ◽  
Normal Subjects ◽  
Second Order ◽  
First Order ◽  
The Relationship ◽  
Perceived Color ◽  
Second Order Nonlinearity ◽  
Visual Evoked

Abstract:The relationship between chromatically modulated stimuli and visual evoked potentials (VEPs) was considered. VEPs of normal subjects elicited by chromatically modulated stimuli were measured under several color adaptations, and their binary kernels were estimated. Up to the second-order, binary kernels obtained from VEPs were so characteristic that the VEP-chromatic modulation system showed second-order nonlinearity. First-order binary kernels depended on the color of the stimulus and adaptation, whereas second-order kernels showed almost no difference. This result indicates that the waveforms of first-order binary kernels reflect perceived color (hue). This supports the suggestion that kernels of VEPs include color responses, and could be used as a probe with which to examine the color visual system.

The Relationship of Root Mean Square Value of Electromyography and Isometric Torque of Quadriceps in Normal Subjects

2016 ◽  
Vol 26 (1) ◽  
pp. 58
Author(s):  
Qiurong XIE ◽  
Zheng JIANG ◽  
Qinglu LUO ◽  
Jie LIANG ◽  
Xiaoling WANG ◽  
...  
Keyword(s):  
Root Mean Square ◽  
Normal Subjects ◽  
Mean Square ◽  
Isometric Torque ◽  
Relationship Of ◽  
The Relationship

Immediate diaphragmatic electromyogram responses to imperceptible mechanical loads in conscious humans

1992 ◽  
Vol 73 (1) ◽  
pp. 248-259 ◽  
Author(s):  
E. J. Kobylarz ◽  
J. A. Daubenspeck
Keyword(s):  
Electrical Activity ◽  
Lung Volume ◽  
Muscle Activity ◽  
Normal Subjects ◽  
Tonic Activity ◽  
Phasic Activity ◽  
Mechanical Loads ◽  
Oral Airway ◽  
Pattern Regulation ◽  
Adaptive Pattern

We used an esophageal electrode to measure the amplitude and neural inspiratory and expiratory (N TE) timing responses of crural diaphragmatic electrical activity in response to flow-resistive (R) and elastic (E) loads at or below the threshold for conscious detection, applied pseudorandomly to the oral airway of eight normal subjects. We observed a rapid first-breath neural reflex that modified respiratory timing such that N TE lengthened significantly in response to R loads in six of eight subjects and shortened in response to E loading in six of seven subjects. The prolongation of N TE with R loading resulted primarily from lengthening the portion of N TE during which phasic activity in the diaphragm is absent (TE NDIA), whereas E loading shortened N TE mainly by reducing TE NDIA. Most subjects responded to both types of loading by decreasing mean tonic diaphragmatic activity, the average level of muscle activity that exists when no phasic changes are occurring, as well as its variability. The observed timing responses are consistent in direction with optimally adaptive pattern regulation, whereas the modulation of tonic activity may be useful in neural regulation of end-expiratory lung volume.

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