Phasic vagal influence on inspiratory motor output in anesthetized human subjects

1980 ◽  
Vol 49 (4) ◽  
pp. 609-619 ◽  
Author(s):  
J. Polacheck ◽  
R. Strong ◽  
J. Arens ◽  
C. Davies ◽  
I. Metcalf ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Human Subjects ◽  
Normal Subjects ◽  
Airway Disease ◽  
Apparent Volume ◽  
Motor Output ◽  
Restrictive Lung Disease ◽  
Tracheal Pressure ◽  
Inspiratory Motor ◽  
Vagal Influence

Vagal influence on inspiratory motor output was assessed in 20 normal subjects and in 12 patients with respiratory disorders under enflurane anethesia using the method of airway occlusion. The change in inspiratory duration during occlusion (delta TI) was measured from mechanical parameters (respiratory flow and tracheal pressure). In eight of the subjects, however, the effect of occlusion and augmentation of tidal volume was further evaluated from diaphragmatic electromyogram. In normal subjects delta TI (mechanical) averaged 0.15 s (range -0.1 to +0.77 s) and correlated with the duration of inspiration during occlusion. Electromyographic observations indicated that the change in neural TI exceeds the change in mechanical TI by approximately 0.2 s and that augmentation of tidal volume shortens TI with no apparent volume threshold. There was a tendency for vagal influence to be higher with restrictive lung disease and lower with obstructive airway disease. These observations indicate that a majority of humans display a significant vagal influence on TI in the spontaneous tidal volume range under anesthesia.

Dissociation between respiratory effort and dyspnoea in a subset of patients with stroke

2002 ◽  
Vol 103 (5) ◽  
pp. 467-473 ◽  
Author(s):  
Barbara LANINI ◽  
Francesco GIGLIOTTI ◽  
Claudia COLI ◽  
Roberto BIANCHI ◽  
Assunta PIZZI ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Tidal Volume ◽  
Normal Subjects ◽  
Carbon Dioxide Tension ◽  
Motor Output ◽  
Control Group ◽  
Quiet Breathing ◽  
Oesophageal Pressure ◽  
Inspiratory Motor ◽  
Tomography Scanning

Dyspnoea is not a prominent complaint of resting patients with recent hemispheric stroke (RHS). We hypothesized that, in patients with RHS presenting abnormalities in respiratory mechanics, increased respiratory motor output could translate into an increased perception of dyspnoea. We studied eight wheelchair-bound patients with RHS (mean age 62.4 years), previously evaluated by computerized tomography scanning, and a control group of normal subjects, matched for age and sex. We assessed routine spirometry, inspiratory and expiratory muscle pressures, breathing pattern and dyspnoea using a modified Borg scale. In six patients, we also measured oesophageal pressure during the maximal sniff manoeuvre and tidal inspiratory swing, and mechanical characteristics of the lung in terms of dynamic elastance during both quiet breathing and a hypercapnic/hyperoxic rebreathing test. During room air breathing, ventilation and tidal volume were similar in patients and controls, while tidal inspiratory swings of oesophageal pressure, an index of inspiratory motor output, were greater in patients (P = 0.005). Patients also exhibited a greater dynamic elastance (P = 0.013). During rebreathing, dynamic elastance remained higher (P = 0.01) and a greater than normal inspiratory motor output was found (P = 0.03). Responses of ventilation and tidal volume to carbon dioxide tension were normal, and in all patients but one a lower Borg score for the unit change in carbon dioxide tension and ventilation was found. In conclusion, a higher than normal inspiratory motor output was unexpectedly associated with a blunted perception of dyspnoea in this subset of RHS patients. This is likely to be due to the modulation of the integration process of respiratory sensation.

Effects of expiratory resistive loading on the sensation of dyspnea

1990 ◽  
Vol 69 (1) ◽  
pp. 91-95 ◽  
Author(s):  
T. Chonan ◽  
M. D. Altose ◽  
N. S. Cherniack
Keyword(s):  
Control Level ◽  
Normal Subjects ◽  
Motor Output ◽  
Loading Level ◽  
Control Frequency ◽  
Linear Resistance ◽  
Level Ii ◽  
Inspiratory Motor ◽  
Residual Capacity ◽  
Level I

To determine whether an increase in expiratory motor output accentuates the sensation of dyspnea (difficulty in breathing), the following experiments were undertaken. Ten normal subjects, in a series of 2-min trials, breathed freely (level I) or maintained a target tidal volume equal to (level II) or twice the control (level III) at a breathing frequency of 15/min (similar to the control frequency) with an inspiratory load, an expiratory load, and without loads under hyperoxic normocapnia. In tests at levels II and III, end-expiratory lung volume was maintained at functional residual capacity. A linear resistance of 25 cmH2O.1(-1).s was used for both inspiratory and expiratory loading; peak mouth pressure (Pm) was measured, and the intensity of dyspnea (psi) was assessed with a visual analog scale. The sensation of dyspnea increased significantly with the magnitude of expiratory Pm during expiratory loading (level II: Pm = 9.4 +/- 1.5 (SE) cmH2O, psi = 1.26 +/- 0.35; level III: Pm = 20.3 +/- 2.8 cmH2O, psi = 2.22 +/- 0.48) and with inspiratory Pm during inspiratory loading (level II: Pm = 9.7 +/- 1.2 cmH2O, psi = 1.35 +/- 0.38; level III: Pm = 23.9 +/- 3.0 cmH2O, psi = 2.69 +/- 0.60). However, at each level of breathing, neither the intensity of dyspnea nor the magnitude of peak Pm during loading was different between inspiratory and expiratory loading. The augmentation of dyspnea during expiratory loading was not explained simply by increases in inspiratory activity. The results indicate that heightened expiratory as well as inspiratory motor output causes comparable increases in the sensation of difficulty in breathing.

Breuer-Hering inflation reflex and breathing pattern in anesthetized humans and cats

1981 ◽  
Vol 51 (5) ◽  
pp. 1162-1168 ◽  
Author(s):  
H. Gautier ◽  
M. Bonora ◽  
J. H. Gaudy
Keyword(s):  
Tidal Volume ◽  
Breathing Pattern ◽  
Respiratory Activity ◽  
Human Subjects ◽  
Threshold Curve ◽  
Ventilatory Pattern ◽  
Tracheal Pressure ◽  
Switch Mechanism

In nine cats and nine human subjects anesthetized with alfaxalone, respiratory activity and tracheal pressure were recorded prior to and during occlusion of the airway at end inspiration or end expiration. Lung inflations at the end of expiration were also performed. In addition, the ventilatory pattern was analyzed during hypercapnia. The results show that occlusions at the end of inspiration or inflations provoked an apnea in both cats and humans. However, concomitant with increases in tidal volume during hypercapnia, inspiratory duration decreased in cats and did not change in human subjects. These results indicate that the Breuer-Hering reflex, which delays the onset of inspiration during inflation was equally operative in cats and humans. In contrast, the “Breuer-Hering threshold curve,” which accounts for the off-switch“ of inspiration was different in cats and humans. Thus, in summary, the Breuer-Hering inflation reflex is operative in human subjects, but it does not seem to be involved in the control of the inspiratory off-switch mechanism during increases respiratory activity resulting from hypercapnia.

Breathing Patterns and Regional Ventilation Distribution in Tetraplegic Patients and in Normal Subjects

1972 ◽  
Vol 42 (2) ◽  
pp. 117-128 ◽  
Author(s):  
B. Bake ◽  
A. R. Fugl-Meyer ◽  
G. Grimby
Keyword(s):  
Tidal Volume ◽  
Cervical Spinal Cord ◽  
Regional Distribution ◽  
Normal Subjects ◽  
Airway Disease ◽  
Breathing Patterns ◽  
Rib Cage ◽  
Small Airway Disease ◽  
Residual Capacity ◽  
Traumatic Transection

1. The regional distribution of ventilation was studied with 133Xe techniques in the sitting position in six patients with complete traumatic transection of the cervical spinal cord, 3–40 months after the lesion, and in four normal subjects. The relative contributions of the rib cage and abdomen to ventilation were determined from chest-wall motions. 2. Total lung capacity (TLC) was decreased and residual volume increased in the patients. After correction for the decreased TLC, the distribution of the regional functional residual capacity in the tetraplegic patients was similar to that of the normal subjects. In the patients, where the abdomen contributed to about half of the tidal volume, decreased ventilation of basal regions was demonstrated from measurements of regional tidal volumes (Vtr) and regional 133Xe wash-in curves. 3. The distribution of ventilation in normal persons, however, was not changed by varying the relative contributions of the rib cage and abdomen to the tidal volume, as shown from Vtr and regional 133Xe wash-out measurements. 4. The results in the tetraplegic patients are interpreted as evidence of ‘small airway disease’, presumably from infection of the air way and impairment of the cough.

Perception of changes in breathing in normal human subjects

1981 ◽  
Vol 50 (1) ◽  
pp. 78-83 ◽  
Author(s):  
N. Wolkove ◽  
M. D. Altose ◽  
S. G. Kelsen ◽  
P. G. Kondapalli ◽  
N. S. Cherniack
Keyword(s):  
Tidal Volume ◽  
Control Volume ◽  
Human Subjects ◽  
Respiratory Muscles ◽  
Intrathoracic Pressure ◽  
Normal Subjects ◽  
Volume Changes ◽  
Elastic Load ◽  
Normal Human ◽  
Pressure Changes

Respiratory sensation was evaluated in normal subjects from their ability to quantitate changes in tidal volume. Subjects attempted to duplicate or double tidal volumes of different sizes while breathing freely or against a resistive or elastic load. When the mechanical conditions during control and test breaths were constant, tidal volume duplication was accomplished with an error of approximately 100 ml, regardless of the control volume. The error in doubling, however, increased progressively with increasing control tidal volume. There was a greater error in both volume duplication and doubling when the mechanical conditions between control and test breaths were changed. When test breaths against a load followed unloaded control breaths, tidal volume failed to double, but intrathoracic pressure changes twice exceeded control values. Conversely, when unloaded test breaths followed loaded control breaths, pressure changes underwent less than a twofold increase while tidal volume more than doubled. The results indicate that tidal volume changes are normally sensed with considerable accuracy and suggest that both tidal volume per se, as well as the forces generated by the respiratory muscles, are used in the estimation of tidal volume changes.

Continuous distribution of specific tidal volume throughout the lung

1964 ◽  
Vol 19 (4) ◽  
pp. 683-692 ◽  
Author(s):  
Domingo M. Gómez ◽  
William A. Briscoe ◽  
Gordon Cumming
Keyword(s):  
Tidal Volume ◽  
Continuous Distribution ◽  
Maximum Amplitude ◽  
Normal Subjects ◽  
Apparent Volume ◽  
Nitrogen Washout ◽  
Maximum Value ◽  
Normal Frequency ◽  
Log Normal ◽  
The Right

An analytical method is presented which, applied to nitrogen washout data from the lung, describes a continuous distribution of specific tidal volume (or ventilation) throughout the air phase of the lung. The technique of computation is described in some detail. Curves of distribution of specific tidal volume are studied for 12 washout data from normal subjects and for 20 washout data from patients with pulmonary emphysema. In normal subjects the pattern of continuous distribution is an asymmetrical one in which the function starts at zero or very nearly so, increases continuously until it reaches a maximum value, then decreases progressively and becomes negligible for comparatively high values of the specific tidal volume. The formulation expressing this law of distribution is neither that of a normal frequency distribution nor that of a log normal one. With increasing over-all tidal volume in normal subjects the curve is progressively displaced toward the right. In contrast, in pulmonary obstructive diseases the maximum amplitude takes place for very low values of the specific tidal volume and tends to vanish slowly toward values that are higher than in the normal subjects. apparent volume of lung Submitted on June 20, 1963

A method for the assessment of phasic vagal influence on tidal volume

1975 ◽  
Vol 38 (2) ◽  
pp. 335-343 ◽  
Author(s):  
M. Younes ◽  
S. Iscoe ◽  
J. Milic-Emili
Keyword(s):  
Tidal Volume ◽  
Respiratory System ◽  
Spontaneous Breathing ◽  
Volume Changes ◽  
Lung Volumes ◽  
Lung Inflation ◽  
Airway Occlusion ◽  
Tracheal Pressure ◽  
Vagal Cooling ◽  
Vagal Influence

Vagal influence related to lung volume changes results in reduction in tidal volume during spontaneous breathing due primarily to premature termination of inspiration. The strength of this vagal influence was traditionally assessed by the duration of apnea following lung inflation, a method recently shown to be inadequate and potentially misleading. An alternate method is described utilizing analysis of the volume tracing of spontaneous breaths and the tracheal pressure tracing during the first breath following airway occlusion at FRC. A formula was devised which, on the basis of previous observations, should predict the tidal volume to be obtained in the absence of phasic vagal influence. The formula was tested in four pentobarbital-anesthetized rabbits using a technique of vagal cooling which rapidly eliminated the vagal influence under study. It was found that the tidal volume obtained following vagal block could be accurately predicted provided allowances were made for the vagally mediated terminal inhibition during spontaneous breathing and the relative stiffness of the respiratory system at high lung volumes.

Effects of galvanic mastoid stimulation in seated human subjects

2009 ◽  
Vol 106 (3) ◽  
pp. 893-903 ◽  
Author(s):  
Z. Ghanim ◽  
J. C. Lamy ◽  
A. Lackmy ◽  
V. Achache ◽  
N. Roche ◽  
...  
Keyword(s):  
Human Subjects ◽  
Normal Subjects ◽  
Standing Position ◽  
Reflex Response ◽  
Emg Activity ◽  
Free Standing ◽  
Vestibular Response ◽  
Vestibular Reflex ◽  
Tendon Jerk ◽  
Biphasic Responses

The vestibular responses evoked by transmastoid galvanic stimulation (GS) in the rectified soleus electromyogram (EMG) in freely standing human subjects disappear when seated. However, a GS-induced facilitation of the soleus monosynaptic (H and tendon jerk) reflex has been described in few experiments in subjects lying prone or seated. This study addresses the issue of whether this reflex facilitation while seated is of vestibulospinal origin. GS-induced responses in the soleus (modulation of the rectified ongoing EMG and of the monosynaptic reflexes) were compared in the same normal subjects while freely standing and sitting with back and head support. The polarity-dependent biphasic responses in the free-standing position were replaced by a non-polarity-dependent twofold facilitation while seated. The effects of GS were hardly detectable in the rectified ongoing voluntary EMG activity, weak for the H reflex, but large and constant for the tendon jerk. They were subject to habituation. Anesthesia of the skin beneath the GS electrodes markedly reduced the reflex facilitation, while a similar, although weaker, facilitation of the tendon jerk was observed when GS was replaced with purely cutaneous stimulation, a tap to the tendon of the sternomastoid muscle, or an auditory click. The stimulation polarity independence of the GS-induced reflex facilitation argues strongly against a vestibular response. However, the vestibular afferent volley, insufficient to produce a vestibular reflex response while seated, could summate with the GS-induced tactile or proprioceptive volley to produce a startle-like response responsible for the reflex facilitation.

scholarly journals Reproducibility of Cerebral Glucose Metabolic Measurements in Resting Human Subjects

1988 ◽  
Vol 8 (4) ◽  
pp. 502-512 ◽  
Author(s):  
Elsa J. Bartlett ◽  
Jonathan D. Brodie ◽  
Alfred P. Wolf ◽  
David R. Christman ◽  
Eugene Laska ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Brain Metabolism ◽  
Human Subjects ◽  
Normal Subjects ◽  
Time Of Day ◽  
Cerebral Glucose Metabolism ◽  
Whole Brain ◽  
Positron Emission ◽  
Subcortical Regions ◽  
Regional Cerebral Glucose Metabolism

Positron emission tomography with 11C-2-deoxyglucose was used to determine the test-retest variability of regional cerebral glucose metabolism in 22 young normal right-handed men scanned twice in a 24-h period under baseline (resting) conditions. To assess the effects of scan order and time of day on variability, 12 subjects were scanned in the morning and afternoon of the same day (a.m.-p.m.) and 10 in the reverse order (p.m.-a.m.) with a night in between. The effect of anxiety on metabolism was also assessed. Seventy-three percent of the total subject group showed changes in whole brain metabolism from the first to the second measurement of 10% or less, with comparable changes in various cortical and subcortical regions. When a scaling factor was used to equate the whole brain metabolism in the two scans for each individual, the resulting average regional changes for each group were no mote than 1%. This suggests that the proportion of the whole brain metabolism utilized regionally is stable in a group of subjects over time. Both groups of subjects had lower morning than afternoon metabolism, but the differences were slight in the p.m.-a.m. group. One measure of anxiety (pulse at fun 1) was correlated with run 1 metabolism and with the percentage of change from run 1 to run 2. No significant run 2 correlations were observed. This is the first study to measure test-retest variability in cerebral glucose metabolism in a large sample of young normal subjects. It demonstrates that the deoxyglucose method yields low Intrasubject variability and high stability over a 24-h period.

Mechanics of the rib cage and diaphragm during sleep

1977 ◽  
Vol 43 (4) ◽  
pp. 600-602 ◽  
Author(s):  
K. Tusiewicz ◽  
H. Moldofsky ◽  
A. C. Bryan ◽  
M. H. Bryan
Keyword(s):  
Tidal Volume ◽  
Supine Position ◽  
Marked Reduction ◽  
Normal Subjects ◽  
Upright Position ◽  
Rapid Eye Movement Sleep ◽  
Sleep State ◽  
Quiet Sleep ◽  
Rib Cage ◽  
The Subject

The pattern of motion of the rib cage and abdomen/diaphragm was studied in three normal subjects during sleep. Sleep state was monitored by electroencephalograph and electrocculograph. Intercostal electromyographs (EMG's) were recorded from the second interspace parasternally. Abdominothoracic motion was monitored with magnetometers and these signals calibrated by isovolume lines either immediately before going to sleep, or if there was movement, on awakening. Respiration was recorded using a jerkin plethysmograph. In the awake subject in the supine position, the rib cage contributed 44% to the tidal volume and had essentially the same contribution in quiet sleep. However, in active or rapid eye movement sleep the rib cage contribution fell to 19% of the tidal volume. This was accompanied by a marked reduction in the intercostal EMG. With the subject in the upright position the rib cage appears to be passively driven by the diaphragm. However, the present data suggest that active contraction of the intercostal muscles is required for normal rib cage expansion in the supine position.

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