Respiratory response to partial paralysis in anesthetized dogs

1984 ◽  
Vol 56 (6) ◽  
pp. 1583-1588 ◽  
Author(s):  
A. Oliven ◽  
E. C. Deal ◽  
S. G. Kelsen ◽  
N. S. Cherniack
Keyword(s):  
Motor Activity ◽  
Respiratory Muscle ◽  
Respiratory Muscles ◽  
Peak Activity ◽  
Inspiratory Time ◽  
Muscle Paralysis ◽  
Anesthetized Dogs ◽  
Spontaneously Breathing ◽  
Partial Paralysis

The ability to maintain alveolar ventilation is compromised by respiratory muscle weakness. To examine the independent role of reflexly mediated neural mechanisms to decreases in the strength of contraction of respiratory muscles, we studied the effects of partial paralysis on the level and pattern of phrenic motor activity in 22 anesthetized spontaneously breathing dogs. Graded weakness induced with succinylcholine decreased tidal volume and prolonged both inspiratory and expiratory time causing hypoventilation and hypercapnia. Phrenic peak activity as well as the rate of rise of the integrated phrenic neurogram increased. However, when studied under isocapnic conditions, increases in the severity of paralysis, as assessed from the ratio of peak diaphragm electromyogram to peak phrenic activity, produced progressive increases in inspiratory time and phrenic peak activity but did not affect its rate of rise. After vagotomy, partial paralysis induced in 11 dogs with succinylcholine also prolonged the inspiratory burst of phrenic activity, indicating that vagal reflexes were not solely responsible for the alterations in respiratory timing. Muscle paresis was also induced with gallamine or dantrolene, causing similar responses of phrenic activity and respiratory timing. Thus, at constant levels of arterial CO2 in anesthetized dogs, respiratory muscle partial paralysis results in a decrease in breathing rate without changing the rate of rise of respiratory motor activity. This is not dependent solely on vagally mediated reflexes and occurs regardless of the pharmacological agent used. These observations in the anesthetized state are qualitatively different from the response to respiratory muscle paralysis or weakness observed in awake subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanical role of expiratory muscles during breathing in upright dogs

1988 ◽  
Vol 64 (3) ◽  
pp. 1060-1067 ◽  
Author(s):  
G. A. Farkas ◽  
R. E. Baer ◽  
M. Estenne ◽  
A. De Troyer
Keyword(s):  
Tidal Volume ◽  
Progressive Increase ◽  
Substantial Contribution ◽  
Postural Changes ◽  
Before And After ◽  
Cervical Vagotomy ◽  
Anesthetized Dogs ◽  
Expiratory Muscles ◽  
Spontaneously Breathing

To examine the mechanical effects of the abdominal and triangularis sterni expiratory recruitment that occurs when anesthetized dogs are tilted head up, we measured both before and after cervical vagotomy the end-expiratory length of the costal and crural diaphragmatic segments and the end-expiratory lung volume (FRC) in eight spontaneously breathing animals during postural changes from supine (0 degree) to 80 degrees head up. Tilting the animals from 0 degree to 80 degrees head up in both conditions was associated with a gradual decrease in end-expiratory costal and crural diaphragmatic length and with a progressive increase in FRC. All these changes, however, were considerably larger (P less than 0.005 or less) postvagotomy when the expiratory muscles were no longer recruited with tilting. Alterations in the elastic properties of the lung could not account for the effects of vagotomy on the postural changes. We conclude therefore that 1) by contracting during expiration, the canine expiratory muscles minimize the shortening of the diaphragm and the increase in FRC that the action of gravity would otherwise introduce, and 2) the end-expiratory diaphragmatic length and FRC in upright dogs are thus actively determined. The present data also indicate that by relaxing at end expiration, the expiratory muscles make a substantial contribution to tidal volume in upright dogs; in the 80 degrees head-up posture, this contribution would amount to approximately 60% of tidal volume.

Failure of tracheal distension to inhibit breathing in anesthetized dogs

1980 ◽  
Vol 48 (5) ◽  
pp. 794-798 ◽  
Author(s):  
T. C. Lloyd ◽  
J. A. Cooper
Keyword(s):  
Tidal Volume ◽  
Lung Volume ◽  
Potential Role ◽  
Minute Volume ◽  
Abdominal Compression ◽  
Frequency Increase ◽  
Before And After ◽  
Anesthetized Dogs ◽  
Spontaneously Breathing

Using anesthetized spontaneously breathing dogs, we compared the respiratory effects of tracheal distension with the effects of changes in lung volume before and after vagotomy. We used an endotracheal tube with a long cuff to distend the trachea to pressures of 10, 20, and 40 cmH2O. Lung volume increases were imposed by expiratory threshold loading, and volume was decreased by abdominal compression, both of which caused outward rib cage displacement. During expiratory loading, the tidal volume was unchanged but respiratory frequency and minute volume fell and an active expiratory effort appeared; whereas frequency and minute volume rose, but tidal volume fell during abdominal compression. Tracheal distension evoked no discernible change in breathing. Following vagotomy, tidal volume and minute volume fell, and frequency rose slightly, during expiratory loading but abdominal compression was without effect. After vagotomy, 40 cmH2O tracheal distension caused a slight frequency increase. We concluded that the potential role of tracheal deformation in the reflex control of breathing is insignificant in comparison with the other airways.

Reflex effect of esophageal distension on respiratory muscle activity and pressure

1989 ◽  
Vol 66 (2) ◽  
pp. 536-541 ◽  
Author(s):  
A. Oliven ◽  
M. Haxhiu ◽  
S. G. Kelsen
Keyword(s):  
Motor Activity ◽  
Electrical Activity ◽  
Respiratory Muscle ◽  
Abdominal Cavity ◽  
Respiratory Muscles ◽  
Abdominal Pressure ◽  
Lung Inflation ◽  
Rib Cage ◽  
Expiratory Muscles ◽  
Crural Diaphragm

The electrical activity of the respiratory skeletal muscles is altered in response to reflexes originating in the gastrointestinal tract. The present study evaluated the reflex effects of esophageal distension (ED) on the distribution of motor activity to both inspiratory and expiratory muscles of the rib cage and abdomen and the resultant changes in thoracic and abdominal pressure during breathing. Studies were performed in 21 anesthetized spontaneously breathing dogs. ED was produced by inflating a balloon in the distal esophagus. ED decreased the activity of the costal and crural diaphragm and external intercostals and abolished all preexisting electrical activity in the expiratory muscles of the abdominal wall. On the other hand, ED increased the activity of the parasternal intercostals and expiratory muscles located in the rib cage (i.e., triangularis sterni and internal intercostal). All effects of ED were graded, with increasing distension exerting greater effects, and were eliminated by vagotomy. The effect of increases in chemical drive and lung inflation reflex activity on the response to ED was examined by performing ED while animals breathed either 6.5% CO2 or against graded levels of positive end-expiratory pressure (PEEP), respectively. Changes in respiratory muscle electrical activity induced by ED were similar (during 6.5% CO2 and PEEP) to those observed under control conditions. We conclude that activation of mechanoreceptors in the esophagus reflexly alters the distribution of motor activity to the respiratory muscles, inhibiting the muscles surrounding the abdominal cavity and augmenting the parasternals and expiratory muscles of the chest wall.

Breathing pattern of anesthetized humans during pancuronium-induced partial paralysis

1988 ◽  
Vol 64 (1) ◽  
pp. 78-83 ◽  
Author(s):  
T. Nishino ◽  
N. Yokokawa ◽  
K. Hiraga ◽  
Y. Honda ◽  
T. Mizuguchi
Keyword(s):  
Tidal Volume ◽  
Respiratory Muscles ◽  
Respiratory Frequency ◽  
Breathing Patterns ◽  
Inspiratory Time ◽  
Muscle Paralysis ◽  
Airway Occlusion ◽  
Enflurane Anesthesia ◽  
Before And After ◽  
The Face

We investigated the breathing patterns of 17 subjects anesthetized with enflurane before and after partial muscle paralysis produced by pancuronium bromide. In the face of significant muscle weakness produced by pancuronium, breathing patterns are characterized by decreases in both tidal volume and respiratory frequency. The decreased tidal volume corresponded to the decrease in occlusion pressure, indicating that the decreased tidal volume results solely from a decreased contractile force of the respiratory muscles. The decreased respiratory frequency was due to prolongation of both inspiratory and expiratory time without changing the ratio of the inspiratory time to the total breath time. Withdrawal of phasic vagal influence by airway occlusion before partial muscle paralysis revealed that an active Breuer-Hering inflation reflex was operative in only 8 of all 17 subjects. Since the contribution of the Breuer-Hering inflation reflex alone does not seem to account for the consistent decrease in respiratory frequency, some other mechanisms modulating respiratory frequency might be involved in the characteristic breathing patterns during partial muscle paralysis under enflurane anesthesia.

scholarly journals Reference values for respiratory muscle strength in brazilian children: a review

2016 ◽  
Vol 26 (3) ◽  
pp. 374
Author(s):  
Camila Isabel Santos Schivinski ◽  
Renata Maba Gonçalves ◽  
Tayná Castilho
Keyword(s):  
Muscle Strength ◽  
Reference Values ◽  
Respiratory Muscle ◽  
Respiratory Muscles ◽  
Respiratory Muscle Strength ◽  
Significant Difference ◽  
Reference Equations ◽  
Predicted Values ◽  
Brazilian Children

Introduction: Reference values and equations show strong variability and regional differences, despite a well-established role of the assessment of respiratory muscle strength (RMS) in children, with the objective to follow up on diseases that affect the function of respiratory muscles and enable adequate growth and development. Objective: To describe reference values and prediction equations of maximal respiratory pressures for Brazilian children. Methods: Literature review was conducted using databases LILACS, MEDLINE and Science Direct, and descriptors established by DeCS of the Virtual Health Library: reference values, child, respiratory muscle strength, predictive equations and their respective synonyms in English. Results: Six clinical trials were carried out, which determined reference values for children in various Brazilian regions. There was a relationship among RMS values and other factors, such as age, height and body mass. However, there was a significant difference among the data in the Brazilian states and divergence among the predicted values. Conclusion: There is a consensus on the relationship among RMS, anthropometric factors and regional influences. The articles studied reported diverging predicted values and reference equations.

Heterogeneity of metabolic activity in the canine parasternal intercostals during breathing

2001 ◽  
Vol 90 (3) ◽  
pp. 811-815 ◽  
Author(s):  
Alexandre Legrand ◽  
Serge Goldman ◽  
Philippe Damhaut ◽  
André De Troyer
Keyword(s):  
Spatial Distribution ◽  
Metabolic Activity ◽  
Volume Expansion ◽  
Respiratory Muscle ◽  
Respiratory Muscles ◽  
Mechanical Advantage ◽  
Fdg Uptake ◽  
Neural Input ◽  
Rostrocaudal Gradient ◽  
Spontaneously Breathing

In the dog, the inspiratory mechanical advantage of the parasternal intercostals shows a marked spatial heterogeneity, whereas the expiratory mechanical advantage of the triangularis sterni is relatively uniform. The contribution of a particular respiratory muscle to lung volume expansion during breathing, however, depends both on the mechanical advantage of the muscle and on its neural input. To evaluate the distribution of neural input across the canine parasternal intercostals and triangularis sterni, we have examined the distribution of metabolic activity among these muscles in seven spontaneously breathing animals by measuring the uptake of the glucose tracer analog [18F]fluorodeoxyglucose (FDG). FDG uptake in any given parasternal intercostal was greatest in the medial bundles and decreased rapidly toward the costochondral junctions. In addition, FDG uptake in the medial parasternal bundles increased from the first to the second interspace, plateaued in the second through fifth interspaces, and then decreased progressively toward the eighth interspace. In contrast, uptake in the triangularis sterni showed no significant rostrocaudal gradient. These results overall strengthen the idea that the spatial distribution of neural input within a particular set of respiratory muscles is closely matched with the spatial distribution of mechanical advantage.

scholarly journals Functional State of Respiratory Muscles in Patients with Chronic Obstructive Pulmonary Disease

2021 ◽  
Vol 99 (6) ◽  
pp. 15-21
Author(s):  
I. G. Kurpаtov ◽  
B. I. Geltser ◽  
V. N. Kotelnikov ◽  
M. F. Kinyaykin
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Pulmonary Disease ◽  
Respiratory Muscle ◽  
Respiratory Muscles ◽  
Strength Characteristics ◽  
Chronic Obstructive ◽  
Bronchial Obstruction ◽  
Muscle Dysfunction ◽  
Obstructive Pulmonary Disease

The objective: to assess the strength of respiratory muscles (RM) in patients with chronic obstructive pulmonary disease (COPD) and determine the role of certain pathogenetic factors of COPD in the development of respiratory muscle dysfunction.Subjects and methods. In in-patient settings, the strength characteristics of respiratory muscles were studied in 85 men aged 39-78 years suffering fromCOPD exacerbation. MicroRPM (CareFusion, UK) was used to determine the levels of maximum inspiratory and expiratory pressures in the oral cavity, maximum rate of their rise during inspiration and expiration as well as the level of intranasal pressure before and after the test with salbutamol.Results. Significant variability in strength characteristics of respiratory muscles was observed depending on the stage of COPD, its phenotype, and the presence of hypoxemia or hypercapnia. In patients at early stage of COPD, only expiratory respiratory muscle dysfunction was documented; at moderate and severe stages, inspiratory and expiratory muscle dysfunction was observed, and at very severe stage – diaphragm dysfunction prevailed. The results of the salbutamol test demonstrated the maximum increase in the strength of respiratory in early and moderate COPD and the minimum increase in extremely severeCOPD indicating the role of the irreversible component of bronchial obstruction in the development of respiratory muscle dysfunction. The emphysematous phenotype of COPD was characterized by inspiratory respiratory muscle dysfunction, while the bronchitic phenotype was characterized by expiratory respiratory muscle dysfunction. In patients with hypoxemia and hypercapnia, the strength of inspiratory respiratory muscle was lower versus normoxemia.

scholarly journals Respiratory muscle function in the newborn: a narrative review

2021 ◽  
Author(s):  
Theodore Dassios ◽  
Aggeliki Vervenioti ◽  
Gabriel Dimitriou
Keyword(s):  
Congenital Anomalies ◽  
Muscle Function ◽  
Respiratory Muscle ◽  
Work Of Breathing ◽  
Respiratory Muscles ◽  
Current Evidence ◽  
Muscle Fibres ◽  
List Type ◽  
Respiratory Muscle Function ◽  
Neurally Adjusted Ventilator Assist

Abstract Our aim was to summarise the current evidence and methods used to assess respiratory muscle function in the newborn, focusing on current and future potential clinical applications. The respiratory muscles undertake the work of breathing and consist mainly of the diaphragm, which in the newborn is prone to dysfunction due to lower muscle mass, flattened shape and decreased content of fatigue-resistant muscle fibres. Premature infants are prone to diaphragmatic dysfunction due to limited reserves and limited capacity to generate force and avoid fatigue. Methods to assess the respiratory muscles in the newborn include electromyography, maximal respiratory pressures, assessment for thoraco-abdominal asynchrony and composite indices, such as the pressure–time product and the tension time index. Recently, there has been significant interest and a growing body of research in assessing respiratory muscle function using bedside ultrasonography. Neurally adjusted ventilator assist is a novel ventilation mode, where the level of the respiratory support is determined by the diaphragmatic electrical activity. Prolonged mechanical ventilation, hypercapnia and hypoxia, congenital anomalies and systemic or respiratory infection can negatively impact respiratory muscle function in the newborn, while caffeine and synchronised or volume-targeted ventilation have a positive effect on respiratory muscle function compared to conventional, non-triggered or pressure-limited ventilation, respectively. Impact Respiratory muscle function is impaired in prematurely born neonates and infants with congenital anomalies, such as congenital diaphragmatic hernia. Respiratory muscle function is negatively affected by prolonged ventilation and infection and positively affected by caffeine and synchronised compared to non-synchronised ventilation modes. Point-of-care diaphragmatic ultrasound and neurally adjusted ventilator assist are recent diagnostic and therapeutic technological developments with significant clinical applicability.

Contraction of dog trachealis muscle in vivo: role of alpha-adrenergic receptors

1980 ◽  
Vol 48 (2) ◽  
pp. 329-336 ◽  
Author(s):  
W. H. Beinfield ◽  
J. Seifter
Keyword(s):  
Adrenergic Receptors ◽  
Beta Blockers ◽  
Systemic Arterial Pressure ◽  
Alpha Adrenergic Receptors ◽  
Bilateral Vagotomy ◽  
Cervical Trachea ◽  
Spontaneously Breathing ◽  
Trachealis Muscle

Contraction, relaxation, and longitudinal tension were recorded by isometric strain gauge arches attached to cervical tracheal muscle (CTM) in 60 spontaneously breathing dogs anesthetized with pentobarbital. Intravenous norepinephrine (NE) (3 X 10(-9), 6 X 10(-9), 1.2 X 10(-8), and 2.4 x 10(-8) mol/kg) increased spontaneous mechanical activities (SMA) and caused dose related contraction of CTM in all dogs even though there was no pretreatment with beta-blockers. These activities were first potentiated by propranolol and then prevented by phentolamine. NE briefly decreased SMA and induced CTM relaxation prior to the onset of contraction in one-third of dogs. Propranolol prevented this initial relaxation. CTM responses induced by NE were 1) not significantly altered by atropine, tripelennamine, bilateral vagotomy, curarization, and complete tracheal transection below transducer sites; 2) unrelated to passive constriction of cervical trachea associated with airway elongation; and 3) independent of reflexes initiated by elevations of systemic arterial pressure. The moles per kilogram doses of acetylcholine were found to exceed those of NE when their intravenous administration caused equal CTM contractions in the same dog. These findings are consistent with the existence of alpha-adrenergic receptors in CTM.

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