Human Chest Wall Function during Epidural Anesthesia

1996 ◽  
Vol 85 (4) ◽  
pp. 761-773 ◽  
Author(s):  
David O. Warner ◽  
Mark A. Warner ◽  
Erik L. Ritman
Keyword(s):  
Chest Wall ◽  
Functional Residual Capacity ◽  
Muscle Activity ◽  
Respiratory Muscle ◽  
Sensory Level ◽  
Wall Function ◽  
Rib Cage ◽  
Residual Capacity ◽  
The Mean ◽  
Respiratory Muscle Activity

Background Although epidural anesthesia (EA) can significantly disrupt the function of the respiratory system, data concerning its effects on respiratory muscle activity and the resulting motion of the chest wall are scarce. This study aimed to determine the effects of lumbar EA on human chest wall function during quiet breathing. Methods Six persons were studied while awake and during mid-thoracic (approximately a T6 sensory level) and high (approximately a T1 sensory level) lumbar EA produced by either 2% lidocaine (two persons) or 1.5% etidocaine (four persons) with 1:200,000 epinephrine. Respiratory muscle activity was measured using fine-wire electromyography electrodes. Chest wall configuration during high EA was determined using images of the thorax obtained by three-dimensional, fast computed tomography. The functional residual capacity was measured using a nitrogen dilution technique. Results High EA abolished activity in the parasternal intercostal muscles of every participant but one, whereas the mean phasic activity of the scalene muscles was unchanged. High EA significantly decreased the inspiratory volume displacement of the rib cage compared with intact breathing but did not have a significant effect on diaphragm displacement. Therefore, high EA decreased the percentage contribution of rib cage expansion to inspiratory increases in thoracic volume (delta Vth) (from 27 +/- 2 [MSE] to 10 +/- 11% of delta Vth). Paradoxic rib cage motion during inspiration (i.e., a net inward motion during inspiration) developed in only one participant. High EA substantially increased the functional residual capacity (by 295 +/- 89 ml), with a significant net caudad motion of the end expiratory position of the diaphragm. In addition, high EA significantly decreased the volume of liquid in the thorax at end expiration in five of the six participants, a factor that also contributed to the increase in functional residual capacity in these persons. Conclusions Rib cage expansion continues to contribute to tidal volume during high EA in most subjects, even when most of the muscles of the rib cage are paralyzed; the mean phasic electrical activity of unblocked respiratory muscles such as scalenes does not increase in response to rib cage muscle paralysis produced by EA; and high EA increases the functional residual capacity, an increase produced in most participants by a caudad motion of the diaphragm and a decrease in intrathoracic blood volume.

Human Chest Wall Function while Awake and during Halothane Anesthesia 

1995 ◽  
Vol 82 (1) ◽  
pp. 6-19 ◽  
Author(s):  
David O. Warner ◽  
Mark A. Warner ◽  
Erik L. Ritman
Keyword(s):  
Chest Wall ◽  
Blood Volume ◽  
Functional Residual Capacity ◽  
Muscle Activity ◽  
Respiratory Muscle ◽  
Halothane Anesthesia ◽  
Intercostal Muscles ◽  
Residual Capacity ◽  
Gas Volume ◽  
Respiratory Muscle Activity

Background Data concerning chest wall configuration and the activities of the major respiratory muscles that determine this configuration during anesthesia in humans are limited. The aim of this study was to determine the effects of halothane anesthesia on respiratory muscle activity and chest wall shape and motion during spontaneous breathing. Methods Six human subjects were studied while awake and during 1 MAC halothane anesthesia. Respiratory muscle activity was measured using fine-wire electromyography electrodes. Chest wall configuration was determined using images of the thorax obtained by three-dimensional fast computed tomography. Tidal changes in gas volume were measured by integrating respiratory gas flow, and the functional residual capacity was measured by a nitrogen dilution technique. Results While awake, ribcage expansion was responsible for 25 +/- 4% (mean +/- SE) of the total change in thoracic volume (delta Vth) during inspiration. Phasic inspiratory activity was regularly present in the diaphragm and parasternal intercostal muscles. Halothane anesthesia (1 MAC) abolished activity in the parasternal intercostal muscles and increased phasic expiratory activity in the abdominal muscles and lateral ribcage muscles. However, halothane did not significantly change the ribcage contribution to delta Vth (18 +/- 4%). Intrathoracic blood volume, measured by comparing changes in total thoracic volume and gas volume, increased significantly during inspiration both while awake and while anesthetized (by approximately 20% of delta Vth, P < 0.05). Halothane anesthesia significantly reduced the functional residual capacity (by 258 +/- 78 ml), primarily via an inward motion of the end-expiratory position of the ribcage. Although the diaphragm consistently changed shape, with a cephalad displacement of posterior regions and a caudad displacement of anterior regions, the diaphragm did not consistently contribute to the reduction in the functional residual capacity. Halothane anesthesia consistently increased the curvature of the thoracic spine measured in the saggital plane. Conclusions The authors conclude that (1) ribcage expansion is relatively well preserved during halothane anesthesia despite the loss of parasternal intercostal muscle activity; (2) an inward displacement of the ribcage accounts for most of the decrease in functional residual capacity caused by halothane anesthesia, accompanied by changes in diaphragm shape that may be related to motion of its insertions on the thoracoabdominal wall; and (3) changes in intrathoracic blood volume constitute a significant fraction of delta Vth during tidal breathing.

Transmission of pressure across the chest wall during the rapid thoracic compression technique in infants

1994 ◽  
Vol 76 (4) ◽  
pp. 1411-1416 ◽  
Author(s):  
S. Stick ◽  
D. Turner ◽  
P. LeSouef
Keyword(s):  
Chest Wall ◽  
Functional Residual Capacity ◽  
Muscle Activity ◽  
Respiratory Muscle ◽  
Pleural Space ◽  
Lung Volumes ◽  
Pressure Transmission ◽  
Residual Capacity ◽  
Static Conditions ◽  
Respiratory Muscle Activity

During the rapid thoracic compression maneuver in infants, the transmission of pressure from compression jacket to pleural space and airway is less at functional residual capacity than at end inspiration. To examine whether reduced pressure transmission at functional residual capacity vs. higher lung volumes is explained by passive characteristics of the chest wall rather than by respiratory muscle activity, we assessed the pressure transmitted across the chest wall in nine anesthetized infants and young children after muscle relaxation. We measured esophageal and airway occlusion pressure during chest compressions at different lung volumes determined by varying distending pressure. In six subjects studied under static conditions, there was an approximately linear relationship between distending pressure and the proportion of pressure transmitted to the airway and esophagus from the compression jacket. The mean r2 value (95% confidence interval) was 0.80 (0.09) for pressure transmission to the airway and 0.85 (0.04) for pressure transmission to the esophagus. This relationship between lung volume and pressure transmission observed under static conditions was also demonstrated dynamically. Thus the reduced transmission of pressure from compression jacket to airway and pleural space at low lung volumes occurs independently of respiratory muscle activity.

Mechanical Significance of Respiratory Muscle Activity in Humans during Halothane Anesthesia

1996 ◽  
Vol 84 (2) ◽  
pp. 309-321. ◽  
Author(s):  
David O. Warner ◽  
Mark A. Warner ◽  
Erik L. Ritman
Keyword(s):  
Functional Residual Capacity ◽  
Muscle Activity ◽  
Respiratory Muscle ◽  
Intercostal Muscle ◽  
Halothane Anesthesia ◽  
Quiet Breathing ◽  
Scalene Muscle ◽  
Rib Cage ◽  
Expiratory Muscle ◽  
Residual Capacity

Background Prior human studies have shown that halothane attenuates activity in the parasternal intercostal muscle and enhances phasic activity in respiratory muscles with expiratory actions. This expiratory muscle activity could contribute to reductions in the functional residual capacity produced by anesthesia. Termination of this activity could contribute to the maintenance of inspiratory rib cage expansion. The purpose of this study was to estimate in humans the mechanical significance of expiratory muscle activity during halothane anesthesia and to search for the presence of scalene muscle activity during halothane anesthesia that might contribute to inspiratory rib cage expansion. Methods Six subjects (3 males, 3 females) were studied while awake and during 1.2 MAC halothane anesthesia, both during quiet breathing and during carbon dioxide rebreathing. Respiratory muscle activity was measured using fine-wire electromyography electrodes. Chest wall configuration was determined using images of the thorax obtained by three-dimensional, fast computed tomography and respiratory impedance plethysmography. Functional residual capacity was measured by a nitrogen dilution technique. Measurements were obtained after paralysis with 0.1 mg/kg vecuronium and mechanical ventilation. Results Phasic inspiratory activity was present in the scalene muscle of four anesthetized subjects during quiet breathing and all anesthetized subjects during rebreathing. Phasic inspiratory activity was present in the parasternal intercostal muscle during halothane anesthesia in only the three female subjects and was enhanced by rebreathing; parasternal intercostal muscle activity was never present in anesthetized males. During anesthesia with quiet breathing, phasic expiratory activity was observed in the transversus abdominis muscles of only the three male subjects. Despite these differences in the pattern of respiratory muscle use, the pattern of chest wall responses to rebreathing was similar between males and females. When expiratory muscle activity was present, paralysis increased the end-expiratory thoracic volume by expanding the rib cage, demonstrating that this activity reduced thoracic volume in these subjects. Changes in thoracic blood volume were significant determinants of the change in functional residual capacity produced by paralysis. Conclusions In humans anesthetized with 1.2 MAC end-tidal halothane, there are marked interindividual differences in respiratory muscle use during quiet breathing that may be related to sex; phasic inspiratory scalene muscle and parasternal intercostal muscle activity may contribute to inspiratory rib cage expansion in some subjects; and when present, expiratory muscle activity significantly constricts the rib cage and contributes to reductions in functional residual capacity caused by halothane anesthesia.

Effects of Inspiratory Load on Chest Wall Kinematics, Breathing Pattern, and Respiratory Muscle Activity of Mouth-Breathing Children

2020 ◽  
Vol 65 (9) ◽  
pp. 1285-1294
Author(s):  
Jéssica Danielle Medeiros da Fonsêca ◽  
Vanessa Regiane Resqueti ◽  
Kadja Benício ◽  
Valéria Soraya de Farias Sales ◽  
Luciana Fontes Silva da Cunha Lima ◽  
...  
Keyword(s):  
Chest Wall ◽  
Muscle Activity ◽  
Respiratory Muscle ◽  
Breathing Pattern ◽  
Mouth Breathing ◽  
Chest Wall Kinematics ◽  
Respiratory Muscle Activity ◽  
Inspiratory Load

scholarly journals Rib Cage Deformities Alter Respiratory Muscle Action and Chest Wall Function in Patients with Severe Osteogenesis Imperfecta

PLoS ONE ◽  
2012 ◽  
Vol 7 (4) ◽  
pp. e35965 ◽  
Author(s):  
Antonella LoMauro ◽  
Simona Pochintesta ◽  
Marianna Romei ◽  
Maria Grazia D'Angelo ◽  
Antonio Pedotti ◽  
...  
Keyword(s):  
Osteogenesis Imperfecta ◽  
Chest Wall ◽  
Respiratory Muscle ◽  
Muscle Action ◽  
Wall Function ◽  
Rib Cage

Chest Wall Responses to Rebreathing in Halothane-anesthetized Dogs

1995 ◽  
Vol 83 (4) ◽  
pp. 835-843. ◽  
Author(s):  
David O. Warner ◽  
Michael J. Joyner ◽  
Erik L. Ritman
Keyword(s):  
Chest Wall ◽  
Muscle Activity ◽  
Respiratory Muscle ◽  
Species Differences ◽  
Minimum Alveolar Concentration ◽  
Electromyographic Activity ◽  
Quiet Breathing ◽  
Rib Cage ◽  
Expiratory Muscle ◽  
Anesthetized Dogs

Background The pattern of respiratory muscle use during halothane-induced anesthesia differs markedly among species breathing quietly. In humans, halothane accentuates phasic activity in rib cage and abdominal expiratory muscles, whereas activity in the parasternal intercostal muscles is abolished. In contrast, halothane abolishes phasic expiratory muscle activity during quiet breathing in dogs, but parasternal muscle activity is maintained. Respiratory muscle responses to CO2 rebreathing were measured in halothane-anesthetized dogs to determine if species differences present during quiet breathing persist over a wide range of central respiratory drive. Methods Chronic electromyogram electrodes were implanted in three expiratory agonists (the triangularis sterni, transversus abdominis, and external oblique muscles) and three inspiratory agonists (the parasternal intercostal muscle, costal and crural diaphragm) of six mongrel dogs. After a 1-month recovery period, the dogs were anesthetized in the supine position with halothane. The rebreathing response was determined by Read's method during anesthesia with stable 1 and 2 minimum alveolar end-tidal concentrations of halothane. CO2 concentrations were measured in the rebreathing bag using an infrared analyzer. Chest wall motion was measured by fast three-dimensional computed tomographic scanning. Results Halothane concentration did not significantly affect the slope of the relationship between minute ventilation (VE) and PCO2 (0.34 +/- 0.04 [M +/- SE] and 0.28 +/- 0.05 l.min-1.mmHg-1 during 1 and 2 minimum alveolar concentration anesthesia, respectively). However, 2 minimum alveolar concentration anesthesia did significantly decrease the calculated VE at a PCO2 of 60 mmHg (from 7.4 +/- 1.2 to 4.0 +/- 0.6 l.min-1), indicating a rightward shift in the response relationship. No electromyographic activity was observed in any expiratory muscle before rebreathing. Rebreathing produced electromyographic activity in at least one expiratory muscle in only two dogs. Rebreathing significantly increased electromyographic activity in all inspiratory agonists. Rebreathing significantly increased inspiratory thoracic volume change (delta Vth), with percentage of delta Vth attributed to outward rib cage displacement increasing over the course of rebreathing during 1 minimum alveolar concentration anesthesia (from 33 +/- 6% to 48 +/- 2% of delta Vth). Conclusions Rebreathing did not produce expiratory muscle activation in most dogs, demonstrating that the suppression of expiratory muscle activity observed at rest persists at high levels of ventilatory drive. Other features of the rebreathing response also differed significantly from previous reports in halothane-anesthetized humans, including (1) an increase in the rib cage contribution to tidal volume during the course of rebreathing, (2) recruitment of parasternal intercostal activity by rebreathing, (3) differences in the response of ventilatory timing, and (4) the lack of effect of anesthetic depth on the slope of the ventilatory response. These marked species differences are further evidence that the dog is not a suitable model to study anesthetic effects on the activation of human respiratory muscles.

Effects of continuous positive airway pressure on upper airway and respiratory muscle activity

1987 ◽  
Vol 62 (5) ◽  
pp. 2026-2030 ◽  
Author(s):  
C. G. Alex ◽  
R. M. Aronson ◽  
E. Onal ◽  
M. Lopata
Keyword(s):  
Continuous Positive Airway Pressure ◽  
Respiratory System ◽  
Muscle Activity ◽  
Airway Pressure ◽  
Respiratory Muscle ◽  
Positive Airway Pressure ◽  
Upper Airway ◽  
Afferent Input ◽  
Residual Capacity ◽  
Respiratory Muscle Activity

To study the effects of continuous positive airway pressure (CPAP) on lung volume, and upper airway and respiratory muscle activity, we quantitated the CPAP-induced changes in diaphragmatic and genioglossal electromyograms, esophageal and transdiaphragmatic pressures (Pes and Pdi), and functional residual capacity (FRC) in six normal awake subjects in the supine position. CPAP resulted in increased FRC, increased peak and rate of rise of diaphragmatic activity (EMGdi and EMGdi/TI), decreased peak genioglossal activity (EMGge), decreased inspiratory time and inspiratory duty cycle (P less than 0.001 for all comparisons). Inspiratory changes in Pes and Pdi, as well as Pes/EMGdi and Pdi/EMGdi also decreased (P less than 0.001 for all comparisons), but mean inspiratory airflow for a given Pes increased (P less than 0.001) on CPAP. The increase in mean inspiratory airflow for a given Pes despite the decrease in upper airway muscle activity suggests that CPAP mechanically splints the upper airway. The changes in EMGge and EMGdi after CPAP application most likely reflect the effects of CPAP and the associated changes in respiratory system mechanics on the afferent input from receptors distributed throughout the intact respiratory system.

Vagal modulation of respiratory muscle activity in awake dogs during exercise and hypercapnia

1992 ◽  
Vol 72 (4) ◽  
pp. 1362-1367 ◽  
Author(s):  
D. M. Ainsworth ◽  
C. A. Smith ◽  
B. D. Johnson ◽  
S. W. Eicker ◽  
K. S. Henderson ◽  
...  
Keyword(s):  
Lung Volume ◽  
Muscle Activity ◽  
Respiratory Muscle ◽  
Treadmill Exercise ◽  
Rib Cage ◽  
Expiratory Muscle ◽  
Vagal Modulation ◽  
Vagal Cooling ◽  
Respiratory Muscle Activity

Using chronically instrumented awake tracheotomized dogs, we examined the contributions of vagal feedback to respiratory muscle activities, both electrical and mechanical, during normoxic hypercapnia (inspired CO2 fraction = 0.03, 0.04, 0.05, and 0.06) and during mild treadmill exercise (3, 4.3, and 6.4 km/h). Cooling exteriorized vagal loops eliminated both phasic and tonic mechanoreceptor input during either of these hyperpneas. At a given chemical or locomotor stimulus, vagal cooling caused a further increase in costal, crural, parasternal, and rib cage expiratory (triangularis sterni) muscles. No further change in abdominal expiratory muscle activity occurred secondary to vagal cooling during these hyperpneas. However, removal of mechanoreceptor input during hypercapnia was not associated with consistent changes in end-expiratory lung volume, as measured by the He-N2 rebreathe technique. We conclude that during these hyperpneas 1) vagal input is not essential for augmentation of expiratory muscle activity and 2) decrements in abdominal expiratory muscle activity may be offset by increments in rib cage expiratory muscle activity and contribute to the regulation of end-expiratory lung volume.

Lung volume for initiation of phonation

1965 ◽  
Vol 20 (3) ◽  
pp. 480-482 ◽  
Author(s):  
Michael S. Hoshiko
Keyword(s):  
Muscle Activity ◽  
Respiratory Muscle ◽  
Vital Capacity ◽  
Young Male ◽  
Standing Position ◽  
Young Female ◽  
Upright Posture ◽  
Quiet Breathing ◽  
The Mean ◽  
Respiratory Muscle Activity

The percent of vital capacity at which phonation is normally initiated was investigated. Thirty normal young male and thirty normal young female adults breathed oxygen in a closed circuit respirometer in a standing position. Vital capacity, expiratory reserve, tidal volume for breathing, and phonation volume were determined for each subject. The mean percent of vital capacity at which phonation is normally initiated was found to be 49.7 for males and 50.3 for females. These values approximate end-inspiratory volumes during quiet breathing in the upright posture. breath stream dynamics; communication; respiratory muscle activity; electromyography; respiration Submitted on July 13, 1964

Surface Recordings of Respiratory Muscle Activity during Speech

1989 ◽  
Vol 32 (3) ◽  
pp. 657-667 ◽  
Author(s):  
David H. McFarland ◽  
Anne Smith
Keyword(s):  
Chest Wall ◽  
Muscle Activity ◽  
Respiratory Muscle ◽  
Respiratory Muscles ◽  
Emg Activity ◽  
Breathing Cycle ◽  
Surface Electrodes ◽  
Disk Electrodes ◽  
Respiratory Muscle Activity ◽  
Accessory Respiratory Muscles

Bipolar electromyographic (EMG) recordings were made from six chest wall and nasal sites with disk electrodes attached to the skin. Electrode locations were based on previous studies of nonspeech breathing and were designed to sample the activity of both primary and accessory respiratory muscles. EMG activity was sampled while subjects performed a series of speech and nonspeeeh tasks. The results revealed that surface electrodes could sample the activity of respiratory muscles during speech and other ventilatory tasks, particularly during the expiratory phases of the breathing cycle.

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