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Illidi CR, Romer LM. Stabilising function of the human diaphragm in response to involuntary augmented breaths induced with or without lower-limb movements. Exp Physiol 2022; 107:1477-1492. [PMID: 36177711 PMCID: PMC10092310 DOI: 10.1113/ep090605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 09/20/2022] [Indexed: 12/14/2022]
Abstract
NEW FINDINGS What is the central question of this study? Is the stabilising function of the diaphragm altered differentially in response to involuntary augmented breaths induced with or without lower-limb movements? What is the main finding and its importance? At equivalent levels of ventilation, the diaphragm generated higher passive pressure but moved significantly less during incremental cycle ergometry compared with progressive hypercapnia. Diaphragm excursion velocity and power output did not differ between the two tasks. These findings imply that the power output of the diaphragm during stabilising tasks involving the lower limbs may be preserved via coordinated changes in contractile shortening. ABSTRACT Activity of key respiratory muscles, such as the diaphragm, must balance the demands of ventilation with the maintenance of stable posture. Our aim was to test whether the stabilising function of the diaphragm would be altered differentially in response to involuntary augmented breaths induced with or without lower-limb movements. Ten healthy volunteers (age 21 (2) years; mean (SD)) performed progressive CO2 -rebreathe (5% CO2 , 95% O2 ) followed 20 min later by incremental cycle exercise (15-30 W/min), both in a semi-recumbent position. Ventilatory indices, intrathoracic pressures and ultrasonographic measures of diaphragm shortening were assessed before, during and after each task. From rest to iso-time, inspiratory tidal volume and minute ventilation increased two- to threefold. At equivalent levels of tidal volume and minute ventilation, mean inspiratory transdiaphragmatic pressure ( P ¯ di ${\bar P_{{\rm{di}}}}$ ) was consistently higher during exercise compared with CO2 -rebreathe due to larger increases in gastric pressure and the passive component of P ¯ di ${\bar P_{{\rm{di}}}}$ (i.e., mechanical output due to static contractions), and yet diaphragm excursion was consistently lower. This lower excursion during exercise was accompanied by a reduction in excursion time with no difference in the active component of P ¯ di ${\bar P_{{\rm{di}}}}$ . Consequently, the rates of increase in excursion velocity (excursion/time) and power output (active P ¯ di ${\bar P_{{\rm{di}}}}$ × velocity) did not differ between the two tasks. In conclusion, the power output of the human diaphragm during dynamic lower-limb exercise appears to be preserved via coordinated changes in contractile shortening. The findings may have significance in settings where the ventilatory and stabilising functions of the diaphragm must be balanced (e.g., rehabilitation).
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Affiliation(s)
- Camilla R Illidi
- Division of Sport, Health and Exercise Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UK
| | - Lee M Romer
- Division of Sport, Health and Exercise Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UK
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Tagliabue G, Ji M, Suneby Jagers JV, Zuege DJ, Kieser TM, Easton PA. Expiratory and Inspiratory Action of Transversus Abdominis During Eupnea and Hypercapnic Ventilation. Respir Physiol Neurobiol 2022; 306:103951. [PMID: 35914691 DOI: 10.1016/j.resp.2022.103951] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 07/20/2022] [Accepted: 07/24/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND Recently, there is interest in the clinical importance of monitoring abdominal muscles during respiratory failure. The clinical interpretation relies on the assumption that expiration is a passive physiologic process and, since diaphragm and abdomen are arranged in series, any inward motion of the abdominal wall represents a sign of diaphragm dysfunction. However, previous studies suggest Transversus Abdominis might be active even during eupnea and is preferentially recruited over the other abdominal muscles. OBJECTIVE 1) Is Transversus Abdominis normally recruited during eupnea? 2) What is the degree of activation of Transversus Abdominis during hypercapnia? 3) Does the end-inspiratory length of Transversus Abdominis change during hypercapnia, while diaphragm function is normal? METHODS In 30 spontaneously breathing canines, awake without confounding anesthetic, we measured directly both electrical activity and corresponding mechanical length and shortening of Transversus Abdominis during eupnea and hypercapnia. RESULTS Transversus Abdominis is consistently recruited during eupnea. During hypercapnia, Transversus Abdominis recruitment is progressive and significant. Throughout hypercapnia, Transversus Abdominis baseline end-inspiratory length is not constant: baseline length decreases progressively throughout hypercapnia. After expiration, into early inspiration, Transversus Abdominis shows a consistent neural mechanical post -expiratory expiratory activity (PEEA) at rest, which progressively increases during hypercapnia. CONCLUSION Transversus Abdominis is an obligatory expiratory muscle, reinforcing the fundamental principle expiration is not a passive process. Beyond expiration, during hypercapnic ventilation, Transversus Abdominis contributes as an "accessory inspiratory muscle" into the early phase of inspiration. Clinical monitoring of abdominal wall motion during respiratory failure may be confounded by action of Transversus Abdominis.
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Affiliation(s)
- Giovanni Tagliabue
- University of Calgary, Department of Critical Care Medicine, Calgary, Alberta, Canada
| | - Michael Ji
- University of Calgary, Department of Critical Care Medicine, Calgary, Alberta, Canada
| | - Jenny V Suneby Jagers
- University of Calgary, Department of Critical Care Medicine, Calgary, Alberta, Canada
| | - Dan J Zuege
- University of Calgary, Department of Critical Care Medicine, Calgary, Alberta, Canada
| | - Teresa M Kieser
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Paul A Easton
- University of Calgary, Department of Critical Care Medicine, Calgary, Alberta, Canada.
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Tagliabue G, Ji MS, Suneby Jagers JV, Zuege DJ, Kortbeek JB, Easton PA. Parasternal intercostal, costal, and crural diaphragm neural activation during hypercapnia. J Appl Physiol (1985) 2021; 131:672-680. [PMID: 34080922 DOI: 10.1152/japplphysiol.00261.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The parasternal intercostal is an obligatory inspiratory muscle working in coordination with the diaphragm, apparently sharing a common pathway of neural response. This similarity has attracted clinical interest, promoting the parasternal as a noninvasive alternative to the diaphragm, to monitor central neural respiratory output. However, this role may be confounded by the distinct and different functions of the costal and crural diaphragm. Given the anatomic location, parasternal activation may significantly impact the chest wall via both mechanical shortening or as a "fixator" for the chest wall. Either mechanical function of the parasternal may also impact differential function of the costal and crural. The objectives of the present study were, during eupnea and hypercapnia, 1) to compare the intensity of neural activation of the parasternal with the costal and crural diaphragm and 2) to examine parasternal recruitment and changes in mechanical action during progressive hypercapnia, including muscle baseline length and shortening. In 30 spontaneously breathing canines, awake without confounding anesthetic, we directly measured the electrical activity of the parasternal, costal, and crural diaphragm, and the corresponding mechanical shortening of the parasternal, during eupnea and hypercapnia. During eupnea and hypercapnia, the parasternal and costal diaphragm share a similar intensity of neural activation, whereas both differ significantly from crural diaphragm activity. The shortening of the parasternal increases significantly with hypercapnia, without a change in baseline end-expiratory length. In conclusion, the parasternal shares an equivalent intensity of neural activation with the costal, but not crural, diaphragm. The parasternal maintains and increases its active inspiratory shortening during augmented ventilation, despite high levels of diaphragm recruitment. Throughout hypercapnic ventilation, the parasternal contributes mechanically; it is not relegated to chest wall fixation.NEW & NOTEWORTHY This investigation directly compares neural activation of the parasternal intercostal muscle with the two distinct segments of the diaphragm, costal and crural, during room air and hypercapnic ventilation. During eupnea and hypercapnia, the parasternal intercostal muscle and costal diaphragm share a similar neural activation, whereas they both differ significantly from the crural diaphragm. The parasternal intercostal muscle maintains and increases active inspiratory mechanical action with shortening during ventilation, even with high levels of diaphragm recruitment.
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Affiliation(s)
- Giovanni Tagliabue
- Department of Critical Care Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Michael Sukjoon Ji
- Department of Critical Care Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jenny V Suneby Jagers
- Department of Critical Care Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Danny J Zuege
- Department of Critical Care Medicine, University of Calgary, Calgary, Alberta, Canada
| | - John B Kortbeek
- Department of Critical Care Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Paul A Easton
- Department of Critical Care Medicine, University of Calgary, Calgary, Alberta, Canada
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Noninvasive Assessment of Neuromechanical Coupling and Mechanical Efficiency of Parasternal Intercostal Muscle during Inspiratory Threshold Loading. SENSORS 2021; 21:s21051781. [PMID: 33806463 PMCID: PMC7961675 DOI: 10.3390/s21051781] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/26/2021] [Accepted: 02/28/2021] [Indexed: 11/17/2022]
Abstract
This study aims to investigate noninvasive indices of neuromechanical coupling (NMC) and mechanical efficiency (MEff) of parasternal intercostal muscles. Gold standard assessment of diaphragm NMC requires using invasive techniques, limiting the utility of this procedure. Noninvasive NMC indices of parasternal intercostal muscles can be calculated using surface mechanomyography (sMMGpara) and electromyography (sEMGpara). However, the use of sMMGpara as an inspiratory muscle mechanical output measure, and the relationships between sMMGpara, sEMGpara, and simultaneous invasive and noninvasive pressure measurements have not previously been evaluated. sEMGpara, sMMGpara, and both invasive and noninvasive measurements of pressures were recorded in twelve healthy subjects during an inspiratory loading protocol. The ratios of sMMGpara to sEMGpara, which provided muscle-specific noninvasive NMC indices of parasternal intercostal muscles, showed nonsignificant changes with increasing load, since the relationships between sMMGpara and sEMGpara were linear (R2 = 0.85 (0.75-0.9)). The ratios of mouth pressure (Pmo) to sEMGpara and sMMGpara were also proposed as noninvasive indices of parasternal intercostal muscle NMC and MEff, respectively. These indices, similar to the analogous indices calculated using invasive transdiaphragmatic and esophageal pressures, showed nonsignificant changes during threshold loading, since the relationships between Pmo and both sEMGpara (R2 = 0.84 (0.77-0.93)) and sMMGpara (R2 = 0.89 (0.85-0.91)) were linear. The proposed noninvasive NMC and MEff indices of parasternal intercostal muscles may be of potential clinical value, particularly for the regular assessment of patients with disordered respiratory mechanics using noninvasive wearable and wireless devices.
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Laghi F, Shaikh H, Littleton SW, Morales D, Jubran A, Tobin MJ. Inhibition of central activation of the diaphragm: a mechanism of weaning failure. J Appl Physiol (1985) 2020; 129:366-376. [PMID: 32673161 PMCID: PMC7473953 DOI: 10.1152/japplphysiol.00856.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
During a T-tube trial following disconnection of mechanical ventilation, patients failing the trial do not develop contractile diaphragmatic fatigue despite increases in inspiratory pressure output. Studies in volunteers, patients, and animals raise the possibility of spinal and supraspinal reflex mechanisms that inhibit central-neural output under loaded conditions. We hypothesized that diaphragmatic recruitment is submaximal at the end of a failed weaning trial despite concurrent respiratory distress. Tidal transdiaphragmatic pressure (ΔPdi) and electrical activity (ΔEAdi) were recorded with esophago-gastric catheters during a T-tube trial in 20 critically ill patients. During the T-tube trial, ∆EAdi was greater in weaning failure patients than in weaning success patients (P = 0.049). Despite increases in ΔPdi, from 18.1 ± 2.5 to 25.9 ± 3.7 cm H2O (P < 0.001), rate of transdiaphragmatic pressure development (from 22.6 ± 3.1 to 37.8 ± 6.7 cm H2O/s; P < 0.0004), and concurrent respiratory distress, ∆EAdi at the end of a failed T-tube trial was half of maximum, signifying inhibition of central neural output to the diaphragm. The increase in ΔPdi in the weaning failure group, while ∆EAdi remained constant, indicates unexpected improvement in diaphragmatic neuromuscular coupling (from 46.7 ± 6.5 to 57.8 ± 8.4 cm H2O/%; P = 0.006). Redistribution of neural output to the respiratory muscles characterized by a progressive increase in rib cage and accessory muscle contribution to tidal breathing and expiratory muscle recruitment contributed to enhanced coupling. In conclusion, diaphragmatic recruitment is submaximal at the end of a failed weaning trial despite concurrent respiratory distress. This finding signifies that reflex inhibition of central neural output to the diaphragm contributes to weaning failure. NEW & NOTEWORTHY Research into pathophysiology of failure to wean from mechanical ventilation has excluded several factors, including contractile fatigue, but the precise mechanism remains unknown. We recorded transdiaphragmatic pressure and diaphragmatic electrical activity in patients undergoing a T-tube trial. Diaphragmatic recruitment was submaximal at the end of a failed trial despite concurrent respiratory distress, signifying that inhibition of central neural output to the diaphragm is an important mechanism of weaning failure.
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Affiliation(s)
- Franco Laghi
- Division of Pulmonary and Critical Care Medicine, Hines Veterans Affairs Hospital, Hines, Illinois.,Division of Pulmonary and Critical Care Medicine, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois
| | - Hameeda Shaikh
- Division of Pulmonary and Critical Care Medicine, Hines Veterans Affairs Hospital, Hines, Illinois.,Division of Pulmonary and Critical Care Medicine, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois
| | - Stephen W Littleton
- Division of Pulmonary and Critical Care Medicine, Hines Veterans Affairs Hospital, Hines, Illinois.,Division of Pulmonary and Critical Care Medicine, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois
| | - Daniel Morales
- Division of Pulmonary and Critical Care Medicine, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois
| | - Amal Jubran
- Division of Pulmonary and Critical Care Medicine, Hines Veterans Affairs Hospital, Hines, Illinois.,Division of Pulmonary and Critical Care Medicine, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois
| | - Martin J Tobin
- Division of Pulmonary and Critical Care Medicine, Hines Veterans Affairs Hospital, Hines, Illinois.,Division of Pulmonary and Critical Care Medicine, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois
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Lozano-Garcia M, Sarlabous L, Moxham J, Rafferty GF, Torres A, Jolley CJ, Jane R. Assessment of Inspiratory Muscle Activation using Surface Diaphragm Mechanomyography and Crural Diaphragm Electromyography. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2018:3342-3345. [PMID: 30441104 DOI: 10.1109/embc.2018.8513046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The relationship between surface diaphragm mechanomyography (sMMGdi), as a noninvasive measure of inspiratory muscle mechanical activation, and crural diaphragm electromyography (oesEMGdi), as the invasive gold standard measure of diaphragm electrical activation, had not previously been examined. To investigate this relationship, oesEMGdi and sMMGdi were measured simultaneously in 6 healthy subjects during an incremental inspiratory threshold loading protocol, and analyzed using fixed sample entropy (fSampEn). A positive curvilinear relationship was observed between mean fSampEn sMMGdi and oesEMGdi (r = 0.67). Accordingly, an increasing electromechanical ratio was also observed with increasing inspiratory load. These findings suggest that sMMGdi could provide useful noninvasive measures of inspiratory muscle mechanical activation.
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7
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Finucane KE, Singh B. Role of bronchodilation and pattern of breathing in increasing tidal expiratory flow with progressive induced hypercapnia in chronic obstructive pulmonary disease. J Appl Physiol (1985) 2018; 124:91-98. [PMID: 28982946 DOI: 10.1152/japplphysiol.00752.2016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hypercapnia (HC) in vitro relaxes airway smooth muscle; in vivo, it increases respiratory effort, tidal expiratory flows (V̇exp), and, by decreasing inspiratory duration (Ti), increases elastic recoil pressure (Pel) via lung viscoelasticity; however, its effect on airway resistance is uncertain. We examined the contributions of bronchodilation, Ti, and expiratory effort to increasing V̇exp with progressive HC in 10 subjects with chronic obstructive pulmonary disease (COPD): mean forced expiratory volume in 1 s (FEV1) 53% predicted. Lung volumes (Vl), V̇exp, esophageal pressure (Pes), Ti, and end-tidal Pco2 ([Formula: see text]) were measured during six tidal breaths followed by an inspiratory capacity (IC), breathing air, and at three levels of HC. V̇exp and V̇ with submaximal forced vital capacities breathing air (V̇sFVC) were compared. Pulmonary resistance ( Rl) was measured from the Pes-V̇ relationship. V̇exp and Pes at end-expiratory lung volume (EELV) + 0.3 tidal volume [V̇(0.3Vt) and Pes(0.3Vt), respectively], Ti, and Rl correlated with [Formula: see text] ( P < 0.001 for all) and were independent of tiotropium. [Formula: see text], Ti, and Pes(0.3Vt) predicted the increasing V̇(0.3Vt)/V̇sFVC(0.3Vt) [multiple regression analysis (MRA): P = 0.001, 0.004, and 0.025, respectively]. At [Formula: see text] ≥ 50 Torr, V̇(0.3Vt)/V̇sFVC(0.3Vt) exceeded unity in 30 of 36 measurements and was predicted by [Formula: see text] and Pes(0.3Vt) (MRA: P = 0.02 and 0.025, respectively). Rl decreased at [Formula: see text] 45 Torr ( P < 0.05) and did not change with further HC. IC and Vl(0.3Vt) did not change with HC. We conclude that in COPD HC increases V̇exp due to bronchodilation, increased Pel secondary to decreasing Ti, and increased expiratory effort, all promoting lung emptying and a stable EELV. NEW & NOTEWORTHY The response of airways to intrapulmonary hypercapnia (HC) is uncertain. In chronic obstructive pulmonary disease (COPD), progressive HC increases tidal expiratory flows by inducing bronchodilation and via an increased rate of inspiration and lung viscoelasticity, a probable increase in lung elastic recoil pressure, both changes increasing expiratory flows, promoting lung emptying and a stable end-expiratory volume. Bronchodilation with HC occurred despite optimal standard bronchodilator therapy, suggesting that in COPD further bronchodilation is possible.
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Affiliation(s)
- Kevin E Finucane
- Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital , Nedlands, Western Australia , Australia.,West Australian Sleep Disorders Research Institute, Queen Elizabeth II Medical Centre , Perth, Western Australia , Australia
| | - Bhajan Singh
- Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital , Nedlands, Western Australia , Australia.,West Australian Sleep Disorders Research Institute, Queen Elizabeth II Medical Centre , Perth, Western Australia , Australia.,Faculty of Science, University of Western Australia, Perth, Western Australia, Australia
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Inspiratory muscle activation increases with COPD severity as confirmed by non-invasive mechanomyographic analysis. PLoS One 2017; 12:e0177730. [PMID: 28542364 PMCID: PMC5436747 DOI: 10.1371/journal.pone.0177730] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/02/2017] [Indexed: 11/19/2022] Open
Abstract
There is a lack of instruments for assessing respiratory muscle activation during the breathing cycle in clinical conditions. The aim of the present study was to evaluate the usefulness of the respiratory muscle mechanomyogram (MMG) for non-invasively assessing the mechanical activation of the inspiratory muscles of the lower chest wall in both patients with chronic obstructive pulmonary disease (COPD) and healthy subjects, and to investigate the relationship between inspiratory muscle activation and pulmonary function parameters. Both inspiratory mouth pressure and respiratory muscle MMG were simultaneously recorded under two different respiratory conditions, quiet breathing and incremental ventilatory effort, in 13 COPD patients and 7 healthy subjects. The mechanical activation of the inspiratory muscles was characterised by the non-linear multistate Lempel–Ziv index (MLZ) calculated over the inspiratory time of the MMG signal. Subsequently, the efficiency of the inspiratory muscle mechanical activation was expressed as the ratio between the peak inspiratory mouth pressure to the amplitude of the mechanical activation. This activation estimated using the MLZ index correlated strongly with peak inspiratory mouth pressure throughout the respiratory protocol in both COPD patients (r = 0.80, p<0.001) and healthy (r = 0.82, p<0.001). Moreover, the greater the COPD severity in patients, the greater the level of muscle activation (r = -0.68, p = 0.001, between muscle activation at incremental ventilator effort and FEV1). Furthermore, the efficiency of the mechanical activation of inspiratory muscle was lower in COPD patients than healthy subjects (7.61±2.06 vs 20.42±10.81, respectively, p = 0.0002), and decreased with increasing COPD severity (r = 0.78, p<0.001, between efficiency of the mechanical activation at incremental ventilatory effort and FEV1). These results suggest that the respiratory muscle mechanomyogram is a good reflection of inspiratory effort and can be used to estimate the efficiency of the mechanical activation of the inspiratory muscles. Both, inspiratory muscle activation and inspiratory muscle mechanical activation efficiency are strongly correlated with the pulmonary function. Therefore, the use of the respiratory muscle mechanomyogram can improve the assessment of inspiratory muscle activation in clinical conditions, contributing to a better understanding of breathing in COPD patients.
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Ghali MGZ, Marchenko V. Effects of vagotomy on hypoglossal and phrenic responses to hypercapnia in the decerebrate rat. Respir Physiol Neurobiol 2016; 232:13-21. [DOI: 10.1016/j.resp.2016.05.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 05/15/2016] [Accepted: 05/15/2016] [Indexed: 11/15/2022]
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10
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Beyer B, Van Sint Jan S, Chèze L, Sholukha V, Feipel V. Relationship between costovertebral joint kinematics and lung volume in supine humans. Respir Physiol Neurobiol 2016; 232:57-65. [PMID: 27421681 DOI: 10.1016/j.resp.2016.07.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 07/11/2016] [Accepted: 07/12/2016] [Indexed: 11/24/2022]
Abstract
This study investigates the relationship between the motion of the first ten costovertebral joints (CVJ) and lung volume over the inspiratory capacity (IC) using detailed kinematic analysis in a sample of 12 asymptomatic subjects. Retrospective codified spiral-CT data obtained at total lung capacity (TLC), middle of inspiratory capacity (MIC) and at functional residual capacity (FRC) were analysed. CVJ 3D kinematics were processed using previously-published methods. We tested the influence of the side, CVJ level and lung volume on CVJ kinematics. In addition, the correlations between anthropologic/pulmonary variables and CVJ kinematics were analysed. No linear correlation was found between lung volumes and CVJ kinematics. Major findings concerning 3D kinematics can be summarized as follows: 1) Ranges-of-motion decrease gradually with increasing CVJ level; 2) rib displacements are significantly reduced at lung volumes above the MIC and do not differ between CVJ levels; 3) the axes of rotation of the ribs are similarly oriented for all CVJ levels.
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Affiliation(s)
- Benoît Beyer
- Laboratory of Anatomy, Biomechanics and Organogenesis (L.A.B.O), Université Libre de Bruxelles, Brussels, Belgium; Laboratory of Functional Anatomy, Université Libre de Bruxelles, Brussels, Belgium; Univ Lyon, Université Claude Bernard Lyon 1, Ifsttar, UMR_T9406, LBMC, F69622 Lyon, France.
| | - Serge Van Sint Jan
- Laboratory of Anatomy, Biomechanics and Organogenesis (L.A.B.O), Université Libre de Bruxelles, Brussels, Belgium
| | - Laurence Chèze
- Univ Lyon, Université Claude Bernard Lyon 1, Ifsttar, UMR_T9406, LBMC, F69622 Lyon, France
| | - Victor Sholukha
- Laboratory of Anatomy, Biomechanics and Organogenesis (L.A.B.O), Université Libre de Bruxelles, Brussels, Belgium; Department of Applied Mathematics, Peter the Great St. Petersburg Polytechnic University (SPbPU), Russia
| | - Véronique Feipel
- Laboratory of Functional Anatomy, Université Libre de Bruxelles, Brussels, Belgium
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11
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Sarlabous L, Torres A, Fiz JA, Gea J, Martínez-Llorens JM, Jané R. Efficiency of mechanical activation of inspiratory muscles in COPD using sample entropy. Eur Respir J 2015; 46:1808-11. [PMID: 26493808 DOI: 10.1183/13993003.00434-2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 07/22/2015] [Indexed: 11/05/2022]
Affiliation(s)
- Leonardo Sarlabous
- Institut de Bioenginyeria de Catalunya (IBEC), Barcelona, Spain CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain
| | - Abel Torres
- Institut de Bioenginyeria de Catalunya (IBEC), Barcelona, Spain CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain Dept ESAII, Universitat Politècnica de Catalunya, Barcelona, Spain
| | - José A Fiz
- Institut de Bioenginyeria de Catalunya (IBEC), Barcelona, Spain CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain Dept of Pulmonology, Germans Trias i Pujol University Hospital, Badalona, Spain
| | - Joaquim Gea
- Respiratory Medicine Dept, Hospital del Mar - IMIM. DCEXS, UPF. CIBERES, ISCiii, Barcelona, Spain
| | - Juana M Martínez-Llorens
- Respiratory Medicine Dept, Hospital del Mar - IMIM. DCEXS, UPF. CIBERES, ISCiii, Barcelona, Spain
| | - Raimon Jané
- Institut de Bioenginyeria de Catalunya (IBEC), Barcelona, Spain CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona, Spain Dept ESAII, Universitat Politècnica de Catalunya, Barcelona, Spain
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12
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Akoumianaki E, Prinianakis G, Kondili E, Malliotakis P, Georgopoulos D. Physiologic comparison of neurally adjusted ventilator assist, proportional assist and pressure support ventilation in critically ill patients. Respir Physiol Neurobiol 2014; 203:82-9. [PMID: 25169117 DOI: 10.1016/j.resp.2014.08.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 08/08/2014] [Accepted: 08/19/2014] [Indexed: 10/24/2022]
Abstract
UNLABELLED To compare, in a group of difficult to wean critically ill patients, the short-term effects of neurally adjusted ventilator assist (NAVA), proportional assist (PAV+) and pressure support (PSV) ventilation on patient-ventilator interaction. METHODS Seventeen patients were studied during NAVA, PAV+ and PSV with and without artificial increase in ventilator demands (dead space in 10 and chest load in 7 patients). Prior to challenge addition the level of assist in each of the three modes tested was adjusted to get the same level of patient's effort. RESULTS Compared to PSV, proportional modes favored tidal volume variability. Patient effort increase after dead space was comparable among the three modes. After chest load, patient effort increased significantly more with NAVA and PSV compared to PAV+. Triggering delay was significantly higher with PAV+. The linear correlation between tidal volume and inspiratory integral of transdiaphragmatic pressure (PTPdi) was weaker with NAVA than with PAV+ and PSV on account of a weaker inspiratory integral of the electrical activity of the diaphragm (∫EAdi)-PTPdi linear correlation during NAVA [median (interquartile range) of r(2), determination of coefficient, 16.2% (1.4-30.9%)]. CONCLUSION Compared to PSV, proportional modes favored tidal volume variability. The weak ∫EAdi-PTPdi linear relationship during NAVA and poor triggering function during PAV+ may limit the effectiveness of these modes to proportionally assist the inspiratory effort.
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Affiliation(s)
- Evangelia Akoumianaki
- Intensive Care Medicine Department, University Hospital of Heraklion, Medical School, University of Crete, Heraklion, Crete, Greece
| | - George Prinianakis
- Intensive Care Medicine Department, University Hospital of Heraklion, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Eumorfia Kondili
- Intensive Care Medicine Department, University Hospital of Heraklion, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Polychronis Malliotakis
- Intensive Care Medicine Department, University Hospital of Heraklion, Medical School, University of Crete, Heraklion, Crete, Greece
| | - Dimitris Georgopoulos
- Intensive Care Medicine Department, University Hospital of Heraklion, Medical School, University of Crete, Heraklion, Crete, Greece.
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Abstract
OBJECTIVES To calculate an index (termed Pmusc/Eadi index) relating the pressure generated by the respiratory muscles (Pmusc) to the electrical activity of the diaphragm (Eadi), during assisted mechanical ventilation and to assess if the Pmusc/Eadi index is affected by the type and level of ventilator assistance. The Pmusc/Eadi index was also used to measure the patient's inspiratory effort from Eadi without esophageal pressure. DESIGN Crossover study. SETTING One general ICU. PATIENTS Ten patients undergoing assisted ventilation. INTERVENTION Pressure support and neurally adjusted ventilator assist delivered, each, at three levels of ventilatory assistance. MEASUREMENT AND MAIN RESULTS Airways flow and pressure, esophageal pressure, and Eadi were continuously recorded. Sixty tidal volumes for each ventilator settings were analyzed off-line, at three time points during inspiration. For each time point, Pmusc/Eadi index was calculated. Pmusc/Eadi index was also calculated from airway pressure drop during end-expiratory occlusions. Pmusc/Eadi index was very variable among patients, but within one patient it was not affected by type and level of ventilator assistance. Pmusc/Eadi index decreased during the inspiration. Pmusc/Eadi index obtained during an occlusion from airway pressure swing was tightly correlated with that derived from esophageal pressure during tidal ventilation and allowed to estimate pressure time product. CONCLUSIONS Pmusc is tightly related to Eadi, by a proportionality coefficient that we termed Pmusc/Eadi index, stable within each patient under different conditions of ventilator assistance. The derivation of the Pmusc/Eadi index from Eadi and airway pressure during an expiratory occlusion enables a continuous estimate of patient's inspiratory effort.
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Finucane KE, Singh B. Diaphragm efficiency estimated as power output relative to activation in chronic obstructive pulmonary disease. J Appl Physiol (1985) 2012; 113:1567-75. [PMID: 22995393 DOI: 10.1152/japplphysiol.01453.2011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Muscle efficiency increases with fiber length and decreases with load. Diaphragm efficiency (Eff(di)) in healthy humans, measured as power output (Wdi) relative to the root mean square of diaphragm electromyogram (RMS(di)), increases with hyperpnea due to phasic activity of abdominal muscles acting to increase diaphragm length at end expiration (L(di ee)) and decrease inspiratory load. In chronic obstructive pulmonary disease (COPD), hyperpnea may decrease Eff(di) if L(di ee) decreases and load increases due to airflow obstruction and dynamic hyperinflation. To examine this hypothesis, we measured Eff(di) in six COPD subjects (mean forced expiratory volume in 1 s: 54% predicted) when breathing air and at intervals during progressive hypercapnic hyperpnea. Wdi was measured as the product of mean inspiratory transdiaphragmatic pressure (ΔPdi(mean)), diaphragm tidal volume measured fluoroscopically, and 1/inspiratory duration. Results were compared with those of six healthy subjects reported previously. In COPD, L(di ee) was normal when breathing air. ΔPdi(mean) and Wdi increased normally, and RMS(di) increased disproportionately (P = 0.01) with hyperpnea, and, unlike health, inspiratory capacity (IC), L(di ee), and Eff(di) did not increase. IC and L(di ee) were constant with hyperpnea because mean expiratory flow increased as expiratory duration decreased (r(2) = 0.65), and because expiratory flow was terminated actively by the balance between expiratory and inspiratory muscle forces near end expiration, and these forces increased proportionately with hyperpnea (r(2) = 0.49). At maximum ventilation, diaphragm radius of curvature at end inspiration increased in COPD (P = 0.04) but not controls; diaphragm radius of curvature at end inspiration and ln(Eff(di)) were negatively correlated (P = 0.01). Thus in COPD with modest airflow obstruction, Eff(di) did not increase normally with hyperpnea due to a constant L(di ee) and inspiratory flattening of the diaphragm.
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Affiliation(s)
- Kevin E Finucane
- Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Nedlands, WA 6009, Australia.
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Liu L, Liu H, Yang Y, Huang Y, Liu S, Beck J, Slutsky AS, Sinderby C, Qiu H. Neuroventilatory efficiency and extubation readiness in critically ill patients. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2012; 16:R143. [PMID: 22849707 PMCID: PMC3580730 DOI: 10.1186/cc11451] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2012] [Accepted: 07/31/2012] [Indexed: 12/28/2022]
Abstract
Introduction Based on the hypothesis that failure of weaning from mechanical ventilation is caused by respiratory demand exceeding the capacity of the respiratory muscles, we evaluated whether extubation failure could be characterized by increased respiratory drive and impaired efficiency to generate inspiratory pressure and ventilation. Methods Airway pressure, flow, volume, breathing frequency, and diaphragm electrical activity were measured in a heterogeneous group of patients deemed ready for a spontaneous breathing trial. Efficiency to convert neuromuscular activity into inspiratory pressure was calculated as the ratio of negative airway pressure and diaphragm electrical activity during an inspiratory occlusion. Efficiency to convert neuromuscular activity into volume was calculated as the ratio of the tidal volume to diaphragm electrical activity. All variables were obtained during a 30-minute spontaneous breathing trial on continuous positive airway pressure (CPAP) of 5 cm H2O and compared between patients for whom extubation succeeded with those for whom either the spontaneous breathing trial failed or for those who passed, but then the extubation failed. Results Of 52 patients enrolled in the study, 35 (67.3%) were successfully extubated, and 17 (32.7%) were not. Patients for whom it failed had higher diaphragm electrical activity (48%; P < 0.001) and a lower efficiency to convert neuromuscular activity into inspiratory pressure and tidal volume (40% (P < 0.001) and 53% (P < 0.001)), respectively. Neuroventilatory efficiency demonstrated the greatest predictability for weaning success. Conclusions This study shows that a mixed group of critically ill patients for whom weaning fails have increased neural respiratory drive and impaired ability to convert neuromuscular activity into tidal ventilation, in part because of diaphragm weakness. Trial Registration Clinicaltrials.gov identifier NCT01065428. ©2012 Liu et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Assessment of patient-ventilator breath contribution during neurally adjusted ventilatory assist. Intensive Care Med 2012; 38:1224-32. [PMID: 22584798 DOI: 10.1007/s00134-012-2588-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Accepted: 04/17/2012] [Indexed: 10/28/2022]
Abstract
PURPOSE During neurally adjusted ventilatory assist (NAVA), it is difficult to quantify the relative contribution of the patient versus the ventilator to the inspiratory tidal volume (Vt(insp)). To solve this problem, we developed an index, the "patient-ventilator breath contribution" (PVBC), using the inspiratory deflection of the diaphragmatic electrical activity (∆EAdi) and Vt(insp) during assisted and non-assisted breaths. This study evaluated the PVBC index in an experimental setup. METHOD Nine intubated and sedated rabbits were studied during repeated ramp increases of the NAVA level. One breath was non-assisted at each NAVA level. The PVBC index was evaluated during resistive loading and after acute lung injury. PVBC was calculated by relating Vt(insp)/∆EAdi of a non-assisted breath to that of the preceding assisted breath. The PVBC was compared to the relative contribution of esophageal pressure (∆Pes) to transpulmonary pressure deflections (∆P (L,dyn)). RESULTS The relationship between PVBC and ∆Pes/∆P (L,dyn) was slightly curvilinear with an intercept different from zero (y = -1x (2 )+ 1.64x + 0.21) and a determination coefficient (R (2)) of 0.95. Squaring the PVBC values resulted in a near perfect linear relationship (y = 1.02x + 0.05) between PVBC(2) and ∆Pes/∆P (L,dyn) with an R (2) of 0.97. CONCLUSION This study shows that Vt(insp) and EAdi can be used to predict the contribution of the inspiratory muscles versus that of the ventilator during NAVA. If clinically applicable, this could serve to quantify and standardize the adjustment of the level of assist, and hence reduce the risks of excessive ventilatory assist. Further studies are required to evaluate if this method is clinically applicable.
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