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Maillart E, Redolfi S, Louapre C, Houot M, Chaugne E, Laveneziana P, Ungureanu A, Stankoff B, Arnulf I, Papeix C, Bodini B, Similowski T, Lubetzki C, Morélot-Panzini C. Clinical correlates of respiratory disorders in patients with severe multiple sclerosis: A cross-sectional cohort. Mult Scler 2024; 30:726-737. [PMID: 38519434 DOI: 10.1177/13524585241238840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2024]
Abstract
BACKGROUND Respiratory disorders remain incompletely described in multiple sclerosis (MS), even though they are a frequent cause of death. METHODS The objective was to describe respiratory disorders in MS patients with Expanded Disability Status Score (EDSS) ⩾ 6.5. Diaphragm dysfunction was defined by at least two of the seven criteria: clinical signs, inspiratory recruitment of neck muscles during wakefulness, reduced upright vital capacity (VC) < 80%, upright-to-supine VC ⩾ 15% of upright VC, decrease in Maximal Inspiratory Pressure < 60%, phasic activation of inspiratory neck muscles during sleep, and opposition of thoracic and abdominal movements during sleep. Cough weakness was defined by a peak cough flow < 270 L/min and/or need for cough assist. Sleep apnea syndrome was defined by an apnea-hypopnea index ⩾ 15. RESULTS Notably, 71 MS patients were included: median age 54 [48, 61] years; median disease duration 21.4 [16.0, 31.4] years. Of these, 52 patients had one or more respiratory disorders; diaphragm dysfunction was the most frequent (n = 34). Patients with diaphragm dysfunction and cough weakness were more disabled. The fatigue score and the cognitive evaluations did not differ between the groups. Five patients required non-invasive ventilation. CONCLUSION Respiratory disorders are frequent in severe MS, mostly diaphragm dysfunction. Of interest, instrumental interventions are available to address these disorders.
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Affiliation(s)
- Elisabeth Maillart
- Department of Neurology, AP-HP, Hôpital Pitié-Salpêtrière, Multiple Sclerosis Center, Paris, France
| | - Stefania Redolfi
- Sleep Disorders Unit, AP-HP, Hôpital Pitié-Salpêtrière, Paris, France
| | - Céline Louapre
- Department of Neurology, AP-HP, Hôpital Pitié-Salpêtrière, Multiple Sclerosis Center, Paris, France
| | - Marion Houot
- Centre of Excellence of Neurodegenerative Disease (CoEN), Salpetriere Hospital, Paris, France
- Institute of Memory and Alzheimer's Disease (IM2A), Department of Neurology, Salpetriere Hospital, AP-HP, Paris, France; Clinical Investigation Centre, Paris Brain Institute (ICM), Pitié-Salpêtrière Hospital, Paris, France
| | - Emeline Chaugne
- Department of Neurology, Fondation A. de Rothshchild Hospital, Paris, France
| | - Pierantonio Laveneziana
- AP-HP, Groupe Hospitalier Universitaire APHP-Sorbonne Université, Hôpitaux Pitié-Salpêtrière, Saint-Antoine et Tenon, Service des Explorations Fonctionnelles de la Respiration, de l'Exercice et de la Dyspnée (Département R3S), Paris, France
- Sorbonne Université, INSERM, UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France
- AP-HP, Groupe Hospitalier Universitaire APHP-Sorbonne Université, Hôpital Pitié-Salpêtrière, Centre de Référence Maladies Rares "Syndrome d'Ondine" (Département R3S), Paris, France
| | - Aurelian Ungureanu
- Department of Neurology, AP-HP, Hôpital Pitié-Salpêtrière, Multiple Sclerosis Center, Paris, France
| | - Bruno Stankoff
- Paris Brain Institute (ICM), AP-HP Sorbonne University, Paris, France
- Department of Neurology, Saint-Antoine Hospital, Paris, France
| | - Isabelle Arnulf
- Sleep Disorders Unit, AP-HP, Hôpital Pitié-Salpêtrière, Paris, France
| | - Caroline Papeix
- Department of Neurology, Fondation A. de Rothshchild Hospital, Paris, France
| | - Benedetta Bodini
- Paris Brain Institute (ICM), AP-HP Sorbonne University, Paris, France
- Department of Neurology, Saint-Antoine Hospital, Paris, France
| | - Thomas Similowski
- Sorbonne Université, INSERM, UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France
- AP-HP, Groupe Hospitalier Universitaire APHP-Sorbonne Université, Hôpital Pitié-Salpêtrière, Centre de Référence Maladies Rares "Syndrome d'Ondine" (Département R3S), Paris, France
| | - Catherine Lubetzki
- Department of Neurology, AP-HP, Hôpital Pitié-Salpêtrière, Multiple Sclerosis Center, Paris, France
| | - Capucine Morélot-Panzini
- Sorbonne Université, INSERM, UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France
- AP-HP, Groupe Hospitalier Universitaire APHP-Sorbonne Université, Hôpital Pitié-Salpêtrière, Centre de Référence Maladies Rares "Syndrome d'Ondine" (Département R3S), Paris, France
- AP-HP, Groupe Hospitalier Universitaire APHP-Sorbonne Université, Hôpital Pitié-Salpêtrière, Service de Pneumologie, Paris, France
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Helou LB, Dum RP. Volitional inspiration is mediated by two independent output channels in the primary motor cortex. J Comp Neurol 2023; 531:1796-1811. [PMID: 37723869 PMCID: PMC10591979 DOI: 10.1002/cne.25540] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 09/04/2023] [Accepted: 09/07/2023] [Indexed: 09/20/2023]
Abstract
The diaphragm is a multifunctional muscle that mediates both autonomic and volitional inspiration. It is critically involved in vocalization, postural stability, and expulsive core-trunk functions, such as coughing, hiccups, and vomiting. In macaque monkeys, we used retrograde transneuronal transport of rabies virus injected into the left hemidiaphragm to identify cortical neurons that have multisynaptic connections with phrenic motoneurons. Our research demonstrates that representation of the diaphragm in the primary motor cortex (M1) is split into two spatially separate and independent sites. No cortico-cortical connections are known to exist between these two sites. One site is located dorsal to the arm representation within the central sulcus and the second site is lateral to the arm. The dual representation of the diaphragm warrants a revision to the somatotopic map of M1. The dorsal diaphragm representation overlaps with trunk and axial musculature. It is ideally situated to coordinate with these muscles during volitional inspiration and in producing intra-abdominal pressure gradients. The lateral site overlaps the origin of M1 projections to a laryngeal muscle, the cricothyroid. This observation suggests that the coordinated control of laryngeal muscles and the diaphragm during vocalization may be achieved, in part, by co-localization of their representations in M1. The neural organization of the two diaphragm sites underlies a new perspective for interpreting functional imaging studies of respiration and/or vocalization. Furthermore, our results provide novel evidence supporting the concept that overlapping output channels within M1 are a prerequisite for the formation of muscle synergies underlying fine motor control.
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Affiliation(s)
- Leah B. Helou
- University of Pittsburgh, Department of Communication Science and Disorders, Pittsburgh, PA 15260
| | - Richard P. Dum
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260
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3
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Ramsook AH, Schaeffer MR, Mitchell RA, Dhillon SS, Milne KM, Ferguson ON, Puyat JH, Koehle MS, Sheel AW, Guenette JA. Voluntary activation of the diaphragm after inspiratory pressure threshold loading. Physiol Rep 2023; 11:e15575. [PMID: 36695772 PMCID: PMC9875816 DOI: 10.14814/phy2.15575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 12/28/2022] [Accepted: 01/01/2023] [Indexed: 06/17/2023] Open
Abstract
After a bout of isolated inspiratory work, such as inspiratory pressure threshold loading (IPTL), the human diaphragm can exhibit a reversible loss in contractile function, as evidenced by a decrease in transdiaphragmatic twitch pressure (PDI,TW ). Whether or not diaphragm fatigability after IPTL is affected by neural mechanisms, measured through voluntary activation of the diaphragm (D-VA) in addition to contractile mechanisms, is unknown. It is also unknown if changes in D-VA are similar between sexes given observed differences in diaphragm fatigability between males and females. We sought to determine whether D-VA decreases after IPTL and whether this was different between sexes. Healthy females (n = 11) and males (n = 10) completed an IPTL task with an inspired duty cycle of 0.7 and targeting an intensity of 60% maximal transdiaphragmatic pressure until task failure. PDI,TW and D-VA were measured using cervical magnetic stimulation of the phrenic nerves in combination with maximal inspiratory pressure maneuvers. At task failure, PDI,TW decreased to a lesser degree in females vs. males (87 ± 15 vs. 73 ± 12% baseline, respectively, p = 0.016). D-VA decreased after IPTL but was not different between females and males (91 ± 8 vs. 88 ± 10% baseline, respectively, p = 0.432). When all participants were pooled together, the decrease in PDI,TW correlated with both the total cumulative diaphragm pressure generation (R2 = 0.43; p = 0.021) and the time to task failure (TTF, R2 = 0.40; p = 0.30) whereas the decrease in D-VA correlated only with TTF (R2 = 0.24; p = 0.041). Our results suggest that neural mechanisms can contribute to diaphragm fatigability, and this contribution is similar between females and males following IPTL.
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Affiliation(s)
- Andrew H. Ramsook
- Department of Physical Therapy, Faculty of MedicineThe University of British ColumbiaVancouverBritish ColumbiaCanada
- Centre for Heart Lung Innovation, Providence ResearchThe University of British Columbia and St. Paul's HospitalVancouverBritish ColumbiaCanada
| | - Michele R. Schaeffer
- Department of Physical Therapy, Faculty of MedicineThe University of British ColumbiaVancouverBritish ColumbiaCanada
- Centre for Heart Lung Innovation, Providence ResearchThe University of British Columbia and St. Paul's HospitalVancouverBritish ColumbiaCanada
| | - Reid A. Mitchell
- Department of Physical Therapy, Faculty of MedicineThe University of British ColumbiaVancouverBritish ColumbiaCanada
- Centre for Heart Lung Innovation, Providence ResearchThe University of British Columbia and St. Paul's HospitalVancouverBritish ColumbiaCanada
| | - Satvir S. Dhillon
- Centre for Heart Lung Innovation, Providence ResearchThe University of British Columbia and St. Paul's HospitalVancouverBritish ColumbiaCanada
| | - Kathryn M. Milne
- Centre for Heart Lung Innovation, Providence ResearchThe University of British Columbia and St. Paul's HospitalVancouverBritish ColumbiaCanada
- Division of Respiratory Medicine, Faculty of MedicineThe University of British ColumbiaVancouverBritish ColumbiaCanada
| | - Olivia N. Ferguson
- Department of Physical Therapy, Faculty of MedicineThe University of British ColumbiaVancouverBritish ColumbiaCanada
- Centre for Heart Lung Innovation, Providence ResearchThe University of British Columbia and St. Paul's HospitalVancouverBritish ColumbiaCanada
| | - Joseph H. Puyat
- Centre for Health Evaluation and Outcome Services, Providence ResearchThe University of British Columbia and St. Paul's HospitalVancouverBritish ColumbiaCanada
| | - Michael S. Koehle
- School of Kinesiology, Faculty of EducationThe University of British ColumbiaVancouverBritish ColumbiaCanada
- Department of Family Practice, Faculty of MedicineThe University of British ColumbiaVancouverBritish ColumbiaCanada
| | - A. William Sheel
- Centre for Heart Lung Innovation, Providence ResearchThe University of British Columbia and St. Paul's HospitalVancouverBritish ColumbiaCanada
- School of Kinesiology, Faculty of EducationThe University of British ColumbiaVancouverBritish ColumbiaCanada
| | - Jordan A. Guenette
- Department of Physical Therapy, Faculty of MedicineThe University of British ColumbiaVancouverBritish ColumbiaCanada
- Centre for Heart Lung Innovation, Providence ResearchThe University of British Columbia and St. Paul's HospitalVancouverBritish ColumbiaCanada
- Division of Respiratory Medicine, Faculty of MedicineThe University of British ColumbiaVancouverBritish ColumbiaCanada
- School of Kinesiology, Faculty of EducationThe University of British ColumbiaVancouverBritish ColumbiaCanada
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Ramsook AH, Schaeffer MR, Mitchell RA, Dhillon SS, Milne KM, Ferguson ON, Puyat JH, Koehle MS, Sheel AW, Guenette JA. Sex Differences in Diaphragm Voluntary Activation after Exercise. Med Sci Sports Exerc 2022; 54:1167-1175. [PMID: 35195102 DOI: 10.1249/mss.0000000000002897] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
INTRODUCTION The female diaphragm develops less fatigue after high-intensity exercise compared with males. Diaphragm fatigability is typically defined as a decrease in transdiaphragmatic twitch pressure (Pdi,TW) and represents the contractile function of the muscle. However, it is unclear whether this sex difference persists when examining changes in voluntary activation, which represents a neural mechanism contributing to fatigability. PURPOSE This study aimed to determine if high-intensity cycling results in a decrease in diaphragm voluntary activation (D-VA) and to explore if the decrease in D-VA is different between sexes. METHODS Twenty-five participants (15 females) completed a single bout of high-intensity constant load cycling. D-VA and Pdi,TW were measured before and after exercise using cervical magnetic stimulation of the phrenic nerves to assess diaphragm fatigability. RESULTS Participants were of similar aerobic fitness when expressed relative to predicted values (females: 114% ± 25% predicted, males: 111% ± 11% predicted; P = 0.769). Pdi,TW decreased relative to baseline to 85.2% ± 16.7% and 70.3% ± 12.4% baseline (P = 0.012) in females and males, respectively, immediately after exercise. D-VA also decreased in both females and males immediately after exercise. The decrease in D-VA was less in females compared with males (95.4% ± 4.9% baseline vs 87.4% ± 10.8% baseline, respectively; P = 0.018). CONCLUSIONS D-VA decreases after whole-body exercise in both females and males, although the magnitude of the decrease is not as large in females compared with males. The findings of this study suggest that the female diaphragm is more resistant to both contractile and neural mechanisms of fatigability after whole-body exercise.
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Affiliation(s)
| | | | | | - Satvir S Dhillon
- Centre for Heart Lung Innovation, Providence Research, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, CANADA
| | | | | | - Joseph H Puyat
- Centre for Health Evaluation and Outcome Sciences, Providence Research, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, CANADA
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5
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Ivan C, Andrea A, Simon ES, Walter P, Leif S, Konrad M, Mathias B, Onnen M, Caspar S. The role of the TMS parameters for activation of the corticospinal pathway to the diaphragm. Clin Neurophysiol 2022; 138:173-185. [DOI: 10.1016/j.clinph.2022.03.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/12/2022] [Accepted: 03/20/2022] [Indexed: 11/03/2022]
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Daniel M, Lang E, Huynh TM, Martin J, Brebion M, Guessous K, Zlotnik D, Gouzien L, Chaouch O, Delval P, Ferraris A, Le Pimpec-Barthes F, Cholley B. Prevalence and time-course of diaphragmatic dysfunction following lung resection: A repeated ultrasonic assessment. Anaesth Crit Care Pain Med 2022; 41:101024. [PMID: 35121186 DOI: 10.1016/j.accpm.2022.101024] [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: 08/06/2021] [Revised: 11/02/2021] [Accepted: 11/03/2021] [Indexed: 11/01/2022]
Abstract
PURPOSE Ultrasound (US) allows non-invasive repeated assessments of diaphragmatic excursion (DE) and thickening fraction (DTF) at the bedside, reflecting diaphragmatic dysfunction (DD). We aimed at determining the prevalence and time-course of DD following elective thoracic surgery and the association with postoperative complications. MATERIAL AND METHODS Prospective, single-centre, observational study with consecutive patients undergoing thoracic surgery. DE/DTF were measured by two observers blinded to each other at 3 different time-points: prior to surgery, immediately after extubation and on postoperative day 3. The changes in DE/DTF of both hemi-diaphragms over time were compared according to the side (operated/non-operated) using a two-way-ANOVA. The association with postoperative complications was assessed using logistic regression. RESULTS Fifty patients, 60% males, aged 60 ± 15 years were included. Surgical procedures included lobectomy (n = 30), wedge-resection (n = 17) or pneumonectomy (n = 3). On the operated side, we observed a decrease in DE/DTF at D0 (-0.71 ± 0.12 mm, P < 0.05; -44 ± 30%, P < 0.05) and D3 (-0.82 ± 0.19 mm, P < 0.05; -39 ± 19%, P < 0.05) with respect to preoperative and non-operated side values over the study period. Persistent DD on the operated side was associated with an increased risk of lung infection (OR: 9.0, 95%CI [1.92-65.93], P = 0.001), ICU-admission (OR: 3.9, 95%CI [1.10-15.53], P = 0.04) according to univariate analysis and a prolonged length in hospital (OR: 1.3, 95%CI [1.1-1.7], P = 0.016) according to multivariate analysis. CONCLUSIONS Thoracic surgery generates DD mainly observed on the operated side, which persists at least up to postoperative D3 and is associated with an increase in hospital stay.
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Affiliation(s)
- Matthieu Daniel
- Department of Anaesthesiology and Intensive Care Medicine, Hôpital Européen Georges Pompidou, AP-HP, Paris, France; Université de Paris, Paris, France.
| | - Elodie Lang
- Department of Anaesthesiology and Intensive Care Medicine, Hôpital Européen Georges Pompidou, AP-HP, Paris, France; Université de Paris, Paris, France
| | - Thi Mum Huynh
- Department of Anaesthesiology and Intensive Care Medicine, Hôpital Européen Georges Pompidou, AP-HP, Paris, France; Université de Paris, Paris, France
| | - Julien Martin
- Department of Anaesthesiology and Intensive Care Medicine, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
| | - Myriam Brebion
- Department of Anaesthesiology and Intensive Care Medicine, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
| | - Karim Guessous
- Department of Anaesthesiology and Intensive Care Medicine, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
| | - Diane Zlotnik
- Department of Anaesthesiology and Intensive Care Medicine, Hôpital Européen Georges Pompidou, AP-HP, Paris, France; Université de Paris, Paris, France
| | - Laura Gouzien
- Department of Anaesthesiology and Intensive Care Medicine, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
| | - Oussama Chaouch
- Department of Anaesthesiology and Intensive Care Medicine, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
| | - Paul Delval
- Department of Anaesthesiology and Intensive Care Medicine, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
| | - Arnaud Ferraris
- Department of Anaesthesiology and Intensive Care Medicine, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
| | - Françoise Le Pimpec-Barthes
- Department of Thoracic surgery, Hôpital Européen Georges Pompidou, AP-HP, Paris, France; Université de Paris, Paris, France
| | - Bernard Cholley
- Department of Anaesthesiology and Intensive Care Medicine, Hôpital Européen Georges Pompidou, AP-HP, Paris, France; Université de Paris, Paris, France; Inserm UMR_S 1140 "Innovations Thérapeutiques en Hémostase", Paris, France
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Abstract
The clinical term dyspnea (a.k.a. breathlessness or shortness of breath) encompasses at least three qualitatively distinct sensations that warn of threats to breathing: air hunger, effort to breathe, and chest tightness. Air hunger is a primal homeostatic warning signal of insufficient alveolar ventilation that can produce fear and anxiety and severely impacts the lives of patients with cardiopulmonary, neuromuscular, psychological, and end-stage disease. The sense of effort to breathe informs of increased respiratory muscle activity and warns of potential impediments to breathing. Most frequently associated with bronchoconstriction, chest tightness may warn of airway inflammation and constriction through activation of airway sensory nerves. This chapter reviews human and functional brain imaging studies with comparison to pertinent neurorespiratory studies in animals to propose the interoceptive networks underlying each sensation. The neural origins of their distinct sensory and affective dimensions are discussed, and areas for future research are proposed. Despite dyspnea's clinical prevalence and impact, management of dyspnea languishes decades behind the treatment of pain. The neurophysiological bases of current therapeutic approaches are reviewed; however, a better understanding of the neural mechanisms of dyspnea may lead to development of novel therapies and improved patient care.
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Affiliation(s)
- Andrew P Binks
- Department of Basic Science Education, Virginia Tech Carilion School of Medicine, Roanoke, VA, United States; Faculty of Health Sciences, Virginia Tech, Blacksburg, VA, United States.
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8
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Epiu I, Gandevia SC, Boswell-Ruys CL, Basha C, Archer SNJ, Butler JE, Hudson AL. Inspiratory muscle responses to sudden airway occlusion in chronic obstructive pulmonary disease. J Appl Physiol (1985) 2021; 131:36-44. [PMID: 33955264 DOI: 10.1152/japplphysiol.00017.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Brief airway occlusion produces a potent reflex inhibition of inspiratory muscles that is thought to protect against aspiration. Its duration is prolonged in asthma and obstructive sleep apnea. We assessed this inhibitory reflex (IR) in chronic obstructive pulmonary disease (COPD). Reflex responses to brief (250 ms) inspiratory occlusions were measured in 18 participants with moderate to severe COPD (age 73 ± 11 yr) and 17 healthy age-matched controls (age 72 ± 6 yr). We compared the incidence and properties of the IR between groups. Median eupneic preocclusion electromyographic activity was higher in the COPD group than controls (9.4 μV vs. 5.2 μV, P = 0.001). Incidence of the short-latency IR was higher in the COPD group compared with controls (15 participants vs. 7 participants, P = 0.010). IR duration for scalenes was similar for the COPD and control groups [73 ± 37 ms (means ± SD) and 90 ± 50 ms, respectively] as was the magnitude of inhibition. IRs in the diaphragm were not detected in the controls but were present in 9 participants of the COPD group (P = 0.001). The higher incidence of the IR in the COPD group than in the age-matched controls may reflect the increased inspiratory neural drive in the COPD group. This higher drive counteracts changes in chest wall and lung mechanics. However, when present, the reflex was similar in size and duration in the two groups. The relation between the IR in COPD and swallowing function could be assessed.NEW & NOTEWORTHY A potent short-latency reflex inhibition of inspiratory muscles produced by airway occlusion was tested in people with COPD and age-matched controls. The reflex was more prevalent in COPD, presumably due to an increased neural drive to breathe. When present, the reflex was similar in duration in the two groups, longer than historical data for younger control groups. The work reveals novel differences in reflex control of inspiratory muscles due to aging as well as COPD.
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Affiliation(s)
- Isabella Epiu
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.,Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Simon C Gandevia
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.,Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Claire L Boswell-Ruys
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.,Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Chanelle Basha
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,Department of Physiotherapy, Macquarie University, Sydney, New South Wales, Australia
| | - Sean N J Archer
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,Department of Physiotherapy, Macquarie University, Sydney, New South Wales, Australia
| | - Jane E Butler
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Anna L Hudson
- Neuroscience Research Australia, Sydney, New South Wales, Australia.,Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
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MacAskill W, Hoffman B, Johnson MA, Sharpe GR, Mills DE. Pressure measurement characteristics of a micro-transducer and balloon catheters. Physiol Rep 2021; 9:e14831. [PMID: 33938126 PMCID: PMC8090844 DOI: 10.14814/phy2.14831] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 03/14/2021] [Indexed: 11/24/2022] Open
Abstract
Respiratory pressure responses to cervical magnetic stimulation are important measurements in monitoring the mechanical function of the respiratory muscles. Pressures can be measured using balloon catheters or a catheter containing integrated micro‐transducers. However, no research has provided a comprehensive analysis of their pressure measurement characteristics. Accordingly, the aim of this study was to provide a comparative analysis of these characteristics in two separate experiments: (1) in vitro with a reference pressure transducer following a controlled pressurization; and (2) in vivo following cervical magnetic stimulations. In vitro the micro‐transducer catheter recorded pressure amplitudes and areas which were in closer agreement to the reference pressure transducer than the balloon catheter. In vivo there was a main effect for stimulation power and catheter for esophageal (Pes), gastric (Pga), and transdiaphragmatic (Pdi) pressure amplitudes (p < 0.001) with the micro‐transducer catheter recording larger pressure amplitudes. There was a main effect of stimulation power (p < 0.001) and no main effect of catheter for esophageal (p = 0.481), gastric (p = 0.923), and transdiaphragmatic (p = 0.964) pressure areas. At 100% stimulator power agreement between catheters for Pdi amplitude (bias =6.9 cmH2O and LOA −0.61 to 14.27 cmH2O) and pressure areas (bias = −0.05 cmH2O·s and LOA −1.22 to 1.11 cmH2O·s) were assessed. At 100% stimulator power, and compared to the balloon catheters, the micro‐transducer catheter displayed a shorter 10–90% rise time, contraction time, latency, and half‐relaxation time, alongside greater maximal rates of change in pressure for esophageal, gastric, and transdiaphragmatic pressure amplitudes (p < 0.05). These results suggest that caution is warranted if comparing pressure amplitude results utilizing different catheter systems, or if micro‐transducers are used in clinical settings while applying balloon catheter‐derived normative values. However, pressure areas could be used as an alternative point of comparison between catheter systems.
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Affiliation(s)
- William MacAskill
- Respiratory and Exercise Physiology Research Group, School of Health and Wellbeing, University of Southern Queensland, Ipswich, Australia.,Centre for Health Research, Institute for Resilient Regions, University of Southern Queensland, Ipswich, Australia
| | - Ben Hoffman
- Respiratory and Exercise Physiology Research Group, School of Health and Wellbeing, University of Southern Queensland, Ipswich, Australia.,Centre for Health Research, Institute for Resilient Regions, University of Southern Queensland, Ipswich, Australia.,School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Australia
| | - Michael A Johnson
- Exercise and Health Research Group, Sport, Health and Performance Enhancement (SHAPE) Research Centre, School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
| | - Graham R Sharpe
- Exercise and Health Research Group, Sport, Health and Performance Enhancement (SHAPE) Research Centre, School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
| | - Dean E Mills
- Respiratory and Exercise Physiology Research Group, School of Health and Wellbeing, University of Southern Queensland, Ipswich, Australia.,Centre for Health Research, Institute for Resilient Regions, University of Southern Queensland, Ipswich, Australia
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10
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Spiesshoefer J, Henke C, Herkenrath S, Randerath W, Brix T, Young P, Boentert M. Assessment of Central Drive to the Diaphragm by Twitch Interpolation: Normal Values, Theoretical Considerations, and Future Directions. Respiration 2020; 98:283-293. [PMID: 31352459 DOI: 10.1159/000500726] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 04/30/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The twitch interpolation technique is a promising tool for assessing central drive to the diaphragm. It is used to quantify the degree of voluntary diaphragm activation during predefined breathing maneuvers. OBJECTIVES This study was designed to (a) determine reference values for the level of voluntary activation of the diaphragm using the twitch occlusion technique in healthy adults and (b) explore the association between central drive to the diaphragm and volitional tests of respiratory muscle strength. METHODS Twenty-seven healthy volunteers aged 26 ± 14 years (18 male) were enrolled. Twitch transdiaphragmatic pressure (Pdi) was determined at relaxed functional residual capacity in response to cervical magnetic stimulation (CMS) of the phrenic nerves. The subjects were then instructed to gradually increase voluntary activation of the diaphragm, and the effects of superimposed magnetic stimuli on voluntary Pdi were assessed. RESULTS The twitch Pdi amplitude following CMS linearly decreased with increasing inspiratory effort. The resulting diaphragm voluntary activation index (DVAI) during maximal voluntary contraction was 75 ± 15% irrespective of gender or age. Twitch duration, half relaxation time, and area under the curve of superimposed Pdi deflections did not show a linear but an exponential association with increasing voluntary activation of the diaphragm. More than 2/3 of the decrease in the above values was evident after 1/3 of voluntary diaphragm contraction. Forced vital capacity (FVC) was inversely correlated with the DVAI. CONCLUSIONS Twitch interpolation allows for assessment of central drive to the diaphragm. The maximum DVAI is independent of gender or age, and significantly related to FVC but not to maximum inspiratory pressure or Pdi as direct measures of diaphragm strength.
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Affiliation(s)
- Jens Spiesshoefer
- Respiratory Physiology Laboratory, Department of Neurology with Institute for Translational Neurology, University of Münster, Münster, Germany,
| | - Carolin Henke
- Respiratory Physiology Laboratory, Department of Neurology with Institute for Translational Neurology, University of Münster, Münster, Germany
| | - Simon Herkenrath
- Bethanien Hospital gGmbH Solingen, Solingen, Germany.,Institute of Pneumology, University of Cologne, Solingen, Germany
| | - Winfried Randerath
- Bethanien Hospital gGmbH Solingen, Solingen, Germany.,Institute of Pneumology, University of Cologne, Solingen, Germany
| | - Tobias Brix
- Institute of Medical Informatics, University of Münster, Münster, Germany
| | - Peter Young
- Medical Park Klinik Reithofpark, Bad Feilnbach, Germany
| | - Matthias Boentert
- Respiratory Physiology Laboratory, Department of Neurology with Institute for Translational Neurology, University of Münster, Münster, Germany
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Ramsook AH, Molgat-Seon Y, Boyle KG, Mitchell RA, Puyat JH, Koehle MS, Sheel AW, Guenette JA. Reliability of diaphragm voluntary activation measurements in healthy adults. Appl Physiol Nutr Metab 2020; 46:247-256. [PMID: 32910865 DOI: 10.1139/apnm-2020-0221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Voluntary activation can be used to assess central fatigue of the diaphragm after tasks such as exercise or inspiratory muscle loading. Cervical magnetic stimulation (CMS) of the phrenic nerves elicits an involuntary contraction, or twitch, of the diaphragm. This twitch is quantified based on a measure of transdiaphragmatic pressure and can be used to evaluate diaphragm contractile function and diaphragm voluntary activation (diaphragm-VA). The test-retest reliability of diaphragm-VA using CMS is currently unknown. Thirteen participants (4 male, 9 female; aged 25 ± 3 years) performed a series of interpolated twitch manoeuvres, which included a maximal inspiratory effort against a semi-occluded mouthpiece and 2 CMS-stimuli, 1 during the inspiratory manoeuvre and 1 after when the participant returned to functional residual capacity to quantify diaphragm-VA. Intraclass correlation coefficients (ICCs) and standard error of measurement (SEM) measured between-day and within-session reliability of diaphragm-VA, respectively. Maximal diaphragm-VA values were 91% (SD: 6; SEM: 3.9) and 92% (SD: 5; SEM: 2.2) during visits 1 and 2 (p = 0.68), respectively, and displayed "good" between-day reliability (ICC: 0.88; 95% confidence interval: 0.67-0.95; SEM: 2.7). Our results suggest that assessing diaphragm-VA using CMS is reliable in young healthy adults. Measuring diaphragm-VA may provide additional insight into the consequences and mechanisms of diaphragm fatigue. Novelty: Magnetic stimulation of the phrenic nerves can reliably measure voluntary activation of the diaphragm. Diaphragm voluntary activation can be used to provide additional insight into fatigability of the diaphragm.
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Affiliation(s)
- Andrew H Ramsook
- Department of Physical Therapy, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Yannick Molgat-Seon
- Department of Physical Therapy, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada.,Department of Kinesiology and Applied Health, Faculty of Kinesiology and Applied Health, The University of Winnipeg, Winnipeg, Manitoba, Canada
| | - Kyle G Boyle
- Department of Physical Therapy, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Reid A Mitchell
- Department of Physical Therapy, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Joseph H Puyat
- Centre for Health Evaluation and Outcome Services, Providence Health Care Research Institute, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Michael S Koehle
- School of Kinesiology, Faculty of Education, The University of British Columbia, Vancouver, British Columbia, Canada.,Department of Family Practice, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada
| | - A William Sheel
- Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada.,School of Kinesiology, Faculty of Education, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Jordan A Guenette
- Department of Physical Therapy, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada.,School of Kinesiology, Faculty of Education, The University of British Columbia, Vancouver, British Columbia, Canada
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12
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Spiesshoefer J, Henke C, Herkenrath S, Brix T, Randerath W, Young P, Boentert M. Transdiapragmatic pressure and contractile properties of the diaphragm following magnetic stimulation. Respir Physiol Neurobiol 2019; 266:47-53. [DOI: 10.1016/j.resp.2019.04.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 02/12/2019] [Accepted: 04/23/2019] [Indexed: 11/28/2022]
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13
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Spiesshoefer J, Henke C, Kabitz HJ, Brix T, Görlich D, Herkenrath S, Randerath W, Young P, Boentert M. The nature of respiratory muscle weakness in patients with late-onset Pompe disease. Neuromuscul Disord 2019; 29:618-627. [PMID: 31327549 DOI: 10.1016/j.nmd.2019.06.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 03/31/2019] [Accepted: 06/18/2019] [Indexed: 11/24/2022]
Abstract
Late-onset Pompe disease (LOPD) causes myopathy of skeletal and respiratory muscles, and phrenic nerve pathology putatively contributes to diaphragm weakness. The aim of this study was to investigate neural contributions to diaphragm dysfunction, usefulness of diaphragm ultrasound, and involvement of expiratory abdominal muscles in LOPD. Thirteen patients with LOPD (7 male, 51±17 years) and 13 age- and gender-matched controls underwent respiratory muscle strength testing, ultrasound evaluation of diaphragm excursion and thickness, cortical and cervical magnetic stimulation (MS) of the diaphragm with simultaneous recording of surface electromyogram and twitch transdiaphragmatic pressure (twPdi; n = 6), and MS of the abdominal muscles with recording of twitch gastric pressure (twPgas; n = 6). The following parameters were significantly reduced in LOPD patients versus controls: forced vital capacity (p<0.01), maximum inspiratory and expiratory pressure (both p<0.001), diaphragm excursion velocity (p<0.05), diaphragm thickening ratio (1.8 ± 0.4 vs. 2.6 ± 0.6, p<0.01), twPdi following cervical MS (12.0 ± 6.2 vs. 19.4 ± 4.8 cmH2O, p<0.05), and twPgas following abdominal muscle stimulation (8.8 ± 8.1 vs. 34.6 ± 17.1 cmH2O, p<0.01). Diaphragm motor evoked potentials and compound muscle action potentials showed no between-group differences. In conclusion, phrenic nerve involvement in LOPD could not be electrophysiologically confirmed. Ultrasound supports assessment of diaphragm function. Abdominal expiratory muscles are functionally involved in LOPD.
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Affiliation(s)
- Jens Spiesshoefer
- Respiratory Physiology Laboratory, Institute for Sleep Medicine and Neuromuscular Disorders, University Hospital Muenster, Muenster, Germany
| | - Carolin Henke
- Respiratory Physiology Laboratory, Institute for Sleep Medicine and Neuromuscular Disorders, University Hospital Muenster, Muenster, Germany
| | - Hans Joachim Kabitz
- Department of Pneumology, Cardiology and Intensive Care Medicine, Academic Teaching Hospital, Klinikum Konstanz, Konstanz, Germany
| | - Tobias Brix
- Institute of Medical Informatics, University of Muenster, Muenster, Germany
| | - Dennis Görlich
- Institute for Biostatistics and Clinical Research, University Hospital, Muenster, Germany
| | - Simon Herkenrath
- Bethanien Hospital gGmbH Solingen, Solingen, Germany; Institute for Pneumology at the University of Cologne, Solingen, Germany
| | - Winfried Randerath
- Bethanien Hospital gGmbH Solingen, Solingen, Germany; Institute for Pneumology at the University of Cologne, Solingen, Germany
| | - Peter Young
- Medical Park Klinik Reithofpark, Bad Feilnbach, Germany
| | - Matthias Boentert
- Respiratory Physiology Laboratory, Institute for Sleep Medicine and Neuromuscular Disorders, University Hospital Muenster, Muenster, Germany.
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14
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Bachasson D, Dres M, Niérat MC, Gennisson JL, Hogrel JY, Doorduin J, Similowski T. Diaphragm shear modulus reflects transdiaphragmatic pressure during isovolumetric inspiratory efforts and ventilation against inspiratory loading. J Appl Physiol (1985) 2019; 126:699-707. [DOI: 10.1152/japplphysiol.01060.2018] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The reference method for the assessment of diaphragm function relies on the measurement of transdiaphragmatic pressure (Pdi). Local muscle stiffness measured using ultrafast shear wave elastography (SWE) provides reliable estimates of muscle force in locomotor muscles. This study aimed at investigating whether SWE could be used as a surrogate of Pdi to evaluate diaphragm function. Fifteen healthy volunteers underwent a randomized stepwise inspiratory loading protocol of 0–60% of maximal isovolumetric inspiratory pressure during closed-airways maneuvers and 0–50% during ventilation against an external inspiratory threshold load. During all tasks, Pdi was measured and SWE was used to assess shear modulus of the right hemidiaphragm (SMdi) at the zone of apposition. Pearson correlation coefficients ( r) and repeated-measures correlation coefficients ( R) were computed to determine within-individual and overall relationships between Pdi and SMdi, respectively. During closed-airways maneuvers, mean Pdi correlated to mean SMdi in all participants [ r ranged from 0.77 to 0.96, all P < 0.01; R = 0.82, 95% confidence intervals (0.76, 0.86), P < 0.01]. During ventilation against inspiratory threshold loading, Pdi swing correlated to maximal SMdi in all participants [ r ranged from 0.40 to 0.90, all P < 0.01; R = 0.70, 95% confidence intervals (0.66, 0.73), P < 0.001]. Changes in diaphragm stiffness as assessed by SWE reflect changes in transdiaphragmatic pressure. SWE provides a new opportunity for direct and noninvasive assessment of diaphragm function. NEW & NOTEWORTHY Accurate and specific estimation of diaphragm effort is critical for evaluating and monitoring diaphragm dysfunction. The measurement of transdiaphragmatic pressure requires the use of invasive gastric and esophageal probes. In the present work, we demonstrate that changes in diaphragm stiffness assessed with ultrasound shear wave elastography reflect changes in transdiaphragmatic pressure, therefore offering a new noninvasive method for gauging diaphragm effort.
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Affiliation(s)
- Damien Bachasson
- Neuromuscular Physiology Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France
| | - Martin Dres
- Service de Pneumologie, Médecine Intensive et Réanimation (Département “R3S”), Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Assistance Publique-Hôpitaux de Paris, Paris, France
- UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Paris, France
| | - Marie-Cécile Niérat
- UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Paris, France
| | - Jean-Luc Gennisson
- Imagerie par Résonance Magnétique Médicale et Multi-Modalités, Centre National de la Recherche Scientifique UMR8081, Université Paris-Saclay, Orsay, France
| | - Jean-Yves Hogrel
- Neuromuscular Physiology Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France
| | - Jonne Doorduin
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Thomas Similowski
- Service de Pneumologie, Médecine Intensive et Réanimation (Département “R3S”), Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Assistance Publique-Hôpitaux de Paris, Paris, France
- UMRS1158 Neurophysiologie Respiratoire Expérimentale et Clinique, Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Paris, France
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15
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Raux M, Demoule A, Redolfi S, Morelot-Panzini C, Similowski T. Reduced Phrenic Motoneuron Recruitment during Sustained Inspiratory Threshold Loading Compared to Single-Breath Loading: A Twitch Interpolation Study. Front Physiol 2016; 7:537. [PMID: 27891099 PMCID: PMC5102887 DOI: 10.3389/fphys.2016.00537] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 10/26/2016] [Indexed: 12/14/2022] Open
Abstract
In humans, inspiratory constraints engage cortical networks involving the supplementary motor area. Functional magnetic resonance imaging (fMRI) shows that the spread and intensity of the corresponding respiratory-related cortical activation dramatically decrease when a discrete load becomes sustained. This has been interpreted as reflecting motor cortical reorganization and automatisation, but could proceed from sensory and/or affective habituation. To corroborate the existence of motor reorganization between single-breath and sustained inspiratory loading (namely changes in motor neurones recruitment), we conducted a diaphragm twitch interpolation study based on the hypothesis that motor reorganization should result in changes in the twitch interpolation slope. Fourteen healthy subjects (age: 21–40 years) were studied. Bilateral phrenic stimulation was delivered at rest, upon prepared and targeted voluntary inspiratory efforts (“vol”), upon unprepared inspiratory efforts against a single-breath inspiratory threshold load (“single-breath”), and upon sustained inspiratory efforts against the same type of load (“continuous”). The slope of the relationship between diaphragm twitch transdiaphragmatic pressure and the underlying transdiaphragmatic pressure was −1.1 ± 0.2 during “vol,” −1.5 ± 0.7 during “single-breath,” and −0.6 ± 0.4 during “continuous” (all slopes expressed in percent of baseline.percent of baseline−1) all comparisons significant at the 5% level. The contribution of the diaphragm to inspiration, as assessed by the gastric pressure to transdiaphragmatic pressure ratio, was 31 ± 17% during “vol,” 22 ± 16% during “single-breath” (p = 0.13), and 19 ± 9% during “continuous” (p = 0.0015 vs. “vol”). This study shows that the relationship between the amplitude of the transdiaphragmatic pressure produced by a diaphragm twitch and its counterpart produced by the underlying diaphragm contraction is not unequivocal. If twitch interpolation is interpreted as reflecting motoneuron recruitment, this study supports motor reorganization compatible with “diaphragm sparing” when an inspiratory threshold load becomes sustained.
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Affiliation(s)
- Mathieu Raux
- Sorbonne Universités, UPMC - University Pierre and Marie Curie Univ Paris 06, Institut National de la Santé et de la Recherche Médicale, UMRS1158 Neurophysiologie Respiratoire Expérimentale et cliniqueParis, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Département d'Anesthésie-RéanimationParis, France
| | - Alexandre Demoule
- Sorbonne Universités, UPMC - University Pierre and Marie Curie Univ Paris 06, Institut National de la Santé et de la Recherche Médicale, UMRS1158 Neurophysiologie Respiratoire Expérimentale et cliniqueParis, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service de Pneumologie et Réanimation Médicale (Département"R3S")Paris, France
| | - Stefania Redolfi
- Sorbonne Universités, UPMC - University Pierre and Marie Curie Univ Paris 06, Institut National de la Santé et de la Recherche Médicale, UMRS1158 Neurophysiologie Respiratoire Expérimentale et cliniqueParis, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service des Pathologies du Sommeil (Département "R3S")Paris, France
| | - Capucine Morelot-Panzini
- Sorbonne Universités, UPMC - University Pierre and Marie Curie Univ Paris 06, Institut National de la Santé et de la Recherche Médicale, UMRS1158 Neurophysiologie Respiratoire Expérimentale et cliniqueParis, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service de Pneumologie et Réanimation Médicale (Département"R3S")Paris, France
| | - Thomas Similowski
- Sorbonne Universités, UPMC - University Pierre and Marie Curie Univ Paris 06, Institut National de la Santé et de la Recherche Médicale, UMRS1158 Neurophysiologie Respiratoire Expérimentale et cliniqueParis, France; AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service de Pneumologie et Réanimation Médicale (Département"R3S")Paris, France
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Improving ultrasonic measurement of diaphragmatic excursion after cardiac surgery using the anatomical M-mode: a randomized crossover study. Intensive Care Med 2015; 41:650-6. [PMID: 25573500 DOI: 10.1007/s00134-014-3625-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 12/16/2014] [Indexed: 12/29/2022]
Abstract
PURPOSE Motion-mode (MM) echography allows precise measurement of diaphragmatic excursion when the ultrasound beam is parallel to the diaphragmatic displacement. However, proper alignment is difficult to obtain in patients after cardiac surgery; thus, measurements might be inaccurate. A new imaging modality named the anatomical motion-mode (AMM) allows free placement of the cursor through the numerical image reconstruction and perfect alignment with the diaphragmatic motion. Our goal was to compare MM and AMM measurements of diaphragmatic excursion in cardiac surgical patients. METHODS Cardiac surgical patients were studied after extubation. The excursions of the right and left hemidiaphragms were measured by two operators, an expert and a trainee, using MM and AMM successively, according to a blinded, randomized, crossover sequence. Values were averaged over three consecutive respiratory cycles. The angle between the MM and AMM cursors was quantified for each measurement. RESULTS Fifty patients were studied. The mean (±SD) angle between the MM and AMM cursors was 37° ± 16°. The diaphragmatic excursion as measured by experts was 1.8 ± 0.7 cm using MM and 1.5 ± 0.5 cm using AMM (p < 0.001). Overall, the diaphragmatic excursion as estimated by MM was larger than the value obtained with AMM in 75 % of the measurements. Bland-Altman analysis showed tighter limits of agreement between experts and trainees with AMM [bias: 0.0 cm; 95 % confidence interval (CI): 0.8 cm] than with MM (bias: 0.0 cm; 95 % CI: 1.4 cm). CONCLUSION MM overestimates diaphragmatic excursion in comparison to AMM in cardiac surgical patients. Using MM may lead to a lack of recognition of diaphragmatic dysfunction.
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Abstract
During dynamic exercise, the healthy pulmonary system faces several major challenges, including decreases in mixed venous oxygen content and increases in mixed venous carbon dioxide. As such, the ventilatory demand is increased, while the rising cardiac output means that blood will have considerably less time in the pulmonary capillaries to accomplish gas exchange. Blood gas homeostasis must be accomplished by precise regulation of alveolar ventilation via medullary neural networks and sensory reflex mechanisms. It is equally important that cardiovascular and pulmonary system responses to exercise be precisely matched to the increase in metabolic requirements, and that the substantial gas transport needs of both respiratory and locomotor muscles be considered. Our article addresses each of these topics with emphasis on the healthy, young adult exercising in normoxia. We review recent evidence concerning how exercise hyperpnea influences sympathetic vasoconstrictor outflow and the effect this might have on the ability to perform muscular work. We also review sex-based differences in lung mechanics.
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Affiliation(s)
- Andrew William Sheel
- The School of Kinesiology, The University of British Columbia, Vancouver, Canada.
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18
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Strategies for Predicting Successful Weaning from Mechanical Ventilation. ACTA ACUST UNITED AC 2013. [DOI: 10.1201/b14020-16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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19
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Verin É. Pathologie du diaphragme. Rev Mal Respir 2010; 27:549. [DOI: 10.1016/j.rmr.2010.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Revised: 05/19/2010] [Indexed: 11/25/2022]
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Sériès F, Wang W, Similowski T. Corticomotor control of the genioglossus in awake OSAS patients: a transcranial magnetic stimulation study. Respir Res 2009; 10:74. [PMID: 19678922 PMCID: PMC2738672 DOI: 10.1186/1465-9921-10-74] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 08/13/2009] [Indexed: 11/16/2022] Open
Abstract
Background Upper airway collapse does not occur during wake in obstructive sleep apnea patients. This points to wake-related compensatory mechanisms, and possibly to a modified corticomotor control of upper airway dilator muscles. The objectives of the study were to characterize the responsiveness of the genioglossus to transcranial magnetic stimulation during respiratory and non-respiratory facilitatory maneuvers in obstructive sleep apnea patients, and to compare it to the responsiveness of the diaphragm, with reference to normal controls. Methods Motor evoked potentials of the genioglossus and of the diaphragm, with the corresponding motor thresholds, were recorded in response to transcranial magnetic stimulation applied during expiration, inspiration and during maximal tongue protraction in 13 sleep apnea patients and 8 normal controls. Main Results In the sleep apnea patients: 1) combined genioglossus and diaphragm responses occurred more frequently than in controls (P < 0.0001); 2) the amplitude of the genioglossus response increased during inspiratory maneuvers (not observed in controls); 3) the latency of the genioglossus response decreased during tongue protraction (not observed in controls). A significant negative correlation was found between the latency of the genioglossus response and the apnea-hypopnea index; 4) the difference in diaphragm and genioglossus cortico-motor responses during tongue protraction and inspiratory loading differed between sleep apnea and controls. Conclusion Sleep apnea patients and control subjects differ in the response pattern of the genioglossus and of the diaphragm to facilitatory maneuvers, some of the differences being related to the frequency of sleep-related events.
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Affiliation(s)
- Frédéric Sériès
- Centre de recherche, Hôpital Laval, Institut universitaire de cardiologie et de pneumologie de l'Université Laval, Quebec City, Quebec, Canada.
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Abstract
The usefulness of diaphragm electromyography recorded from an oesophageal electrode depends on a reliable signal which is free of artefact. The diaphragm EMG (electromyogram) recorded from chest wall surface electrodes may be unreliable because of signal contamination from muscle activity other than the diaphragm. Initially, the oesophageal electrode catheter for human studies had only one electrode pair, which could be difficult to position accurately and was influenced by a change in lung volume. Recently, a multipair oesophageal electrode has been developed which allows a high-quality EMG to be recorded. In the present review, the progress of oesophageal electrode design is outlined. The effects of signal contamination, electrode movement and particularly the effect of change in lung volume on the diaphragm EMG are discussed. The diaphragm EMG, recorded from a multipair oesophageal electrode, is useful to assess neural respiratory drive and diaphragm function in different groups of patients with respiratory disease, including patients with neuromuscular disease and sleep-disordered breathing, and those in the intensive care unit. When combined with cervical and cranial magnetic stimulation, an oesophageal electrode can be used to partition the central respiratory response time and phrenic nerve conduction time.
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22
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Assessment of voluntary muscle activation using magnetic stimulation. Eur J Appl Physiol 2008; 104:49-55. [DOI: 10.1007/s00421-008-0782-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2008] [Indexed: 10/22/2022]
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Sériès F, Wang W, Mélot C, Similowski T. Concomitant responses of upper airway stabilizing muscles to transcranial magnetic stimulation in normal men. Exp Physiol 2008; 93:496-502. [DOI: 10.1113/expphysiol.2007.039610] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Wang W, Similowski T, Sériès F. Interaction between genioglossus and diaphragm responses to transcranial magnetic stimulation in awake humans. Exp Physiol 2007; 92:739-47. [PMID: 17412750 DOI: 10.1113/expphysiol.2007.037572] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
UNLABELLED The modulation of activity of the upper airway dilator and respiratory muscles plays a key role in the regulation of ventilation, but little is known about the link between their neuromuscular activation processes in vivo. This study investigated genioglossus and diaphragm responses to transcranial magnetic stimulation applied in different facilitatory conditions. The amplitude and latency of motor-evoked potential responses and the stimulation intensity threshold leading to a motor response (motor threshold) were recorded with stimulation applied at the vertex and anterolateral area in 13 awake normal subjects. Stimuli were applied during inspiration with and without resistance, during expiration with and without maximal tongue protrusion and during deep inspiration. In each stimulation location and condition, no diaphragmatic response was obtained without previous genioglossus activity (diaphragmatic and genioglossus responses latencies during expiration: 18.1 +/- 2.9 and 6.3 +/- 2.6 ms, respectively, mean +/- s.d., P < 0.01). Genioglossus motor-evoked potential amplitude, latency and motor threshold were significantly modified with tongue protrusion with a maximal effect observed for stimulation in the anterolateral area. Deep inspiration was associated with a significant facilitatory effect on both genioglossus and diaphragm motor responses. The facilitatory effects of respiratory and non-respiratory manoeuvres were also observed during focal stimulation where isolated genioglossus responses were observed. Genioglossus and diaphragm differed in their motor threshold both at baseline and following facilitatory manoeuvres. CONCLUSIONS (1) transcranial magnetic stimulation-induced genioglossus response systematically precedes that of diaphragm; (2) this sequence of activation is not modified by respiratory and non-respiratory manoeuvres; and (3) the genioglossus and diaphragm are differently influenced by these manoeuvres in terms of latency of the motor response and of motor threshold.
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Affiliation(s)
- Wei Wang
- Centre de recherche, Hôpital Laval, Institut universitaire de cardiologie et de pneumologie de l'Université Laval, Quebec City, Quebec, Canada
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Miscio G, Gukov B, Pisano F, Mazzini L, Baudo S, Salvadori A, Mauro A. The cortico-diaphragmatic pathway involvement in amyotrophic lateral sclerosis: neurophysiological, respiratory and clinical considerations. J Neurol Sci 2006; 251:10-6. [PMID: 17078971 DOI: 10.1016/j.jns.2006.05.059] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2005] [Revised: 05/18/2006] [Accepted: 05/19/2006] [Indexed: 11/23/2022]
Abstract
Cortico-diaphragmatic pathway was investigated by means of transcranial magnetic stimulation (TMS), in 14 patients affected by definite amyotrophic lateral sclerosis (ALS) without clinical signs of respiratory impairment. Spirometry, gas analysis, and measurement of static inspiratory and expiratory pressures were performed in all patients. Forced vital capacity, forced expiratory volume at the first and second peak expiratory flow, sniff effort from FRC level (SNIP), maximal inspiratory and expiratory pressure at mouth (MIP/MEP), maximal transdiaphragmatic pressure (Pdimx) were considered. TMS was performed, recording by surface electrodes from hemidiaphragm, bilaterally. Latency of cortical and spinal motor-evoked potentials (Cx-MEP/Sp-MEP) and central motor conduction time (CMCT) were measured. None of the patients showed altered spirometry and gas levels. Seven patients showed decreased Pdimx and eight of MEP values. Four patients showed a delayed Sp-MEP. In one patient the Cx-MEP was abolished while the mean values of both Cx-MEP and CMCT were significantly increased (19.2+/-4.1 ms, P<0.0001; 10.8+/-4.8 ms, P<0.0001). Cx-MEP and CMCT did not show significant correlations with any of the respiratory measures. The patients with prolonged Sp-MEP, showed longer disease duration, lower Norris score, lower Pdimx and MEP values. In conclusion, cortico-diaphragmatic study is a sensitive measure to reveal subclinical diaphragmatic impairment although not correlated to respiratory measures.
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Affiliation(s)
- Giacinta Miscio
- Department of Neurology and Neurorehabilitation, Istituto Auxologico Italiano, IRCCS, Piancavallo (VB), Italy.
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Sharshar T, Hopkinson NS, Ross ET, Jonville S, Dayer MJ, Nickol AH, Lofaso F, Moxham J, Polkey MI. Motor control of the costal and crural diaphragm – insights from transcranial magnetic stimulation in man. Respir Physiol Neurobiol 2005; 146:5-19. [PMID: 15733775 DOI: 10.1016/j.resp.2004.10.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2004] [Indexed: 11/28/2022]
Abstract
The costal and crural parts of the diaphragm differ in their embryological development and physiological function. It is not known if this is reflected in differences in their motor cortical representation. We compared the response of the costal and crural diaphragms using varying intensities of transcranial magnetic stimulation of the motor cortex at rest and during submaximal and maximal inspiratory efforts. The costal and crural motor evoked potential recruitment curves during submaximal inspiratory efforts were similar. The response to stimulation before, during and at 10 and 30 min after 44 consecutive maximal inspiratory efforts was also the same. Using paired stimulations to investigate intra-cortical facilitatory and inhibitory circuits we found no difference between the costal and crural response with varying interstimulus intervals, or when conditioning and test stimulus intensity were varied. We conclude that supraspinal control of the costal and crural diaphragm is identical during inspiratory tasks.
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Affiliation(s)
- Tarek Sharshar
- Respiratory Muscle Laboratory, Royal Brompton and Harefield NHS Trust, Fulham Road, London, SW3 6NP, UK
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Vérin E. Quelles explorations spécialisées pour les muscles respiratoires : de la stimulation magnétique à l’imagerie. Rev Mal Respir 2005. [DOI: 10.1016/s0761-8425(05)85462-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Sharshar T, Hopkinson NS, Jonville S, Prigent H, Carlier R, Dayer MJ, Swallow EB, Lofaso F, Moxham J, Polkey MI. Demonstration of a second rapidly conducting cortico-diaphragmatic pathway in humans. J Physiol 2004; 560:897-908. [PMID: 15272049 PMCID: PMC1665270 DOI: 10.1113/jphysiol.2004.061150] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2004] [Accepted: 07/20/2004] [Indexed: 11/08/2022] Open
Abstract
Functional imaging studies in normal humans have shown that the supplementary motor area (SMA) and the primary motor cortex (PMC) are coactivated during various breathing tasks. It is not known whether a direct pathway from the SMA to the diaphragm exists, and if so what properties it has. Using transcranial magnetic stimulation (TMS) a site at the vertex, representing the diaphragm primary motor cortex, has been identified. TMS mapping revealed a second area 3 cm anterior to the vertex overlying the SMA, which had a rapidly conducting pathway to the diaphragm (mean latency 16.7 +/- 2.4 ms). In comparison to the vertex, the anterior position was characterized by a higher diaphragm motor threshold, a greater proportional increase in motor-evoked potential (MEP) amplitude with voluntary facilitation and a shorter silent period. Stimulus-response curves did not differ significantly between the vertex and anterior positions. Using paired TMS, we also compared intracortical inhibition/facilitation (ICI/ICF) curves. In comparison to the vertex, the MEP elicited from the anterior position was not inhibited at short interstimulus intervals (1-5 ms) and was more facilitated at long interstimulus intervals (9-20 ms). The patterns of response were identical for the costal and crural diaphragms. We conclude that the two coil positions represent discrete areas that are likely to be the PMC and SMA, with the latter wielding a more excitatory effect on the diaphragm.
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Affiliation(s)
- Tarek Sharshar
- Respiratory Muscle Laboratory, Royal Brompton and Harefield NHS Trust, Fulham Road, London SW3 6NP, UK
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Hopkinson NS, Sharshar T, Ross ET, Nickol AH, Dayer MJ, Porcher R, Jonville S, Moxham J, Polkey MI. Corticospinal control of respiratory muscles in chronic obstructive pulmonary disease. Respir Physiol Neurobiol 2004; 141:1-12. [PMID: 15234671 DOI: 10.1016/j.resp.2004.04.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2004] [Indexed: 11/17/2022]
Abstract
Patients with chronic obstructive pulmonary disease (COPD) face an increased respiratory load and in consequence have an elevated respiratory drive. We used transcranial magnetic stimulation (TMS) to investigate associated changes in corticospinal excitability both at rest and during voluntary facilitation at different levels of inspiratory effort. Diaphragm and abdominal motor thresholds were significantly lower in COPD than healthy controls, but the quadriceps response was the same. In patients there was a significant increase in diaphragm response from rest during 20% inspiratory efforts but no further increase with greater efforts. In controls there was a further stepwise increase at 40% and 60% of inspiratory effort. The cortical silent period was significantly shorter in COPD. Using paired stimulation to study intracortical inhibitory and excitatory circuits we found significantly less excitability of intracortical facilitatory circuits in patients at long (>7 ms) interstimulus intervals. These results suggest that there is a ceiling effect in motor control output to the respiratory muscles of patients with COPD.
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Sharshar T, Ross ET, Hopkinson NS, Porcher R, Nickol AH, Jonville S, Dayer MJ, Hart N, Moxham J, Lofaso F, Polkey MI. Depression of diaphragm motor cortex excitability during mechanical ventilation. J Appl Physiol (1985) 2004; 97:3-10. [PMID: 15020575 DOI: 10.1152/japplphysiol.01099.2003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effect of mechanical ventilation on the diaphragm motor cortex remains unknown. We assessed the effect of mechanical ventilation on diaphragm motor cortex excitability by measuring the costal and crural diaphragm motor-evoked potential (MEP) elicited by single and paired transcranial magnetic stimulation. In six healthy subjects, MEP recruitment curves of the costal and crural diaphragms were assessed at relaxed end expiration during spontaneous breathing [baseline tidal volume (Vtbaseline)] and isocapnic volume cycled ventilation delivered noninvasively (NIV) at three different levels of tidal volume (Vtbaseline, Vtbaseline + 5 ml/kg liters, and Vtbaseline + 10 ml/kg liters). The costal and crural diaphragm response to peripheral stimulation of the right phrenic nerve was not reduced by NIV. NIV reduced the costal and crural MEP amplitude during NIV ( P < 0.0001) with the maximal reduction at Vtbaseline + 5 ml/kg. Response to paired TMS showed that NIV (Vtbaseline + 5 ml/kg) significantly increased the sensitivity of the cortical motoneurons to facilitatory (>9 ms) interstimulus intervals ( P = 0.002), suggesting that the diaphragm MEP amplitude depression during NIV is related to neuromechanical inhibition at the level of motor cortex. Our results demonstrate that mechanical ventilation directly inhibits central projections to the diaphragm.
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Affiliation(s)
- Tarek Sharshar
- Respiratory Muscle Laboratory, Royal Brompton Hospital, Sydney St, London SW3 6NP UK
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Sharshar T, Ross E, Hopkinson NS, Dayer M, Nickol A, Lofaso F, Moxham J, Similowski T, Polkey MI. Effect of voluntary facilitation on the diaphragmatic response to transcranial magnetic stimulation. J Appl Physiol (1985) 2003; 95:26-34. [PMID: 12639850 DOI: 10.1152/japplphysiol.00918.2002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We assessed recruitment curves of the surface diaphragm motor-evoked potential (MEP) after transcranial magnetic stimulation during relaxation and at three different levels of facilitation (20, 40, and 60% of maximal inspiratory esophageal pressure) in 10 healthy subjects (six young and four elderly). MEP amplitude recruitment curves varied between individuals during relaxation and at each level of facilitation. Amplitude recruitment curves during relaxation were reproducible in individual subjects. Inspiratory maneuvers caused a decrease in motor threshold and latency and an increase in MEP amplitude, positively correlated to the intensity of facilitation. These changes were similar in young and elderly subjects. The best fit for MEP amplitude recruitment curves for each condition was obtained with a Boltzmann model. The performance of repeated submaximal inspiratory maneuvers did not affect the amplitude recruitment curves of the relaxed diaphragm. We conclude that the recruitment curve of the diaphragm with transcranial magnetic stimulation is repeatable and changes consistently with facilitation and will, therefore, be a robust experimental tool for the investigation of supraspinal pathways to the diaphragm.
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Affiliation(s)
- Tarek Sharshar
- Respiratory Muscle Laboratory, Royal Brompton and Harefield National Health Service, Trust and King's College Hospital, London SW3 6NP, UK.
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Delpech N, Jonville S, Denjean A. Mouth pressure twitches induced by cervical magnetic stimulation to assess inspiratory muscle fatigue. Respir Physiol Neurobiol 2003; 134:231-7. [PMID: 12660102 DOI: 10.1016/s1569-9048(02)00219-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
This study aimed at determining whether twitch mouth pressure (TwPmo) induced by cervical magnetic stimulation (CMS) was sensitive to inspiratory muscle fatigue produced by whole body exercise (WBE) in normal subjects. Twenty subjects performed one or two of the following protocols: (i). cycling at 85% V(O(2),max) until exhaustion; (ii). inspiratory resistive load (IRL) breathing at 62% of maximal inspiratory pressure until task failure. In eight subjects, oesophageal (TwPoes), gastric (TwPga) and transdiaphragmatic (TwPdi) pressures were recorded. The TwPmo was significantly reduced (P<0.05) 20 min after both WBE and IRL, from 17.5+/-4.4 to 15.9+/-3.9 cmH(2)O and from 19.4+/-4.9 to 17.7+/-4.5 cmH(2)O, respectively. Subsequently to IRL, the TwPdi decrease was associated with a reduction in TwPoes/TwPga ratio; not after WBE. Independently of the mode of ventilatory loading, inspiratory muscle fatigue was detected. Thus, inspiratory muscle fatigue after WBE can be assessed in normal subjects with a noninvasive technique.
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Affiliation(s)
- N Delpech
- Laboratoire d'Analyse de la Performance Motrice Humaine, UPRES EA 2253, Faculté des Sciences du Sport, Université de Poitiers, 4 allée Jean Monnet, 86000 Poitiers, France.
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Miscio G, Guastamacchia G, Priano L, Baudo S, Mauro A. Are the neurophysiological techniques useful for the diagnosis of diaphragmatic impairment in multiple sclerosis (MS)? Clin Neurophysiol 2003; 114:147-53. [PMID: 12495775 DOI: 10.1016/s1388-2457(02)00339-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To characterize cortico-diaphragmatic pathway involvement in multiple sclerosis (MS) by means of transcranial magnetic stimulation (TMS), and verify its clinical impact. METHODS TMS from diaphragm (Dia), and abductor digiti minimi (AbdV degrees ) was performed in 26 MS patients. Phrenic nerve (PN) conduction study was also performed. Expanded disability status scale (EDSS) and fatigue descriptive scale (FDS) were measured. Forced vital capacity (FVC), forced expiratory volume at the first second (FEV1), peak expiratory flow (PEF) were tested: the predicted percentage value (% pred) was considered. RESULTS Cortical motor evoked potential (Cx-MEP) latency and central motor conduction time (CMCT) were prolonged, respectively, in 31 and 23% of patients from Dia, in 76 and 79% from AbdV degrees. PN-compound motor action potential (CMAP) was normal. EDSS correlated to Cx-MEP from AbdV degrees (P<0.01), and PN-CMAP amplitude (P<0.05), FEV1 % pred (P<0.01), PEF % pred (P<0.01). PN-CMAP amplitude correlated to FVC % pred P=0.05, FEV1 % pred P<0.01, PEF % pred P<0.01. Fatigue was related to AbdV degrees Cx-MEP and CMCT (P<0.05 and P<0.01). CONCLUSIONS Cortico-diaphragmatic pathway is impaired only in a minority of MS patients. Lack of correlation between TMS findings from Dia and respiratory tests argues against its routinary use to detect subclinical respiratory alterations. Fatigue seems to be related to the motor impairment rather than to respiratory distress.
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Affiliation(s)
- G Miscio
- Department of Neurology and Neurorehabilitation, Istituto Auxologico Italiano, IRCCS, 'San Giuseppe' Hospital, Stada L. Cadorna 90, 28824 (VB), Piancavallo - Oggebbio, Italy.
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36
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Verin E, Straus C, Demoule A, Mialon P, Derenne JP, Similowski T. Validation of improved recording site to measure phrenic conduction from surface electrodes in humans. J Appl Physiol (1985) 2002; 92:967-74. [PMID: 11842028 DOI: 10.1152/japplphysiol.00652.2001] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Phrenic nerve stimulation, electrical (ES) or from cervical magnetic stimulation (CMS), allows one to assess the diaphragm contractile properties and the conduction time of the phrenic nerve (PNCT) through recording of an electromyographic response, traditionally by using surface electrodes. Because of the coactivation of extradiaphragmatic muscles, signal contamination can jeopardize the determination of surface PNCTs. To address this, we compared PNCTs with ES and CMS from surface and needle diaphragm electrodes in five subjects (10 phrenic nerves). At a modified recording site, lower and more anterior than usual (lowest accessible intercostal space, costochondral junction) with electrodes 2 cm apart, surface and needle PNCTs were similar (CMS: 6.0 +/- 0.25 ms surface vs. 6.2 +/- 0.13 ms needle, not significant). Electrodes recording the activity of the most likely sources of signal contamination, i.e., the serratus anterior and pectoralis major, showed distinct responses from that of the diaphragm, their earlier occurrence strongly arguing against contamination. With ES and CMS, apparently uncontaminated signals could be consistently recorded from surface electrodes.
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Affiliation(s)
- Eric Verin
- UPRES EA 2397, Université Pierre et Marie Curie Paris VI, 75013 Paris, France
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37
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Gudjonsdottir M, Appendini L, Baderna P, Purro A, Patessio A, Vilianis G, Pastorelli M, Sigurdsson SB, Donner CF. Diaphragm fatigue during exercise at high altitude: the role of hypoxia and workload. Eur Respir J 2001; 17:674-80. [PMID: 11401063 DOI: 10.1183/09031936.01.17406740] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The effect of high altitude (HA) on exercise-induced diaphragm fatigue in normal subjects was examined. Eight normal subjects completed an incremental exercise test at sea level (SL) and at 3,325 m. Before (baseline), during, and after exercise (recovery), maximal transdiaphragm pressure (Pdi,sniff), breathing pattern, and diaphragmatic effort (PTPdi) were measured. Arterialized blood lactate was measured at baseline and during recovery. At maximal exercise (WRmax) Pdi,sniff fell to 72% and 61% of baseline at SL and HA respectively, recovering to baseline in 60 min at SL, and >60 min at HA. At the 5th min of recovery, circulating lactate was six-fold and seven-fold baseline at SL and HA, respectively. The time course of circulating lactate recovery was as for Pdi,sniff. At WRmax PTPdi was 80.74+/-9.87 kPa.s(-1) at SL and 64.13+/-8.21 kPa.s(-1) at HA. HA WRmax compared to isowork rate, SL data showed a lower Pdi,sniff (8.90+/-0.68 versus 11.24+/-0.59 kPa) and higher minute ventilation (117+/-11 versus 91+/-13 L.min(-1)), PTPdi being equal. To conclude, in normal subjects hypoxia-related effects, and not an increase in diaphragm work, hastens exercise-induced diaphragm fatigue and delays its recovery at high altitude compared to sea level.
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Affiliation(s)
- S Hadjikoutis
- Department of Medicine (Neurology), University Hospital of Wales, Cardiff, UK
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Luo YM, Polkey MI, Lyall RA, Moxham J. Effect of brachial plexus co-activation on phrenic nerve conduction time. Thorax 1999; 54:765-70. [PMID: 10456968 PMCID: PMC1745563 DOI: 10.1136/thx.54.9.765] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Diaphragm function can be assessed by electromyography of the diaphragm during electrical phrenic nerve stimulation (ES). Whether phrenic nerve conduction time (PNCT) and diaphragm electrical activity can be reliably measured from chest wall electrodes with ES is uncertain. METHODS The diaphragm compound muscle action potential (CMAP) was recorded using an oesophageal electrode and lower chest wall electrodes during ES in six normal subjects. Two patients with bilateral diaphragm paralysis were also studied. Stimulations were deliberately given in a manner designed to avoid or incur co-activation of the brachial plexus. RESULTS For the oesophageal electrode the PNCT was similar with both stimulation techniques with mean (SE) values of 7.1 (0.2) and 6.8 (0.2) ms, respectively (pooled left and right values). However, for surface electrodes the PNCT was substantially shorter when the brachial plexus was activated (4.4 (0.1) ms) than when it was not (7.4 (0.2) ms) (mean difference 3.0 ms, 95% CI 2.7 to 3.4, p<0.0001). A small short latency CMAP was recorded from the lower chest wall electrodes during stimulation of the brachial plexus alone. CONCLUSIONS The results of this study show that lower chest wall electrodes only accurately measure PNCT when care is taken to avoid stimulating the brachial plexus. A false positive CMAP response to phrenic stimulation could be caused by inadvertent stimulation of the brachial plexus. This finding may further explain why the diaphragm CMAP recorded from chest wall electrodes can be unreliable with cervical magnetic stimulation during which brachial plexus activation occurs.
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Affiliation(s)
- Y M Luo
- Respiratory Muscle Laboratory, King's College Hospitals, London SE5 9PJ, UK
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Sériès F, Demoule A, Marc I, Sanfaçon C, Derenne JP, Similowski T. Inspiratory flow dynamics during phrenic nerve stimulation in awake normals during nasal breathing. Am J Respir Crit Care Med 1999; 160:614-20. [PMID: 10430737 DOI: 10.1164/ajrccm.160.2.9812036] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The loss of upper airway (UA) dilators preactivation before inspiratory muscle contraction is an important determinant of the pathophysiology of obstructive sleep apnea. We hypothetized that phrenic nerve stimulation could provide a practical way to explore the effects of the dissociation between UA dilators and inspiratory muscles, and possibly to determine UA critical closing pressure during wakefulness. The pattern of inspiratory airflow was therefore studied in normal awake subjects during diaphragm twitches induced by either electrical phrenic stimulation (ES) or cervical magnetic stimulation (CMS) (n = 9) and with and without a nasal stent during ES (n = 7). End-expiratory stimulations applied during exclusive nasal breathing induced 200 to 300 ms twitch inspiratory flow. The average maximal twitch flow of flow-limited twitches was higher during CMS than ES (1.18 +/- 0.29 L.
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Affiliation(s)
- F Sériès
- Unité de Recherche, Centre de pneumologie de l'Hôpital Laval, Université Laval, Québec, Canada.
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Sinderby C, Beck J, Spahija J, Weinberg J, Grassino A. Voluntary activation of the human diaphragm in health and disease. J Appl Physiol (1985) 1998; 85:2146-58. [PMID: 9843538 DOI: 10.1152/jappl.1998.85.6.2146] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Intersubject comparison of the crural diaphragm electromyogram, as measured by an esophageal electrode, requires a reliable means for normalizing the signal. The present study set out 1) to evaluate which voluntary respiratory maneuvers provide high and reproducible diaphragm electromyogram root-mean-square (RMS) values and 2) to determine the relative diaphragm activation and mechanical and ventilatory outputs during breathing at rest in healthy subjects (n = 5), in patients with severe chronic obstructive pulmonary disease (COPD, n = 5), and in restrictive patients with prior polio infection (PPI, n = 6). In all groups, mean voluntary maximal RMS values were higher during inspiration to total lung capacity than during sniff inhalation through the nose (P = 0.035, ANOVA). The RMS (percentage of voluntary maximal RMS) during quiet breathing was 8% in healthy subjects, 43% in COPD patients, and 45% in PPI patients. Despite the large difference in relative RMS (P = 0.012), there were no differences in mean transdiaphragmatic pressure (P = 0.977) and tidal volumes (P = 0.426). We conclude that voluntary maximal RMS is reliably obtained during an inspiration to total lung capacity but a sniff inhalation could be a useful complementary maneuver. Severe COPD and PPI patients breathing at rest are characterized by increased diaphragm activation with no change in diaphragm pressure generation.
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Affiliation(s)
- C Sinderby
- Guy-Bernier Research Center, Maisonneuve-Rosemont Hospital, University of Montreal, Montreal, Quebec H3C 3J7, Canada H3A 2B2
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Luo YM, Polkey MI, Johnson LC, Lyall RA, Harris ML, Green M, Moxham J. Diaphragm EMG measured by cervical magnetic and electrical phrenic nerve stimulation. J Appl Physiol (1985) 1998; 85:2089-99. [PMID: 9843530 DOI: 10.1152/jappl.1998.85.6.2089] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of the study was to compare electrical stimulation (ES) and cervical magnetic stimulation (CMS) of the phrenic nerves for the measurement of the diaphragm compound muscle action potential (CMAP) and phrenic nerve conduction time. A specially designed esophageal catheter with three pairs of electrodes was used, with control of electrode positioning in 10 normal subjects. Pair A and pair B were close to the diaphragm (pair A lower than pair B); pair C was positioned 10 cm above the diaphragm to detect the electromyogram from extradiaphragmatic muscles. Electromyograms were also recorded from upper and lower chest wall surface electrodes. The shape of the CMAP measured with CMS (CMS-CMAP) usually differed from that of the CMAP measured with ES (ES-CMAP). Moreover, the latency of the CMS-CMAP from pair B (5.3 +/- 0.4 ms) was significantly shorter than that from pair A (7.1 +/- 0.7 ms). The amplitude of the CMS-CMAP (1.00 +/- 0.15 mV) was much higher than that of ES-CMAP (0.26 +/- 0.15 mV) when recorded from pair C. Good-quality CMS-CMAPs could be recorded in some subjects from an electrode positioned very low in the esophagus. The differences between ES-CMAP and CMS-CMAP recorded either from esophageal or chest wall electrodes make CMS unreliable for the measurement of phrenic nerve conduction time.
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Affiliation(s)
- Y M Luo
- King's College, London SE5 9PJ, United Kingdom
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Similowski T, Straus C, Attali V, Duguet A, Derenne JP. Cervical magnetic stimulation as a method to discriminate between diaphragm and rib cage muscle fatigue. J Appl Physiol (1985) 1998; 84:1692-700. [PMID: 9572819 DOI: 10.1152/jappl.1998.84.5.1692] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Inspiratory muscle fatigue can probably determine hypercapnic respiratory failure. Diaphragm fatigue is detected by electrical phrenic stimulation (ELS), but there is no simple tool to assess rib cage muscle (RCM) fatigue. Cervical magnetic stimulation (CMS) costimulates the phrenic nerves and RCM. We reasoned that changes in transdiaphragmatic pressure twitch (Pdi,tw) with CMS and ELS should be different after selective diaphragm vs. RCM fatigue. Five volunteers performed inspiratory resistive tasks while voluntarily uncoupling diaphragm and RCM. Baseline Pdi,twELS and Pdi,twCMS were 28.57 +/- 1.68 and 32.83 +/- 2.92 cmH2O. After selective diaphragm loading, Pdi,twELS and Pdi,twCMS were reduced by 39 and 26%, with comparable decreases in gastric pressure twitch (Pga,tw). Esophageal pressure twitch (Pes,tw) was better preserved with CMS. Therefore Pes,tw/Pga,tw was lower with ELS than CMS (-1.24 +/- 0.16 vs. -1.73 +/- 0.11, P = 0.05). After selective RCM loading, there was no diaphragm fatigue, but Pes,twCMS was significantly reduced (-30%). These findings support the role of rib cage stiffening by CMS-related RCM contraction in the ELS-CMS differences and suggest that CMS can be used to assess RCM fatigue.
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Affiliation(s)
- T Similowski
- Laboratoire de Physiopathologie Respiratoire,Service de Physiopatholog ie Respiratoire, Paris, France
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Abstract
Measurement of respiratory muscle strength is useful in order to detect respiratory muscle weakness and to quantify its severity. In patients with severe respiratory muscle weakness, vital capacity is reduced but is a non-specific and relatively insensitive measure. Conventionally, inspiratory and expiratory muscle strength has been assessed by maximal inspiratory and expiratory mouth pressures sustained for 1 s (PImax and PEmax) during maximal static manoeuvre against a closed shutter. However, PImax and PEmax are volitional tests, and are poorly reproducible with an average coefficient of variation of 25%. The sniff manoeuvre is natural and probably easier to perform. Sniff pressure, and sniff transdiaphragmatic pressure are more reproducible and useful measure of diaphragmatic strength. Nevertheless, the sniff manoeuvre is also volition-dependent, and submaximal efforts are most likely to occur in patients who are ill or breathless. Non-volitional tests include measurements of twitch oesophageal, gastric and transdiaphragmatic pressure during bilateral electrical and magnetic phrenic nerve stimulation. Electrical phrenic nerve stimulation is technically difficult and is also uncomfortable and painful. Magnetic phrenic nerve stimulation is less painful and transdiaphragmatic pressure is reproducible in normal subjects. It is a relatively easy test that has the potential to become a widely adopted method for the assessment of diaphragm strength. The development of a technique to measure diaphragmatic sound (phonomyogram) during magnetic phrenic nerve stimulation opens the way for noninvasive assessment of diaphragmatic function.
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Affiliation(s)
- N Syabbalo
- Faculty of Medicine, Kuwait University, Safat, Kuwait
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45
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Chéliout-Héraut F, Loubert G, Masri-Zada T, Aubrun F, Pasteyer J. Evaluation of early motor and sensory evoked potentials in cervical spinal cord injury. Neurophysiol Clin 1998; 28:39-55. [PMID: 9562998 DOI: 10.1016/s0987-7053(97)89577-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
To determine the efficacy of motor evoked potentials (MEP) and sensory evoked potentials (SEP) in the assessment of severe cervical injury, 17 subjects with severe cervical injury were studied. During the 1st week post-injury and post-surgical treatment, all subjects were submitted to electromyogram (EMG) recordings, dermatomal somatosensory evoked potentials (D.SEP), posterior tibial nerve somatosensory evoked potentials (PTN.SEP), MEP and bilateral cervical electrical stimulations with recording of the diaphragm. For the D.SEP, the latencies of the N9 and N20 responses and the conduction time (N9-N20) were measured in the upper limbs; the latencies of the P40 and P60 responses were measured in the lower limbs. MEP were recorded from distal upper and lower limb muscles following transcranial electrical stimulation of the cortex. (Magnetic stimulation was not indicated because of implanted metallic material in the cervical skull of many patients.) A SEP and MEP grading system was used to improve the assessment of different root neurological levels. In patients with incomplete lesions PTN.SEP, D.SEP and MEP responses could be recorded in territories that were clinically deficient. Patients with complete lesions and absent SEP and MEP responses had a poor outcome. A good correlation was found between the severity of the spinal cord injury and SEP grading. For MEP, the presence or absence of intercostal responses (C4) to cervical and cortical stimulation was the best prognostic indicator. The combined electrophysiological exploration of MEP and SEP proved to be a useful tool for monitoring patients with severe spinal cord injury.
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Affiliation(s)
- F Chéliout-Héraut
- Service d'explorations fonctionnelles, Hôpital Raymond-Poincaré, CHU Paris-Ouest, Garches, France
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46
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Attali V, Mehiri S, Straus C, Salachas F, Arnulf I, Meininger V, Derenne JP, Similowski T. Influence of neck muscles on mouth pressure response to cervical magnetic stimulation. Am J Respir Crit Care Med 1997; 156:509-14. [PMID: 9279232 DOI: 10.1164/ajrccm.156.2.9612053] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Measurement of mouth pressure (Pm) in response to electrical phrenic nerve stimulation (Es) provides a simple noninvasive means to assess diaphragm function. An even simpler measure would be to use the Pm twitch response (Pm,t) to cervical magnetic stimulation (CMS) rather than to Es. Because CMS coactivates the diaphragm and inspiratory neck muscles (INM), CMS-Pm,t accurately reflects diaphragm function only if the corresponding INM contraction does not produce inspiratory pressures by itself. In patients with recent-onset bilateral diaphragm paralysis, it has been demonstrated that CMS-Pm,t was indeed zero; however, INM hypertrophy could change this situation and lead CMS-Pm,t to overestimate the performance of the diaphragm. To address this issue, we studied nine patients with amyotrophic lateral sclerosis (ALS) who had evidence of diaphragmatic paralysis and compensatory hypertrophy and hyperactivity of inspiratory neck muscles. The response to CMS was described in terms of diaphragm electromyogram (EMG), Pm, and abdominal (AB) and rib cage (RC) motion. No EMG response to CMS could be observed in most cases, and CMS was always associated with AB paradox. Nevertheless, a negative Pm,t swing was recorded with an amplitude of -2.6 +/- 1.0 cm H2O (mean +/- SD). We conclude that inspiratory neck muscle hypertrophy can significantly influence the Pm response to CMS. This should be taken into account when using the CMS-Pm combination in patients with possible chronic diaphragm dysfunction.
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Affiliation(s)
- V Attali
- Laboratoire de Physiopathologie Respiratoire, Groupe Hospitalier Pitié-Salpêtrière, Paris, France
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47
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Similowski T, Mehiri S, Duguet A, Attali V, Straus C, Derenne JP. Comparison of magnetic and electrical phrenic nerve stimulation in assessment of phrenic nerve conduction time. J Appl Physiol (1985) 1997; 82:1190-9. [PMID: 9104856 DOI: 10.1152/jappl.1997.82.4.1190] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Cervical magnetic stimulation (CMS), a nonvolitional test of diaphragm function, is an easy means for measuring the latency of the diaphragm motor response to phrenic nerve stimulation, namely, phrenic nerve conduction time (PNCT). In this application, CMS has some practical advantages over electrical stimulation of the phrenic nerve in the neck (ES). Although normal ES-PNCTs have been consistently reported between 7 and 8 ms, data are less homogeneous for CMS-PNCTs, with some reports suggesting lower values. This study systematically compares ES- and CMS-PNCTs for the same subjects. Surface recordings of diaphragmatic electromyographic activity were obtained for seven healthy volunteers during ES and CMS of varying intensities. On average, ES-PNCTs amounted to 6.41 +/- 0.84 ms and were little influenced by stimulation intensity. With CMS, PNCTs were significantly lower (average difference 1.05 ms), showing a marked increase as CMS intensity lessened. ES and CMS values became comparable for a CMS intensity 65% of the maximal possible intensity of 2.5 Tesla. These findings may be the result of phrenic nerve depolarization occurring more distally than expected with CMS, which may have clinical implications regarding the diagnosis and follow-up of phrenic nerve lesions.
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Affiliation(s)
- T Similowski
- Service de Pneumologie et Réanimation and Laboratoire de Physiopathologie Respiratoire, Groupe Hospitalier Pitié-Salpêtrière,Paris, France.
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48
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Straus C, Zelter M, Derenne JP, Pidoux B, Willer JC, Similowski T. Putative projection of phrenic afferents to the limbic cortex in humans studied with cerebral-evoked potentials. J Appl Physiol (1985) 1997; 82:480-90. [PMID: 9049727 DOI: 10.1152/jappl.1997.82.2.480] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Respiratory sensations may rely in part on cortical integration of respiratory afferent information. In an attempt to study such projections, we recorded evoked potentials at scalp and cervical sites in 10 normal volunteers undergoing transcutaneous phrenic stimulation (0.1-ms square pulses, intensity liminal for diaphragmatic activation, series of 600 shocks at 2 Hz). A negative cerebral component of peak latency (12.79 +/- 0.54 ms; N13) was constant, and a negative spinal component (7.09 +/- 1.04 ms; N7) could also be recorded, all results being reproducible over time. Monitoring of cardiac frequency, skin anesthesia, and stimulation adjacent to the phrenic nerve made the phrenic origin of N7 and N13 the foremost hypothesis. Increasing stimulation frequency and comparison with median nerve stimulation provided arguments for the neural nature of the signals and their cerebral origin. Recordings from intracerebral electrodes in a patient showed a polarity reversal of the evoked potentials at the level of the cingulate gyrus. In conclusion, phrenic stimulation could allow one to study projections of phrenic afferents to the central nervous system in humans. Their exact site and physiological meaning remain to be clarified.
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Affiliation(s)
- C Straus
- Laboratoire de Physiopathologie Respiratoire, Groupe Hospitalier Pitié-Salpêtrière, Paris, France
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Similowski T, Straus C, Attali V, Duguet A, Jourdain B, Derenne JP. Assessment of the motor pathway to the diaphragm using cortical and cervical magnetic stimulation in the decision-making process of phrenic pacing. Chest 1996; 110:1551-7. [PMID: 8989076 DOI: 10.1378/chest.110.6.1551] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Phrenic nerve pacing is a recognized substitute to positive pressure ventilation via tracheotomy in patients with high cervical cord lesions or central hypoventilation. Although its indications are infrequent, reliable strategies need to be used in the determinations of patients who may benefit from this treatment; contraindications should be carefully respected. STUDY OBJECTIVES To determine whether modern and noninvasive means to study the motor pathway to the diaphragm, namely cortical magnetic stimulation (CxMS) and cervical magnetic stimulation (CMS), can contribute to the selection of patients who may benefit from phrenic pacing. DESIGN AND SETTING Prospective study (18 months), on a consecutive basis, of patients referred for possible phrenic pacing to a 10-bed ICU associated with a respiratory neurophysiology laboratory. PATIENTS Seven patients (high cervical cord injury, n = 5; central hypoventilation following neurosurgery, n = 1; idiopathic acquired central hypoventilation, n = 1). INTERVENTION, MEASUREMENTS, AND RESULTS: Electromyography of the diaphragm and transdiaphragmatic pressure were assessed in response to CxMS and CMS. In three cases, no interruption of the corticodiaphragmatic pathway was evidenced, the decision of pacing was postponed, and the patients eventually recovered a spontaneous breathing activity. In two cases, the diagnosis of irreversible peripheral phrenic dysfunction was reached and pacing was denied. In two cases, complete interruption of the corticodiaphragmatic pathway and integrity of peripheral conduction led to the decision of phrenic pacemaker implantation. CONCLUSION CxMS and CMS can be used to refine the assessment of patients proposed for phrenic pacing. CxMS can possibly identify those in whom there is a possibility for eventual recovery, and therefore substantiate a decision to postpone the pacing.
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Affiliation(s)
- T Similowski
- Unité de Réanimation, Groupe Hospitalier Pitié-Salpêtrière, Paris, France
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