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Hyun SE, Hwang W, Ji HM, Shin HI. Effect of body position on peak expiratory flow during mechanical insufflation-exsufflation in people with cervical spinal cord injury: a pilot study. Sci Rep 2023; 13:16548. [PMID: 37783754 PMCID: PMC10545699 DOI: 10.1038/s41598-023-43256-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 09/21/2023] [Indexed: 10/04/2023] Open
Abstract
This prospective pilot study investigated the influence of body position on peak cough flow (PCF) during mechanical insufflation-exsufflation (MI-E) treatment in people with tetraplegia. Fifteen participants with cervical spinal cord injury (C-SCI) were randomized into two groups, which differed in the starting position, that is, the patients were either supine or reclined. Four sessions of MI-E in alternating positions with each session comprising three different maneuvers: five voluntary coughs, five MI-E-assisted coughs, and five MI-E-assisted with manual thrusts were performed with continuous airflow measurement reporting PCF from every cough. PCF was associated with the application maneuvers, total insufflation volume (TIV), and interaction between position and maneuvers but not with the application position. The estimated mean PCF was 1.808, 3.529, and 3.925 L/s when supine and 1.672, 3.598, and 3.909 L/s when reclined from voluntary cough, MI-E, and MI-E with manual thrust, respectively. The estimated PCF change compared to voluntary cough was 1.721 (95% CI, 1.603-1.838) L/s from the combined MI-E and 2.116 (95% CI, 2.005-2.228) L/s from the MI-E with manual thrust, calculated from the linear mixed-model analysis. PCF moderately correlated with TIV (R2 = 0.64). Therefore, either position can be used for C-SCI patients as long as MI-E can be performed with manual thrust and sufficient TIV is provided.
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Affiliation(s)
- Sung Eun Hyun
- Department of Rehabilitation Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
- Department of Rehabilitation Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Wonjae Hwang
- Department of Rehabilitation Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
- Department of Rehabilitation Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Hye Min Ji
- Department of Rehabilitation Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
- Veterans Medical Research Institute, Veterans Health Service Medical Center, Seoul, Korea
| | - Hyung-Ik Shin
- Department of Rehabilitation Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.
- Department of Rehabilitation Medicine, Seoul National University Hospital, Seoul, Republic of Korea.
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Yang L, Gao Z, Cao X, Fu F, Möller K, Frerichs I, Dai M, Zhao Z. The influence of gravity on electrical impedance tomography measurements during upper body position change. Heliyon 2023; 9:e15910. [PMID: 37215814 PMCID: PMC10192413 DOI: 10.1016/j.heliyon.2023.e15910] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 04/19/2023] [Accepted: 04/26/2023] [Indexed: 05/24/2023] Open
Abstract
Objective The aim of the study was to examine the influence of gravity on regional ventilation measured by electrical impedance tomography (EIT) with the standard electrode belt position at the 5th intercostal space during tilting from supine to sitting positions. Methods A total of 30 healthy volunteers were examined prospectively in supine position during quiet tidal breathing. Subsequently, the bed was tilted so that the upper body of the subjects achieved 30, 60 and 90° every 3 min. Regional ventilation distribution and end-expiratory lung impedance (EELI) were monitored with EIT throughout the whole experiment. Absolute tidal volumes were measured with spirometry and the volume-impedance ratio was calculated for each position. Results The volume-impedance ratio did not differ statistically between the studied body positions but 11 subjects exhibited a large change in ratio at one of the positions (outside 99.3% coverage). In general, ventilation distribution became more heterogeneous and moved towards dorsal regions as the upper body was tilted to 90-degree position. EELI increased and tidal volume decreased. The lung regions identified at various positions differed significantly. Conclusion Gravity has non-negligible influence on EIT data, as the upper body tilted from supine to sitting positions. The standard electrode belt position might be reconsidered if ventilation distribution is to be compared between supine and sitting positions.
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Affiliation(s)
- Lin Yang
- Department of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Zhijun Gao
- Department of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Xinsheng Cao
- Department of Aerospace Medicine, Fourth Military Medical University, Xi'an, China
| | - Feng Fu
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Knut Möller
- Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
| | - Inéz Frerichs
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre of Schleswig-Holstein Campus Kiel, Germany
| | - Meng Dai
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China
| | - Zhanqi Zhao
- Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
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Suárez-Iglesias D, Ayán C, González-Devesa D, Rubiera Hidalgo M, Villa-Vicente J. A blow darts program for adults with spinal cord injuries: Feasibility and effects on respiratory function. Sci Sports 2023. [DOI: 10.1016/j.scispo.2022.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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Pitts T, Iceman KE, Huff A, Musselwhite MN, Frazure ML, Young KC, Greene CL, Howland DR. Laryngeal and swallow dysregulation following acute cervical spinal cord injury. J Neurophysiol 2022; 128:405-417. [PMID: 35830612 PMCID: PMC9359645 DOI: 10.1152/jn.00469.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Laryngeal function is vital to airway protection. While swallow is mediated by the brainstem, mechanisms underlying increased risk of dysphagia after cervical spinal cord injury (SCI) are unknown. We hypothesized that loss of descending phrenic drive affects swallow and breathing differently, and loss of ascending spinal afferent information alters swallow regulation. We recorded electromyograms from upper airway and chest wall muscles in freely breathing pentobarbital-anesthetized cats and rats. Inspiratory laryngeal activity increased ~two-fold following C2 lateral-hemisection. Ipsilateral to the injury, crural diaphragm EMG amplitude was reduced during breathing (62 ± 25% change post-injury), but no animal had complete termination of activity; 75% of animals increased contralateral diaphragm recruitment, but this did not reach significance. During swallow, laryngeal adductor and pharyngeal constrictor muscles increased activity, and diaphragm activity was bilaterally suppressed. This was unexpected because of the ipsilateral-specific response during breathing. Swallow-breathing coordination was also disrupted and more swallows occurred during early expiration. Finally, to determine if the chest wall is a major source of feedback for laryngeal regulation, we performed T1 total transections in rats. As in the C2 lateral-hemisection, inspiratory laryngeal recruitment was the first feature noted. In contrast to the C2 lateral-hemisection, diaphragmatic drive increased after T1 transection. Overall, we found that SCI alters laryngeal drive during swallow and breathing, and reduced swallow-related diaphragm activity. Our results show behavior-specific effects, suggesting SCI affects swallow more than breathing, and emphasizes the need for additional studies on the effects of ascending afferents from the spinal cord on laryngeal function.
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Affiliation(s)
- Teresa Pitts
- Kentucky Spinal Cord Injury Center, Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Kimberly E Iceman
- Kentucky Spinal Cord Injury Center, Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Alyssa Huff
- Center for Integrative Brain Research, Seattle Children's Hospital, Seattle, WA, United States
| | - Matthew Nicholas Musselwhite
- Kentucky Spinal Cord Injury Center, Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Michael L Frazure
- Kentucky Spinal Cord Injury Center, Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Kellyanna C Young
- Kentucky Spinal Cord Injury Center, Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Clinton L Greene
- Kentucky Spinal Cord Injury Center, Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Dena Ruth Howland
- Kentucky Spinal Cord Injury Center, Department of Neurological Surgery, University of Louisville, Louisville, KY, United States.,Research Service, Robley Rex VA Medical Center, Louisville, KY, United States
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Patel N, Chong K, Baydur A. Methods and Applications in Respiratory Physiology: Respiratory Mechanics, Drive and Muscle Function in Neuromuscular and Chest Wall Disorders. Front Physiol 2022; 13:838414. [PMID: 35774289 PMCID: PMC9237333 DOI: 10.3389/fphys.2022.838414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 05/10/2022] [Indexed: 11/13/2022] Open
Abstract
Individuals with neuromuscular and chest wall disorders experience respiratory muscle weakness, reduced lung volume and increases in respiratory elastance and resistance which lead to increase in work of breathing, impaired gas exchange and respiratory pump failure. Recently developed methods to assess respiratory muscle weakness, mechanics and movement supplement traditionally employed spirometry and methods to evaluate gas exchange. These include recording postural change in vital capacity, respiratory pressures (mouth and sniff), electromyography and ultrasound evaluation of diaphragmatic thickness and excursions. In this review, we highlight key aspects of the pathophysiology of these conditions as they impact the patient and describe measures to evaluate respiratory dysfunction. We discuss potential areas of physiologic investigation in the evaluation of respiratory aspects of these disorders.
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Rosales-Antequera C, Viscor G, Araneda OF. Inflammation and Oxidative Stress as Common Mechanisms of Pulmonary, Autonomic and Musculoskeletal Dysfunction after Spinal Cord Injury. BIOLOGY 2022; 11:biology11040550. [PMID: 35453749 PMCID: PMC9032591 DOI: 10.3390/biology11040550] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/19/2022] [Accepted: 03/28/2022] [Indexed: 11/16/2022]
Abstract
Simple Summary When a spinal cord injury occurs, the neurons that regulate our voluntary movements, those involved in environment and somatic perception and those that regulate vegetative functions are affected. Once neuronal damage is established, the cells of other tissues are also affected in their functions, altering the interaction between organs and altering the proper functioning of the organism. Multiple studies in animal models, as well as in humans, have recognized as factors involved in organ damage the imbalance between the formation of highly reactive molecules called pro-oxidants and defensive mechanisms called antioxidants. Closely associated with this phenomenon, the inflammatory response is also pathologically activated. In this narrative review, we have analyzed the information involving these pathological processes at the level of the lung, the autonomic nervous system and the skeletal musculature after spinal cord injury. Knowing the abnormal functioning mechanisms that occur after a spinal cord injury not only offers a better understanding of the organic events but also offers future possibilities for therapeutic interventions that may benefit the thousands of patients suffering this pathology. Abstract One of the etiopathogenic factors frequently associated with generalized organ damage after spinal cord injury corresponds to the imbalance of the redox state and inflammation, particularly of the respiratory, autonomic and musculoskeletal systems. Our goal in this review was to gain a better understanding of this phenomenon by reviewing both animal and human studies. At the respiratory level, the presence of tissue damage is notable in situations that require increased ventilation due to lower thoracic distensibility and alveolar inflammation caused by higher levels of leptin as a result of increased fatty tissue. Increased airway reactivity, due to loss of sympathetic innervation, and levels of nitric oxide in exhaled air that are similar to those seen in asthmatic patients have also been reported. In addition, the loss of autonomic control efficiency leads to an uncontrolled release of catecholamines and glucocorticoids that induce immunosuppression, as well as a predisposition to autoimmune reactions. Simultaneously, blood pressure regulation is altered with vascular damage and atherogenesis associated with oxidative damage. At the muscular level, chronically elevated levels of prooxidants and lipoperoxidation associated with myofibrillar atrophy are described, with no reduction or reversibility of this process through antioxidant supplementation.
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Affiliation(s)
- Cristián Rosales-Antequera
- Physical Medicine and Rehabilitation Unit, Clínica Universidad de los Andes, Santiago 8320000, Chile;
- Integrative Laboratory of Biomechanics and Physiology of Effort, LIBFE, School of Kinesiology, Faculty of Medicine, Universidad de los Andes, Santiago 8320000, Chile
| | - Ginés Viscor
- Physiology Section, Department of Cell Biology, Physiology and Immunology, Faculty of Biology, Universitat de Barcelona, 08028 Barcelona, Spain;
| | - Oscar F. Araneda
- Integrative Laboratory of Biomechanics and Physiology of Effort, LIBFE, School of Kinesiology, Faculty of Medicine, Universidad de los Andes, Santiago 8320000, Chile
- Correspondence:
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DiMarco AF, Geertman RT, Tabbaa K, Nemunaitis GA, Kowalski KE. Restoration of cough via spinal cord stimulation improves pulmonary function in tetraplegics. J Spinal Cord Med 2020; 43:579-585. [PMID: 31809251 PMCID: PMC7534376 DOI: 10.1080/10790268.2019.1699678] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Background: Spinal cord injury (SCI) results in significant loss in pulmonary function secondary to respiratory muscle paralysis. Retention of secretions and atelectasis and, recurrent respiratory tract infections may also impact pulmonary function. Objective: To determine whether usage of lower thoracic spinal cord stimulation (SCS) to restore cough may improve spontaneous pulmonary function in individuals with chronic SCI. Design/Methods: 10 tetraplegics utilized SCS system on a regular daily basis. Spontaneous inspiratory capacity (IC), maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) were measured at baseline prior to usage of the device and repeated every 4-5 weeks over a 20-week period. Maximum airway pressure generation (P) during SCS (40 V, 50 Hz, 0.2 ms) at total lung capacity (TLC) with subject maximal expiratory effort, at the same timepoints were determined, as well. Results: Following daily use of SCS, mean IC improved from 1636 ± 229 to 1932 ± 239 ml (127 ± 8% of baseline values) after 20 weeks (P < 0.05). Mean MIP increased from 40 ± 7, to 50 ± 8 cmH2O (127 ± 6% of baseline values) after 20 weeks, respectively (P < 0.05). MEP also improved from 27 ± 3.7 to 33 ± 5 (127 ± 14% of baseline values) (NS). During SCS, P increased from baseline in all participants from mean 87 ± 8 cmH2O to 117 ± 14 cmH2O at weeks 20, during TLC with subject maximal expiratory effort, respectively (P < 0.05). Each subject stated that they experienced much greater ease in raising secretions with use of SCS. Conclusion: Our findings indicate that use of SCS not only improves expiratory muscle function to restore cough but also results in improvement inspiratory function, as well.
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Affiliation(s)
- Anthony F. DiMarco
- Department of Physical Medicine and
Rehabilitation, Case Western Reserve University, MetroHealth Medical
Center, Cleveland, Ohio,
USA
- Department of Research, Case Western Reserve
University, MetroHealth Medical Center, Cleveland,
Ohio, USA
| | - Robert T. Geertman
- Department of Neurosurgery, Case Western Reserve
University, MetroHealth Medical Center, Cleveland,
Ohio, USA
| | - Kutaiba Tabbaa
- Department of Anesthesiology, Case Western
Reserve University, MetroHealth Medical Center, Cleveland,
Ohio, USA
| | - Gregory A. Nemunaitis
- Department of Physical Medicine and
Rehabilitation, Case Western Reserve University, MetroHealth Medical
Center, Cleveland, Ohio,
USA
| | - Krzysztof E. Kowalski
- Department of Research, Case Western Reserve
University, MetroHealth Medical Center, Cleveland,
Ohio, USA
- Department of Medicine, Case Western Reserve
University, MetroHealth Medical Center, Cleveland,
Ohio, USA
- Research Service, Louis Stokes Cleveland VA
Medical Center, Cleveland, Ohio,
USA
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Katz S, Arish N, Rokach A, Zaltzman Y, Marcus EL. The effect of body position on pulmonary function: a systematic review. BMC Pulm Med 2018; 18:159. [PMID: 30305051 PMCID: PMC6180369 DOI: 10.1186/s12890-018-0723-4] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Accepted: 09/17/2018] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Pulmonary function tests (PFTs) are routinely performed in the upright position due to measurement devices and patient comfort. This systematic review investigated the influence of body position on lung function in healthy persons and specific patient groups. METHODS A search to identify English-language papers published from 1/1998-12/2017 was conducted using MEDLINE and Google Scholar with key words: body position, lung function, lung mechanics, lung volume, position change, positioning, posture, pulmonary function testing, sitting, standing, supine, ventilation, and ventilatory change. Studies that were quasi-experimental, pre-post intervention; compared ≥2 positions, including sitting or standing; and assessed lung function in non-mechanically ventilated subjects aged ≥18 years were included. Primary outcome measures were forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC, FEV1/FVC), vital capacity (VC), functional residual capacity (FRC), maximal expiratory pressure (PEmax), maximal inspiratory pressure (PImax), peak expiratory flow (PEF), total lung capacity (TLC), residual volume (RV), and diffusing capacity of the lungs for carbon monoxide (DLCO). Standing, sitting, supine, and right- and left-side lying positions were studied. RESULTS Forty-three studies met inclusion criteria. The study populations included healthy subjects (29 studies), lung disease (nine), heart disease (four), spinal cord injury (SCI, seven), neuromuscular diseases (three), and obesity (four). In most studies involving healthy subjects or patients with lung, heart, neuromuscular disease, or obesity, FEV1, FVC, FRC, PEmax, PImax, and/or PEF values were higher in more erect positions. For subjects with tetraplegic SCI, FVC and FEV1 were higher in supine vs. sitting. In healthy subjects, DLCO was higher in the supine vs. sitting, and in sitting vs. side-lying positions. In patients with chronic heart failure, the effect of position on DLCO varied. CONCLUSIONS Body position influences the results of PFTs, but the optimal position and magnitude of the benefit varies between study populations. PFTs are routinely performed in the sitting position. We recommend the supine position should be considered in addition to sitting for PFTs in patients with SCI and neuromuscular disease. When treating patients with heart, lung, SCI, neuromuscular disease, or obesity, one should take into consideration that pulmonary physiology and function are influenced by body position.
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Affiliation(s)
- Shikma Katz
- Chronic Ventilator-Dependent Division, Herzog Medical Center, POB 3900, Jerusalem, Israel
- 0000 0004 1937 0511grid.7489.2Recanati School for Community Health Professions, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel
| | - Nissim Arish
- Pulmonary Institute, Shaare Zedek Medical Center, POB 3235, Jerusalem, Israel
- 0000 0004 1937 0538grid.9619.7Hebrew University-Hadassah Faculty of Medicine, Jerusalem, Israel
| | - Ariel Rokach
- Pulmonary Institute, Shaare Zedek Medical Center, POB 3235, Jerusalem, Israel
- 0000 0004 1937 0538grid.9619.7Hebrew University-Hadassah Faculty of Medicine, Jerusalem, Israel
| | - Yacov Zaltzman
- Chronic Ventilator-Dependent Division, Herzog Medical Center, POB 3900, Jerusalem, Israel
| | - Esther-Lee Marcus
- Chronic Ventilator-Dependent Division, Herzog Medical Center, POB 3900, Jerusalem, Israel
- 0000 0004 1937 0538grid.9619.7Hebrew University-Hadassah Faculty of Medicine, Jerusalem, Israel
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Effect of Upright and Slouched Sitting Postures on the Respiratory Muscle Strength in Healthy Young Males. BIOMED RESEARCH INTERNATIONAL 2018; 2018:3058970. [PMID: 29682532 PMCID: PMC5845520 DOI: 10.1155/2018/3058970] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 01/30/2018] [Indexed: 11/17/2022]
Abstract
Objective The present study compared the effects of upright and slouched sitting postures on the respiratory muscle strength in healthy young males. Methods A total of 35 adult male subjects aged 18–35 years participated in this study. Respiratory muscle strength was determined by measurement of sniff nasal inspiratory pressure (SNIP) using a MicroRPM device in the upright and slouched sitting positions. The subjects were asked to perform the pulmonary function test including peak expiratory flow (PEF), forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio at baseline. Body composition was also determined. Results There was a significant difference of SNIP score between upright sitting and slouched sitting positions (p = 0.04). The mean difference of SNIP score between upright sitting and slouched sitting positions was 8.7 cmH2O. Significant correlations were found between SNIP in upright sitting and FEV1% predicted values [R = .651], SNIP in slouched sitting and FEV1% predicted values [R = .579], and SNIP in upright sitting and SNIP in slouched sitting positions [R = .926] (p < 0.05 for all). There were no significant correlations between SNIP scores, demographic variables, and other baseline clinical data (p > 0.05). Conclusions The slouched sitting position had a lower SNIP score compared to upright sitting position suggesting a reduced diaphragm tension and movement as a result of altered body posture.
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Watanabe S, Nojima I, Agarie Y, Watanabe T, Fukuhara S, Fujinaga T, Oka H. Electrically induced mechanomyograms reflect inspiratory muscle strength in young or elderly subjects. Respir Investig 2016; 54:436-444. [PMID: 27886855 DOI: 10.1016/j.resinv.2016.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 06/02/2016] [Accepted: 06/03/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND Respiratory muscle strength has been used as a tool for evaluating respiratory rehabilitation in chronic obstructive pulmonary disease. However, mouth pressure measurement evaluated by maximum expiratory mouth pressure (PEmax) or inspiratory mouth pressure (PImax) offers an indirect method for measuring respiratory muscle strength. We demonstrated the evaluation of diaphragm contractility using a mechanomyogram (MMG), which is the mechanical signal generated by the motion of the diaphragm induced by the electric stimulation of the phrenic nerve. METHODS Study participants were 21 young and 20 elderly subjects with no symptoms of respiratory disease. The elderly subjects were divided into non-smoker or smoker groups. The smoker group was defined as subjects having a Brinkman Index of greater than 300. We measured basic spirometric parameters, mouth pressure (PEmax, PImax), and diaphragmatic MMG. RESULTS Diaphragmatic MMG showed more clear contrast between young subjects and elderly non-smoker or smoker subjects than the conventional method for respiratory muscle contraction (PEmax, PImax). In addition, the diaphragmatic MMG strongly correlated with inspiratory muscle strength. CONCLUSIONS Diaphragmatic MMG may reflect diaphragmatic contractility more directly and sensitively than the conventional method.
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Affiliation(s)
- Shogo Watanabe
- Department of Medical Technology, Graduate School of Health Sciences, Okayama University, 2-5-1, Shikata-cho, Kita-ku, Okayama 700-8558, Japan.
| | - Ippei Nojima
- Department of Physical and Occupational Therapy, Nagoya University Graduate School of Medicine, 1-1-20, Daiko-Minami, Higashi-ku, Nagoya, Aichi, Japan.
| | - Yuuna Agarie
- Department of Rehabilitation Science, Nagoya University School of Health Sciences, 1-1-20, Daiko-Minami, Higashi-ku, Nagoya, Aichi, Japan.
| | - Tatsunori Watanabe
- Department of Physical and Occupational Therapy, Nagoya University Graduate School of Medicine, 1-1-20, Daiko-Minami, Higashi-ku, Nagoya, Aichi, Japan.
| | - Shinichi Fukuhara
- Department of Medical Technology, Graduate School of Health Sciences, Okayama University, 2-5-1, Shikata-cho, Kita-ku, Okayama 700-8558, Japan; Department of Medical Engineering, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, 288, Matsushima, Kurashiki, Okayama, Japan.
| | - Takeshi Fujinaga
- Department of Medical Technology, Graduate School of Health Sciences, Okayama University, 2-5-1, Shikata-cho, Kita-ku, Okayama 700-8558, Japan.
| | - Hisao Oka
- Department of Medical Technology, Graduate School of Health Sciences, Okayama University, 2-5-1, Shikata-cho, Kita-ku, Okayama 700-8558, Japan.
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