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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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Wanke T, Auinger M, Lahrmann H, Merkle M, Formanek D, Irsigler K, Zwick H. Diaphragmatic function in patients on continuous ambulatory peritoneal dialysis. Lung 1994; 172:231-40. [PMID: 8028391 DOI: 10.1007/bf00164440] [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: 01/28/2023]
Abstract
We investigated 8 patients undergoing continuous ambulatory peritoneal dialysis (CAPD) for diaphragmatic strength and the neuromechanical efficiency of the diaphragm while the abdomen was filled with dialysate and while it was empty. Maximum transdiaphragmatic pressure (Pdimax) served as parameter for diaphragmatic strength; diaphragmatic efficiency was assessed by simultaneously monitoring transdiaphragmatic pressure (Pdi) and diaphragmatic electromyogram (EMGdi) during room-air breathing and hyperoxic CO2-rebreathing. After instilling dialysate, Pdimax increased from 76.7 +/- 12.1 cmH2O to 92.2 +/- 16.3 cmH2O (P < 0.05). While the slopes of the regression lines relating minute ventilation (VE) to arterial CO2 tension, and the change in VE for a given change in Pdi during hypercapnic rebreathing were similar in both states, the slope of EMGdi vs Pdi was significantly steeper when the abdomen was filled (P < 0.05). The increase in Pdimax observed in the filled state may suggest an adaptive rightward shift in the diaphragm's force-length relationship in CAPD patients, although this mechanism is insufficient to prevent a reduction of neuromechanical efficiency of the diaphragm.
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Affiliation(s)
- T Wanke
- Pulmonary Department, Lainz Hospital, Vienna, Austria
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Taylor NA, Clarke JR. Pulmonary function hysteresis during compression to, and decompression from 31.3 ATA. ACTA PHYSIOLOGICA SCANDINAVICA 1993; 148:371-8. [PMID: 8213192 DOI: 10.1111/j.1748-1716.1993.tb09572.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Tracheal gas density breathing heliox at 31.3 atmospheres absolute (O2 at 0.42 ATA) is 6.287 g l-1, or approximately 5.5 times greater than air at 1 ATA. This constitutes a significant respiratory load, previously shown to induce respiratory adaptation. During a saturation dive to 31.3 ATA, five divers were exposed to this load for 16 days. This project aimed at investigating possible hysteresis in pulmonary function during dive compression, adaptation and decompression phases. Pulmonary function tests were performed at the surface in air, and at four pressure stops during compression and decompression, with divers breathing the helium-oxygen gas mixture. Significant hysteresis patterns were observed for pooled maximal voluntary ventilation, forced expired volume at 1 s, peak expiratory flow, and maximum expiratory flows (P < 0.05), with post-adaptation flows consistently exceeding those observed during compression. Two mechanisms may explain these observations. Differences may be attributable to positive effort-dependence in the forced expiratory flow; or it is possible the subjects adapted to the respiratory load by modifying neural input to airway smooth muscle, thereby modifying airway resistance.
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Affiliation(s)
- N A Taylor
- Department of Biomedical Sciences, University of Wollongong, Australia
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