New Jersey Institute of Technology Digital Commons @ NJIT Theses Electronic Theses and Dissertations Fall 10-31-1994 Correlation between tidal volume measured by spirometry and impedance pneumography Krithika Seshadri New Jersey Institute of Technology Follow this and additional works at: https://digitalcommons.njit.edu/theses Part of the Biomedical Engineering and Bioengineering Commons Recommended Citation Seshadri, Krithika, "Correlation between tidal volume measured by spirometry and impedance pneumography" (1994). Theses. 1696. https://digitalcommons.njit.edu/theses/1696 This Thesis is brought to you for free and open access by the Electronic Theses and Dissertations at Digital Commons @ NJIT. It has been accepted for inclusion in Theses by an authorized administrator of Digital Commons @ NJIT. For more information, please contact [email protected]. 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Please Note: The author retains the copyright while the New Jersey Institute of Technology reserves the right to distribute this thesis or dissertation Printing note: If you do not wish to print this page, then select “Pages from: first page # to: last page #” on the print dialog screen The Van Houten library has removed some of the personal information and all signatures from the approval page and biographical sketches of theses and dissertations in order to protect the identity of NJIT graduates and faculty. ABSTRACT CORRELATION BETWEEN TIDAL VOLUME MEASURED BY SPIROMETRY AND IMPEDANCE PNEUMOGRAPHY by Krithika Seshadri In this study, an alternative method, impedance pneumography was used to measure the respiration volume. The respiration volume was measured both by using a conventional spirometer and an impedance pneumograph, and evaluated quantitatively in 17 subjects using linear and nonlinear regression algorithms. Data were collected from 17 normal, healthy subjects during rest and paced breathing conditions. A technique was developed to measure tidal volume by impedance pneumography. The respiration volume measured by the spirometer was correlated with the volume measured by the pneumograph. Different electrode positions and postures were included in the study to determine the position and posture which would yield optimum correlations. Correlations between the tidal volume measured by the spirometer and the tidal volume measured by the pneumograph, the rates of respiration (exhalation and inhalation widths), and the means and standard deviations of the exhalation ranges were computed. Results showed high correlations between the two techniques used. The position of the electrodes played a major role in affecting correlations. It was concluded that the posterior electrode position yielded relatively high correlations for the seated and standing postures and that the lateral position yielded good correlations for the supine posture, but further exploration is necessary to determine other factors which would influence the results. CORRELATION BETWEEN TIDAL VOLUME MEASURED BY SPIROMETRY AND IMPEDANCE PNEUMOGRAPHY by Krithika Seshadri A Thesis Submitted to the Faculty of New Jersey Institute of Technology in Partial Fulfillment of the Requirements for the Degree Master of Science in Biomedical Engineering Biomedical Engineering Committee October 1994 APPROVAL PAGE CORRELATION BETWEEN TIDAL VOLUME MEASURED BY SPIROMETRY AND IMPEDANCE PNEUMOGRAPHY Krithika Seshadri Dr. Stanley Reisman, Thesis Adviser Date Professor of Electrical Engineering and Biomedical Engineering, NJIT, NJ Dr. David Kristol, Committee Member Date Director of Biomedical Engineering program, NJIT, NJ Dr. Thomas Findley, Committee Member Date Director of Research, Kessler Institute for Rehabilitation, West Orange, NJ BIOGRAPHICAL SKETCH Author: Krithika Seshadri Degree: Master of Science in Biomedical Engineering Date: October 1994 Undergraduate and Graduate Education: • Master of Science in Biomedical Engineering New Jersey Institute of Technology, Newark, NJ, 1994 • Bachelor of Science in Engineering Sri Jayachamarajendra College of Engineering, Mysore, India, 1991 Major: Biomedical Engineering Presentations and Publications: K. Seshadri, S. Reisman, M. Daum, R. Zorowitz, and R. DeMeersman, "Heart Rate Variability in Stroke Population and Normals: A Comparison using Spectral Analysis". 20th Annual Northeast Bioengineering Conference. Springfield, Massachusetts, 17-18 March 1994. iv This Thesis is dedicated to my loving husband Suresh Sundararaman, who encouraged and helped me accomplish this, my parents Sathy & Seshadri, my brother Kannan, my grandmother Ponnamma Swamy and Rattu who always believed in me. v ACKNOWLEDGMENT The author wishes to express her sincere gratitude to her adviser, Dr. Stanley Reisman for his guidance, moral support and encouragement without which this research would have been impossible. Special thanks to Dr. Ronald DeMeersman and Ms. Miriam Daum, who took time out of their busy schedules to answer the author's physiology-related questions. The author is thankful to Dr. David Kristol, for having given her an opportunity to continue her education. The author is particularly grateful to Dr. Thomas Findley and Kessler Institute for Rehabilitation for providing a stimulating and intellectual environment that encourages research. The author's sincere thanks to Ms.Melissa Leifer who helped the author learn the system at Kessler. The author is indebted to John Andrews for his help. Finally, the author extends her appreciation to all the subjects who sacrificed their comfort for the advancement of science and all others who have helped during the course of this project. vi TABLE OF CONTENTS Chapter Page 1 BACKGROUND 1.1 Introduction .1 1.2 Purpose of project 1 1.3 Cardiovascular Physiology 2 1.4 The Heart-Anatomy 5 1.5 Respiratory system-Organization 6 1.6 Ventilation and Lung Mechanics 10 1.7 Lung volumes 18 1.8 Impedance Pneumography 19 1.9 Prior research 23 2 METHODS 2.1 Methods 28 2.2 Data Acquisition 32 2.3 Signal processing 35 2.4 Data analysis 37 3 RESULTS 3.1 Frequency response of the impedance pneumograph 42 3.2 Lead II electrode configuration results 47 3.3 Linear regression results 48 3.4 Nonlinear modeling 51 4 DISCUSSION AND CONCLUSIONS 4.1 Discussion 60 4.2 Conclusions 66 4.3 Suggestions for future research 67 vii Chapter Page APPENDIX 1 Data acquisition 73 APPENDIX 2 Correlation 74 APPENDIX 3 S-Plus programs 75 APPENDIX 4 Matlab filter design 84 APPENDIX 5 S-Plus functions 85 APPENDIX 6 Tables 95 REFERENCES 106 viii LIST OF TABLES Table Page 3.1 Correlation coefficients for the lead II electrode configuration 47 3.2 Linear regression results for subject #1 ......................................................................50 3.3 Linear regression results for subject #2 96 3.4 Linear regression results for subject #3 97 3.5 Linear regression results for subject #4 98 3.6 Linear regression results for subject #5 99 3.7 Linear regression results for subject #6 100 3.8 Results of the GAM using 3 transform functions and 2 predictors 54 3.9 Improved results of the GAM using 3 transform functions and 5 predictors 55 3.10 Nonlinear regression results for subject #1 59 3.11 Nonlinear regression results for subject #2 101 3.12 Nonlinear regression results for subject #3 102 3.13 Nonlinear regression results for subject #4 103 3.14 Nonlinear regression results for subject #5 104 3.15 Nonlinear regression results for subject #6 105 ix LIST OF FIGURES Figure Page 1.1 Circulation 3 1.2 The heart 4 1.3 Diagrammatic section of the heart 6 1.4 Respiratory system organization 7 1.5 Fick's law of diffusion 8 1.6 Airway branching 10 1.7 Steps of respiration 12 1.8 Muscles of respiration 13 1.9 Intercostal muscles 14 1.10 Pressure-Volume curve of an excised lung 15 1.11 Surface tension 16 1.12 Measurement of regional differences using radioactive xenon 16 1.13 Effects of compliance and airway resistance 17 1.14 Simple representation of the lungs 18 1.15 Spirometer recording of lung volumes and capacities 19 1.16 Impedance pneumograph 22 1.17 Amplitude modulation 22 1.18 Impedance changes versus electrode positions in man 24 2.1 Different electrode positions used in the study 30 2.2 Typical respiration signal acquired from the pneumograph 33 x Figure Page 2.3 Spirometer recording of tidal volume 34 2.4 Superimposed spirometer and pneumograph signals 35 2.5 Superimposed spirometer and smoothed respiration signals 36 2.6 Flowchart for obtaining the positions of exhalation and inhalation widths 38 2.7 Flowchart for obtaining the respiratory volume from the pneumograph 39 2.8 Flowchart for obtaining the tidal volume from the spirometer 40 2.9 Flowchart for obtaining the mean and standard deviation of exhalation widths 41 3.1 Response